US010375327B2(12) United States Patent( 10) Patent No.: US 10 ,375 ,327 B2(45) Date of Patent:
Aug. 6 , 2019

Kester(54 ) MOBILE GAS AND CHEMICAL IMAGING

References Cited
U . S . PATENT DOCUMENTS(56 )CAMERA(71) Applicant: REBELLION PHOTONICS, INC .,3 ,841, 763 A
3,849,005 A

Houston , TX (US )(Continued )(72 ) Inventor : Robert Timothy Kester, Friendswood ,TX (US)(73 ) Assignee : Rebellion Photonics, Inc., Houston , TX

FOREIGN PATENT DOCUMENTS
2 365 866
2 787 303

(US)

(65 )

US 10 ,113,914 B2, 10 /2018, Kester et al. (withdrawn)(Continued )Primary Examiner — Marcus H Taningco

Oct. 20, 2017(74 ) Attorney, Agent, or Firm — Knobbe, Martens, Olson

Prior Publication Data
US 2018 /0191967 A1 Jul. 5 , 2018

& Bear LLP

ABSTRACT(57)

Related U .S . Application Data
(60 ) Provisional application No. 62 /411,480 , filed on Oct.
21, 2016 .
(51) Int. Cl.
H04N 5 /33
GO1J 3 /02

9 / 2000
7 /2011(Continued )OTHER PUBLICATIONS

Subject to any disclaimer, the term of thispatent is extended or adjusted under 35
U . S .C . 154 (b ) by 0 days .
(21 ) Appl. No.: 15 /789 ,811
( * ) Notice :(22 ) Filed :10 / 1974 Lewis
11/ 1974 Girard et al.

In one embodiment, an infrared (IR ) imaging system fordetermining a concentration of a target species in an object
is disclosed . The imaging system can include an opticalsystem including an optical focal plane array (FPA ) unit. The

optical system can have components defining at least two
optical channels thereof, said at least two optical channels
being spatially and spectrally different from one another.
Each of the at least two optical channels can be positioned( 2006 .01)

( 2006 .01)
(Continued )to transfer IR radiation incident on the optical system(52) U .S . Ci.
CPC .................. HO4N 5 /33 (2013 .01 ); G01J 3 /02(2013 .01); GO1J 370232 ( 2013 .01);(Continued )(58 ) Field of Classification Search
CPC .......... GO1J 3 /02 ; G01J 3/ 0232; GO1J 3 /0256 ;G01J 3/ 28; G01J 3/ 2803 ; G01J 5 /0014 ;(Continued )Objecttowards the optical FPA . The system can include a process
ing unit containing a processor that can be configured toacquire multispectral optical data representing said target
species from the IR radiation received at the optical FPA .

Said optical system and said processing unit can be con

tained together in a data acquisition and processing module

configured to be worn or carried by a person .
6 Claims, 57 Drawing Sheets

Front object lensSpectrally divided pupil

Re-Imaging lens array
16
Detector array

GAS
CLOUD
Towards
processor

120

120
130
Moveable reference sourceUS 10 ,Page
375 ,2327 B2(51) Int. Ci.

GO1J 3 / 28

8 ,653 , 461 B1
8 ,654, 328 B2
9 , 395 ,516 B2
9 , 562, 849 B2( 2006 .01)

GO1J 5 /00( 2006 .01)

H04N 5 /225

( 2006 .01)

GOIN 21/3504
GO2B 5 /20( 2014 .01)
(2006 .01)

G06K 9 /00

G06K 9 /20( 2006 .01)
( 2006 .01 )GO1J 5 / 08

( 2006 .01)

GO1J 5 / 02

( 2006 . 01)

9 , 599, 508 B2
9 ,625,318 B2
9 ,641,772 B2
9 ,644 , 562 B2

3 / 2017 Kester et al.
4 / 2017 Kester et al.
5 / 2017 Yujiri
5 /2017 Fujita

9 ,756 , 263 B2
10 ,084 ,975 B2
2001/0040216 Al

9 /2017 Kester et al.
9 /2018 Kester et al.
11/ 2001 Knauth et al.

2002/0121370 AL

9 /2002 Kurkjian et al.

2002/0015151 AL(52 ) U . S . CI.

2 /2014 Benson et al.
2 /2014 Tkaczyk et al.
7 /2016 Katsunuma et al .
2 / 2017 Kester et al.

2 /2002 Gorin

CPC .. . ..... . .. GO1J 3 /0256 (2013 .01); GO1J 3 / 28

2002 /0159101 Al( 2013 .01 ); GOIJ 3/ 2803 (2013 .01); G01J
5 /0014 ( 2013 .01); G01J 5/ 02 (2013 .01); G01J

2003/0134426 A1

7 / 2003 Jiang et al.

2003 /0183756 Al

10 /2003 Huniu

570834 (2013.01); GOIN 21/3504 (2013.01);
GO2B 5 /201 (2013 .01) ; GO2B 5 /208
( 2013.01); G06K 9 /00624 (2013 .01) ; G06K

9 /209 (2013 .01 ); H04N 5 /2258 (2013 .01)

(58 ) Field of Classification Search

CPC .. ... GO1J 5 /02 ; G01J 5 /0834 ; GOIN 21 /3504 ;GO2B 5 / 201; GO2B 5 /208 ; G06K
9 / 00624 ; G06K 9/ 209 ; H04N 5 /2258 ;H04N 5 / 33

See application file for complete search history .
References Cited(56 )U . S . PATENT DOCUMENTS
4 , 134,683 A
4 ,464, 789 A
4 ,933, 555 A
4 , 963, 963 A
5 ,127,742 A
5 , 136 ,421 A
5 ,157,258 A
5 ,354, 987 A
5 ,550, 373 A
5 ,559,336 A
5 ,604,346 A

5 ,822,222 A
5 , 877,500 A
5 , 920 ,066 A
5 , 926 ,283 A
5 ,973, 844 A *11 / 1999 Tsuchimoto et al.
2 / 2000 Bodkin359 /621

6 , 184, 529 B1 2 / 2001 Contini
6 ,268 ,883 B1 7/ 2001 Zehnder et al.
6 ,456 ,261 B1
9 / 2002 Zhang
6 , 465, 785 B1 10 / 2002 McManus
6 ,556 , 853 B1 4 / 2003 Cabib et al.
6 ,680 ,778 B2
1 / 2004 Hinnrichs et al.
6 ,700 , 527 B13 / 2004 Martin et al.
7 , 109 ,488 B2
9 / 2006 Milton
7 , 119 ,337 B1 10 /2006 Johnson et al.
7 ,242, 478 B1 7 / 2007 Dombrowski et al.
7 ,315 , 377 B2 1/2008 Holland et al.
7 ,321,119 B2
1/ 2008 King
7 , 364,697 B2 4 /2008 McFarland et al.
7 ,433, 042 B1 10 / 2008 Cavanaugh et al.
7 ,606 ,484 B1 10 / 2009 Richards et al.
7 ,634, 157 B1 12 / 2009 Richards et al .
7 ,750 , 802 B1 7 /2010 Parish et al.
7 ,835 ,002 B2 11 / 2010 Muhammed et al.

7 ,888,624 B1
8 ,027 ,041 B1
8, 153, 980 B1
8 , 159, 568 B2
8 ,212 ,213 B2
8 , 373,757 B1

8 ,629, 930 B2 *2 /2011 Murguia et al.
9 / 2011 Mitchell et al.
4 /2012 Brady et al.
4 / 2012 Ahdoot
7 / 2012 Myrick et al.
2/2013 Nguyen

6 /2003 Myers et al .

5/ 2004 Braig et al.

2004 /0111232 A1
2004 /0252300 Al
2005/ 0029453 Al
2005 /0103989 Al
2006 /0044562 A1

6 / 2004 Butler et al.
12 / 2004 Slater2 / 2005 Allen et al.
5 /2005 Watson et al.
3 /2006 Hagene et al.

2006 /0183241 A1
2006 /0232675 A1

8 /2006 Lehmann et al.
10 / 2006 Chamberlain et al.

2006 /0279632 A

12 /2006 Anderson

2007 /0018105 A

1/ 2007 Grimberg

2007/ 0075888 Al
2007/0108385 Al
2007/0170359 Al
2007/0170363 A1

4 / 2007 Kelly et al.
5 /2007 Mantese et al .
7 / 2007 Syllaios et al.
7 /2007 Schimert et al.

2008 /0170140 A1
2008/ 0204744 Al

7 / 2008 Silver et al.
8 / 2008 Mir et al.

2009 /0252650 Al

10 /2009 Lakshmanan

2010 /0162206 A1
2010 /0171866 A1

6 / 2010 Roth et al.
7 /2010 Brady et al.

2010 /0211333 A1
2010 /0309467 All

8 /2010 Pruet et al.
12/2010 Fox et al.

2011 /0261321 Al
2012 /0273680 AL

10 / 2011 Ramella -Roman et al.
11/2012 Furry

2013 /0235256 Al
2013/0250124 Al
2013/0307991 Al

11/ 2013 Olsen et al.

2011/0176577 Al
2011/0185048 A1

10 / 1998 Kaplinsky et al.
3 / 1999 Braig et al .
7 / 1999 DiRenzo et al.
7 / 1999 Hopkins
10 / 1999 Burger.... GO2B 3/ 0056

5 ,994, 701 A

2004 /0093167 A1

10 / 2002 Alderson et al.

2008/0231719 Al 9 /2008 Benson et al.
2008/ 0251724 Al 10 / 2008 Baliga et al.

1/ 1979 Goetz et al.
8 / 1984 Sternberg
6 / 1990 Smith
10 / 1990 Dorman
7 / 1992 Fraden
8 / 1992 Sagan
10 / 1992 Gunning , III et al.
10 / 1994 MacPherson
8 / 1996 Cole et al.
9 / 1996 Kosai et al.
2 / 1997 Hamrelius et al.

6 ,023 ,061 A

2003 /0102435 A1

1/ 2014 Brueckner ........... HO4N 5 / 3572
348 /335

2013 /0181836 A1
2013 /0206990 A1
2013 /0228887 A1

7 /2011 Bandara et al.
7/2011 Yew et al.

7 / 2013 Cardoso et al.
8 / 2013 Hsu et al .
9 /2013 Wehner et al.
9 / 2013 Kodama
9 /2013 Furry

2013 /0321806 Al 12 /2013 Kester et al.
2013 /0341509 Al 12/2013 Nelson et al.
2013 /0342680 Al 12 / 2013 Zeng et al.
2014 /0002639 AL 1/ 2014 Cheben et al.
2014 /0139643 A1 5 /2014 Högasten et al .

2014 /0320843 A1* 10 /2014 Streuber ................. F41G 7 /008
356 /4 .01
2015 /0069239 A1* 3 /2015 Kester ..........
GO1J 3 / 36
250 / 332
2015 /0136981 A1 * 5 /2015 Kester ......... ...... GOIN 21/ 3504
250 / 330

2015/0136982 A1* 5 /2015 Kester ..............

GO1J 3/ 2823

2015 /0138534 AL
2015 / 0144770 Al
2015 / 0226613 A1 *5 /2015 Tidhar
5 / 2015 Choi
8 / 2015 Bauer

GO1J 5 /061

2015/0288894 Al

10 /2015 Geelen et al.

2015 /0316473 A1 * 11/2015 Kester .....

2016 /0037089 Al 2 /2016 Silny et al.
2016 /0041095 Al 2 /2016 Rothberg et al.
2016 /0097713 Al 4 /2016 Kester et al.
2016 /0097714 Al 4 /2016 Zeng et al.
2016 /0238454 Al 8 / 2016 Pillans
2016 / 0245698 A1 8 /2016 Pau et al.
2016 /0313181 Al 10 /2016 Golub et al.
2016 /0349228 A1 12 / 2016 Kester et al.

2016 /0356702 Al 12 / 2016 Hinnrichs

250 / 332

250 /349

G06K 9 /22
250 /339 .02

US 10 ,Page
375 ,3327 B2References Cited( 56 )U . S . PATENT DOCUMENTS
2016 /0380014 A1 12/ 2016 Ganapathi et al.

2017/0026588 AL
1/ 2017 Kester et al .
2017 / 0205290 A1 7 / 2017 Kester et al.
2017 / 0234761 AL 8 / 2017 Augusto2017 /0248517 Al 8 / 2017 Scherer et al.
2017 / 0350758 A1 12/ 2017 Kester et al.
2017 / 0356802 A112/ 2017 Kester et al.
2018 /0077363 AL 3/ 2018 Kester et al.

EP

EP
EP

EP
GB
GB
JP
WO
WO
WO
WO
WO
WO
WO

WO
WO
WO
WO

WO
WO
WO

Air and Radiation (6202J), EPA430 - B -03 -018 , Oct. 2003 available
Eriksson et al., “ Radiative Cooling Computed for Model Atmo

at https://www3.epa . gov /gasstar/ documents /II _ dimgasproc .pdf.

7 / 2018 Kester et al.
1/ 2019 Kester et al.

spheres” , Applied Optics, Dec . 1, 1982, vol. 21 , No. 23 , pp .
4381- 4388 .

FOREIGN PATENT DOCUMENTS

Sensors: A Comparison ,” Applied Optics, 1986 , vol. 25 , No . 23 , pp .
4253 - 4260 .
Gålfalk et al., “Making Methane Visible ” , Nature Climate Change ,2018 /0188163 A1
2019 /0003984 ALEP

Chu et al., “ The NIST Quantitative Infrared Database ” , Journal of

Research of the National Institute of Standards and Technology ,Jan .- Feb . 1999, vol. 104, No . 1, pp . 59 - 81.
DiPietro et al., “ Hyperspectral Matched Filter with False -Alarm
Mitigation” , Optical Engineering, Jan . 2012 , vol. 51, No. 1, pp .
016202 - 1- 016202 - 7 .
“ Directed Inspection and Maintenance at Gas Processing Plants andBooster Stations,” United States Environmental Protection Agency

0 837 600
2 871 452
2 942 615
2 955 496
3 040 706
101476925182242013 - 128185
WO 2004 /097389

4 / 1998

5 /2015
12 /2015
7 / 2016

11/ 2015

12 / 1965

3 /2015
6 / 2013
11 / 2004

WO 2007 /008826

1 /2007

WO 2008/ 109183
WO 2009/094782
WO 2010 /053979

9 /2008
8 /2009

WO 2012 /078417

WO 2012 /082366
WO 2013 / 173541

WO 2015 / 108236
WO 2016 / 196224

WO 2017 / 201194
WO 2018 /075957
WO 2018 /075964
WO 2018 / 156795

5 /20106 / 2012
6 /2012

11/ 2013
7 / 2015
12 / 201611 / 20174 / 2018
4 / 2018
8 /2018

OTHER PUBLICATIONS
Adams, et al., “ Advances in Detectors : Hot IR sensors improve IR
camera size, weight, and power” , Laser Focus World , vol. 50 , Issue
1 , Jan . 17 , 2014 , 6 pages . Also available at http ://www .ircameras .

com /articles/advances-detectors -hot-ir-sensors-improve -ir-camera

size -weight -power/.
Allen et al., “Measurements of Methane Emissions at Natural Gas

Production Sites in the United States” , PNAS, Oct. 29 , 2013 , vol.
110 , No . 44 , pp . 7 .
Alvarez et al., “ Greater Focus Needed on Methane Leakage fromNaturalGas Infrastructure” , PNAS, Apr. 24 , 2012 , vol. 109 , No . 17 ,pp . 12 .

Bedard et al., “ Image Mapping Spectrometry : Calibration andCharacterization ” , Optical Engineering, Nov . 2012 , vol. 51 , No. 11,
pp . 111711 - 1 - 111711 - 13 .
Ben -David et al., “ Probability Theory for 3 -Layer Remote Sensing
Radiative Transfer Model: Univariate Case,” Optics Express, Apr.
2012 , vol. 20 , No. 9 , pp . 10004 - 10033 .
Ben -David et al., “ Probability Theory for 3 -Layer Remote Sensing
Radiative Transfer Model: Errata,” Optics Express, May 20 , 2013 ,vol. 21, No. 10 , pp. 11852 .
Brady et al., “ Multiscale Lens Design ” , Optics Express, Jun . 22,
2009, vol. 17 , No. 13 , pp . 10659 - 10674 .
Brochure provided by Lofty Designs to Rebellion Photonics on Oct.

31, 2012 as noted from the email. Subsequent to that date brochure
was used in connection with potential customers.
Caulton et al., " Toward a Better Understanding and QuantificationofMethane Emissions from Shale Gas Development” , PNAS, Apr.

29, 2014 , vol. 111, No. 17 , pp . 7 .
Chen et al., “ Quantitative Sectioning and Noise Analysis for Structured Illumination Microscopy : Erratum ” , Optics Express, Oct. 19 ,2015 , vol. 23 , No. 21, pp . 27633 - 27634 .
Chidley et al., “ Flow -Induced Birefringence: The Hidden PSF

Killer in High Performance Injection -Molded Plastic Optics” , Endoscopic Microscopy , Proceedings of SPIE vol. 6082, 2006 , pp . 11.

Flanigan , “ Detection of Organic Vapors with Active and Passive

Apr. 2016 , vol. 6 , pp . 426 - 430 .
Gålfalk et al., “Making Methane Visible " , Supplementary Informa

tion , Nature Climate Change , 2015 , pp. 1 - 14 .
Gallagher et al., “ Error Analysis for Estimation of Trace Vapor

Concentration Pathlength in Stack Plumes” , Applied Spectroscopy ,2003, vol. 57 , No. 6 , pp . 614 -621 .
Pathlength in Plumes for Remote Sensing Applications from
Hyperspectral Images ” , Analytica Chimica Acta , 2003 , vol. 490 , pp .

Gallagher et al., “ Estimation of Trace Vapor Concentration
139 - 152 .

Gao et al.,“ Compact Image Slicing Spectrometer (ISS) for Hyperspectral
Fluorescence Microscopy ” , Optics Express, Jul. 20 , 2009, vol. 17 ,No. 15 , pp . 12293 - 12308.
Gao et al., “ Depth -Resolved Image Mapping Spectrometer (IMS)with Structured Illumination ” , Optics Express , Aug . 29 , 2011 , vol.
19, No. 18 , pp. 17439 - 17452.
Gao et al., “ Optical Design of a Snapshot High - Sampling Image
Mapping Spectrometer (IMS) forHyperspectralMicroscopy” , Three
Dimensional and MultidimensionalMicroscopy : Image Acquisition

and Processing XVII , Proceedings of SPIE vol. 7570 , 2010 , pp . 1 - 7 .
Gao et al., “ Quantitative Comparison Between Full -Spectrum andFilter- Based Imaging in Hyperspectral Fluorescence Microscopy” ,Journal of Microscopy , 2012, vol. 246 , No. 2 , pp . 113 -123 .
Gao et al.,“ Snapshot Image -Mapping Spectrometer for Hyperspectral
Fluorescence Microscopy ” , Optics and Photonics News, Nov . 2010 ,vol. 21, No. 12 , p . 50 .
Gao et al., " Snapshot Image Mapping Spectrometer (IMS) withHigh Sampling Density for Hyperspectral Microscopy ” , Optics
Express , Jul. 5 , 2010 , vol. 18 , No . 4 , pp . 14330 - 14344 .

Gerhart et al., “ Detection and Tracking of Gas Plumes in LWIR
Hyperspectral Video Sequence Data ,” Algorithmsand Technologies
for Multispectral, Hyperspectral, and Ultraspectral Imagery XIX ,2013, SPIE Proceedings vol. 8743 , pp . 1 - 14 .
Gittins, Christopher M ., “ Detection and Characterization of Chemi
cal Vapor Fugitive Emissions by Nonlinear Optimal Estimation :Theory and Simulation ” , Applied Optics, Aug. 10 , 2009, vol. 48,

No . 23, pp . 4545 -4561.

Goldberg et al., “ Dual Band MWIR /LWIR Focal Plane Array Test
Results,” Army Research Lab , Adelphi, MD , Aug . 1999 , pp . 18 .
Golowich et al., “ Performance Limits of LWIR Gaseous Plume
Quantification ” , Algorithms and Technologies for Multispectral,Hyperspectral, and Ultraspectral Imagery XVII, 2011, Proceedingsof SPIE vol . 8048, pp . 1 - 12 .

Griffin et al ., “ The Herschel — SPIRE 1 - 15 Instrument and its
In -Flight Performance,” Astronomy and Astrophysics, Jul. 1, 2010 ,vol. 518 , pp . 7 .
Gross et al., “ Remote Identification and Quantification of Industrial
Smokestack Effluents via Imaging Fourier- Transform Spectros
copy ” , Environmental Science & Technology , 2010 , vol. 44 , No . 24 ,pp. 9390 -9397.

Gupta et al., “Miniature Snapshot Multispectral Imager,” OpticalEngineering, 2011, vol. 50 , pp . 033203 - 1 -033203 -9 .
Hadlington , Simon , “ New Camera Makes Methane Visible" , Chem

istry World , http ://web .archive .org /web / 20160305234907/http ://www .rsc .org/ chemistryworld / 2015 / 12 /methane - camera -infraredgreenhouse - gas, Dec . 14 , 2015, pp . 2 .

US 10 ,Page
375,4327 B2( 56 )

References Cited
OTHER PUBLICATIONS
Hagen et al., “ Analysis of Computed Tomographic Imaging Spec
trometers. I. Spatial and Spectral Resolution ” , Applied Optics , Oct.

1 , 2008, vol. 47, No. 28, pp . F85 - F95 .
Hagen et al., “ Coded Aperture DUV Spectrometer for Standoff
Raman Spectroscopy” , Next-Generation Spectroscopic Technolo
gies II, Proceedings of SPIE vol. 7319 , 2009, pp. 1- 10 .
Hagen et al ., “ Compound Prism Design Principles, I” , Applied
Optics , Sep . 1 , 2011 , vol. 50 , No . 25, pp . 4998 - 5011.

Hagen et al., “ Compound Prism Design Principles, II : Triplet andJanssen Prisms” , Applied Optics, Sep . 1, 2011, vol. 50 , No. 25 , pp .
5012 - 5022 .

Hagen et al., “ Compound Prism Design Principles, III: Linear-in
Wavenumber and Optical Coherence Tomography Prisms” , Applied
Optics, Sep . 1, 2011, vol. 50 , No. 25 , pp. 5023 -5030 .
Hagen et al., “ Fourier Methods of Improving Reconstruction Speed
for CTIS Imaging Spectrometers” , Imaging Spectrometry XII ,Proceedings of SPIE vol. 6661, 2007, pp . 11.

Hagen et al., “ Foveated Endoscopic Lens” , Journal of Biomedical
Optics , Feb . 2012 , vol. 17 , No. 2 , pp . 021104 -1 -021104 -6 .
Hagen et al., “ Gaussian Profile Estimation in One Dimension ” ,Applied Optics, Aug. 1, 2007, vol. 46 , No . 22 , pp . 5374 - 5383 .

Hagen et al., " Gaussian Profile Estimation in Two Dimensions” ,Applied Optics, Dec . 20 , 2008 , vol. 47 , No. 36 , pp . 6842 -6851 .
Hagen et al., “ Quantitative Sectioning and Noise Analysis for
Structured Illumination Microscopy ” , Optics Express, Jan . 2 , 2012 ,vol. 20 , No. 1 , pp . 403-413 .
Hagen et al., “ Quantitative Sectioning and Noise Analysis for

Structured Illumination Microscopy: Errata ” , Optics Express , Feb .
Hagen et al., “ Real- Time Quantitative Hydrocarbon Gas Imaging

27 , 2012 , vol. 20 , No . 5 , pp . 5343.

Kester et al., “ A Real- Time Gas Cloud Imaging Camera for Fugitive
Emission Detection and Monitoring ” , Imaging and Applied Optics
Technical Digest , 2012 , pp. 3.
Kester et al., “ Development of Image Mappers for Hyperspectral
Biomedical Imaging Applications ” , Applied Optics, Apr. 1 , 2010 ,vol. 49, No. 10 , pp. 1886 - 1899 .

Kester et al., “ High Numerical Aperture Microendoscope Objective
for a Fiber Confocal Reflectance Microscope ” , Optics Express,Mar.

5 , 2007, vol. 15 . No. 5 , pp . 2409 - 2420 .

Kester et al., “ Low Cost, High Performance , Self- Aligning Minia
ture Optical Systems” , Applied Optics, Jun . 20 , 2009, vol. 48, No .

18 , pp . 3375 -3384 .
Kester et al., “ Real- Time Snapshot Hyperspectral Imaging Endo
scope” , Journal of Biomedical Optics,May 2011 , vol. 16 , No. 5 , pp .
056005 - 1 -056005 - 12 .
Kudenov et al., “ Fourier Transform Channeled Spectropolarimetry

in the MWIR ” , Optics Express, Oct. 1, 2007 , vol. 15 , No. 20 , pp .
12792 -12805.

Kudenov et al., " Snapshot Imaging Mueller Matrix Polarimeter
Using Polarization Gratings” , Optics Letters , Apr. 15 , 2012 , vol. 37 ,No. 8 , pp . 1367- 1369.
Landau et al., “ Design and Evaluation of an Ultra - Slim Objective
for in - vivo Deep Optical Biopsy ” , Optics Express, Mar. 1 , 2010 ,vol. 18, No. 5, pp. 4758 -4775 .
Levi, Michael A ., “ Comment on ‘Hydrocarbon Emissions Characterization in the Colorado Front Range : A Pilot Study ' by Gabrielle
Pétron et al.” , Journal of Geophysical Research , 2012 , vol. 117 , No .

D21203 , pp . 1 -5 .
Levi, Michael A ., “ Reply to “ Reply to 'Comment on Hydrocarbon
Emissions Characterization in the Colorado Front Range - A Pilot
Study ' by Michael A . Levi”” by Gabrielle Pétron et al.” , Journal ofGeophysical Research : Atmospheres , 2013 , vol. 118 , pp . 3044
3046 .

with the Gas Cloud Imager (GCI)” , Proceedings of SPIE , vol. 8358 ,Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE)
Sensing XIII, May 1 , 2012 , pp . 7 .

Low et al., “ Remote Sensing and Characterization of Stack Gases by

Optical Engineering , Sep . 2013 , vol. 52 , No. 9 , pp . 090901- 1

Luo et al., “ Fast Processing of Imaging Spectrometer Data Cube

Hagen et al., “Review of Snapshot Spectral Imaging Technologies ” ,090901-23
Hagen et al., “ Snapshot Advantage : A Review of the Light Collec
tion Improvement for Parallel High -Dimensional Measurement
Systems,” Optical Engineering, Jun . 13 , 2012, vol. 51, No. 11 , p .
111702 - 1 - 111702 - 7 .
Hagen et al., “ SnapshotMueller Matrix Spectropolarimeter" Optics
Letters, Aug. 1, 2007, vol. 32 , No . 15 , pp . 2100 -2102.

Infrared Spectroscopy . An Approach by Using Multiple - Scan Inter
ferometry " , Environmental Science & Technology , Jan . 1967 , vol.
1 , No . 1 , pp . 73 - 74.

Based on FPGA Design ” , MIPPR 2007: Multispectral Image Pro

cessing , Proceedings of SPIE vol. 6787 , pp . 7 .
Manolakis et al., “ Long-Wave Infrared Hyperspectral Remote Sens
ing of Chemical Clouds”, IEEE Signal Processing Magazine, Jul.
2014 , vol. 31, No. 4 , pp . 120 -141.
Mathews, “ Design and Fabrication of a Low -Cost, Multispectral

Imaging System ,” Applied Optics , 2008 , pp . F71 - F76 , vol. 47.

Hagen et al., “ Spectrally - Resolved Imaging of Dynamic TurbidMedia ” , Multimodal Biomedical Imaging VI, Proceedings of SPIE
vol. 7892 , 2011, pp . 1 - 7 .
Hagen et al., “ Video - Rate Spectral Imaging of Gas Leaks in the
Longwave Infrared ,” Chemical, Biological, Radiological, Nuclear,and Explosives (CBRNE ) Sensing XIV , May 29 , 2013 , SPIE

Naranjo et al., “ IR Gas Imaging in an Industrial Setting,” Thermosense
XXXII, Published in SPIE Proceedings vol. 7661, May 4 , 2010 , pp .

Harley et al., “ Remote Quantification of Smokestack Effluent Mass
Flow Rates Using Imaging Fourier Transform Spectrometry,” Chemi
cal, Biological, Radiological, Nuclear, and Explosives (CBRNE)
Sensing XII, Apr. 25 - 29, 2011, SPIE Proceedings vol. 8018, pp .

Niu et al., “New Approach to Remote Gas - Phase Chemical Quan
tification : Selected -Band Algorithm ” , Optical Engineering, Feb .

Proceedings vol. 8710 , pp . 7 .

1 - 13 .
Hayden et al., “ Determination of Trace -Gas Amounts in Plumes by

the Use of Orthogonal Digital Filtering of Thermal-Emission Spectra” , Applied Optics, Jun . 1, 1996 , vol. 35 , No. 16 , pp . 2802-2809.
Hirsch et al., “ Detection of Gaseous Plumes in IR Hyperspectral
Images Using Hierarchical Clustering” , Applied Optics, Sep . 1,

2007, vol. 46 , No. 25 , pp . 6368 -6374 .
Johnston et al., " A Real- Time FPGA Implementation of a BarrelDistortion Correction Algorithm ” , Projects, 2003 , vol. 10 , pp .
91 - 96 .
Karion et al., “Methane Emissions Estimate from Airborne Mea

surements Over a Western United States NaturalGas Field ” , Geophysical Research Letters , 2013, vol. 40 , pp . 4393-4397 .
Keshava et al., “ A Survey of Spectral Unmixing Algorithms” ,Lincoln Laboratory Journal, 2003, vol. 14 , No. 1, pp . 55-78 .

1 - 8.
tem using Image Mapping Spectrometer” , Biomedical Optics and
3D Imaging OSA , 2012 , pp . 3 .

Nguyen et al., " Snapshot 3D Optical Coherence Tomography Sys

2014 , vol. 53 , No . 2 , pp . 021111 - 1 -021111- 10 .

“ Oil and Natural Gas Sector Leaks" , U . S . EPA Office of Air Quality
Planning and Standards (OAQPS ), Review Panel, Apr. 2014 , pp .63.
Pétron et al., “ Hydrocarbon Emissions Characterization in the
Colorado Front Range : A Pilot Study ” , Journal of GeophysicalResearch , 2012 , vol. 117 , No. D04304 , pp . 1 - 19 .
Pétron et al., “ Reply to Comment on ‘Hydrocarbon Emissions
Characterization in the Colorado Front Range A Pilot Study ' byMichael A . Levi” , Journal ofGeophysical Research : Atmospheres,
2013, vol. 118 , pp . 236 - 242 .
Pisano et al., “ Thermal Illuminators for Far-Infrared and Submil
limeter Astronomical Instruments,” Applied Optics , Jun . 1, 2005 ,vol. 44 , No. 16 , pp. 3208 -3217 .

Polak et al., “ Passive Fourier- Transform Infrared Spectroscopy ofChemical Plumes: An Algorithm for Quantitative Interpretation andReal- Time Background Removal” , Applied Optics, Aug. 20 , 1995 ,vol. 34 , No . 24 , pp . 5406 - 5412 .

US 10 ,Page
375,5327 B2( 56 )

References Cited

OTHER PUBLICATIONS
Rebellion Photonics, “ Gas Cloud Imaging Camera: A Breakthroughin Leak Monitoring for the Rig & Refinery Safety Market” , Pre

sentation at SPIE Defense Security and Sensing , 28 pages, Apr.
29-May 3 , 2013
Sandsten et al., “ Development of Infrared Spectroscopy Techniques

for Environmental Monitoring” , Doctoral Thesis, Aug . 2000, pp .
123 .

Sandsten et al., “ Real- Time Gas-Correlation Imaging Employing
Thermal Background Radiation ” , Optics Express , Feb . 14 , 2000 ,vol. 6 , No . 4 , pp . 92 - 103.

Sandsten et al., “ Volume Flow Calculations on Gas Leaks Imaged
with Infrared Gas -Correlation ,” Optics Express, 2012 , vol. 20 , No.
18 , pp . 20318 - 20329 .
Shogenji et al., “Multispectral Imaging Using Compact Compound

Optics,” Optics Express, Apr. 19 , 2004 , vol. 12 , No. 8 , pp . 1643
1655 .
Telops, “ Hyper -Cam ” ,http ://web .archive.org /web / 20160608180941/
http://www .telops.com / en /hyperspectral- cameras/hyper-cam as archived
Jun . 8, 2016 in 2 pages .
Telops, “ Innovative Infrared Imaging” , http ://web . archive.org /web /2016060321729 /http ://www .telops .com /en / as archived Jun . 3 , 2016
in 2 pages.
Walter Jr., et al., “ Detection of Atmospheric Pollutants: a Correlation Technique” , Applied Optics, Jun . 1975 , vol. 14 , No . 6 , pp .
1423 - 1428 .

Wikipedia entry https:// en .wikipedia .org /wiki/Mobile _ computing lastmodified on Dec . 30 , 2016 ; retrieved from the internet on Feb . 2 ,2017 in 6 pages.

Williams et al., “ Dual- Band MWIRLWIR Radiometer for Absolute
Temperature Measurements,” SPIE Thermosense Conference XXVIII —Manuscript 6205- 23 , Apr. 18 , 2006 , pp . 13 .
Young et al., " An In -SceneMethod for Atmospheric Compensationof Thermal Hyperspectral Data ” , Journal of Geophysical Research ,2002, vol. 107 , No. D24, pp . 14 - 1 - 14 - 20 .
Zheng et al., " A Static Multiplex Fabry -Perot Spectrometer” , Sensors, Cameras , and Systems for Industrial/Scientific Applications X ,Proceedings of SPIE - IS & T Electronic Imaging, SPIE vol. 7249 ,
2009, pp . 8 .

Zheng et al., “ Analytic -Domain Lens Design with Proximate Ray

Tracing” , Journal of the Optical Society of America A , Aug. 2010 ,vol. 27 , No. 8 , pp . 1791- 1802.
Preliminary Amendment as filed in U . S . Appl.No. 14 /538, 827 dated
Jan . 28 , 2015 in 6 pages.
Office Action received in U .S . Appl. No. 14 /538 ,827 dated Jun . 30 ,2015 in 8 pages.
Non -Final Office Action Response as filed in U . S . Appl. No .
14 / 538 , 827 dated Dec . 28 , 2015 in 11 pages.
Notice of Allowance received in U . S . Appl. No. 14 /538 ,827 dated

Office Action received in U .S . Appl. No. 14 /543 ,692 dated Nov. 3 ,2015 in 7 pages.

Interview Summary received in U .S . Appl. No. 14 /543,692 dated

Feb . 17 , 2016 in 5 pages.

Response to Office Action as filed in U .S . Appl. No. 14 /543 ,692

dated May 2 , 2016 in 9 pages .

Office Action received in U .S . Appl. No. 14 /543 ,692 dated Jun . 1 ,2016 in 18 pages.

Response to Final Action as filed in U . S . Appl. No. 14 /543,692
dated Nov. 30 , 2016 in 12 pages.
Notice of Allowance received in U . S . Appl. No. 14 / 543 ,692 dated
Dec. 9 , 2016 in 12 pages.
Amendment after Allowance as filed in U .S . Appl. No. 14 /543 ,692
dated Mar. 3 , 2017 in 6 pages .
Notice of Allowance received in U .S . Appl. No. 14 /543 ,692 dated

Mar. 17 , 2017 in 4 pages .
Preliminary Amendment as filed in U .S . Appl. No. 15 /471,398 dated
Oct. 6 , 2017 in 6 pages.

Notice of Allowance received in U .S . Appl. No. 14 /571,398 dated

Oct. 18 , 2017 in 8 pages .
Notice of Allowance received in U .S . Appl. No. 14 /571,398 dated
Feb . 7 , 2018 in 20 pages.

Office Action received in U .S .Appl. No. 14 /539 ,899 dated Mar. 26 ,2015 in 6 pages.
Non - Final Office Action Response as filed in U . S . Appl. No.
14 /539, 899 dated Aug. 26 , 2015 in 8 pages.

Final Office Action received in U .S . Appl. No. 14 /539 ,899 dated
Amendment as filed in U . S. Appl. No. 14 /539 ,899 dated Jun. 9 ,Dec . 11 , 2015 in 9 pages .

2016 in 6 pages.
Notice of Allowance received in U . S . Appl. No. 14 /539 , 899 dated
Jun . 21, 2016 in 17 pages .
Notice of Allowance received in U . S . Appl. No. 14 / 539 ,899 dated
Oct. 31, 2016 in 10 pages .

Amendment as filed in U . S. Appl. No. 14 /539 ,899 dated Jan . 27 ,2017 in 5 pages.
Official Communication received in U . S . Appl. No. 15 /462,352
dated Sep . 28 , 2017 in 6 pages.

Amendment as filed in U .S . Appl. No. 15 /462, 352 dated Feb . 28 ,2018 in 5 pages.

Extended European Search Report received in European Application No. 14192862 .2 dated Mar. 30 , 2015 in 10 pages .

Official Communication received in European Application No.
14192862 . 2 dated Apr. 19 , 2016 in 6 pages.
International Search Report in PCT Application No. PCT/US2013 /
041278 dated Aug . 27 , 2013 in 4 pages.
International Preliminary Report on Patentability in PCT Application No. PCT/US2013/041278 dated Nov. 27 , 2014 in 10 pages .
Preliminary Amendment as filed in U .S . Appl. No. 14 / 700 ,791 dated

Jul. 13 , 2015 in 8 pages.
Notice of Allowance received in U .S . Appl. No. 14 /700 ,791 dated
Jun. 9 , 2016 in 11 pages .

Feb . 1, 2016 in 18 pages.

Notice of Allowance received in U .S . Appl. No. 14 /700 ,791 dated

Corrected Notice of Allowance received in U .S . Appl. No. 14 / 538 ,827

Notice of Allowance received in U .S . Appl. No. 14 /700 ,791 dated
Feb . 21, 2017 in 20 pages.

Corrected Notice of Allowance received in U .S . Appl. No. 14 /538 ,827
dated Feb . 10 , 2016 in 4 pages.
dated Feb . 22 , 2016 in 4 pages .
Request for Continued Examination and Response to Correct Application Papers as filed in U . S . Appl. No. 14 /538 ,827 dated Apr. 29 ,2016 in 14 pages .

Notice of Allowance received in U . S . Appl. No. 14 /538, 827 dated

May 26 , 2016 in 9 pages.

Notice of Allowance received in U .S . Appl. No. 14 /538,827 dated

Sep . 19 , 2016 in 9 pages .

Amendment as filed in U .S . Appl. No. 14 /538 ,827 dated Dec . 16 ,2016 in 9 pages .
Official Communication received in U . S . Patent Application No .
15 /418, 532 dated Jun . 23 , 2017 in 7 pages.

Amendment as filed in U .S . Appl. No. 15/418 ,532 dated Nov. 22 ,2017 in 8 pages .

Official Communication received in U .S . Appl. No. 15 /418 ,532
dated Dec. 11, 2017 in 21 pages.

Sep . 30 , 2016 in 19 pages.

Comments on Allowance received in U .S . Appl. No. 14 /700 ,791
Notice of Allowance received in U .S . Appl. No. 14 /700 ,791 dated
dated May 19 , 2017 in 2 pages.

Jul. 10 , 2017 in 24 pages.

Preliminary Amendmentas filed in U . S . Appl. No. 15/623, 942 dated
Notice of Allowance received in U .S . Appl. No. 15 /623 ,942 dated
Jan . 24 , 2018 in 22 pages .
Extended European Search Report received in European Application No. 15165877.0 dated Oct. 8, 2015 in 12 pages .
Official Communication received in European Application No.
15165877 .0 dated Jan . 3, 2017 in 9 pages .
Preliminary Amendment as filed in U .S . Appl. No. 14 /700 ,567 dated
Jul. 10 , 2015 in 6 pages.
Publication Request as filed in U .S . Appl. No. 14 /700 ,567 dated
Aug . 24 , 2016 in 237 pages .
Dec . 7 , 2017 in 6 pages .

US 10 ,Page
375,6327 B2( 56 )

References Cited
OTHER PUBLICATIONS
Official Communication received in U .S . Appl. No . 14 /700 ,567

dated Jun. 14 , 2017 in 29 pages.
Amendment as filed in U .S . Appl. No. 14 /700 , 567 dated Dec . 13 ,2017 in 12 pages.
Official Communication received in U .S . Appl. No . 14 /700 ,567
dated Mar. 5 , 2018 in 38 pages .
Extended European Search Report received in European Application No. EP 15165880.4 dated Nov. 24 , 2015 in 8 pages.
Preliminary Amendment as filed in U . S . Appl. No. 14 /792, 477 dated
Dec . 21 , 2015 in 7 pages.

Official Communication received in U .S . Appl. No. 14 /792 ,477
dated Jan . 27 , 2017 in 10 pages.
Response to Restriction Requirement submitted in U .S . Appl. No .
14 / 792,477 dated May 8 , 2017 in 6 pages.

Official Communication received in U . S . Appl. No. 14 /792,477
dated Jul. 19 , 2017 in 20 pages.
Amendment as filed in U . S . Appl. No. 14 /792 ,477 dated Jan . 18 ,2018 in 10 pages.
Preliminary Amendment as filed in U . S . Appl. No. 15 / 166,092 dated
Aug. 15 , 2016 in 7 pages .

International Search Report in PCT Application No. PCT/US2016 /

034455 dated Oct. 24 , 2016 in 12 pages .

International Preliminary Report on Patentability in PCT Application No. PCT/US2016 /034455 Dec . 5 , 2017 in 8 pages .
Preliminary Amendment as filed in U .S . Appl. No. 15 /789 , 811 dated
Mar. 20 , 2018 in 6 pages.
Invitation to Pay Additional Fees in PCT Application No. PCT/US2017 /057725 dated Dec. 14 , 2017 in 3 pages.
International Search Report in PCT Application No. PCT /US2017 /
057725 dated Feb . 14 , 2018 in 14 pages.
Preliminary Amendment as filed in U . S . Appl. No. 15 /789 , 829 dated
Mar. 20, 2018 in 8 pages.
Invitation to Pay Additional Fees in PCT Application No. PCT/US2017 /057712 dated Jan . 10 , 2018 in 2 pages .
International Search Report in PCT Application No . PCT/US2017 /
057712 dated Mar. 6 , 2018 in 12 pages.
Cossel et al., " Analysis of Trace Impurities in Semiconductor Gas
Via Cavity - Enhanced Direct Frequency Comb Spectroscopy ” , Applied
Physics B , Sep . 2010 , vol. 100 , No. 4 , pp . 917 -924 .
Notice of Allowance received in U . S . Appl. No . 15 /418 ,532 dated
Jun . 15 , 2018 in 12 pages .
Corrected Notice of Allowance received in U .S . Appl. No. 15 /418 ,532
dated Jul. 6 , 2018 in 3 pages.

Amendment after Allowance as filed in U .S . Appl. No. 15 /418 , 532
dated Sep . 14 , 2018 in 6 pages.

Notice of Allowance received in U .S . Appl. No. 15 /418 ,532 dated
Dec. 5 , 2018 in 11 pages .

Notice of Allowance received in U . S . Appl. No. 14 /571 ,398 dated

Jul. 2 , 2018 in 8 pages .
Notice of Allowance received in U .S . Appl. No. 14 / 571, 398 dated
Oct. 24 , 2018 in 7 pages.

Notice of Allowance received in U . S . Appl. No. 15 /462,352 dated
Jul. 17 , 2018 in 25 pages .

Notice to File Corrected Application Papers received in U . S . Appl.
No. 15 /462,352 dated Aug. 8 , 2018 in 3 pages.
Response to Notice to File Corrected Application Papers filed in

U . S . Appl. No. 15 / 462 , 352 dated Oct. 8 , 2018 in 3 pages .

Notice of Allowance received in U .S . Appl. No. 15/ 462, 352 dated
Oct. 31 , 2018 in 9 pages.
Official Communication received in European Application No.
13732285 .5 dated Jul. 26 , 2018 in 6 pages.
Official Communication received in European Application No .
14192862.2 dated May 2 , 2018 in 3 pages.
Notice of Allowance received in U .S . Appl. No. 15 /623 ,942 dated
May 24 , 2018 in 23 pages.
Comments on Allowance filed in U . S. Appl. No. 15 /623 ,942 dated
Aug. 23 , 2018 in 2 pages.

Amendment
as filed in U .S. Appl. No. 14/700 ,567 dated Jul . 5, 2018
in 10 pages.

Office Action as filed in U .S . Appl. No. 14 /700, 567 dated Aug. 27,
Notice of Allowance received in U .S . Appl. No. 14 /792 ,477 dated
Apr. 19 , 2018 in 13 pages.
Notice of Allowance received in U . S . Appl. No. 14 /792 ,477 dated
2018 in 36 pages .

Sep . 20 , 2018 in 14 pages.

Official Communication received in U . S. Appl. No. 15 /166 ,092
dated May 15 , 2018 in 30 pages.
Amendment as filed in U .S . Appl. No. 15 / 166 ,092 dated Nov . 15 ,2018 in 11 pages .

Official Communication received in U . S . Appl. No. 15 /789 ,829

dated Jun . 5 , 2018 in 16 pages.
Amendment as filed in U . S . Appl. No. 15 / 789 ,829 dated Dec . 4 ,2018 in 9 pages .

Preliminary Amendment as filed in U .S . Appl. No. 15/902,336 dated
Sep . 20 , 2018 in 9 pages.

International Search Report in PCT Application No. PCT/US2018 /
019271 dated Jun. 27 , 2018 in 15 pages.

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MOBILE GAS AND CHEMICAL IMAGINGCAMERA

optical channels thereof, said at least two optical channels
being spatially and spectrally different from one another.

Each of the at least two optical channels can be positioned
to transfer IR radiation incident on the optical system
5 towards the optical FPA . The system can include a process
ing unit containing a processor that can be configured toacquire multispectral optical data representing said target
Any and all applications for which a foreign or domestic 49
from the IR radiation received at the optical FPA .
priority claim is identified in the Application Data Sheet as
as speciesopticalsystem and said processing unit can be con
filed with the present application are hereby incorporated by 10 Saidtainedtogetherin a data acquisition and processing module
reference under 37 CFR 1. 57 .
configured
tobeworn or carried by a person .
This application claims priority to U .S . Provisional Patent
In another embodiment, an infrared (IR ) imaging system
Application No . 62/411, 480 , filed Oct. 21, 2016 , entitledfor determining a concentration of a target species in an“MOBILE GAS AND CHEMICAL IMAGING CAMERA,"INCORPORATION BY REFERENCE TO ANYPRIORITY APPLICATIONS

is disclosed . The imaging system can comprise an
the contents of which is hereby incorporated by reference 15 object
optical system including an optical focal plane array (FPA )herein in its entirety and for all purposes .

STATEMENT REGARDING FEDERALLYSPONSORED R & D

unit. The optical system can have components defining atleast two optical channels thereof, said at least two opticalchannels being spatially and spectrally different from one
another. Each of the at least two optical channels can be

Funding for some portions of the technology disclosed in 20 positioned to transfer IR radiation incident on the opticalthis application was provided by the Advanced Research
Projects Agency _ Enerov ( ARPÁLE ) under Contract Num
ber DE -AR0000541 . The government may have certain

rights in these portions of the technology .
FIELD OF THE INVENTION

system towards the optical FPA . The system can include aured to acquire multispectral optical data representing said

processing unit containing a processor that can be config

target species from the IR radiation received at the optical
25 FPA . Said data acquisition and processing module can havedimensions less than 8 inchesx6 inchesx6 inches .

In another embodiment, an infrared (IR ) imaging system

The present invention generally relates to a system andfor determining a concentration of a target species in an
method for gas cloud detection and , in particular , to a systemobject is disclosed . The imaging system can include an
and method of detecting spectral signatures of chemical 30 optical system including an optical focal plane array ( FPA )compositions in infrared spectral regions.
DESCRIPTION OF THE RELATEDTECHNOLOGY
Spectral imaging systems and methods have applications

in a variety of fields. Spectral imaging systems and methods

unit. The optical system can have components defining atleast two optical channels thereof, said at least two opticalchannels being spatially and spectrally different from one

another. Each of the at least two optical channels can be

35 positioned to transfer IR radiation incident on the opticalsystem towards the optical FPA . The system can include a

processing unit containing a processor that can be config

obtain a spectral image of a scene in one or more regions of ured to acquire multispectral optical data representing said
the electromagnetic spectrum to detect phenomena , identify
target species from the IR radiation received at the opticalmaterial compositions or characterize processes . The spec - 40 FPA . Said data acquisition and processing module can havetral image of the scene can be represented as a three a volume of less than 300 cubic inches.
dimensional data cube where two axes of the cube represent
In yet another embodiment, a method of identifying a
two spatial dimensions of the scene and a third axis of the target species or quantifying or characterizing a parameter ofdata cube represents spectral information of the scene in

the target species in an object is disclosed . The method cancessed using mathematical methods to obtain information

ing module . The data acquisition and processing module cansystems generate the data cube by scanning the scene in thespatial domain (e . g ., by moving a slit across the horizontal

munication with the optical system , the optical system
including an optical focal plane array (FPA ) unit. The

different wavelength regions. The data cube can be pro - 45 include wearing or carrying a data acquisition and process

about the scene. Some of the existing spectral imaging

comprise an optical system and a processing unit in com

dimensions of the scene ) and / or spectral domain ( e . g ., by 50 method can include capturing multispectral infrared ( IR )scanning a wavelength dispersive element to obtain images

image data at the FPA unit from at least two optical channelsof the scene in different spectral regions ). Such scanningthat are spatially and spectrally different from one another.

approaches acquire only a portion of the full data cube at a
The method can include acquiring multispectral optical data
time. These portions of the full data cube are stored and thenrepresenting the target species from the IR radiation
later processed to generate a full data cube .
55 received at the FPA .
In another embodiment, a system for monitoring the
SUMMARY
presence of one or more target gases at one or moreinstallation sites is disclosed . The system can include a
The systems, methods and devices of this disclosure eachplurality of infrared (IR ) imaging systems, each imaging
have several innovative aspects, no single one of which is 60 system comprising a data acquisition and processing modsolely responsible for the desirable attributes disclosed

ule . The data acquisition and processing module can beherein .

configured to capture infrared images of the one or more

In one embodiment, an infrared (IR ) imaging system fordetermining a concentration of a target species in an object

target gases in real - time. The data acquisition and processing

module can be configured to associate each captured infra

is disclosed . The imaging system can include an optical 65 red image with a location at which the one or more target

system including an optical focal plane array (FPA ) unit . The

gases are present. The data acquisition and processing

optical system can have components defining at least two

module can be configured to transmit image data associatedUS 10 ,375 ,327 B2
with the one or more target gases and location data associ

FIGS. 9A and 9B illustrate a cross -sectional view of

ated with the location of the one or more target gases to acentral server.

In yet another embodiment, a method for monitoring thedifferent embodiments of an imaging system comprising an
arrangement of reference sources and mirrors that can bepresence of one or more target gases at one or more 5

installation sites is disclosed . The method can comprisereceiving image data from a plurality of IR imaging systems
located at a plurality of installation sites and configured to beworn or carried by a person . Each IR imaging system can beused for dynamic calibration .

FIGS. 10A - 10C illustrate a plan view of different embodi

ments of an imaging system comprising an arrangement ofreference sources and mirrors that can be used for dynamic

FIG . 11A is a schematic diagram illustrating a mobile

configured to capture infrared images of the one or more 10 infra
infrared imaging system configured to be carried or worn bytarget gases in real-time and to associate each captured
a human user .
infrared image with a location at which the one or moreis a schematic diagram illustrating an installa
target gases are present. The method can include processing tionFIGsite. 11Bthatcanbe monitored by multiple infrared imaging
the received image data to identify the installation sites at 15 systems
which the one or more target gases is detected .
FIG . 12 is a schematic system block diagram showing a
Details of one or more implementations of the subject

mobile infrared imaging system , according to one embodi

matter described in this disclosure are set forth in theaccompanying drawings and the description below . Other
features, aspects , and advantages will become apparent fromment.

drawn to scale .

ments .

FIG . 13A is a schematic system diagram of an opticalthe description , the drawings and the claims. Note that the 20 system configured to be used in the mobile infrared imaging
relative dimensions of the following figures may not be systems disclosed herein , according to various embodi

BRIEF DESCRIPTION OF THE DRAWINGSFIG . 1 shows an embodiment of an imaging system
including a common front objective lens that has a pupil
divided spectrally and re - imaged with a plurality of lenses
onto an infrared FPA .

FIG . 13B is a schematic system diagram of an opticalsystem configured to be used in the mobile infrared imaging

25 systems disclosed herein , according to other embodiments .
FIG . 14A is a schematic perspective view of a mobile

infrared imaging system mounted to a helmet , according tovarious embodiments .
FIG . 14B is an enlarged schematic perspective view ofthe

FIG . 2 shows an embodimentwith a divided front objecC -- 3030 mobile infrared imaging system shown in FIG . 14A .
tive lens and an array of infrared sensing FPAs.
FIG . 14C is a perspective cross - sectional view of the

FIG . 3A represents an embodiment employing an array of
infrared imaging system shown in FIGS . 14A - 14B .
front objective lenses operably matched with the re - imaging mobileFIG.
a schematic perspective view of a system ,lens array. FIG . 3B illustrates a two - dimensional array of 25 according15Ato isvarious
embodiments.

optical components corresponding to the embodiment of 35 acoFIG . 15B is a schematic rear perspective view of the
FIG . 3A .
shown in FIG . 15A .
FIG . 4 is a diagram of the embodiment employing an system
FIG . 15C is a schematic front perspective view of aarray of field references ( e .g ., field stops that can be used as
references for calibration ) and an array of respectively
corresponding relay lenses .

FIG . 5A is a diagram of a 4 -by -3 pupil array comprising
circular optical filters ( and IR blocking materialbetween the

optical filters ) used to spectrally divide an optical wavefront
imaged with an embodiment of the system .

system according to various embodiments .

40 FIG . 15D is a schematic system diagram of a mobile
computing device having a first port configured to electrically and physically couple with a divided - aperture infrared

spectral imaging (DAISI) system , according to various

embodiments.
FIG . 5B is a diagram of a 4 -by -3 pupil array comprising 45 FIG . 15E is a schematic system diagram of a mobile
rectangular optical filters (and IR blocking material between
computing device , according to various embodiments .

the optical filters ) used to spectrally divide an optical
wavefront imaged with an embodiment of the system .
FIG . 6A depicts theoretical plots of transmission charac

FIG . 16A is a schematic diagram of a DAISI system thatcan be used in accordance with any of the embodiments
caldisclosed herein .

teristics of a combination of band -pass filters used with an 50 FIG . 16B is a schematic front perspective view of a
DAISI system , according to various embodiments, with theembodiment of the system .

FIG . 6B depicts theoretical plots of transmission charac -teristics of a spectrally multiplexed notch -pass filter combi-

housing removed for purposes of illustration only .

FIG . 16C is a schematic rear perspective view of the
DAISI system of FIG . 16B .
FIG . 6C shows theoretical plots of transmission charac - 55 FIG . 16D is a schematic front perspective view of thenation used in an embodiment of the system .

teristics of spectrally multiplexed long -pass filter combina -optical system of the DAISI system of FIG . 16B .

FIG . 16E is a schematic perspective cross -sectional viewtion used in an embodiment of the system .
FIG . 6D shows theoretical plots of transmission charac of the optical system of the DAISI system ofFIG . 16B , withteristics of spectrally multiplexed short-pass filter combina - the shutter omitted for illustration purposes .
tion used in an embodiment of the system .
60 FIG . 17A is a front plan view of the shutter illustrated in
FIG . 7 is a set of video -frames illustrating operability of FIGS . 16B and 16D , according to various embodiments .
FIG . 17B is a schematic perspective exploded view of aan embodiment of the system used for gas detection .
FIGS. 8A and 8B are plots (on axes of wavelength in s hutter according to some embodiments .
microns versus the object temperature in Celsius represent
FIG . 17C is a front view of the shutter of FIG . 17B in a
ing effective optical intensity of the object) illustrating 65 closed configuration .
results of dynamic calibration of an embodiment of the
FIG . 17D is a front view of the shutter of FIGS . 17B andsystem .
17C in an open configuration .

US 10 ,375,327 B2
FIGS. 18A and 18B show an embodiment of an imaging

aspects of this disclosure. However, a person having ordi

system including an array of lenses formed with monolithic

nary skill in the art will readily recognize that the teachings

lens substrates, according to various embodiments .

herein can be applied in a multitude of different ways. The

FIG . 18C shows an embodiment of an imaging systemdescribed implementations may be implemented in any

including an array of lenses formed with individual lens 5 device, apparatus, or system that can be configured to
substrates , according to various embodiments .
operate as an imaging system such as in an infra -red imaging
FIG . 18D is an exploded perspective of the imaging system. The methods and systems described herein can besystem having an array of lenses formed with individual lens
included in or associated with a variety of devices such as,
substrates shown in FIG . 18C .
but not limited to devices used for visible and infrared
FIG . 18E is a cross - sectional view of a lens assembly

spectroscopy, multispectral and hyperspectral imaging
formed from individual lens substrates of the type shown in 10 devices
used in oil and gas exploration , refining , and trans

FIGS. 18C and 18D .

portation , agriculture, remote sensing , defense and home

FIG . 19 is a schematic diagram of a patterned array of
optical filters that may be used in an imaging system having

land security , surveillance , astronomy, environmental moni
toring, etc . The methods and systems described herein havedivided apertures , according to various embodiments.
FIGS. 20A - 20C illustrate a filter body and an array of 15 applications in a variety of fields including but not limited toindividual optical filters that may be used in an imaging

agriculture, biology, physics, chemistry , defense and homesystem having divided apertures, according to various

land security, environment, oil and gas industry, etc. The
teachings are not intended to be limited to the implementa

embodiments .

FIG . 21 shows a schematic system diagram of a mobile
cooling systems, according to various embodiments .
FIG . 22A is a ray trace diagram illustrating one example
of optical crosstalk between the optical channels of lenstions depicted solely in the Figures, but instead have wide

infrared imaging system including one or more optional 20 applicability as will be readily apparent to one having

ordinary skill in the art .
The spectral image of the scene can be represented as athree - dimensional data cube where two axes of the cube

assembly of FIG . 18D , according to various embodiments .
represent two spatial dimensions of the scene and a third
FIG . 22B is an exploded perspective view of a lens 25 axes of the data cube represents spectral information of theassembly configured to at least partially reduce optical scene in different wavelength regions. The data cube can becrosstalk , which can be used in conjunction with a DAISI

processed using mathematical methods to obtain informa
tion about the scene . Some of the existing spectral imaging
FIG . 22C is a forward facing schematic diagram of the systems
generate the data cube by scanning the scene in the
optical detector depicting another example of optical cross30
spatialdomain(e.g., by moving a slit across the horizontal
talk between neighboring optical channels , and the resulting and vertical dimensionsof the scene ) and/or spectral
non -uniformity in usable image size due to the crosstalk , domain . Such scanning approaches
acquire only a portion ofsystem , according to various embodiments.

according to various embodiments .

FIG . 22D depicts illumination regions indicative of light the full data cube at a time. These portions of the full datatransferred from the object to the optical detector, in which cube are stored and then later processed to generate a fullthe lens assembly may be configured to increase the usable 35 data cube.
image area at the optical detector with reduced vignetting,
Various embodiments disclosed herein describe a divided

aperture infrared spectral imaging (DAISI) system that isaccording to various embodiments .
FIG . 22E is a frontplan view of an example lens assembly structured and adapted to provide identification of target
that is dimensioned so as to transfer radiation to the illumi- chemical contents of the imaged scene . The system is based
nation regions illustrated in FIG . 22D .
40 on spectrally -resolved imaging and can provide such iden
FIG . 22F is an example simulation of the intensity roll -off tification with a single -shot (also referred to as a snapshot)
across the usable region of FIG . 22D .
comprising a plurality of images having different wave
FIG . 22G illustrates an example vignetting of an image of length compositions that are obtained generally simultane
a scene, according to various embodiments .
ously . Without any loss of generality , snapshot refers to a
FIGS. 23A - 23D are schematic side views of an athermal-- 4545 system in which most of the data elements that are collectedathermalization system , according to various embodiments.
are continuously viewing the light emitted from the scene. In
FIG . 24A is a schematic system diagram of a DAISI contrast
in scanning systems, at any given time only asystem that can include a motion compensation system ,minority of data elements are continuously viewing a scene ,followed by a different set of data elements , and so on , until
FIG . 24B is a plot illustrating an example set of motion 50 thefull dataset is collected . Relatively fast operation can beaccording to various embodiments .

thresholds that may be used by the DAISI system of FIG . 3
24A to activate itself only when the motion of the DAISI
system is less than the motion thresholds.
FIG . 24C is a flowchart illustrating an example method

to various embodiments .

FIG . 24D is a plot of the error profile of the motion
compensation systems and methods described herein ,according to various embodiments .

Like reference numbers and designations in the various

drawings indicate like elements.

DETAILED DESCRIPTION

I. Overview of Various Embodiments

achieved in a snapshot system because it does not need touse spectral or spatial scanning for the acquisition of infra
red ( IR ) spectral signatures of the target chemical contents .
Instead , IR detectors (such as, for example , infrared focal
55 plane arrays or FPAs) associated with a plurality of different
optical channels having different wavelength profiles can beused to form a spectral cube of imaging data . Although
spectral data can be obtained from a single snapshot com

prising multiple simultaneously acquired images corre

60 sponding to differentwavelength ranges, in various embodi

ments , multiple snap shots may be obtained . In various

embodiments, these multiple snapshots can be averaged .
Similarly , in certain embodiments multiple snap shots may

be obtained and a portion of these can be selected and

65 possibly averaged . Also , in contrast to commonly used IR
The following description is directed to certain imple spectral imaging systems, the DAISI system does notmentations for the purposes of describing the innovative require cooling . Accordingly , it can advantageously use

US 10 ,375,327 B2
uncooled infrared detectors. For example, in various imple -mentations, the imaging systems disclosed herein do notinclude detectors configured to be cooled to a temperature

fit within a volume less than about 100 cubic inches. For

example , in some arrangements , the DAISI system can besized and shaped to fit within a volume in a range of about

below 300 Kelvin . As another example , in various imple
50 cubic inches to about 300 cubic inches. In other arrange
mentations, the imaging systems disclosed herein do not 5 ments, the DAISI system can be sized and shaped to fit
include detectors configured to be cooled to a temperature within a volume in a range of about 80 cubic inches to about
below 273 Kelvin . As yet another example , in various 200 cubic inches.
implementations, the imaging systems disclosed herein do
Advantageously , such a portable and /or wearable DAISI
not include detectors configured to be cooled to a tempera - system can enable the user to monitor installations in remoteture below 250 Kelvin . As another example , in various 10 locations and to detect the presence of various gases (e. g.,
implementations , the imaging systems disclosed herein do
not include detectors configured to be cooled to a tempera -poisonous gases ) in real-time. Further, the portable DAISI
system can enable the user to travel to different installations

ture below 200 Kelvin .

to monitor the presence of gases or chemicals in multiple

Implementations disclosed herein provide several advan -locations. For example , the user may travel to an oil drillingtages over existing IR spectral imaging systems,most if not 15 installation in which oil is pumped from the ground . The

all of which may require FPAs that are highly sensitive andcooled in order to compensate , during the optical detection ,for the reduction of the photon flux caused by spectrum scanning operation . The highly sensitive and cooled FPA

user can carry or attach the portable DAISI system to his or
her clothing or body ( e. g.,by way of a clip , hat, etc .) and canactivate the system while he or she is on - site . Opticalcomponents on board the portable DAISI system can capturesystems are expensive and require a great deal of mainte - 20 one ormore snapshotmultispectral images of portions of thenance . Since various embodiments disclosed herein are

installation susceptible to gas or chemical leaks . Computing

configured to operate in single- shot acquisition mode without spatial and/ or spectral scanning , the instrument canreceive photons from a plurality of points ( e. g., every point)

units on board the portable DAISI system can process thecaptured multispectral image data to detect and /or classify
gases or chemicals present at the site . A communications

described herein can collect a substantially greater amountmodule can send a notification to a user interface ( such as aof the object substantially simultaneously , during the single 25 module can notify the user of the detected gases. For
reading . Accordingly, the embodiments of imaging system
example , in various embodiments, the communicationsof optical power from the imaged scene ( for example , an
set of computing eyeglasses , a mobile computing device
order ofmagnitude more photons) at any given moment insuch as a mobile smartphone , a tablet computing device , atime especially in comparison with spatial and /or spectral 30 laptop computing device, or any other suitable interface ),scanning systems. Consequently, various embodiments of and the user interface can display information about thethe imaging systems disclosed herein can be operated using detected gases to the user in real- time, e.g ., at the oil drilling
uncooled detectors (for example , FPA unit including an installation .
array of microbolometers ) that are less sensitive to photons
in the IR but are well fit for continuous monitoring appli - 35
II. Examples of Divided Aperture Infrared Spectral
Imagers Systems
cations . For example , in various implementations, the imag
ing systems disclosed herein do not include detectors con

figured to be cooled to a temperature below 300 Kelvin . As
FIG . 1 provides a diagram schematically illustrating spa
another example, in various implementations, the imaging tial and spectral division of incoming light by an embodi
systems disclosed herein do not include detectors configured 40 ment 100 of a divided aperture infrared spectral imager

to be cooled to a temperature below 273 Kelvin . As yet
another example , in various implementations , the imaging(DAISI) system that can image an object 110 possessing IR
spectral signature ( s ). The system 100 includes a front objec

systems disclosed herein do not include detectors configured tive lens 124 , an array of optical filters 130 , an array of
to be cooled to a temperature below 250 Kelvin . As another reimaging lenses 128 and a detector array 136 . In various
example , in various implementations, the imaging systems 45 embodiments , the detector array 136 can include a single
disclosed herein do not include detectors configured to be FPA or an array of FPAs. Each detector in the detector array
cooled to a temperature below 200 Kelvin . Imaging systems
including uncooled detectors can be capable of operating in
extreme weather conditions, require less power, are capable

136 can be disposed at the focus of each of the lenses in thearray of reimaging lenses 128 . In various embodiments, thedetector array 136 can include a plurality of photo -sensitiveof operation during day and night, and are less expensive . 50 devices . In some embodiments , the plurality of photo

Some embodiments described herein can also be less sus ceptible to motion artifacts in comparison with spatiallyand / or spectrally scanning systemswhich can cause errors insensitive devices may comprise a two -dimensional imaging
sensor array that is sensitive to radiation having wavelengths
between 1 um and 20 um ( for example , in near infra - redeither the spectral data , spatial data , or both .

wavelength range , mid infra -red wavelength range , or longsystem can be mobile . For example , the DAISI system canplurality of photo - sensitive devices can include CCD or

In various embodiments disclosed herein , the DAISI 55 infra -red wavelength range , ). In various embodiments , thebe configured to be worn or carried by a person, e .g ., theCMOS sensors, bolometers , microbolometers or other

DAISI system can be miniaturized to fit in a relatively small

detectors that are sensitive to infra - red radiation .

housing or compartment. For example, the components ofAn aperture of the system 100 associated with the front
the DAISI system can be sized and shaped to fit within small 60 objective lens system 124 is spatially and spectrally divided
dimensions and can have a mass sufficiently small to enable by the combination of the array of optical filters 130 and thethe human user to carry or wear the system without undue
array of reimaging lenses 128 . In various embodiments, theexertion. As explained herein , in some embodiments, the combination of the array of optical filters 130 and the arrayof reimaging lenses 128 can be considered to form aof less than about 300 cubic inches, or in some embodi- 65 spectrally divided pupil that is disposed forward of thements, less than about 200 cubic inches. In still other optical detector array 136 . The spatial and spectral divisionembodiments, the DAISI system can be sized and shaped toof the aperture into distinct aperture portions forms a plu
DAISI system can be sized and shaped to fit within a volume

US 10 ,375 ,327 B2
rality of optical channels 120 along which light propagates .

In various embodiments, the array 128 of re -imaging lenses
128a and the array of spectral filters 130 which respectively
correspond to the distinct optical channels 120 . The plurality

10
figured to maintain the reference source 160 at a desired

temperature . For example , in various implementations, theembodiment 100 can include two reference shutters maintained at different temperatures . The reference source 160 isof optical channels 120 can be spatially and /or spectrally 5 removably and , in one implementation , periodically inserted

distinct. The plurality of optical channels 120 can be formed

into an optical path of light traversing the system 100 fromin the object space and /or image space . In one implemen -the object 110 to the detector array ( e . g ., FPA component )tation , the distinct channels 120 may include optical chan nels that are separated angularly in space . The array of

136 along at least one of the channels 120 . The removablereference source 160 thus can block such optical path .

spectral filters 130 may additionally include a filter-holding 10 Moreover, this reference source 160 can provide a reference

aperture mask ( comprising, for example , IR light -blocking
materials such as ceramic ,metal, or plastic ). Light from the

IR spectrum to recalibrate various components including thedetector array 136 of the system 100 in real time. The

object 110 ( for example a cloud of gas), the optical prop -configuration of the moveable reference source 160 is furerties of which in the IR are described by a unique absorp - ther discussed below .
tion , reflection and / or emission spectrum , is received by the 15 In the embodiment 100 , the front objective lens system
aperture of the system 100 . This light propagates through124 is shown to include a single front objective lens posieach of the plurality of optical channels 120 and is further

tioned to establish a common field -of- view (FOV ) for thelenses 128a can be spatially aligned with a respectively corresponding spectral region . In the illustrated implemen -size as or slightly larger than the plurality of smaller limiting
apertures corresponding to different optical channels 120 . As

tation , each filter element from the array of spectral filtersa result, the positions for spectral filters of the different

the array of spectral filter 130 can coincide with (or form ) ashown as a surface between the lens system 124 and theimaged onto the optical detector array 136 . In various reimaging lenses 128a and to define an aperture stop for the
implementations , the detector array 136 can include at least whole system . In this specific case , the aperture stop sub
one FPA . In various embodiments , each of the re- imaging 20 stantially spatially coincides with and /or is about the same
130 corresponds to a different spectral region . Each re optical channels 120 coincide with the position of theimaging lens 128a and the corresponding filter element of 25 aperture stop of the whole system , which in this example isportion of the divided aperture and therefore with respec tively -corresponding spatial channel 120 . Accordingly, invarious embodiment an imaging lens 128a and a corre -array 128 of the reimaging lenses 128a . In various imple
mentations , the lens system 124 can be an objective lens
124 . However, the objective lens 124 is optional and various

sponding spectral filter can be disposed in the optical path of 30 embodiments of the system 100 need not include the objec
one of the plurality of optical channels 120 . Radiation fromthe object 110 propagating through each of the plurality oftive lens 124 . In various embodiments , the objective lens

124 can slightly shift the images obtained by the different

optical channels 120 travels along the optical path of eachdetectors in the array 136 spatially along a direction per

re - imaging lens 128a and the corresponding filter element ofpendicular to optical axis of the lens 124 , thus the function(e.g ., sub - image ) of the object 110 . The image formed by thethe field apertures corresponding to different optical chan

spectral information of the object 110 . The different spatial
information results from some parallax because of thecertain implementations . In one implementation , the field
apertures corresponding to different optical channels can bedifferent spatial locations of the smaller apertures of thedivided aperture . In various embodiments , adjacent sub

located in different planes and the different planes can be
optical conjugates of one another. Similarly, while all of thespectral signatures. The detector array ( e .g ., FPA compo nent ) 136 is further operably connected with a processor 150

embodiment 100 are shown to lie in one plane, generally
different filter elements of the array of spectral filter 130 can(not shown ). The processor 150 can be programmed tobe disposed in different planes . For example , different filter

the array of spectral filter 130 and is incident on the detector 35 ality of the system 100 is not necessarily compromised whenarray ( e. g ., FPA component ) 136 to form a single image the objective lens 124 is not included. Generally , however,detector array 136 generally includes a plurality of sub - nels may be located in the same or different planes. These
images formed by each of the optical channels 120 . Each of field apertures may be defined by the aperture of the reim
the plurality of sub - images can provide different spatial and 40 aging lens 128a and /or filters in the divided aperture 130 inimages can be characterized by close or substantially equal 45 filter elements in the array of spectral filters 130 of theaggregate the data acquired with the system 100 into aelements of the array of spectral filters 130 can be disposed
spectral data cube. The data cube represents , in spatial (x , y ) 50 in different planes that are optically conjugate to one
and spectral (a ) coordinates, an overall spectral image of theanother. However, in other embodiments , the different filter
object 110 within the spectral region defined by the combielements can be disposed in non - conjugate planes .

nation of the filter elements in the array of spectral filters
In contrast to the embodiment 100 , the frontobjective lens
130. Additionally, in various embodiments, the processor or 124 need not be a single optical element, but instead canprocessing electronics 150 may be programmed to deter- 55 include a plurality of lenses 224 as shown in an embodimentmine the unique absorption characteristic of the object 110 . 200 of the DAISI imaging system in FIG . 2. These lenses
Also , the processor/processing electronics 150 can , alterna - 224 are configured to divide an incoming optical wavefront
tively or in addition , map the overall image data cube intofrom the object 110 . For example , the array of front objec

a cube of data representing, for example , spatial distribution

tive lenses 224 can be disposed so as to receive an IRof concentrations, c , of targeted chemical components 60 wavefront emitted by the object that is directed toward thewithin the field of view associated with the object 110 .
Various implementations of the embodiment 100 can

include an optional moveable temperature -controlled refer -DAISI system . The plurality of front objective lenses 224
divide the wavefront spatially into non -overlapping sections .

FIG . 2 shows three objective lenses 224 in a front opticalence source 160 including, for example , a shutter system
portion of the optical system contributing to the spatial
comprising one or more reference shutters maintained at 65 division of the aperture of the system in this example . The
different temperatures. The reference source 160 can include

plurality of objective lenses 224 , however, can be configured

a heater, a cooler or a temperature - controlled element con

as a two-dimensional (2D ) array of lenses. FIG . 2 presents

US 10 ,375 ,327 B2
a general view of the imaging system 200 and the resultant

12elements (i.e. pixels ) for recording of the three -dimensional

field of view of the imaging system 200. An exploded view

data cube in a single acquisition event ( i.e . one snapshot) . In

202 of the imaging system 200 is also depicted in greater
detail in a figure inset of FIG . 2 . As illustrated in the detailed

various embodiments, an array of microbolometers more
efficiently utilizes the detector pixels of the array of FPAs

The field reference 204 can be used to truncate the field ofexist when using a single microbolometer .

tional advantage over embodiment 100 of FIG . 1 in that thethe imaging system in which the number of the front

view 202, the embodiment of the imaging system 2005 (e . g ., each FPA ) as the number of unused pixels is reduced ,includes a field reference 204 at the front end of the system . minimized and/or eliminated between the images that may
view . The configuration illustrated in FIG . 2 has an opera

FIG . 3A illustrates schematically an embodiment 300 of

overall size and / or weight and / or cost ofmanufacture of the 10 objective lenses 324a in the lens array 324 , the number of

embodiment 200 can be greatly reduced because the objec
tive lens is smaller. Each pair of the lenses in the array 224
and the array 128 is associated with a field of view ( FOV ).

re-imaging lenses 128a in the lens array 128 , and the number
of FPAs 336 are the same. So configured , each combinationof respectively corresponding front objective lens 324 , reEach pair of lenses in the array 224 and the array 128

imaging lens 128a, and FPAs 336 constitutes an individual

receives light from the object from a different angle . Accord - 15 imaging channel. Such a channel is associated with acqui

ingly, the FOV of the different pairs of lenses in the array sition of the IR light transmitted from the object 110 throughan individual filter elementof the array of optical filters 130 .
of parallax . As the distance between the imaging system 200 A field reference 338 of the system 300 is configured to have(portion 202 ) and the object 110 increases, the overlapping a uniform temperature across its surface and be character
region 230 between the FOVs of the individual lenses 224 20 ized by a predetermined spectral curve of radiation emanat
increases while the amount of parallax 228 remains approxi
ing therefrom . In various implementations, the field refermately the same, thereby reducing its effect on the systemence 338 can be used as a calibration target to assist in
200 . When the ratio of the parallax - to -object- distance is calibrating or maintaining calibration of the FPA . Accord
224 and the array 128 do not completely overlap as a result

substantially equal to the pixel- size -to - system - focal length

ingly, in various implementations, the field reference 338 isratio then the parallax effect may be considered to be 25 used for dynamically adjusting the data output from eachnegligible and , for practical purposes , no longer distinguish able . While the lenses 224 are shown to be disposed sub -FPA 336 after acquisition of light from the object 110 . This
dynamic calibration process helps provide that output of thelenses in the array of front objective lenses 224 can becorrect acquired data , with respect to the other FPAs 336 forstantially in the same plane, optionally different objective

different (e.g ., most, or each of the ) FPA 336 represents

disposed in more than one plane. For example , some of the 30 analysis , as discussed below in more detail .

individual lenses 224 can be displaced with respect to someother individual lenses 224 along the axis 226 (not shown)

FIG . 3B illustrates the plan view perpendicular to the axis
226 of an embodiment 300 of the imaging system illustrated

and/ or have different focal lengths as compared to somein FIG . 3A . For the embodiment shown in FIG . 3B , theother lenses 224 . As discussed below , the field reference 204

optical components ( e. g., objective lenses 324a , filter ele

substrate . Such an arrangement can reduce the costs andthe temperature controlled reference target 160 . The fieldof individual lenses within the system . An individual lens
224 can optionally include a lens with varying magnifica tion . As one example , a pair of thin and large diameter

block a peripheral portion of the bundle of light propagatingfrom the object 110 towards the FPA units 336 . As a result,the field reference 338 obscures and/ or blocks the border or

can be useful in calibrating the multiple detectors 236 .
35 ments of the array of spectral filters 130 , re - imaging lenses
In one implementation , the front objective lens system
128a and FPA units 336 ) are arranged as a 4x3 array . In one
such as the array of lenses 224 is configured as an array of implementation , the 4x3 array 340 of optical components
lenses integrated or molded in association with a monolithic(lenses 324a , 128a ; detector elements 336 ) is used behindcomplexity otherwise accompanying the optical adjustment 40 reference aperture 338 can be adapted to obscure and / orAlvarez plates can be used in at least a portion of the front

peripheral portion (s ) of the images of the object 110 formed

Alvarez plates can produce a change in focal length whentranslated orthogonally with respect to the optical beam .
In further reference to FIG . 1 , the detector array 136 ( e . g .,FPA component ) configured to receive the optical datadetector system . Generally , two elements of the FPA unit
will produce substantially equal values of digital counts
when they are used to observe the same portion of the scene
in the same spectral region using the same optical train . If

objective lens system . Without any loss of generality , the 45 on the FPA elements located along the perimeter 346 of therepresenting spectral signature ( s ) of the imaged object 110 50 any of these input parameters ( for example , scene to be

can be configured as a single imaging array ( e . g ., FPA ) 136 .
This single array may be adapted to acquire more than one

observed , spectral content of light from the scene, or opticalelements delivering light from the scene to the two detector

image ( formed by more than one optical channel 120 )simultaneously . Alternatively , the detector array 136 mayelements ) differ, the counts associated with the elements of
the FPA unit will differ as well. Accordingly , and as aninclude a FPA unit . In various implementations, the FPA unit 55 example , in a case when the two FPAs of the FPA unit 336

can include a plurality of optical FPAs. At least one of theseplurality of FPAs can be configured to acquire more than one
spectrally distinct image of the imaged object. For example ,as shown in the embodiment 200 of FIG . 2 , in various(such as those denoted as # 6 and # 7 in FIG . 3B ) remain
substantially un- obscured by the field reference 338 , theoutputs from these FPAs can be dynamically adjusted to the
output from one of the FPAs located along perimeter 346

embodiments , the number of FPAs included in the FPA unit 60 ( such as , for example , the FPA element # 2 or FPA element

may correspond to the number of the front objective lenses
224 . In the embodiment 200 of FIG . 2 , for example , three

FPAs 236 are provided corresponding to the three objective# 11 ) that processes light having similar spectral character
istics .

FIG . 4 illustrates schematically a portion of anotherlenses 224 . In one implementation of the system , the FPA
embodiment of an imaging system 400 that contains an array
unit can include an array of microbolometers . The use of 65 424 of front objective lenses 424a . The array 424 of lenses
multiple microbolometers advantageously allows for an
424a adapted to receive light from the object 110 and relay

inexpensive way to increase the total number of detection

the received light to the array 128 of re -imaging lenses 128a

US 10 ,375 ,327 B2

13

14

through an array 438 of field references (or field stops) 438a ,FIGS . 1 , 2 , 3, and 4 ) may be carried out in a single spectral

and through an array 440 of the relay lenses . The spectral

bandwidth or multiple spectral bandwidths . Referring again

characteristics of the field references / field stops 438a can beto the embodiments 100 , 200 , 300 , 400 of FIGS. 1 throughknown . The field references 438a are disposed at corre 4 , and in further reference to FIG . 3B , examples of a 4 -by -3
sponding intermediate image planes defined , with respect to 5 array of spectral filters 130 is shown in FIGS. 5A and 5B .
the object 110 , by respectively corresponding front objective

Individual filters 1 through 12 are juxtaposed with a suplenses 424a . When refractive characteristics of all of the

porting opto -mechanical element (not shown ) to define afront objective lenses 424a are substantially the same, all offilter-array plane that is oriented , in operation, substantiallythe field references 438a are disposed in the same plane . A
perpendicularly to the general optical axis 226 of the imag
field reference 438a of the array 438 obscures ( or casts a 10 ing system . In various implementations , the individual filters
shadow on ) a peripheral region of a corresponding image
1 through 12 need not be discrete optical components .
( e .g ., sub -image ) formed at the detector plane 444 throughInstead , the individual filters 1 through 12 can comprise onea respectively corresponding spatial imaging channel 450 of or more coatings that are applied to one or more surfaces ofthe system 400 prior to such image being spectrally pro
then transmits light along each of the imaging channels 450

the reimaging lenses (such as a lens 128a of FIGS. 1, 2 , 3,
The optical filtering configuration of various embodi

FPA .

optical FPA and the object). In particular, and in further

It is configured to provide a spectrally known object within

136 , 236 , 336 , 456 include microbolometers , the predomi

cessed by the processor 150. The array 440 of relay lenses 15 and 4 ) or the surfaces of one or more detectors.

through different spectral filters 454a of the filter array 454 , ments disclosed herein may advantageously use a bandpass
past the calibration apparatus that includes two temperaturefilter defining a specified spectral band . Any of the filters ( acontrolled shutters 460a, 460b , and then onto the detector through 3a, the transmission curves of which are shown inmodule 456 . In various embodiments , the detector module 20 FIG . 6A may, for example , be used . The filters may be
456 can include a microbolometer array or some other IR
placed in front of the optical FPA (or generally , between the

The embodiment 400 has several operational advantages .

reference to FIGS. 1, 23, and 4 ,when optical detector arrays

every image ( e . g ., sub - image ) and for every snapshot acqui- 25 nant contribution to noise associated with image acquisition
sition which can be calibrated against . Such spectral cer is due to detector noise . To compensate and /or reduce thetainty can be advantageous when using an array of IR FPAs

like microbolometers, the detection characteristics of which
can change from one imaging frame to the next due to , innoise , various embodiments disclosed herein utilize spec

trally -multiplexed filters . In various implementations, thespectrally -multiplexed filters can comprise a plurality ofpart, changes in the scene being imaged as well as the 30 long pass filters , a plurality long pass filters , a plurality ofthermal effects caused by neighboring FPAs. In various

band pass filters and any combinations thereof. An example

ment 400 — can be disposed within the Rayleigh range

multiplexed filters Ob through 3d for use with various(approximately corresponding to the depth of focus) asso

embodiments of imaging systems disclosed herein isembodiments , the field reference array 438 of the embodi-of the spectral transmission characteristics of spectrally

ciated with the front objective lenses 424 , thereby removing 35 depicted in FIG . 6B . Filters of FIG . 6C can be referred to as

unusable blurred pixels due to having the field reference

long -wavelength pass , LP filters . An LP filter generally

outside of this range . Additionally, the embodiment 400 of

attenuates shorter wavelengths and transmits (passes ) longer

FIG . 4 can be more compact than , for example , the con -wavelengths ( e . g ., over the active range of the target IR

figuration 300 of FIG . 3A . In the system shown in FIG . 3A ,portion of the spectrum ). In various embodiments, short

tributed by the field reference to an image formed at a

the target IR portion of the spectrum ). At least in part due todetector plane .

the snap - shot/non -scanning mode of operation , embodi

for example , the field reference 338 may be separated from 40 wavelength -pass filters , SP, may also be used . An SP filter
the lens array 324 by a distance greater than several ( for generally attenuates longer wavelengths and transmits
example, five ) focal lengths to minimize /reduce blur con(passes ) shorter wavelengths (e.g., over the active range ofIn various embodiments , the multi-optical FPA unit of the 45 ments of the imaging system described herein can use less
IR imaging system can additionally include an FPA config sensitive microbolometers without compromising the SNR .
ured to operate in a visible portion of the spectrum . In
The use of microbolometers , as detector -noise -limited
reference to FIG . 1 , for example , an image of the scene of devices, in turn not only benefits from the use of spectrallyinterest formed by such visible - light FPA may be used as a multiplexed filters, but also does not require cooling of the
background to form a composite image by overlapping an IR 50 imaging system during normal operation .

image with the visible -light image . The IR image may beoverlapped virtually, with the use of a processor and spe -Referring again to FIGS .6A , 6B , 6C , and 6D , each of thefilters ( 0b . . . 3d ) transmits light in a substantially wider

cifically -designed computer program product enabling suchregion of the electromagnetic spectrum as compared to thosedata processing , or actually, by a viewer. The IR image mayof the filters ( 0a . . . 3a). Accordingly , when the spectrally

vidual FPAs 136 . The so - formed composite image facilitates
the identification of the precise spatial location of the target

embodiment of the imaging system , the overall amount oflight received by the FPAs ( for example , 236 , 336 ) is larger

be created based on the image data acquired by the indi- 55 multiplexed set of filters (0b . . . 0d ) is used with an
species, the spectral signatures of which the system is able
to detect/recognize .

Optical Filters.

than would be received when using the bandpass filters (0a. . 4a ). This added ” transmission of light defined by the use
60 of the spectrally -multiplexed LP (or SP ) filters facilitates ansystem , that define spectrally -distinct IR image (e . g ., sub -The optical filters, used with an embodiment of theimage ) of the object can employ absorption filters , interfer

increase of the signal on the FPAs above the level of thethe imaging system , filters having spectral bandwidths

ence filters , and Fabry -Perot etalon based filters , to namegreater than those of band -pass filters , the uncooled FPAs ofdetector noise . Additionally , by using , in an embodiment ofjust a few . When interference filters are used , the image 65 the embodiment of the imaging system experience lessacquisition through an individual imaging channel defined heating from radiation incident thereon from the imaged

by an individual re -imaging lens (such as a lens 128a ofscene and from radiation emanating from the FPA in ques

US 10 ,375 ,327 B2

16

15
tion itself. This reduced heating is due to a reduction in the

may not be necessarily appropriate for the optical embodi

back -reflected thermal emission ( s ) coming from the FPA

ments disclosed herein . An S -matrix approach (which is

and reflecting off of the filter from the non -band -pass

restricted to having a number of filters equal to an integer

regions. As the transmission region of the multiplexed LP

that is multiple of four minus one ) or a row - doubled Had( or SP ) filters is wider , such parasitic effects are reduced 5 amard matrix ( requiring a number of filters to be equal to an

thereby improving the overall performance of the FPA unit.
In one implementation , the LP and SP filters can be
combined, in a spectrally -multiplexed fashion , in order toincrease or maximize the spectral extent of the transmission

integer multiple of eight ) can be used in various embodi
ments. Here , possible numbers of filters using an S -matrix
setup are 3 , 7 , 11, etc . and , if a row - doubled Hadamard
matrix setup is used , then the possible number of filters is 8 ,region of the filter system of the embodiment.
10 16 , 24, etc . For example, the goal of the measurement may
The advantage of using spectrally multiplexed filters is be to measure seven spectral band f; intensities using sevenappreciated based on the following derivation , in which asystem of M filters is examined (although it is understoodmeasurements g ; as follows:that in practice an embodiment of the invention can employ

81= fi +O + f3 +0 + f3 + 0 + fz +11)

of M = 7 is considered . Analysis presented below relates to
one spatial location in each of the images (e. g ., sub - images )82 = 0 + f2 = f3 + 0 + 0 + f3 +f- +12,

any number of filters). As an illustrative example , the case 15

formed by the differing imaging channels (e . g ., different
optical channels 120 ) in the system . A similar analysis canbe performed for each point at an image ( e . g ., sub -image ), 20
and thus the analysis can be appropriately extended as
required .

83 = fi + f2 +0 + 0 + fs + O +f7+nz,
84 +0 +0 + 0 + f4 + fs +f7+ f8 +14,
85 = f1+ 0 + f3+ f4+ 0 + f6+ 0 + ng,

86 = 0 + f2 + 3 + f4 + f3 +0 + 0 + N6,

The unknown amount of light within each of the M
spectral channels (corresponding to these M filters ) is

87= fi +f2 + 0 +f4 + 0 +0 +f7+17,
denoted with f1, fn, fz, fz . . . fm and readings from 25
corresponding detector elements receiving light transmitted
Optical transmission characteristics of the filters
by each filter is denoted as 81, 82, 83 · . . SM , while described above are depicted in FIG . 6B . Here , a direct
measurement errors are represented by n , ny, nz, . . . ny
estimate of the f, is no longer provided through a relationship
Then , the readings at the seven FPA pixels each of which issimilar to ( g ;) = f;. Instead , if a “ hat” notation is used to
optically filtered by a corresponding band -pass filter of FIG . 30 denote an estimate of a given value, then a linear combina

6A can be represented by :& i= f4 +n13
82 =42 +12,

tion of the measurements can be used such as, for example ,f1 =1/4 (+ 81- 82 + 83- 84 + 85 - 86 + 87),

86 - 86 +16,

12 =1/4(- 81 + g2+ 83- 84 - 85 + 86 +87),
f3= 1/4(+ 81+ 82-83- 84+ 85 + 86 - 87),
1/4(-81-82- 83 +g4+ g5 + 86 +87),
fs = 1/4(+ 91- 82 + g3 +84 - 85 + 86 - 87),
fo = 1/4( -81+ g2 + g3+ 84 + 85 - 86 - 87),

87= +17,

f_=14(+81+82-83+84- 85 -86 +87 ),35

835f3 +n3,
84 = f4 +14)
85 = f5 +15,

40

These readings (pixel measurements ) g , are estimates of 45 These fi are unbiased estimates when the n ; are zero mean
the spectral intensities f;. The estimates g , are not equal to thestochastic variables , so that ( f; - f;) = 0 . The measurement
corresponding f, values because of the measurement errors
variance corresponding to it measurement is given by then ;. However, if the measurement noise distribution has zeroequation below :mean , then the ensemble mean of each individualmeasure( U -S2) =1/100
ment can be considered to be equal to the true value, i.e . 50 From the above equation , it is observed that by employing( g :) = f;. Here, the angle brackets indicate the operation of-multiplexed system the signal- to -noise ratio
calculating the ensemble mean of a stochastic variable . The (spectrally
SNR)of
a measurement is improved by a factor ofvariance of themeasurement can , therefore, be represented
V16 /7 = 1.51V716 = 0 .66 .
as :55 For N channels, the SNR improvement achieved with a((81–83)2)= (n ?)= o?
spectrally -multiplexed system can be expressed as (N + 1 )/( 2In embodiments utilizing spectrally -multiplexed filters , in VN ). For example, an embodiment employing 12 spectral
comparison with the embodiments utilizing band -pass fil - channels (N = 12 ) is characterized by a SNR improvement,ters , the amount of radiant energy transmitted by each of the over a non -spectrally -multiplexed system , comprising aspectrally -multiplexed LP or SP filters towards a given 60 factor of up to 1. 88 .
detector element can exceed that transmitted through a
Two additional examples of related spectrally -multi
spectral band of a band - pass filter. In this case , the intensities plexed filter arrangements Oc through 3c and Od through 3dof light corresponding to the independent spectral bands can that can be used in various embodiments of the imaging
be reconstructed by computational means. Such embodisystems described herein are shown in FIGS . 6C and 6D ,65 respectively. The spectrally -multiplexed filters shown inments can be referred to as a “ multiplex design ” .
One matrix of such “multiplexed filter” measurements
FIGS. 6C and 6D can be used in embodiments of imaging
includes a Hadamard matrix requiring “ negative ” filters thatsystems employing uncooled FPAs (such as microbolomUS 10 ,375 ,327 B2
17

18

eters ). FIG . 6C illustrates a set of spectrally -multiplexed

not only the offset values corresponding to each of thelong -wavelength pass (LP ) filters used in the system . An LP
filter generally attenuates shorter wavelengths and transmits(passes) longer wavelengths (e.g ., over the active range ofindividual FPAs pixels can be adjusted but also the gain
values of these FPAs. In an alternative embodiment, thesystem having first and second temperature zones may

the target IR portion of the spectrum ). A single spectral 5 include a single or multi -portion piece. This single orchannel having a transmission characteristic corresponding
to the difference between the spectral transmission curves ofat least two of these LP filters can be used to procure
imaging data for the data cube using an embodiment of themulti- portion piece may comprise for example a plate . This
piece may be mechanically -movable across the optical axis
with the use of appropriate guides and having a first portion
at a first temperature and a second portion at a second

system described herein . In various implementations, the 10 temperature .

spectral filters disposed with respect to the different FPAS
can have different spectral characteristics . In various imple mentations, the spectral filters may be disposed in front ofIndeed , the process of calibration of an embodiment of theimaging system starts with estimating gain and offset by
performing measurements of radiation emanating, indepen

only some of the FPAs while the remaining FPAs may be dently, from at least two temperature -controlled shutters ofconfigured to receive unfiltered light. For example , in some 15 known and different radiances. The gain and offset can vary
implementations, only 9 of the 12 detectors in the 4x3 array from detector pixel to detector pixel. Specifically, first theof detectors described above may be associated with a

response of the detector unit 456 to radiation emanating

spectral filter while the other 3 detectors may be configured

from one shutter is carried out. For example , the first shutter

The use of microbolometers, as detector-noise - limited
devices, in turn not only can benefit from the use of

460a is removed from the optical path of light traversing theembodiment and another second shutter ( for example , 460b )to receive unfiltered light. Such a system may be configured
460a blocks the FOV of the detectors 456 and the tempera
to acquire spectral data in 10 different spectral channels in 20 ture T is measured directly and independently with therma single data acquisition event.
istors . Following such initialmeasurement, the first shutter

spectrally multiplexed filters , but also does not require

is inserted in its place across the optical axis 226 to prevent

cooling of the imaging system during normal operation . In 25 the propagation of light through the system . The temperature

contrast to imaging systems that include highly sensitiveof the second shutter 460b can be different than the firstments of imaging systems described herein can employ lessis also independently measured with thermistors placed in

FPA units with reduced noise characteristics , the embodi-

shutter ( T2 + T ). The temperature of the second shutter 4605

sensitive microbolometers without compromising the SNR .
contact with this shutter, and the detector response to radia
This result is at least in part due to the snap -shot/non - 30 tion emanating from the shutter 460b is also recorded .

scanning mode of operation .
As discussed above , an embodiment may optionally , andDenoting operational response of FPA pixels ( expressed indigital numbers , or " counts " ) as g ; to a source of radiance Ligin addition to a temperature - controlled reference unit ( forthe readings corresponding to the measurements of the two

example temperature controlled shutters such as shutters shutters can be expressed as:
160, 460a , 460b ) , employ a field reference component (e . g ., 35
g1 = YL (T )+ g offset
field reference aperture 338 in FIG . 3A ), or an array of fieldreference components ( e. g ., filed reference apertures 438 in

FIG . 4 ), to enable dynamic calibration . Such dynamic cali

82 = y22 (T2)+ goffset

bration can be used for spectral acquisition of one or more
Here , & offset is the pixel offset value (in units of counts),
or every data cube . Such dynamic calibration can also be 40 and y is the pixel gain value in units of counts per radianceused for a spectrally -neutral camera -to - camera combinationunit). The solutions of these two equations with respect toto enable dynamic compensation of parallax artifacts . The the two unknowns goffset and y can be obtained if the values

use of the temperature - controlled reference unit ( forof g , and g , and the radiance values L , and L , are available .

example, temperature -controlled shutter system 160 ) and

These values can , for example , be either measured by afield -reference component( s ) facilitates maintenance of 45 reference instrument or calculated from the known tempera
proper calibration of each of the FPAs individually and the tures T , and T , together with the known spectral response of
the optical system and FPA . For any subsequent measureentire FPA unit as a whole .
In particular, and in further reference to FIGS. 1, 2 , 3 , and ment, one can then invert the equation (s ) above in order to
4 , the temperature -controlled unit generally employs a sys estimate the radiance value of the object from the detector

tem having first and second temperature zones maintained at 50 measurement, and this can be done for each pixel in eachfirst and second different temperatures . For example, shutter

system of each of the embodiments 100 , 200 , 300 and 400

can employ not one but at least two temperature - controlled

FPA within the system .

A s already discussed , and in reference to FIGS . 1 through4 , the field - reference apertures may be disposed in an object

shutters that are substantially parallel to one another and space or image space of the optical system , and dimensioned
transverse to the general optical axis 226 of the embodi- 55 to block a particular portion of the IR radiation receivedment(s ) 100 , 200, 300 , 400 . Two shutters at two different from the object. In various implementations, the field
temperatures may be employed to provide more information reference aperture, the opening ofwhich can be substantiallyfor calibration ; for example , the absolute value of thesimilar in shape to the boundary of the filter array ( fordifference between FPAs at one temperature as well as theexample , and in reference to a filter array of FIGS. 3B ,change in that difference with temperature change can be 60 5B - e . g ., rectangular ). The field - reference aperture can berecorded . Referring, for example , to FIG . 4 , in which such
multi- shutter structure is shown , the use ofmultiple shuttersenables the user to create a known reference temperature
difference perceived by the FPAS 456 . This reference tem -placed in front of the objective lens ( 124 , 224 , 324 , 424 ) at

a distance that is at least several times (in one implemen

tation at least five times ) larger than the focal length of thelens such that the field - reference aperture is placed closer toperature difference is provided by the IR radiation emitted 65 the object. Placing the field - reference aperture closer to theby the shutter ( s ) 460a , 460b when these shutters are posi -object can reduce the blurriness of the image . In the embodi

tioned to block the radiation from the object 110 . As a result,ment 400 of FIG . 4 , the field -reference aperture can beUS 10 ,375,327 B2
placed within the depth of focus of an image conjugate plane20
images in equivalent units (so that, for example , the reading

formed by the front objective lens 424 . The field reference ,from the FPA pixels can be re - calculated in units of tem

generally , can facilitate , effectuates and/ or enable dynamic

perature or radiance units , etc . ). Moreover , the calibrationcompensation in the system by providing a spectrally known
and stabilize the output from the different FPAs in the array.

process can also allow the FPAs ( e.g ., each of the FPAs) to
pixel of a particular FPA can be optically re-mapped throughand temporally - stable object within every scene to reference 5 be spatially co -registered with one another so that a given

Because each FPA 's offset value is generally adjusted

from each frame to the next frame by the hardware , com -the optical system to the same location at the object as thecorresponding pixel of another FPA .

paring the outputs of one FPA with another can have an error
To achieve at least some of these goals, a spectral differthat is not compensated for by the static calibration param - 10 encing method may be employed . The method involves
eters goffset and y established , for example , by the movable
forming a difference image from various combinations of
shutters 160. In order to ensure that FPAs operate in radio - the images from different channels . In particular, the images
metric agreement over time, it is advantageous for a portion

used to form difference images can be registered by two orof each detector array to view a reference source ( such as themore different FPAs in spectrally distinct channels having

field reference 338 in FIG . 3A , for example ) over a plurality 15 different spectral filters with different spectral characterisof frames obtained over time. If the reference source spec tics . Images from different channels having different spectral

trum is known a priori ( such as a blackbody source at aknown temperature ), one can measure the response of eachcharacteristics will provide different spectral information .

comparing (e . g ., subtracting) these images , can therefore

FPA to the reference source in order to estimate changes toyield valuable spectral based information. For example , if
the pixel offset value . However, the temperature of the 20 the filter element of the array of spectral filters 130 correreference source need not be known . In such implementa sponding to a particular FPA 336 transmits light from thetions , dynamic calibration of the different detectors can be object 110 including a cloud of gas , for example , with aperformed by monitoring the change in the gain and the certain spectrum that contains the gas absorption peak or aoffset for the various detectors from the time the movablegas emission peak while another filter element of the array
shutters used for static calibration are removed . An example 25 of spectral filters 130 corresponding to another FPA 336
calculation of the dynamic offset proceeds as follows.
does not transmit such spectrum , then the difference between
Among the FPA elements in an array of FPAs in an
the images formed by the two FPAs at issue will highlightembodiment of the imaging system , one FPA can be selected the presence of gas in the difference image .
to be the “ reference FPA ” . The field reference temperature
shortcoming of the spectral differencing method is thatmeasured by all the other FPAs can be adjusted to agree with 30 contributions of some auxiliary features associated withthe field reference temperature measured by the reference asimaging (not just the target species such as gas itself) can
discussed below . The image obtained by each FPA includes also be highlighted in and contribute to the difference image .
a set of pixels obscured by the field reference 338 . Using theSuch contributing effects include, to name just a few , parpreviously obtained calibration parameters goffset and y (theallax -induced imaging of edges of the object, influence ofof the field reference as measured by each FPA is estimatedusing the equation below :channels, and differences in rotational positioning and ori
entation between the FPAs. While magnification -related
errors and FPA -rotation -caused errors can be compensatedpixel offset and gain ), the effective blackbody temperature T ; 35 magnification differences between the two or more optical

T;=mean {(g +Agi+ 8ofsedy} =mean {(8 -Sofset)/y}+ AT;
for by increasing the accuracy of the instrument construction
Using the equation above, the mean value over all pixels 40 as well as by post-processing of the acquired imaging,that are obscured by the field reference is obtained . In theabove equation Ag, is the difference in offset value of thecurrent frame from Agoffset obtained during the calibration
step . For the reference FPA , Ag, can be simply set to zero .

parallax is scene-induced and is not so easily correctable. In
addition , the spectral differencing method is vulnerable toradiance calibration errors . Specifically, if one FPA registers
radiance of light from a given feature of the object as having

Then , using the temperature differences measured by each 45 a temperature of 40° C ., for example , while the data fromanother FPA represents the temperature of the same object
FPA , one obtains

feature as being 39° C ., then such feature of the object will

T;- Trefset)mean{(g+ Ag;+ offsetY}+ AT;-mean {(8 -8of
be enhanced or highlighted in the difference image (formed/Y } +AT;
at least in part based on the images provided by these twoOnce AT; for each FPA is measured , its value can be 50 FPAs) due to such radiance-calibration error.

subtracted from each image in order to force operational

One solution to some of such problems is to compare

agreement between such FPA and the reference FPA . While(e. g ., subtract) images from the same FPA obtained at

the calibration procedure has been discussed above in ref erence to calibration of temperature , a procedurally similardifferent instances in time. For example , images can becompared to or subtracted from a reference image obtained

methodology of calibration with respect to radiance value 55 at another time. Such reference image, which is subtracted

can also be implemented .

Prior to optical data acquisition using an embodiment offrom other later obtained images, may be referred to as atemporal reference image . This solution can be applied tospectral difference images as well. For example , the image

the IR imaging system as described herein , one or more ,data resulting from spectral difference images can be nor

Examples of Methodology of Measurements .

most , or potentially all the FPAs of the system can be 60 malized by the data corresponding to a temporal reference
calibrated . For example , greater than 50 % , 60 % , 70 % , 80 %image . For instance , the temporal reference images can beor 90 % of the FPAS 336 can be initially calibrated . As shown
subtracted from the spectral difference image to obtain thein FIG . 3A , these FPAs 336 may form separate images of thetemporal difference image . This process is referred to , forobject using light delivered in a corresponding optical the purposes of this disclosure , as a temporal differencing
channel that may include the combination of the correspond - 65 algorithm or method and the resultant image from subtract
ing front objective and re - imaging lenses 324 , 128 . The

ing the temporal reference image from another image ( suchcalibration procedure can allow formation of individual

as the spectral difference image ) is referred to as the tem

US 10 ,375 ,327 B2
21

22poral difference image. In some embodiments where spec tral differencing is employed , a temporal reference image
may be formed , for example , by creating a spectral differ -that is formed from the images of at least two different FPAS
to estimate parallax effects. Parallax error can be determinedby comparing the images from two different FPAs where theence image from the two or more images registered by the

position between the FPAs is known . The parallax can be

two or more FPAs at a single instance in time. This spectral 5 calculated from the known relative position difference . Dif

difference image is then used as a temporal reference image .
The temporal reference image can then be subtracted fromferences between the images from these two FPAs can be
attributed to parallax , especially, if the FPA have the sameother later obtained images to provide normalization that canspectral characteristics , for example have the same spectral

be useful in subtracting out or removing various errors or

filter or both have no spectral filters. Parallax error correc

deleterious effects . For example , the result of the algorithm 10 tion , however, can still be obtained from two FPAs that haveis not affected by a prior knowledge of whether the object orscene contains a target species (such as gas of interest),

different spectral characteristics or spectral filters , especially
if the different spectral characteristics, e . g ., the transmission

because the algorithm can highlight changes in the scene

spectra of the respective filters are known and / or negligible .

characteristics . Thus, a spectral difference image can be

Use of more than two FPAs or FPAs of different locations

calculated from multiple spectral channels as discussed 15 such as FPAs spaced farther apart can be useful. For

above based on a snap -shot image acquisition at any later

example, when the spectral differencing of the image data is

time and can be subtracted from the temporal reference

performed with the use of the difference between the images

image to form a temporal difference image . This temporalcollected by the outermost two cameras in the array ( such as,

difference image is thus a normalized difference image . The

for example , the FPAs corresponding to filters 2 and 3 of theimage ) can highlight the target species ( gas ) within thenormalized difference image , since this species was nota " difference image 2 - 3 ” is formed . In this case , the alter
native “ difference image 1 - 4 ” is additionally formed fromdifference between the two images ( the temporal difference 20 array of filters of FIG . 5A ), a difference image referred to aspresent in the temporal reference frame. In various embodi-

the image data acquired by, for example , the alternative

same spectral characteristic, then the images obtained by the

pixels corresponding to parallax- induced features in thements, more than two FPAs can be used both for registering FPAs corresponding to filters 1 and 4 of FIG . 5A . Assuming
the temporal reference image and a later- acquired difference 25 or ensuring that both of these two alternative FPAs haveimage to obtain a better SNR figure ofmerit. For example ,approximately the same spectral sensitivity to the target
if two FPAs are associated with spectral filters having the species , the alternative “ difference image 1 - 4 ” will highlight
two FPAs can be combined after they have been registeredimage . Accordingly , based on positive determination that the
30 same pixels are highlighted in the spectral “ difference image
to get a better SNR figure .
While the temporal differencing method can be used to
2 - 3 ” used for target species detection , a conclusion can be

reduce or eliminate some of the shortcomings of the spectral

made that the image features corresponding to these pixels

differencing , it can introduce unwanted problems of its own .

are likely to be induced by parallax and not the presence ofFor example , temporal differencing of imaging data is less target species in the imaged scene . It should be noted thatsensitive to calibration and parallax induced errors than the 35 compensation of parallax can also be performed using
spectral differencing of imaging data . However, any change images created by individual re -imaging lenses , 128a, whenin the imaged scene that is not related to the target species using a single FPA or multiple FPA 's as discussed above .

of interest (such as particular gas , for example ) is high -FPAs spaced apart from each other in different directions canlighted in a temporally - differenced image . Thus such change

also be useful. Greater than 2, for example , 3 or 4 , or more

location of the target species triggering, therefore , an error
in detection of target species. For example , if the tempera -tion . In certain embodiments two central FPAs and one
corner FPA are used for parallax correction . These FPA may ,as compared to the measurement taken earlier in time.

is the ability to perform the volumetric estimation of a gas

in the imaged scene may be erroneously perceived as a 40 FPAs can be used to establish parallax for parallax correc

ture of the background against which the gas is being
detected changes (due to natural cooling down as the day

in certain embodiments, have substantially similar or thesame spectral characteristics, for example , have filters hav
progresses , or increases due to a person or animal or another 45 ing similar or the same transmission spectrum or have no
object passing through the FOV of the IR imaging system ), filter at all .
then such temperature change produces a signal difference
Another capability of the embodiments described herein

Accordingly , the cause of the scenic temperature change (thecloud . This can be accomplished by using (instead ofcooling object, the person walking, etc .) may appear as the 50 compensating or negating ) the parallax induced effects

detected target species (such as gas ). It follows, therefore ,described above. In this case, the measured parallax between

that an attempt to compensate for operational differences

two or more similar spectral response images (e . g ., two oramong the individual FPAs of a multi-FPA IR imaging

more channels or FPAs) can be used to estimate a distancesystem with the use of methods that turn on spectral or

between the imaging system and the gas cloud or between

to false detection of target species . Among these problemss ystem . The parallax induced transverse image shift, d ,are scene -motion -induced detection errors and parallax

between two images is related to the distance , z , between thecaused errors that are not readily correctable and /or com -cloud or object 110 and the imaging system according to thepensatable . Accordingly, there is a need to compensate forequation z= - sZ '/d . Here , s, is the separation between two

temporal differencing can cause additional problems leading 55 the imaging system and an object in the field of view of theimage data acquisition and processing errors caused by 60 similar spectral response images , and z ' is the distance to the

motion of elements within the scene being imaged . Various

image plane from the back lens. The value for z' is typicallyembodiments of data processing algorithms described herein
approximately equal to the focal length f of the lens of theaddress and fulfill the need to compensate for such motion - imaging system . Once the distance z between the cloud andthe imaging system is calculated , the size of the gas cloud
induced and parallax -induced image detection errors.
In particular, to reduce or minimize parallax -induced 65 can be determined based on the magnification , m = f/z , where
differences between the images produced with two or moreeach image pixel on the gas cloud , Ax', corresponds to apredetermined FPAs, another difference image can be used physical size in object space Ax= Ax '/m . To estimate theUS 10 ,375,327 B2
23

24

volume of the gas cloud , a particular symmetry in the

spectrum of the various gases of interest can be obtained bythickness of the cloud based on the physical size of the cloud
can be assumed . For example , the cloud image can becomparing the measured brightness with an estimate of the
expected brightness . The spectral unmixing methodology

rotated about a central axis running through the cloud image

can also benefit from temporal, parallax , and motion com

to create a three dimensional volume estimate of the gas 5 pensation techniques .
cloud size . It is worth noting that in the embodiments
In various embodiments , a method of identifying thedescribed herein only a single imaging system is required forpresence of a target species in the object includes obtaining

such volume estimation . Indeed , due to the fact that thethe radiance spectrum ( or the absorption spectrum ) from theinformation about the angle at which the gas cloud is seen

object in a spectral region indicative of the presence of theby the system is decoded in the parallax effect, the image 10 target species and calculating a correlation ( e . g ., a correla

data includes the information about the imaged scenetion coefficient) by correlating the obtained radiance spec

viewed by the system in association with at least two angles .

trum (or the absorption spectrum ) with a reference spectrum

processing the acquired imaging data, a change in the scene

species can be determined based on an amount of correlation

When the temporal differencing algorithm is used forfor the target species. The presence or absence of the target

that is not caused by the target species can inadvertently be 15 ( e . g ., a value of correlation coefficient) . For example , thehighlighted in the resulting image. In various embodiments,

presence of the target species in the object can be confirmed

compensation for this error makes use of the temporal
differencing between two FPAs that are substantially equally

if the amount of correlation or the value of correlation
coefficient is greater than a threshold . In various implemen

intensity of which have changed in time (and not in wave length ). Therefore , subtracting the data corresponding to

between a filtered optical channel and /or another filtered
optical channel/ unfiltered optical channel or any combina

these pixels on both FPAs, which are substantially equallytions thereof.
For example, an embodiment of the system configured tospectrally sensitive to the target species . In this case , the tations, the radiance spectrum (or the absorption spectrum )temporal difference image will highlight those pixels the 20 can be obtained by obtaining a spectral difference image

spectrally sensitive to the target species, to form the result-ing image , excludes the contribution of the target species to 25 detect the presence of methane in a gas cloud comprises
the resulting image . The differentiation between (i ) changes
optical components such that one or more of the plurality ofin the scene due to the presence of target species and (ii)changes in the scene caused by changes in the background
not associated with the target species is, therefore , possible .

optical channels is configured to collect IR radiation toprovide spectral data corresponding to a discrete spectral
band located in the wavelength range between about 7 . 9 um

In some embodiments , these two channels having the same 30 and about 8 .4 um corresponding to an absorption peak ofor substantially similar spectral response so as to be sub methane . The multispectral data obtained in the one or morestantially equally spectrally sensitive to the target species
also be noted that, the data acquired with a visible lightFPA

may comprise FPAs that operate using visible light. It should

optical channels can be correlated with a predeterminedabsorption spectrum of methane in the wavelength range
between about 7 .9 um and 8 .4 um . In various implementa(when present as part of the otherwise IR imaging system ) 35 tions, the predetermined absorption spectrum of methane

can also be used to facilitate such differentiation and com -pensation of the motion -caused imaging errors . Visible

cameras generally have much lower noise figure than IR
cameras (at least during daytime). Consequently, the tem -can be saved in a database or a reference library accessibleby the system . Based on an amount of correlation (e.g ., avalue of correlation coefficient), the presence or absence of
methane in the gas cloud can be detected .

poral difference image obtained with the use of image data 40 Examples of Practical Embodiments and Operationfrom the visible light FPA can be quite accurate . The visible
The embodiment 300 of FIG . 3 is configured to employ 12
FPA can be used to compensate for motion in the system as optical channels and 12 corresponding microbolometer

well as many potential false - alarms in the scene due to

FPAs 336 to capture a video sequence substantially imme

motion caused by people, vehicles, birds, and steam , fordiately after performing calibration measurements . The

visible region of the spectra . This has the added benefit ofproviding an additional level of false alarm suppression

ratory scene and the calibration measurements are performed with the use of a reference source including two

without reducing the sensitivity of the system since many

shutters, as discussed above , one at room temperature andexample , as long as themoving object can be observed in the 45 video sequence corresponds to images of a standard labo

targets such as gas clouds cannot be observed in the visible
one 5º C . above room temperature . The use of 12 FPAS
spectral region . In various implementations, an IR camera 50 allows increased chance of simultaneous detection and esti

can be used to compensate for motion artifacts.
Another method for detection of the gases is to use amation of the concentrations of about 8 or 9 gases present at

ment spectrum . The component spectra are generally taken

the SNR commonly used in visible spectrum instruments .

the scene . In various embodiments, the number of FPAs 336

spectral unmixing approach . A spectral unmixing approach
can vary , depending on the balance between the operational
assumes that the spectrum measured at a detector pixel is requirements and consideration of cost.
composed of a sum of component spectra ( e . g ., methane and 55 Due to the specifics of operation in the IR range of theother gases ). This approach attempts to estimate the relative
spectrum , the use of the so - called noise -equivalent tempera
weights of these components needed to derive the measure - ture difference (or NETD ) is preferred and is analogous tofrom a predetermined spectral library ( for example , from
The array of microbolometer FPAs 336 is characterized todata collection that has been empirically assembled ), though 60 perform at NETDs72 mK at an f-number of 1 .2 . Eachsometimes one can use the scene to estimate these as well(often called “ endmember determination ” ) . In various

measurement was carried out by summing four consecutive
frames , and the reduction in the NETD value expected due

embodiments, the image obtained by the detector pixel is a

to such summation would be described by corresponding

radiance spectrum and provides information about thefactor of V4 = 2 . Under ideal measurement conditions, therebrightness of the object. To identify the contents of a gas 65 fore , the FPA NETD should be about 36 mK .
cloud in the scene and/ or to estimate the concentration of the
It is worth noting that the use of optically - filtered FPAs invarious gases in the gas cloud , an absorption /emission

various embodiments of the system described herein canUS 10 ,375 ,327 B2
25

provide a system with higher number ofpixels . For example ,embodiments including a single large format microbolom

eter FPA array can provide a system with large number of26

imaging the scene surrounding the system (the laboratory )with known temperature differences . The result of imple

menting the dynamic correction procedure is shown inpixels. Various embodiments of the systems described FIGS . 8A , 8B , where the curves labeled " obj” ( or “ A ” )herein can also offer a high optical throughput for a sub - 5 represent temperature estimates of an identified region in the
stantially low number of optical channels . For example , the. The abscissa in each of the plots of FIGS . 8A , 8B
systems described herein can provide a high optical through scene
indicates
the number of a FPA , while the ordinate corre
put for a number of optical channels between 4 and 50 . By
sponds to temperature ( in degrees C .). Accordingly , it ishaving a lower number of optical channels ( e . g ., between 4
thatwhen all detector elements receive radiant data
and 50 optical channels), the systems described herein have 10 expected
that, when interpreted as the object's temperature, indicateswider spectral bins which allows the signals acquired withineach spectral bin to have a greater integrated intensity .
An advantage of the embodiments described herein overvarious scanning based hyperspectral systems that are conthat the object' s temperature perceived by all detector ele
ments is the same, any given curve would be a substantiallyparallax and motion compensation algorithms mentioned
above . Indeed , as the imaging data required to implement

as about 2 . 5° C . In addition , all of the temperature estimatesa re steadily drifting in time, from frame to frame. The curves

these algorithms are collected simultaneously with the tarlabeled “ ref” (or “ C ” ) correspond to the detectors' estimateswith respect to data acquired at another time interval. This
rapid data collection thus improves the accuracy of the datacompensation process . In addition , the frame rate of dataout after
after eachhas beenbee subjected to theouteach detector
detector nivel
pixel hasflat line. Data corresponding to each of the multiple “ obj”
figured for target species detection ( for example , gas cloud 155 curves are taken from a stream of video frames separated
from one another by about 0 .5 seconds (for a total of 50
detection ) is that, the entire spectrum can be resolved in asnapshotmode ( for example , during one image frame acqui frames). The recorded “ obj” curves shown in FIG . 8A
sition by the FPA array ). This feature enables the embodiindicate that the detector elements disagree about thements of the imaging systems described herein to take object's temperature, and that difference in object's tem
advantage of the compensation algorithms such as the 20 perature perceived by different detector elements is as highget -species related data , the compensation algorithms areof the temperature of the aperture 338 of the embodimentcarried out with respect to target-species related data and not 25 300 of FIG . 3A . The results of detection of radiation carried
dynamic calibration procedure described above areexpressed with the curved labeled “ obj corr” (or “ B ” ). Now ,thein estimated temperature of the object among
the imaging system described herein can operate at video 30 the difference
detectorelements
reduced to about 0 .5º C . (thereby
rates from about 5 Hz and higher. For example , various improving the originalisreadingat least by a factor of 5 ).
embodiments described herein can operate at frame rates
FIG.
8B
represents
theresultsof similar measurementsfrom about 5 Hz to about 60 Hz or 200 Hz. Thus , the usercorrespondingtoadifferent
locationin the scene (a location
is able to recognize in the images the wisps and swirls
typical of gas mixing without blurring out of these dynamic 35 which is at a temperature about 9° C . above the estimatedtemperature of the aperture 338 of FIG . 3A ). As shown, theimage features and other artifacts caused by the change of correction
algorithm discussed above is operable and effec
scene (whether spatial or spectral) during the lengthy mea
surements . In contradistinction , scanning based imaging tive and applicable to objects kept at different temperature .
systems involve image data acquisition over a period of time Accordingly , the algorithm is substantially temperatureacquisition is much higher. For example , embodiments ofexceeding a single - snap -shot time and can , therefore , blur 40 independent.
the target gas features in the image and inevitably reduce the Dynamic Calibration Elements and References

otherwise achievable sensitivity of the detection . This result
is in contrast to embodiments of the imaging systemdescribed herein that are capable of detecting the localized

FIGS. 9A and 9B illustrates schematically different imple
that include a variety of temperature calibration elements tomentations 900 and 905 respectively of the imaging system

concentrations of gas without it being smeared out with the 45 facilitate dynamic calibration of the FPAs. The temperatureareas of thinner gas concentrations . In addition , the higher

calibration elements can include mirrors 975a , 975b ( repframe rate also enables a much faster response rate to a leakresented as M , 4 , M , , etc .) as well as reference sourcesof gas (when detecting such leak is the goal) . For example ,972a and 972b . The implementation 900 can be similarly

an alarm can trigger within fractions of a second rather thanconfigured as the embodiment 300 and include one or more
50 front objective lens , a divided aperture , one or more spectral
To demonstrate the operation and gas detection capability
filters, an array of imaging lenses 928a and an imagingof the imaging systems described herein , a prototype waselement 936 . In various implementations , the imaging ele
constructed in accordance with the embodiment 300 of FIG . ment 936 (e . g ., camera block ) can include an array of
3A and used to detect a hydrocarbon gas cloud of propylene
cameras . In various implementations , the array of cameras
several seconds.

at a distance of approximately 10 feet. FIG . 7 illustrates 55 can comprise an optical FPA unit. The optical FPA unit canvideo frames 1 through 12 representing gas-cloud -detection

comprise a single FPA , an array of FPAs. In various imple

output 710 (seen as a streak of light ) in a sequence from t1 =to t= 12 . The images 1 through 12 are selected frames takenfrom a video - data sequence captured at a video -rate of 15

m entations, the array of cameras can include one or more
detector arrays represented as detector array 1, detector array
5 , detector array 9 in FIGS . 9A and 9B . In various embodi

frames /sec . The detected propylene gas is shown as a streak 60 ments , the FOV of each of the detector arrays 1, 5 , 9 can beof light 710 (highlighted in red ) near the center of eachdivided into a central region and a peripheral region . With
image . The first image is taken just prior to the gas emerging out any loss of generality, the central region of the FOV offrom the nozzle of a gas- contained , while the last image each of the detector arrays 1 , 5 , 9 can include the region
represents the system output shortly after the nozzle has where the FOV of all the detector arrays 1 , 5 , 9 overlap . In
65 the embodiment illustrated in FIG . 9A , the reference sources
been turned off.
The same prototype of the system can also demonstrate972a and 972b are placed at a distance from the detector
the dynamic calibration improvement described above by arrays 1 , 5 , 9 , for example , and mirrors 975a and 975b that

US 10 ,375 ,327 B2

27

28

can image them onto the detector arrays are then placed at
the location of the scene reference aperture (e. g ., 338 of FIG .
3A ).
In FIG . 9A , the mirrors 975a and 975b are configured to972b can comprise a surface that can be associated withsensors, temperature controllers.

In FIG . 9B , the temperature - calibration elements com

prise temperature - controlled elements 972a and 972b (e .g .,reflect radiation from the reference sources 972a and 972b 5 a thermally controlled emitter, a heating strip , a heater or a
( represented as ref A and ref B ). The mirrors 975a and 975b
cooler ) disposed a distance from the detector arrays 1 , 5 , 9 .

can be disposed away from the central FOV of the detector

In various embodiments, the temperature - controlled ele

arrays 1, 5 , 9 such that the central FOV is not blocked or

ments 972a and 972b can be disposed away from the central

array 5 could be greater than the FOV of the detector arrays

source 972a and 972b . The radiation emitted from the

obscured by the image of the reference source 972a and FOV of the detector arrays 1, 5 , 9 such that the central FOV
972b . In various implementations , the FOV of the detector 10 is not blocked or obscured by the image of the reference

1 and 9 . In such implementations, the mirrors 975a and 975b
reference sources 972a and 972b is also imaged by thecan be disposed away from the central FOV of the detector detector array 936 along with the radiation incident from thearray 5 at a location such that the reference source 972a andobject. Depending on the position of the reference sources972b is imaged by the detector array 5 . The mirrors 975a and 15 972a and 972b the image obtained by the detector array of975b may comprise imaging optical elements having optical

the reference sources can be blurred (or defocused ) or sharp

the detector arrays 1 and 9 . In this example, the reference

980f of the temperature -controlled elements 972a and 972

power that image the reference sources 972a and 972b onto(or focused ). The images 980a , 980b , 980c , 9800, 980e andsources 972a and 972b can be disposed in the same plane as can be used as a reference to dynamically calibrate the one
the re -imaging lenses 928a , however, the reference sources 20 or more cameras in the array of cameras.
972a and 972b can be disposed in a different plane or in

In the implementations depicted in FIGS . 9A and 9B , thedifferent locations. For example , the reference sources 972a

detector arrays 1 , 5 and 9 are configured to view (or image )and 972b can be disposed in a plane that is conjugate to theplane in which the detector array 1 , detector array 5 , andboth the reference sources 972a and 972b . Accordingly ,multiple frames ( e. g ., every or substantially every frame)

detector array 9 are disposed such that a focused image of 25 within a sequence of images contains one or more regions in

the reference sources 972a and 972b is formed by thedetector arrays . In some implementations, the reference
sources 972a and 972b can be disposed in a plane that isspaced apart from the conjugate plane such that a defocused

the image in which the object image has known thermal andspectral properties. This allows multiple ( e. g ., most or each )cameras within the array of cameras to be calibrated to agreewith other ( e. g ., most or every other ) camera imaging theimage of the reference sources 972a and 972b is formed by 30 same reference source ( s ) or surface ( s ). For example , detec

the detector arrays . In various implementations, the refer -ence sources 972a and 972b need not be disposed in thesame plane .

tor arrays 1 and 9 can be calibrated to agree with each other.

As another example , detector arrays 1, 5 and 9 can be

As discussed above , in some embodiments , the reference

calibrated to agree with each other. In various embodiments,
the lenses 928a provide blurred (or defocused ) images of theother embodiments , the image of reference sources 972a andthe lenses 928a are described as providing blurred or defo

972b formed on the detector array 1 , and detector array 9 are

cused images, in various embodiments, reference sources orsources 972a and 972b are imaged onto the detector array 1 35 reference sources 972a , 972b on the detector arrays 1 and 9
and detector array 9 , without much blur such that the because the location of the reference sources are not exactly
reference sources 972a and 972b are focused . In contrast, inin a conjugate planes of the detector arrays 1 and 9 . Althoughblurred such that the reference sources 972a and 972b are 40 surfaces are imaged on the detectors arrays 1 , 5 , 9 without

defocused , and thereby provide some averaging, smoothing ,and / or low pass filtering. The reference sources 972a andsuch blur and defocus and instead are focused images .
Additionally optical elements may be used , such as for

972b may comprise a surface of known temperature andmay or may not include a heater or cooler attached thereto

example , the mirrors shown in FIG . 9A to provide such
focused images .

or in thermal communication therewith . For example , the 45 The temperature of the reference sources 972b , 972a canreference source 972a and 972b may comprises heaters and be different. For example , the reference source 972a can becoolers respectively or may comprise a surface with atemperature sensor and a heater and sensor respectively indirect thermal communication therewith to control the tem -at a temperature T4 , and the reference source 972b can be at

a temperature TR lower than the temperature T2. A heater canbe provided under the temperature -controlled element 972aperature of the reference surface . In various implementa - 50 to maintain it at a temperature T4, and a cooler can betions , the reference sources 972a and 972b can include a

provided underneath the temperature - controlled element

sources 972a and 972b at a known temperature . In somementations, the embodiments illustrated in FIGS. 9A and 9B

temperature controller configured to maintain the reference
implementations, the reference sources 972a and 972b can

972b to maintain it at a temperature TB . In various imple
can be configured to image a single reference source 972

be associated with one or more sensors that measure the 55 instead of two references sources 972a and 972b maintained
temperature of the reference sources 972a and 972b andat different temperatures . It is understood that the single
communicate the measured temperature to the temperaturereference source need not be thermally controlled . For
controller. In some implementations , the one or more sen example , in various implementations, a plurality of detectors
sors can communicate the measured temperature to the in the detector array can be configured to image a samedata - processing unit . In various implementations, the refer - 60 surface of at least one calibration element whose thermal

ence sources 972a and 972b may comprise a surface ofand spectral properties are unknown . In such implementa

unknown temperature . For example , the reference sources

tions, one of the plurality of detectors can be configured as

may comprise a wall of a housing comprising the imaging
system . In some implementations, the reference sources

a reference detector and the temperature of the surface of theat least one calibration element imaged by the plurality of

972a and 972b can comprise a surface that need not be 65 detectors can be estimated using the radiance spectrum
associated with sensors , temperature controllers . However,obtained by the reference detector. The remaining plurality

in other implementations, the reference sources 972a andof detectors can be calibrated such that their temperatureUS 10 ,375 ,327 B2
30
and /or spectral measurements agree with the reference
detector. For example, detector arrays 1 and 9 can becalibrated to agree with each other. As another example,
detector arrays 1, 5 and 9 can be calibrated to agree withor each camera ) to accurately estimate the temperature of aplurality of elements (for example , most or each element in

the scene ) immediately after the calibration is complete . It
cannot, however, prevent the cameras ' estimates from drift

5 ing away from one another during the process of imaging aneach other.
The reference sources 972a and 972b can be coated withunknown scene. The dynamic calibration can be used toa material to make it behave substantially as a blackbody( for which the emission spectrum is known for any given
temperature ). If a temperature sensor is used at the location

reduce or prevent this drift, so that all cameras imaging ascene can be forced to agree on the temperature estimate of
the reference sources /surfaces , and adjust this correctionof each reference source , then the temperature can be 10 during every frame.

tracked at these locations. As a result, the regions in the
FIG . 10A illustrates schematically a related embodimentimage of each camera (e . g ., on the detector arrays 1 and 9 )1000 of the imaging system , in which one or more mirrors
in which the object has such known temperature ( and, Mp4 , . . .M114 and Mop , . . .M e are placed within the fields
therefore , spectrum ) can be defined . A calibration procedureof view of one or more cameras 0 , . . . , 11 , partially blocking
can thus be used so that most of the cameras (if not every 15 the field of view . The cameras 0 , . . . , 11 are arranged to form
camera ) so operated agrees, operationally , with most or an outer ring of cameras including cameras 0 , 1 , 2 , 3 , 7 , 11 ,every other camera , for objects at the temperatures repre 10 , 9 , 8 and 4 surrounding the central cameras 5 and 6 . In
sented by those two sources . Calibrating infrared cameras various implementations , the FOV of the central cameras 5
using sources at two different temperatures is known as a and 6 can be less than or equal to the FOV of the outer ring
" two -point" calibration , and assumes that the measured 20 of cameras 0 , 1 , 2 , 3 , 7 , 11, 10, 9 , 8 and 4 . In suchsignal at a given pixel is linearly related to the incident

irradiance . Since this calibration can be performed duringmultiple , more , or even every frame of a sequence , it isreferred to as a " dynamic calibration ” .

implementations, the one or moremirrors MoA; . . . M114 andMob , . . . M , can be placed outside the central FOV of thecameras 5 and 6 and is placed in a peripheral FOV of thecameras outer ring of cameras 0 , 1 , 2 , 3 , 7 , 11 , 10 , 9 , 8 andAn example of the dynamic calibration procedure is as 25 4 which does not overlap with the central FOV of thefollows. If there is a temperature sensor on the reference
sources or reference surface , then the temperature measure -cameras 5 and 6 such that the reference sources A and B are
not imaged by the cameras 5 and 6 . In various implemenments obtained by these temperature sensors can be used totations , the FOV of the central cameras 5 and 6 can befor the “ reference temperatures” of sources/surfaces A , B ,more mirrors Moa , . . . M114 and Mob; . . . M116 can begiven camera , forcing it to agree with the reference tem -cameras 0 , 1 , 2 , 3 , 7 , 11, 10 , 9 , 8 and 4 such that the reference

determine their expected emission spectra . These tempera - greater than the FOV of the outer ring of cameras 0 , 1 , 2 , 3 ,ture measurements are labeled as T [ R ], T [ R ], and T [ R ] 30 7 , 11 , 10 , 9 , 8 and 4 . In such implementations, the one or
and C . These temperature measurements can be used as
scalar correction factors to apply to the entire image of aplaced in a peripheral FOV of the cameras 5 and 6 which
does overlap with the central FOV of the outer ring ofperatures . Correcting the temperature estimate of a given 35 sources A and B are imaged by the cameras 5 and 6 .

pixel from T to T' can use formulae analogous to thoseThis design is an enhancement to the systems 300 and 400

discussed below in reference to FIGS . 10A , 10B , 10C . If noshown in FIGS. 3A and 4A . In the system 1000 shown in

direct temperature sensor is used , then one of the cameras

FIG . 10A , an array of two or more imaging elements ( curved

can be used instead. This camera can be referred to as the mirrors , for example ) is installed at a distance from the" reference camera ” . In this case , the same formulae as those 40 FPAs, for example , in the plane of the reference aperture 160
provided in paragraph below can be used , but with TA[R ] shown in FIG . 3A . These elements (mirror or imaging
and T [R ] representing the temperatures of the reference
elements ) are used to image one or more temperaturesources / surfaces A and B as estimated by the reference

controlled reference sources A and B onto the detector

camera . By applying the dynamic calibration correction elements of two or more of the cameras . The primaryformulae, all of the other cameras are forced to match the 45 difference between embodiment 1000 and embodiment 300
temperature estimates of the reference camera .
or 400 is that now a plurality ormost or all of the outer ring

In the configuration illustrated in FIG . 9B , the referenceof cameras in the array can image both the reference sources

sources on the detector arrays are blurred . The configuration

A and B . Accordingly , most or all of the outer ring ofsources 972a and 972b are placed such that the images of the

A and B instead of imaging one of the two reference source

illustrated in FIG . 9A is similar to the system 400 illustrated 50 cameras image an identical reference source or an identicalin FIG . 4 where the reference sources are placed at an

set of reference sources ( e. g ., both the reference sources Aintermediate image plane ( e . g ., a conjugate image plane ). In
this configuration , the array of reference apertures , similar toand B ) rather than using different reference sources fordifferent cameras or imaging different portions of the refer

reference apertures 438a in FIG . 4 , will have an accompa -ence sources as shown in FIGS. 3A and 4A . Thus , thisnying array of reference sources or reference surfaces such 55 approach improves the robustness of the calibration , as itthat the reference sources or surfaces ( e .g ., each reference
source or surface ) are imaged onto a camera or a detector
array such as FPAs 1 , 5 , 9 . With this approach , the reference
source or surface images are at a conjugate image plane andeliminates potential failures and errors due to the having
additional thermal sensors estimating each reference source .
The imaging elements in the system 1000 ( shown as
mirrors in FIGS. 10A and 10B ) image one or more conthus are not appreciably blurred , so that their images can be 60 trolled -temperature reference sources or a surface of amade to block a smaller portion of each camera ' s field ofview .

A " static" calibration (a procedure in which the scene islargely blocked with a reference source such as the moving

calibration element (shown as A and B in FIGS. 10A and
10B ) into the blocked region of the cameras' fields of view .

FIG . 10B shows an example in which mirror Mo, images

reference source /surface A onto camera 0 , and mirror Mor

shutters 960 in FIGS . 9A and 9B , so that imaging of an 65 images reference source / surface B onto camera 0 , andunknown scene cannot be performed in parallel with cali-

bration ) allows a plurality of the cameras ( for example , most

likewise for cameras 1, 2 , and 3 . This way, each of themirrors is used to image a reference source /surface onto a

US 10 ,375 ,327 B2
31

32

detector array of a camera , so that many, most, or every

make it behave approximately as a blackbody, for which theframe within a sequence of images contains one or more

emission spectrum is known for any given temperature . Ifregions in the image in which the object image has known many, most, or each camera in the array of cameras images
thermal and spectral properties . This approach allowsmost both of references A and B , so that there are known regionsof the camera , if not each camera , within the array of 5 in the image of these cameras in which the object has acameras to be calibrated to agree with most or every other known temperature ( and therefore spectrum ), then one cancamera imaging the same reference source or sources . For perform a calibration procedure . This procedure can provide

example , cameras 0 , 1 , 2 , 3 , 7 , 11 , 10 , 9 , 8 and 4 can be that many , most or every camera so operated agrees withvarious , most, or every other camera , for objects at thecalibrated to agree with each other. As another example , temperaturesby those two sources. For
cameras 0 , 1, 2 and 3 can be calibrated to agree with each 10 example , two, represented
three, four, five , six , seven , eight, nine, ten ,other. As yet another example , cameras 0 , 1 , 2 , 3 , 7 , 11 , 10 ,
9 , 8 , 4 , 5 and 6 can be calibrated to agree with each other.
Accordingly, in various implementations, two, three , four,

five , six , seven , eight, nine , ten , eleven or twelve cameras

eleven or twelve cameras can be calibrated to agree witheach other. In certain embodiments, however, not all thecameras are calibrated to agree with each other. For

example , one, two, or more cameras may not be calibrated
can be calibrated to agree with each other. In certain 15 to agree with each other while others may be calibrated toembodiments, however, not all the cameras are calibrated toagree with each other. For example, one , two, or moreagree with each other. As discussed above, calibration of
infrared cameras using sources at two different temperatures

pixels a given FPA . Without any loss of generality, FIGS .
10A and 10B represent a top view of the embodiment showntemperature T' from the initial temperature T estimated ateach pixel in a camera using the following formulae :1050 of the imaging system , in which one ormore ’ reference

T [x,y,c]=(7[x,y,c]- TA[R ])G [c]+ TA[R ]where is TA [R ] is a dynamic offset correction factor, and,cameras may notbe calibrated to agree with each other while
is known as a " wo -point” calibration and assumes that theothers may be calibrated to agree with each other. In various measured signal at a given pixel is linearly related to theembodiments, these mirrors may be configured to image the 20 incident irradiance .
reference sources/surfaces A and B onto different respective
The dynamic calibration is used to obtain a correctedin FIG . 9A .
FIG . 10C illustrates schematically a related embodiment 25

sources Roa . . . , R114 and Robe . . . , R118 are disposed

around the array of detectors 0 , . . . , 11 . In various

TB [ R ] – TA [R ]implementations, the one or more reference sources

G [c] = TB [c] – Ta [c ]ROA , . . . , Rua and Rob , . . . , RUB can be a single reference 30

source that is imaged by the detectors 0, . . . , 11. In various
implementations , central detector arrays 5 and 6 can have a

is a dynamic gain correction factor. The term c discussed

FOV that is equal to or lesser than the FOV of the outer ringof the detectors 0 , 1 , 2 , 3 , 7 , 11 , 10 , 9 , 8 and 4 . In such

above is a camera index that identifies the camera whose
data is being corrected .

be disposed away from the central FOV of the detector
arrays 5 and 6 such that the radiation from the reference

III. Examples of a Mobile DAISI System

implementations, the reference sources ROA . . . , R114 can 35

sources Roq , . . . , Ru is imaged only by the outer ring of

The DAISI systems disclosed herein can be configured todetectors 0 , 1 , 2, 3 , 7 , 11 , 10 , 9 , 8 and 4 . In various be installed at a suitable location on a long -term basis ,implementations , central detector arrays 5 and 6 can have a 40 according to some embodiments . For example, the DAISIFOV that is greater than the FOV of the outer ring of thesystems disclosed in Section II above can be affixed to a

detectors 0 , 1, 2 , 3, 7 , 11 , 10 , 9, 8 and 4 . In such imple disposed in the peripheral FOV of the detector arrays 5 andmentations, the reference sources Ro4, . . . , R 14 can be

fixture mounted to the ground at a location to continuously
the location . In some embodiments, for example, the DAISI

or periodically monitor the presence of gases or chemicals at

6 such that the radiation from the reference sources 45 systems can be attached to a pole , post, or any suitable

is imaged only by the outer ring of detectors
Ro . . . R,
0 , 1 , 2 , 3 , 7 , 11 , 10 , 9 , 8 and 4 . The radiation from the

fixture at the location to bemonitored . In such arrangements ,the DAISI system can continuously or periodically capturereference sources R24 , . . . , R1 is therefore imaged by themultispectral, multiplexed image data of the scene , and anouter ring of detectors 0 , 1, 2 , 3 , 7, 11, 10 , 9 , 8 and 4 as wellon -board or remote computing unit can process the captured

as central cameras 5 and 6 . Without any loss of generality , 50 image data to identify or characterize gases or chemicals at

FIG . 10C represents a top view of the embodiment shown in

FIG . 9B .

In various implementations , a heater can be provided
underneath , adjacent to , or in thermal communication withthe location . A communications module can communicate
data relating to the identified gases or chemicals to any

suitable external system , such as a central computing server,

etc . For such long -term installations of the DAISI system ,reference source /surface A to give it a higher temperature 55 the installation site may include a power source ( e . g .,Ty, and a cooler can be provided underneath , adjacent to , orin thermal communication with reference source B to give ita lower temperature TR . In various implementations , theembodiments illustrated in FIGS. 10A , 10B and 10C can beelectrical transmission lines connected to a junction box at

the site ) and network communications equipment (e .g .,network wiring, routers, etc .) to provide network commu
nication between the DAISI system and the external sys

configured to image a single reference source A instead of 60 tems.

two references sources A and B maintained at different
It can be advantageous to provide a mobile DAISI systemtemperatures. As discussed above , the embodiments illus configured to be worn or carried by a user. For example , it
trated in FIGS. 10A , 10B and 10C can be configured to may be unsuitable or undesirable to install a DAISI system
image a same surface of a calibration element. In suchat some locations on a long-term basis. As an example , some
implementations, the temperature of the surface of the 65 oil well sites may not have sufficient infrastructure, such as
calibration element need not be known . Many, most or eachpower sources or network communication equipment, toreference source/surface can be coated with a material to support the DAISI system . In addition , it can be challenging

US 10 ,375 ,327 B2

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34

to move the DAISI system from site to site to monitor
different locations. For example , installing and removing the
DAISI system from a site for transport may involve sub -captured in a short timeframe, e . g ., less than about 3
seconds , less than about 2 seconds, or less than about 1. 5
seconds ( for example , in about 1 second , in some embodi

stantial effort and time for the user when the system isments). The single snapshot can be captured in greater thanconnected to infrastructure at the site to be monitored . 5 about 5 milliseconds, greater than about 0 . 2 seconds, or

Accordingly , it can be desirable to provide a DAISI system

greater than about 0 .5 seconds. The captured image data canthat can be used independently of the facilities or infrastruc-be processed on board the system 1000 by a processing unit ,advantageous to implement the DAISI system in a form

processing unit can process the image data from the different

ture at the site to be monitored . Furthermore , it can be

as explained in further detail herein . For example, thefactor and with a weight that can be carried or worn by a 10 optical channels and can compare the captured spectral

user. For example , a mobile DAISI system can enable theuser to easily transport the system from site -to - site , while
monitoring the presence of gases or chemicals in real-time.
It should be appreciated that each of the systems disclosed

information with a database of known chemicals to identify
and /or characterize the gases that are included in the gas
cloud 1202 .
A communications module on board the system 1000 canherein can be used to monitor potential gas leaks in any 15 transmit information relating to the identified gases orsuitable installation site , including , without limitation , drillchemicals to any suitable external device . For example , theing rigs, refineries, pipelines, transportations systems, ships

communications module can wirelessly communicate ( e. g .,or other vessels (such as off-shore oil rigs, trains, tanker

by Bluetooth , WiFi, etc .) the information to a suitable

trucks , petro - chemical plants , chemical plants, etc . In addi- mobile computing device , such as an electronic eyeweartion , each of the embodiments and aspects disclosed and 20 apparatus 1201, a tablet computing device 1212 , a mobile
illustrated herein such as above , e. g ., with respect to FIGS.
smartphone, a laptop or notebook computer 1203 , or any
1 - 10C , can be used in combination with each of the embodi
other suitable mobile computing device . In some embodi
ments disclosed and illustrated herein with respect to FIGS . ments, if a gas cloud is detected , the system 1000 can warn
the user by way of sending a signal to the mobile device
11A - 14C .
FIG . 11A is a schematic diagram illustrating a mobile 25 ( e . g ., tablet computing device 1212 or a mobile smartphone.
infrared imaging system 1000 (e . g ., a mobile or portable

The mobile device can emit an audible ring and / or can

DAISI system ) configured to be carried or worn by a humanvibrate to notify the user of a potential gas leak . In thewhen he travels to a site to be monitored , such as an oil well

1 201 can include a user interface comprising a display thatuser 1275 . The user 1275 may wear a hat or helmet 1200

embodiment of FIG . 11A , the electronic eyewear apparatus

site , a refinery , etc . The system 1000 shown in FIG . 11A is 30 the user 1275 can view in real-time as he visits the site . In

attached to the helmet 1200 by way of a support 1204 thatsome embodiments , the electronic eyewear apparatus 1201

securely mounts the system 1000 to the helmet 1200 . For
example , the support 1204 can comprise a fastener, a strap ,comprises eyewear that includes a display . The electronics
eyewear apparatus 1201 can be further configured to present

or any other suitable structure. Advantageously , mounting

images from this display to the wearer. The electronics

the system 1000 to the helmet 1200 can enable the user 1275 35 eyewear apparatus 1201 may for example include projection

to capture images within the system 's field of view (FOV )optics that projects the image into the eye . The electronic

by turning his head to face a particular location to bemonitored . For example , the user 1275 can walk through theeyewear apparatus 1201 may comprise heads up display
optics the presents the image on the lens portion (s ) of thesite and can capture video images of each portion of the site ,eyewear so that the wearer can view the image and also see

chemical leaks, such as valves, fittings , etc . Thus , in theembodiment shown in FIG . 11A , the user 1275 can image

Other configurations are possible . In some arrangements, theeyewear apparatus 1201 can comprise a Google Glasseach portion of the site by facing the area to be imaged andensuring that the system 1000 is activated . In addition, bydevice , sold by Google, Inc ., of Mountain View , Calif.
The processing unit can configure the processed imagee . g ., various structures that may be susceptible to gas or 40 through the eyewear and peer at objects in the distance .

mounting the system 1000 to the user ' s helmet 1200, the 45 data such that the types of identified gases are displayed touser 1275 may use his hands for other tasks while the system
the user 1275 on the display of the eyewear apparatus 1201 .

1000 images the site . Although the system 1000 of FIG . 11A

For example, in some embodiments, color -coded data may

is shown as being mounted to the user' s helmet 1200 , itrepresent different types of gases or concentrations of ashould be appreciated that the system 1000 can instead beparticular gas , and may be overlaid on a visible light image

worn on other parts of the user' s clothing or can be carried 50 of the scene . For example , the color- coded data and image

by the user, e . g ., in a bag , case , or other suitable container
Furthermore, in some embodiments, a wind sensor can beprovided to the user , e . g ., on the user' s clothing and/ or on orof the gas cloud can be seen by the user on the electronic
eyewear apparatus 1201. In various embodiments , text dataand statistics about the composition of the gas cloud 1202

near the system 1000 . The wind sensor can be used to may also be displayed to the user 1275 . Thus, the user 1275
estimate wind conditions at the installation site , which can 55 can walk the site and can view the different types of gases
be used to improve the detection of gas leaks. In other in the gas cloud 1202 substantially in real- time. Advanta
embodiments, the system 1000 can be coupled to or formed

geously , such real-time display of the composition of the gas

with a housing that defines a “ gun ” - like structure which cancloud 1202 can enable the user 1275 to quickly report urgent

be aimed or pointed by the user in a particular direction .

events , such as the leakage of a toxic gas or chemical. In

As explained herein , a gas cloud 1202 emitted from a 60 some embodiments , detection of a toxic leak can trigger an

structure at the site can be imaged by pointing the system
1000 towards the gas cloud 1202 and capturing an image ofthe gas cloud 1202 when the cloud 1202 is within the FOV

alarm , which may cause emergency personnel to help evacu
ate the site and/ or fix the leak .
In some embodiments, the processed image data can beof the system 1000 . Unlike other systems, the system 1000

transmitted from the system 1000 to the tablet computing

can capture multispectral image data of a single scene over 65 device 1212 , laptop computer 1203, and /or smartphone. Thea range of IR wavelengths with a single snapshot, as

user 1275 can interact with the table computing device 1212

explained in further detail herein . The single snapshot can beor laptop computer 1203 to conduct additional analysis ofUS 10 ,375 ,327 B2

35
the imaged and processed gas cloud 1202 . Furthermore ,information about the gas cloud (including the processed

36

inchesx3 inchesx3 inches. In some embodiments , the dataacquisition and processing module 1020 ( including thedata and / or the raw image data ) may also be transmitted toimaging optics , focal plane array, and on board processinga central server for centralized collection , processing , andelectronics may ) can be sized and shaped to fit within atem (GPS ) module can also be installed on board the system
1000 and /or on the mobile computing device ( such as a

inches . In some embodiments, the data acquisition andprocessing module 1020 ( including the imaging optics , focal

tablet computing device , smartphone, etc .). The GPS mod -plane array , and on board processing electronicsmay ) can be

captured image data can be stored on the central server forments, the data acquisition and processing module 1020
( including the imaging optics, focal plane array, and on

analysis . In various arrangements , a global positioning sys - 5 box - shaped boundary smaller than 6 inchesx4 inchesx4

ule can identify the coordinates of the user 1275 when asized and shaped to fit within a box - shaped boundary
particular image is captured . The location data for the 10 smaller than 2 inchesx2 inchesx6 inches . In some embodi
further analysis .

Thus, the system 1000 shown in FIG . 11A can enable theuser 1275 to image multiple locations of a particular site toboard processing electronics may ) can be sized and shaped

to fit within a box - shaped boundary having dimensions

be monitored , such as an oil well site . Advantageously, the 15 larger than 4 inchesx2 inchesx2 inches. In some embodi
optical components , the processing components, and the ments, the data acquisition and processing module 1020
communications components of the system 1000 can be
including the imaging optics , focal plane array, and on
integrated within a relatively small housing that can be
carried or worn by the user 1275 . For example , in various

board processing electronics may ) can be sized and shaped
to fit within a box - shaped boundary having dimensions

embodiments, the system 1000 does not include complex 20 larger than 3 inchesx3 inchesx7 inches. In some embodi

mechanical components for movement, such as gimbals,
actuators , motors , etc . Without such components, the size ofments , the data acquisition and processing module 1020
(including the imaging optics, focal plane array, and on

the system 1000 can be reduced relative to other systems.

board processing electronics may) can be sized and shaped

user 1275 moves about the site . Indeed , it can be very

can have dimensions less than 2 inchesx2 inchesx6 inches.

Unlike other systems, in which the system components
to fit within a box -shaped boundary having dimensions
are bulky or are assembled over a large form factor, the 25 larger than 2 inchesx1 inchesx1 inches . The data acquisition
mobile system 1000 can be sized and shaped in such aand processing module 1020 (including the imaging optics ,manner so as to be easily moved and manipulated when the
focal plane array , and on board processing electronics may)challenging to integrate the various system components in a

The data acquisition and processing module 1020 (including

small form - factor. Advantageously , the systems 1000 can be 30 the imaging optics , focal plane array, and on board process

worn or carried by a human user . For example , the compo

nents of the system 1000 can be contained together in a dataacquisition and processingmodule 1020 , which may include

ing electronics may ) can have dimensions greater than 1

inchesx1 inchesx3 inches. The data acquisition and process

ing module 1020 ( including the imaging optics, focal planea housing to support the system components. The compo
array, and on board processing electronics may ) can havenents of the system 1000 (including the optical or imaging 35 dimensions greater than 2 inchesx2 inchesx4 inches . said
components , the focal plane array, the on -board processing data acquisition and processing module has dimensions lesselectronics, and the communications components ) may be
packaged or assembled in the data acquisition and process

than 6 inchesx3 inchesx3 inches . The data acquisition andprocessing module 1020 ( including the imaging optics , focal

ing module 1020 and may occupy a volume less than aboutplane array, and on board processing electronics may ) can

processing electronics, and the communications compo -inchesx2 inches . The data acquisition and processing mod

greater than about 2 cubic inches, or greater than about 16
The data acquisition and processing module 1020 (withacquisition and processing module 1020 ( including the

300 cubic inches , less than about 200 cubic inches, or less 40 have dimensions less than 4 inchesx3 inchesx3 inches . The
than about 100 cubic inches . In various embodiments , the data acquisition and processing module 1020 (including thecomponents of the system 1000 ( including the optical or
imaging optics, focal plane array, and on board processing
imaging components, the focal plane array, the on -board
electronics may ) can have dimensions less than 3 inchesx2
nents ) may be packaged or assembled in the data acquisition 45 ule 1020 (including the imaging optics , focal plane array ,and processing module 1020 and may occupy a volume and on board processing electronics may ) can have dimen
cubic inches.

sions greater than 2 inchesx1 inchesxl inches . The data
imaging optics, focal plane array, and on board processing

the system components mounted therein or thereon ) may be 50 electronics may ) can have dimensions greater than 1 inchesx
sized and shaped to fit within a box - shaped boundary having
0 .5 inchx0 .5 inch . The data acquisition and processing

dimensions XxYxZ . For example , the data acquisition andprocessing module 1020 , including the imaging optics, focal

module 1020 (including the imaging optics , focal planearray, and on board processing electronics may ) can have aplane array, and on board processing electronics, may bevolume less than 30 cubic inches. The data acquisition andand / or solar module . In some embodiments , the data acqui-tion and processing module 1020 ( including the imaging

sition and processing module 1020 ( including the imaging

optics , focal plane array , and on board processing electronics

included in a package that is sized and shaped to fit within 55 processing module 1020 ( including the imaging optics , focal
the box - shaped boundary having dimensions XxYxZ . This plane array , and on board processing electronics may ) can
package may also contain a power supply, such as a battery have a volume less than 20 cubic inches . The data acquisi
optics , focalplane array, and on board processing electronics 60 may ) can have a volume less than 15 cubic inches . The datamay ) can be sized and shaped to fit within a box - shaped
acquisition and processing module 1020 ( including theboundary smaller than 8 inchesx6 inchesx6 inches. In someembodiments, the data acquisition and processing module

imaging optics , focal plane array, and on board processing

electronics may) can have a volume less than 10 cubic

1020 (including the imaging optics, focal plane array , and on
inches . The data acquisition and processing module 1020
board processing electronics may ) can be sized and shaped 65 (including the imaging optics, focal plane array, and on
to fit within a box -shaped boundary smaller than 7 inchesx5 board processing electronics may ) can have a volume moreinchesx5 inches , e.g ., a box -shaped boundary small than 7than 1 cubic inches. The data acquisition and processingUS 10 ,375,327 B2

37module 1020 ( including the imaging optics , focal plane

38

The systems 1000 shown in FIG . 11B can comprise aarray , and on board processing electronics may ) can have amobile DAISI system , similar to that illustrated in FIG . 11A .

volume more than 4 cubic inches. The data acquisition andprocessing module 1020 (including the imaging optics, focal

In other embodiments , the systems 1000 can comprise alarger DAISI system configured for use on a relatively

plane array, and on board processing electronics may ) can 5 long -term basis . For example , the stationary imaging system

shown in FIG . 11B can be installed on a pole 1309
have a volumemore 5 cubic inches. The data acquisition and 1000A
suitable structure for monitoring a storage tankprocessingmodule 1020 (including the imaging optics, focal or1301othersolar panel 1300 can be provided at or near theplane array, and on board processing electronics may ) can system. A 1000
provide power to the system 1000 . An
have a volumemore 10 cubic inches. This packagemay also 10 antenna 1303tocanhelpelectricallycouple to the system and cancontain a power supply , including a battery and /or solar provide wireless communication
the system 1000
module, a communications module , or both and fit into the and any other external entity , suchbetween
as a central server, forabove - referenced dimensions. It should be appreciated thatstoring and/ or processing the data captured by the system.
directions shown in FIG . 11A with respect to X , Y , and Z . 15 . 1000
A DAISI system such as system 1000 may, if desired , beMoreover, the system 1000 can have a mass and weight
coupled to a unit that adjusts the pan , tilt , rotation , height, or
sufficiently small so as to enable the user 1275 to easily carry other position of the system 1000 . As an example, system

the dimensions disclosed herein may not correspond to theor wear the data acquisition and processing module 1020 at 1000 may be mounted to a pan and tilt unit. The pan and tilt
the site . Thus, the embodiment shown in FIG . 11A can be unit may be able to rotate the front of system 1000 left andsized and shaped and configured to have a mass that enables 20 right (e.g ., yaw system 1000 left and right) and able to rotate
a human user to easily and effectively manipulate the system the front of system 1000 up and down (e.g., pitch system
1000 .
1000 up and down ), thereby enabling system 1000 to focus
FIG . 11B is a schematic diagram illustrating an installa - on a particular portion of the surrounding environment and ,tion site ( e . g ., an oil well site , etc .) that can be monitored bywhen desired , to scan different areas of the surrounding
multiple infrared imaging systems 1000 ( e . g ., a DAISI 25 environment (i. e ., to move through a desired scan path ). The

system ). For example , as shown in FIG . 11B , an imaging
system 1000A can be mounted to a pole 1309 or otherpan and tilt unit (or any other unit that adjusts the positionof system 1000 may include motors, actuators, or otherstationary structure at the site . An imaging system 1000B

suitable mechanisms to drive movements of system 1000 .

can be worn or carried by multiple users 1275 , an imaging

The operation of a pan and tilt unit (or any other unit thatsystem 1000C can be mounted on a truck 1500 , and / or an 30 adjusts the position of system 1000 ) may be controlled byimaging system 1000D can be mounted on an aerial plat system 1000 , by the pan and tilt unit, by a remote system , byform 1501, such as an unmanned aerial vehicle (UAV ) or apiloted airplane . In some arrangements , the UAV can com prise an airplane, a helicopter (such as a quad helicopter ),a control system capable of controlling one or more systems
1000 and /or corresponding pan and tilt units , or by any
suitable and desired control system .

site in an efficient manner. Indeed , each installation site cansuch as by leaking from a broken valve , then the system

include any suitable number and type of system 1000A -1000A can capture a multispectral, snapshot image or seriessystems 1000A - 1000D , greater than ten systems 1000A
1000D , greater than twenty systems 1000A - 1000D . Each

1000A can include imaging , processing , and communica
tions components on board the system 1000A to identify andinstallation site may include less than about 100 systems

characterize the types of gases in the cloud 1302 and to

etc . The embodiments disclosed herein can utilize the image 35 The stationary infrared imaging system 1000A can bedata captured by any combination of the systems 1000A - programmed to continuously or periodically monitor the
1000D at the installation site to image the entire installationsite . If a gas cloud 1302 escapes from the storage tank 1301,
1000D . For example , each installation site can include 40 of images ( e . g ., a video stream ) of the gas cloud 1302 . As
greater than two systems 1000A - 1000D , greater than five with the embodiment of FIG . 11A , the imaging system

45 transmit the processed data to the central server, e. g ., by way
For example , the central server can track the real-time of the antenna 1303 .
locations of each imaging system 1000A -1000D based on
The imaging systems 1000B worn or carried by thethe GPS coordinates of the particular system or on pre - multiple users 1275 can advantageously capture and process
determined knowledge about the system ' s stationary loca - multispectral image data of the portions of the installation
tion . The distributed nature of the imaging systems 1000A - 50 site that each user 1275 visits. It should be appreciated that
1000A - 1000D .

1000D can provide rich information to the central server
about the types and locations of gas leaks or other problems

the different users 1275 may work in or travel throughdifferent portions of the installation site (and also to athroughout multiple installation sites. Although FIG . 11B

number of installation sites ) over a period of time. Whenillustrates a stationary system 1000A mounted to a fixture , aactivated , the imaging systems 1000B worn or carried by the

portable system 1000B to be worn or carried by a human , a 55 users 1275 can continuously or periodically capture multitruck - based system 1000C , and an aerial-based system
1000D , it should be appreciated that other types of systems

spectral image data of the different locations at the instal
lation site ( s ) to which the user 1275 travels . As explained

may be suitable . For example , in some embodiments , aherein , the system 1000B can transmit the image data androbotic vehicle or a walking robot can be used as a platformthe location at which the image was captured to the central
for the systems 1000 disclosed herein . In various embodi- 60 server. If the system 1000B or the central server detects aments, a floating platform (such as a boat) can be used as aproblem ( such as a gas leak ), then the central server canplatform for the systems 1000 disclosed herein . It should associate that leak with a particular location and time.
also be appreciated that the systems disclosed herein can
Furthermore,because the central server can receive image
utilize any combination of the platforms (e .g ., stationary data and location data from multiple users at different
fixtures such as a pole , human user (s ), truck (s ) or other 65 locations and viewing from different perspectives, the cenvehicle , aerial platform ( s ), floating platform (s ), robotic plat- tral server can create an organization -wide mapping of gas

form (s ), etc .) to support the systems 1000 .

leaks that include, e.g ., the locations of gas leaks in any ofUS 10 ,375, 327 B2

39

40

multiple installation sites, the type and concentrations and1000 disclosed herein can thus provide a ubiquitous moni

expanse or extent of each gas leaked , the particular user

toring system for decision making In addition , the systems

1275 that captured the image data , and the time at which theimage was taken . Thus, each user 1275 that carries or wears

1000 disclosed herein can be used in a feedback control
process to improve various manufacturing procedures based

a portable imaging system 1000B can contribute information 5 on the gases detected by the system ( s ) 1000 . Accordingly, ato the central server that, when aggregated by the central
server, provides rich details on the status of any gas leaks atcontrolmodule may be provided to adjust themanufacturing
procedure and /or parameters according to the gases mea

any installation sites across the organization .

sured by the system 1000 .

The truck -mounted imaging system 1000C can be

The embodiments of the mobile infrared imaging system

mounted to a truck or other type of vehicle ( such as a car , 10 1000 disclosed herein provide various advantages over othervan , all -terrain vehicle , etc .). As shown in FIG . 11B , thesystems. As explained above , aggregation of data about aimaging system 1000C can be connected to an end of ansite and its potential gas leaks can provide an organization
extendable pole or extension member mounted to the truckor system -wide mapping of potential problems. Further
1500 . The system 1000C can be raised and lowered by a more , automatic detection of gas leaks (and identification ofcontrol system to enable the system 1000C to image a wide 15 the gases in the gas cloud ) can simplify operation of thearea of the installation site . In some embodiments, actuators
system 1000 and can reduce the risk of user errors incan be provided to change the angular orientation of theattempting to detect or identify gas cloudsmanually . Moresystem 1000C , e . g ., its pitch and yaw . A vibration isolation

over , the small size of the systems 1000 disclosed herein are

or reduction mechanism can also be provided to reduce more easily carried or worn by the user than other systems.
vibrations , which may disturb the imaging process . The 20 In addition , the systems 1000 disclosed herein can overlay
system 1000C can be battery powered and/ or can be pow -the identified gas clouds on a visible image of the scene andered by the truck ; in some embodiments, a generator can be

can color code the gas cloud according to , e.g., type of gas,

detect gas leaks. As explained herein , the location of the1000 can include a data acquisition and processing module

used to supply power to the system 1000C . A user can drive
concentration , etc .
the truck 1500 throughout the installation site to image
FIG . 12 is a schematic system block diagram showing avarious portions of the site to detect leaks . In addition , the 25 mobile infrared imaging system 1000 ( e . g ., a mobile DAISI
user can drive the truck 1500 to other installation sites tosystem ), according to one embodiment. The imaging system

truck 1500 can be communicated to the central server andthe location of the truck 1500 can be associated with each1020 configured to be worn or carried by a person . The dataacquisition and processing module 1020 can include, concaptured image. The truck 1500 may include GPS electron - 30 tain , or house an optical system 1015 , a processing unit

ics to assist in tracking the location of the truck 1500 and /or

1021 , a power supply 1026 , a communication module 1025 ,system 1000C over time as the user drives from place toand GPS module 1025 . In other embodiments, the data

unmanned aerial vehicle, or UAV ) can support the imaging

to be mounted to a structure at the site to be monitored , suchsites to capture multispectral image data to detect gas clouds.

provide power to the various system components, such asdata regarding the existence of leaks at numerous installa -communication module 1024 , and /or the GPS module 1025 .

place . Similarly , the aerial platform 1501 (such as an

acquisition and processing module 1020 can be configured

system 1000D . The aerial platform 1501 can be piloted 35 as a post. The power unit 1026 can be provided on board the( either remotely or non -remotely ) to numerous installation
system 1000. The power unit 1026 can be configured toThus , the systems 1000A - 1000D can provide extensive

the optical system 1015 , the processing unit 1021, thetions across an organization . Monitoring numerous cameras 40 In some embodiments , the power unit 1026 can comprisesimultaneously or concurrently across an organization , site ,one or more batteries (which may be rechargeable ) to power

region , or the entire country can be enabled at least in partby providing wireless ( or wired ) communication between

the system components . In some embodiments , the power
unit 1026 can include a solar power system including one or

the systems 1000A - 1000D and one or more central servers.

more solar panels for powering the system by sunlight. In

Advantageously , the collection of image data from multiple 45 some embodiments , the power unit 1026 can include various

sources and multiple platforms can enable the organization
to create a real-time mapping of potential gas leaks , thepower electronics circuits for converting AC power suppliedby standard power transmission lines to DC power fortypes and amounts of gases being leaks, the locations of thepowering the system components . Other types of power

leaks , and the time the image data of the leak was captured
supply may be suitable for the power unit 1026 .
In some arrangements , the aggregation of data about a site 50 The system 1000 can include an optical system 1015
can improve the safety of installation sites . For example , ifconfigured to capture multispectral image data in a single
a gas leak is detected at a particular installation , the embodisnapshot, as explained herein . The optical system 1015 canments disclosed herein can alert the appropriate personnel,

correspond to any suitable type of DAISI system , such as,

who can begin safety and/or evacuation procedures . More - but not limited to , the optical systems and apparatus illus
over, the aggregation of data across an organization (such as 55 trated in FIGS. 1 - 10C above and/ or in the optical systems

an oil service company ) can provide site -wide, region -wide ,1015 illustrated in FIGS. 13A - 13B below . For example , theand / or company -wide metrics for performance . For
example , a given facility can monitor its total emissions overoptical system 1015 can include an optical focal plane array(FPA ) unit and components that define at least two opticaltime and use the resulting data to help determine thechannels that are spatially and spectrally different from one

metropolitan area , a state , etc .) can monitor trends in emis sions over time, providing a value on which to base deci-transfer IR radiation incident on the optical system towards
the optical FPA . The multiple channels can be used tofacility ' s overall performance. A given region ( such as a 60 another . The two optical channels can be positioned tosions . Likewise , a company can look at the emissions
performance at all of its facilities and can make decisions

multiplex different spectral images of the same scene and to
image the different spectral images on the FPA unit .

about whether some facilities should make new investments 65 The processing unit 1021 can also be provided on board
to improve performance , and /or whether the entire company the data acquisition and processing module 1020 . The pro
should make various improvements. The mobile systems cessing unit 1021 can include a processor 1023 and a

US 10 ,375 ,327 B2
41
memory 1022 . The processor 1023 can be in operable
cooperation with the memory 1022 , which can contain acomputer- readable code that, when loaded onto the proces -sor 1023, enables the processor 1023 to acquire multispec

wireless communication module can provide data commu
nication between the system 1000 and an external device
remote from the system 1000 , such as a central server. For

example , the processed image data and / or the raw image

tral optical data representing a target species of gas or 5 data may be transmitted over a telecommunications network

chemical from IR radiation received at the optical FPA unitof the optical system 1015 . The memory 1022 can be any

to the central server for storage and /or further analysis. In
some embodiments, the processed or raw image data can besuitable type ofmemory ( such as a non -transitory computer -uploaded to the mobile device ( e . g ., notebook computer,readable medium ) that stores data captured by the opticalsmartphone , tablet computing device, etc .), which can insystem 1015 and /or processed by the processing unit 1021. 10 turn communicate the image data to the central server.

The memory 1022 can also store the software that is

executed on the processor 1023 . The processor 1023 can be

configured to execute software instructions that process themultispectral image data captured by the optical system

The GPS module 1025 can be configured to determine thelocation of the data acquisition and processing module 1020

at a particular time. The processing unit 1021 can store thelocation data and can associate the location data with a1015 . For example , the processor 1023 can analyze the 15 particular image captured by the optical system 1015 indifferent images detected by the FPA and can compare the some arrangements. The location data associated with thecaptured data with known signatures of various types of captured images can be transmitted by the communication
gases or chemicals. Based on the analysis of the captured module 1024 (or by an external device ) to a central server inimage data , the processor can be programmed to determine some arrangements .
the types and concentrations of gases in a gas cloud . Further, 20 The optical system 1015 , the processing unit 1021, theas explained herein , the processor 1023 can analyze cali bration data provided by the optical system 1015 to improve
the accuracy of the measurements .
Advantageously, the processor 1023 can comprise one or

power supply 1026 , the communication module 1024 , and /or the GPS module 1025 may be contained or housed in the

carried or worn by the user. The components of the system

execute methods used in the analysis of the images capturedby the optical system 1015 . For example , the FPGA can
include logic gates and read access memory (RAM ) blocks
that are designed to quickly implement the computations

components, and the communications components ) may be
packaged or assembled in the data acquisition and process
ing module 1020 and may occupy a volume less than about
300 cubic inches, less than about 200 cubic inches , or lessdata acquisition and processingmodule 1020 , which can be
more field -programmable gate arrays (FPGA ) configured to 25 1000 (including the optical components , the processing

used to detect the types of gases in a gas cloud . The small 30 than about 100 cubic inches. In various embodiments, thesize /weight, and high performance characteristics of the components of the system 1000 ( including the optical com

FPGA can enable on board computation and analysis within
the data acquisition and detection unit 1020 worn or carried

ponents, the processing components , and the communica
tions components ) may be packaged or assembled in theby the user. The use of FPGA ( or similar electronics) ondata acquisition and processing module 1020 and may

board the system 1000 can reduce costs associated with 35 occupy a volume greater than about 2 cubic inches, orusing an off-site central server or larger computing device toconduct the image analysis computations . In addition ,enabling computation with one or more FPGA devices on

greater than about 16 cubic inches . A power supply, includ
ing a battery and /or solar module may also be included

among the components packaged or assembled in the data

board the wearable system can also prevent or reduce

acquisition and processing module 1020 and fit into thecommunication bottlenecks associated with wirelessly trans - 40 above- referenced volumetric dimensions.

mitting large amounts of raw data from the system 1000 toa remote server or computer , which can be used in someembodiments .

The data acquisition and processing module 1020 (withthe system components mounted therein or thereon , includ
ing the imaging optics, focal plane array , and on board

The communication module 1024 can be configured toprocessing electronics may ) may be sized and shaped to fit

communicate with at least one device physically separate 45 within a box -shaped boundary having dimensions XxYxZ .
from the data acquisition and processing module 1020 . For

F or example , in some embodiments , the data acquisition andexample , the communication module 1024 can include a

processing module 1020 ( including the imaging optics , focal

wireless communication module configured to wirelessly

plane array, and on board processing electronics may ) can becommunicate with the at least one separate device . The
sized and shaped to fit within a box - shaped boundary
wireless communication module can be configured to pro - 50 smaller than 8 inchesx6 inchesx6 inches . In some embodi
vide wireless communication over wireless networks ( e . g ., ments, the data acquisition and processing module 1020
WiFi internet networks, Bluetooth networks, etc .) and /or(including the imaging optics, focal plane array , and on
over telecommunications networks ( e .g ., 3G networks, 4G
board processing electronics may ) can be sized and shaped
to fit within a box -shaped boundary smaller than 7 inchesx5
networks, etc . ).
In some embodiments, for example , the wireless commu- 55 inchesx5 inches. In some embodiments, the data acquisition
nication module can provide data communication between
and processing module 1020 (including the imaging optics ,the data acquisition and processing module 1020 and a
focal plane array , and on board processing electronics may)
mobile device such as an electronic eyewear apparatus, a

can be sized and shaped to fit within a box - shaped boundary

tablet computing device , a mobile smartphone, a laptop or smaller than 6 inchesx4 inchesx4 inches . In some embodi
notebook computer, or any other suitable mobile computing 60 ments , the data acquisition and processing module 1020

device. As explained herein , the mobile device can include (including the imaging optics , focal plane array, and on
a display on which the processed image data can be dis - board processing electronics may ) can be sized and shaped
played to the user. For example , the types (and/or concen - to fit within a box -shaped boundary having dimensions
trations ) of gases in a gas cloud can be illustrated on thelarger than 4 inches by 2 inchesx2 inches. In some embodi
display, e.g ., by color coding or other suitable illustration 65 ments , the data acquisition and processing module 1020
scheme. The processed data can overlie a visible image of (including the imaging optics, focal plane array, and on
the scene in some arrangements . In some embodiments , the board processing electronics may ) can be sized and shapedUS 10 ,375,327 B2
43
to fit within a box -shaped boundary having dimensions

44

including a battery and /or solar module, a communications
module, or both may be included in the data acquisition anduser. The lens array 1002 can be monolithically formed inany suitable manner. For example , in various embodiments ,the lens array 1002 can be formed by a diamond milling tool.
In some embodiments, the lens array 1002 can comprise adimensions . It should be appreciated that the dimensions
disclosed herein may not correspond to the directions shownin FIG . 11A with respect to X , Y , and Z . Moreover, thesystem 1000 can have a mass and weight sufficiently small

regions shaped into curved refractive surfaces for creating
separate lenses . In some embodiments, the lenses can beinserted into an array of openings formed in a plate or
substrate to create the lens array 1002.

larger than 2 inches by 1 inchesx1 inches . A power supply,

processing module 1020 and fit into the above -referenced 5 monolithic piece of transparent material which has separate

so as to enable the user 1275 to easily carry or wear the data 10

acquisition and processing module 1020 at the site.
FIG . 13A is a schematic system diagram of an optical

The optical system 1000 can also include an array of

infrared ( IR ) filters 1001 configured to filter wavelengths ofinfrared light in an appropriate manner. Examples of IR

system 1015 configured to be used in the mobile infrared filters and filtering techniques are disclosed herein , forimaging systems 1000 disclosed herein , according to various
example , with respect to FIGS. 5A -6D . As shown in FIG .
embodiments . As explained herein , the optical system 1015 15 13A , the IR filters 1001 can be disposed between the lens
shown in FIG . 13A can be provided in the data acquisition array 1002 and the FPA unit 1008 . The IR filters 1001 canand processing module 1020 to be worn or carried by the at least partially define the multiple optical channels to beuser. The optical system 1015 can be configured to capture imaged by the FPA unit 1008 . In some embodiments, the IR

multispectral image data of an object 1007 , such as a gas
filters 1001 can be positioned between the lens array 1002
cloud , chemical spill , etc . The components of the optical 20 and the first and second moveable blackbody sources 1009 ,system 1015 shown in FIG . 13A may be similar to or the1010 .

explained herein with respect to FIGS. 1- 10C . The opticalsystem 1015 configured to be used in the mobile infraredsystem 1000 . As shown in FIG . 13A , the FPA unit 1008 may

shown in FIG . 13B can be provided in the data acquisition

tem .

user. The components of the optical system 1015 shown insame as the components of the optical systems and devices

FIG . 13B is a schematic system diagram of an opticalsystem 1015 can include a focal plane array ( FPA ) unit 1008
imaging systems 1000 disclosed herein , according to various
configured to record infrared image data captured by the 25 embodiments . As explained herein , the optical system 1015

advantageously be uncooled , e .g., devoid of a cooling sys

and processing module 1020 to be worn or carried by the

The optical system 1015 can include a front window 1006
FIG . 13B may be similar to or the same as the components
through which light from the object 1007 passes. A first 30 of the optical systems and devices explained herein withmoveable blackbody source 1003 and a second moveable
blackbody source 1004 can be provided to enable calibration

The optical system 1015 of FIG . 13B can include an FPAof the optical system 1015 . The moveable sources 1003 ,unit 1408 configured to image an object 1409, such as a gas

1004 can be moved in front of the field of view such that thecloud or chemical leak . As with the embodiment illustrated

optics image these sources for calibration . For example , the 35 in FIG . 13A , the system 1015 of FIG . 13B can include afirst and second blackbody sources 1003 , 1004 can be

front window 1406 through which light from the object 1409

maintained at different known temperatures in a stablemanner. For example, a heater and a temperature sensor canbe attached to each blackbody source 1003, 1004 to provide

passes, first and second moveable blackbody sources 1403 ,
1404 , an IR filter array 1401, and a lens array 1402 . As withthe embodiment of FIG . 13A , the lens array 1402 canfeedback to create a stable and known temperature differ - 40 comprise a unitary or monolithic body . In the embodimentence (e .g ., at least 50 mK in some arrangements ) betweenof FIG . 13B , the lens array 1402 may be disposed between

the filter array 1401 and the FPA unit 1408. In otherIn addition , the optical system 1000 can include aarrangements , the filter array 1401 may be disposed between
dynamic calibration apparatus to dynamically calibrate the the lens array 1402 and the FPA unit 1408 .
system 1000. As shown in FIG . 13A , one or more calibration 45 The optical system 1015 of FIG . 13B can include asources 1009 , 1010 can be provided . The calibration sources
cooling unit 1430 configured to cool the FPA unit 1408 . The
1009 , 1010 can comprise a thermal electrically controlled
cooling unit 1430 can comprise a cooling finger configured
different spatial regions of the sources .

( TEC ) material with a temperature sensor attached thereto .

to cryogenically cool the FPA array 1408 in various arrange

The calibration sources 1009, 1010 can be coated with aments . As shown in FIG . 13B , the filter array 1401, the lens

spectrally measured coating or paint. Light from the cali - 50 array 1402, and the FPA unit 1408 can be disposed in a
bration sources 1009 , 1010 can be reflected from one orcooled region 1440 . The blackbody sources 1403 , 1404 andmore mirrors 1005 and directed through the lens array 1002

front window 1406 can be disposed in an uncooled region(described below ) to be imaged on a portion of the FPA unit
1008 to assist in dynamically calibrating the system 1000

1450. Disposing the blackbody sources 1403, 1404 at
uncooled temperatures and the filter array 1401 , lens array(e. g.,while imaging of the target gas cloud is simultaneously 55 1402, and FPA unit 1408 at cooled temperatures can assist
being imaged ).
in the periodic calibration of the system 1000.
The optical system 1000 can include a lens array 1002 to
FIG . 14A is a schematic perspective view of a mobile
focus the incoming light onto the FPA unit 1008. As shown
infrared imaging system 1000 ( e .g ., mobile DAISI system )in FIG . 13A , each lens of the lens array 1002 can at least mounted to a helmet 1200 , according to various embodi
partially define or be included in an optical channel to be 60 ments . FIG . 14B is an enlarged schematic perspective view

imaged by the FPA unit 1008. To improve the mobility andof the mobile infrared imaging system 1000 shown in FIG .

partially enable the system 1000 to be worn or carried by thesuch as an oil well site, a refinery, etc. The system 1000 can

portability of the mobile imaging system 1000, the lens array
1 4A . The helmet 1200 can comprise a portion of a user 's
1002 can comprise an integrated unit formed from or personal protective equipment and can also advantageously
assembled into a single unitary body . Such an integrated lens be used as a platform for the imaging system 1000 . As
array 1002 can reduce the size of the imaging system 1015 , 65 explained above , the helmet 1200 can be worn by a user as
and therefore , the size of the system 1000 , to at least the user visits a particular installation site to be monitored ,US 10 ,375,327 B2
45
be activated to continuously monitor and analyze the sitesthat the user visits . The system 1000 can thereby continu
ously and actively search for gas leaks wherever the user
visits and can initiate an alarm or other notification if a leakis detected .

In the embodiment illustrated in FIG . 14B , the imaging

system 1000 can comprise a housing 1590 , within or to46
components of the system 1000 ( including the optical or
imaging components , the focal plane array, the on -board
processing electronics , and the communications compo
nents) may be packaged or assembled in the data acquisition

5 and processing module 1020 and may occupy a volume in arange of about 4 cubic inches to about 6 .5 cubic inches, e.g .,about 5 .63 cubic inches in one embodiment . In somewhich a data acquisition and processing module 1020 ( see ,embodiments , the components of the system 1000 ( includ

e . g ., FIG . 12 and associated description ) is mounted ori ng the optical or imaging components, the focal plane array ,coupled . A support 1592 can be coupled to or formed with 10 the on -board processing electronics, and the communica

the housing 1590 and can be configured to attach to thehelmet 1200 or to any other suitable platform . For example,

tions components ) may be packaged or assembled in thedata acquisition and processing module 1020 and may

in some embodiments , the support 1592 can include one or

occupy a volume in a range of about 9 cubic inches to about

more mounting holes for attaching to the helmet 1200 by

13 cubic inches , e .g ., about 11 . 25 cubic inches in one

way of, e . g ., screws, bolts , or other fasteners . In addition , as 15 embodiment. In some embodiments , the components of theshown in FIG . 14B , a front window 1506 can be provided at

system 1000 (including the optical or imaging components ,a front end of the housing 1590 . The front window 1506 canthe focal plane array, the on -board processing electronics,

the aperture of the system 1000 . In some embodiments , theassembled in the data acquisition and processing module

be transparent to IR radiation and can at least partially define

and the communications components ) may be packaged orwindow 1506 comprises germanium . A diamond like coat- 20 1020 and may occupy a volume in a range of about 6 cubicing (DLC ) or other coating or layer can be disposed over theinches to about 10 cubic inches .
The data acquisition and processing module 1020 (withwindow 1506 to provide a durable surface .

As explained herein , the system 1000 can be configured

the system components mounted therein or thereon ) may be

to be worn or carried by a human user. Accordingly, the data
sized and shaped to fit within a box -shaped boundary having
acquisition and processing module 1020 can be suitably 25 dimensions XxYxZ . For example, the data acquisition anddimensioned such that a user can easily wear or carry theprocessingmodule 1020 , including the imaging optics, focal

system 1000 . For example , the data acquisition and processplane array, and on board processing electronics may be

ing module 1020 can be defined at least in part by dimen

included in a package that is sized and shaped to fit within

the box - shaped boundary having dimensions XxYxZ . This
sions XxYXZ , as shown in FIGS . 14A and 14B .
Unlike other systems, in which the system components 30 package may also contain a power supply , such as a battery
are bulky or are assembled over a large form factor, theand / or solar module . In some embodiments , the data acquimobile system 1000 can be sized and shaped in such asition and processing module 1020 (including the imaging

manner so as to be easily moved and manipulated when the

optics, focal plane array, and on board processing electronics

user moves about the site . Indeed , it can be very challenging
form - factor. Advantageously, the systems 1000 disclosedmay ) can be sized and shaped to fit within a box -shaped
embodiments , the data acquisition and processing module

to integrate the various system components in a small 35 boundary smaller than 8 inchesx6 inchesx6 inches . In someherein can be worn or carried by a human user. For example,
the components of the system 1000 can be contained
together in the data acquisition and processing module 1020 ,1020 ( including the imaging optics, focalplane array, and on
to fit within a box -shaped boundary smaller than 7 inchesx5

board processing electronics may ) can be sized and shaped

which may include the housing 1590 to support the system 40 inchesx5 inches . In some embodiments, the data acquisition
components . The components of the system 1000 (including
and processing module 1020 (including the imaging optics ,the optical or imaging components , the focal plane array, thefocal plane array , and on board processing electronics may)on -board processing electronics, and the communications

can be sized and shaped to fit within a box - shaped boundary

components ) may be packaged or assembled in the data
smaller than 6 inchesx4 inchesx4 inches . In some embodi
acquisition and processing module 1020 and may occupy a 45 ments , the data acquisition and processing module 1020
volume less than about 300 cubic inches , less than about 200(including the imaging optics, focal plane array, and on

cubic inches, or less than about 100 cubic inches. In various

embodiments, the components of the system 1000 (includ ing the optical or imaging components , the focal plane array,board processing electronics may ) can be sized and shaped

to fit within a box - shaped boundary smaller than 6 inchesx2
inchesx2 inches . In some embodiments, the data acquisition

the on -board processing electronics, and the communica - 50 and processing module 1020 (including the imaging optics,

tions components ) may be packaged or assembled in the

focal plane array, and on board processing electronics may )data acquisition and processing module 1020 and may

can be sized and shaped to fit within a box -shaped boundary

imaging components , the focal plane array, the on -board
processing electronics , and the communications compo nents )may be packaged or assembled in the data acquisitionand processing module 1020 and may occupy a volume in aarray, and on board processing electronics may ) can be sized
and shaped to fit within a box -shaped boundary having
dimensions larger than 2 inchesx1 inchesx1 inches. The dataacquisition and processing module 1020 ( including theoccupy a volume greater than about 2 cubic inches, or having dimensions larger than 4 inchesx2 inchesx2 inches .
greater than about 16 cubic inches. In some embodiments ,In some embodiments , the data acquisition and processing
the components of the system 1000 ( including the optical or 55 module 1020 ( including the imaging optics , focal plane

range of about 4 cubic inches to about 15 cubic inches. In 60 imaging optics, focal plane array, and on board processing
some embodiments , the components of the system 1000
electronics may ) can have dimensions less than 3 inchesx2( including the optical or imaging components , the focal inchesx2 inches . The data acquisition and processing modplane array, the on -board processing electronics, and the ule 1020 ( including the imaging optics, focal plane array ,communications components) may be packaged orand on board processing electronics may) can have dimen
assembled in the data acquisition and processing module 65 sions greater than 1 inchesx0 .5 inchx0 .5 inch . The data
1020 and may occupy a volume in a range of about 5 cubicacquisition and processing module 1020 ( including theinches to about 12 cubic inches. In some embodiments, the imaging optics , focal plane array, and on board processingUS 10 ,375 ,327 B2
48

47electronics may) can have a volume less than 30 cubicof the window 1506 and a lens assembly 1502 rear of the( including the imaging optics , focal plane array , and on
board processing electronics may) can have a volume lessforward ) of the second lens array 1502B , and an optical
focal plane array (FPA ) unit 1508 can be disposed rear of theinches . The data acquisition and processing module 1020

shutter(s ) 1503 . A filter array 1501 can be disposed rear (orthan 20 cubic inches . The data acquisition and processing 5 filter array 1501 . The optical FPA unit 1508 can be mechani

module 1020 (including the imaging optics , focal planearray , and on board processing electronics may ) can have acally and electrically coupled with one or more substrates
1586 , which may comprise printed circuit board or PCB

volume less than 15 cubic inches. The data acquisition andsubstrates. In various embodiments , the FPA unit 1508

processingmodule 1020 (including the imaging optics, focal
comprises a single FPA or detector array . Additionally, as
plane array, and on board processing electronics may ) can 10 explained herein , the lens assembly 1502, filter array 1501,

have a volume less than 10 cubic inches. The data acquisi -tion and processing module 1020 (including the imaging
optics, focal plane array, and on board processing electronics

and optical FPA unit can at least partially define one or more

optical channels that are spatially and spectrally different. A
number of the optical channels can be at least 4 , at least 5 ,may ) can have a volumemore than 1 cubic inches. The data at least 8, at least 9 , at least 12 , at least 13 , or at least 20. In
acquisition and processing module 1020 ( including the 15 some embodiments , a number of the optical channels is
imaging optics , focal plane array, and on board processing between 4 and 50 .
electronics may ) can have a volume more than 4 cubic

inches. The data acquisition and processing module 1020
(including the imaging optics, focal plane array, and on

One or more batteries 1588 can supply power to thesystem 1000 by way of the substrate(s ) 1586 . In addition , avisible light imaging sensor 1580 can be disposed in theboard processing electronics may ) can have a volumemore 20 housing 1590 and can be configured to provide a visible light

5 cubic inches. The data acquisition and processing module
image of the scene being captured by the system 1000 . The
1020 (including the imaging optics, focal plane array, and on
processed IR image data can be overlaid upon the visible
board processing electronics may ) can have a volume more
light image . In various embodiments the visible light imag
10 cubic inches . This package may also contain a power ing sensor 1580 can be used for reduction of scene -motion
supply , including a battery and /or solar module , a commu - 25 induced detection errors , for example , to detect a moving

nications module, or both and fit into the above -referenced
dimensions . It should be appreciated that the dimensions

object that enters the field of view (such as an animal or
person ) and would interfere with the data being collected .

disclosed herein may not correspond to the directions shown

As explained herein , the movable shutter (s ) 1503 can bein FIG . 11A with respect to X , Y , and Z . This package may

configured to provide spectral-radiometric calibration foralso contain a power supply , including a battery and /or solar 30 the system 1000 . The shutter (s ) 1503 can be configured tomove in and out of the field of view of the lens assembly
above -referenced dimensions. It should be appreciated that 1502 periodically, e .g ., in a time period in a range of about

module, a communications module , or both and fit into thethe dimensions disclosed herein may not correspond to the
1 minute to about 15 minutes, or more particularly , in a
directions shown in FIG . 11A with respect to X , Y , and Z .
range of about 3 minutes to about 7 minutes , e . g ., about 5
In some embodiments , the dimension X shown in FIG . 35 minutes . Although one shutter 1503 is illustrated in FIG .

14B can be in a range of about 2 inches to about 7 inches ,14C , it should be appreciated that two or more shutters may

or more particularly, in a range of about 2 inches to about 4

be provided . The shutter (s ) 1503 can be used in static

embodiments, the dimension X shown in FIG . 14B can be intemperature values . In some embodiments , only static cali

inches , e . g., about 2 . 5 inches in one embodiment. In somecalibration procedures to provide the system with absolutea range of about 4 inches to about 6 inches, e . g ., about 5 40 bration is performed , e . g ., no dynamic calibration is per

inches in one embodiment. In some embodiments , theformed . In some embodiments , both static and dynamic

dimension Y shown in FIG . 14B can be in a range of about

calibration procedures are performed .

1 inch to about 5 inches , or more particularly, in a range of

The lens assembly 1502 can include a first lens array

about 1 inch to about 3 inches, e. g., about 1 .5 inches in one

1502A and a second lens array 1502B . In some embodi

inches, or more particularly, in a range of about 1 inch to1502A , 1502B . In some embodiments , the lens assembly

embodiment. In some embodiments, the dimension Z shown 45 ments , the lens assembly 1502 can comprise an array ofin FIG . 14B can be in a range of about 1 inch to about 5
two -part lenses denoted by the first and second arrays
about 3 inches, e .g ., about 1 . 5 inches in one embodiment.
1502 can comprise an array of two separate lenses denoted
Moreover, the system 1000 can have a mass and weight by the first and second arrays 1502A , 1502B . Each of thesufficiently small so as to enable the user 1275 to easily carry 50 lens arrays 1502A , 1502B can comprise a 4x3 array ofor wear the data acquisition and processing module 1020 at lenses, each of which may correspond to a particular detec
the site . For example , the system 1000 can have a weight in
tor region in the FPA unit 1508 and can define an opticala range of about 0 . 5 pounds to 5 pounds, or more particu -channel of the system 1000 . The lenses used in the first lenslarly, in a range of about 0 .5 pounds to 2 pounds, or morearray 1502A may be different from the lenses used in theparticularly in a range of about 0 . 25 pounds to about 2 55 second lens array 1502B . The lenses can be any suitable typepounds, ormore particularly , in a range of about 0 .25 pounds of lens , including, e . g ., spherical lenses , aspheric lenses , rod
to about 1 .5 pounds. In one embodiment, for example , the lenses, etc . or any combination thereof. For example , thesystem 1000 can weight about 1 pound . In another embodilenses used in the first lens array 1502A can comprisement, for example , the system 1000 can weigh about 0 . 5
aspheric lenses , and the lenses used in the second lens array
pounds . Thus, the embodiment shown in FIG . 11A can be 60 1502B can comprise rod lenses . Although the lens assembly

sized and shaped and configured to have a mass that enables

a human user to easily and effectively manipulate the system
1000 .

FIG . 14C is a perspective cross -sectional view of the1502 shown in FIG . 14C includes two lens arrays , it should

be appreciated that additional lens arrays may be used , e. g .,three lens arrays , four lens arrays, five lens arrays , etc . In

addition , to assist in enabling a small system size , themobile infrared imaging system 1000 shown in FIGS . 14A - 65 diameter of each lens in the assembly 1502 can be less than
14B . The mobile infrared imaging system 1000 can include
one or more movable shutters 1503 ( e. g ., two shutters ) rearabout 0 . 5 " , e .g ., in a range of about 0 . 1 " to about 0 .5 " . The
f-number of each lens can be less than about 2 , e . g ., in a

US 10 ,375,327 B2
49
range of about 0 .2 to 2 , or more particularly , in a range ofabout 0 .5 to 2 , or 1. 0 to 2 or 1. 1 to 2 .
The first lens array 1502A and the second lens array

1502B can be coupled to one another by way of a mounting

50
individual detector elements of the microbolometer arraycan be spaced relatively close together to at least partiallyenable a small , compact system . For example , adjacentdetector elements of the array can be spaced apart by aplate 1584 sized and shaped to support or receive each lens 5 distance in a range of about 7 microns to about 15 microns,

array 1502A , 1502B . For example , the first lens array 1502Aor more particularly in a range of about 9 microns to about
can be mounted on one side of themounting plate 1584 , and13 microns , e . g ., about 11 microns . The individual lenses
the second lens array 1502B can be mounted on an opposite
can be spaced apart by a distance in a range of about 20 mmside of the mounting plate 1584 . The mounting plate 1584 to about 35 mm , e . g . in a range of about 24 mm to about 30
can be machined to have diameter tolerances of about + / - 25 10 mm , e .g ., about 27 .5 mm . Likewise the spatially and spec
microns. The lenses of the arrays 1502A , 1502B can be trally spaced channels may be physically spaced apart by 20
secured to the mounting plate 1584 with a curable epoxy . to 35 mm , 24 mm to 30 mm , etc . Although various embodi
For example , the lenses may fit into opposite sides of holes ments of the system are described as including an FPA
formed in the mounting plate 1584 .
comprising for example a microbolometer array, certain
The optical FPA unit 1508 can comprise any suitable type 15 embodiments comprise a plurality of FPAs. In some embodi
of detector array that is configured to detect infrared radia -ments , a single optical FPA is used . In some embodiments ,tion , for example, greater than 1 micron , or greater than 2 detectors of the optical FPA are configured to detect radia
microns, or greater than 3 microns or greater than 5 microns, tion in the same band of IR wavelengths .
or greater than 6 microns and possibly lower than 20
The on - board processing electronics of the data acquisi
microns, or 15 microns, or 13 microns, or 12 microns or 10 20 tion and processing module 1020 can process the IR optical

microns , in wavelength , and may be cooled or uncooled . In
some embodiments the optical FPA unit 1508 comprises one
or more microbolometer arrays, which may be uncooled . For
example , an array of about 1000x1000 microbolometerdata to detect and /or identify a target species from the IRradiation received at the optical FPA . For example , themodule 1020 can be configured to acquire multispectral
image data and analyze the acquired image data to identify

arrays may be used in the embodiments disclosed herein . 25 the target species. For example , the mobile imaging systems
Microbolometer arrays such as those manufactured by DRS
1000 disclosed herein can be configured to image a 10 mx10

Technologies of Arlington , Va ., and Sofradir EC , Inc., ofm object area at a distance of about 17 m at a resolution of

Fairfield , N . J., may be suitable for the embodiments dis

about 0 .04 m . In this example , any gas leaks that generate aclosed herein . For example , the DRS U8000 FPA manufac - gas cloud of at least about 1. 5 inches in size can be detected
tured by DRS Technologies may be used in some embodi- 30 and /or identified by the system 1000 . The detection andments. In some arrangements, themicrobolometer arraymay
identification methods can be performed substantially inhave a resolution of 1024x768 with a pixel pitch of 12

real-time such that the user can be alerted if any leaks arehaving image detection regions that form part of the array .

As explained above , the infrared image data captured by

microns . The array of lenses can form separate channels

identified .

For example , 12 channels can be included in the 1024x768 35 the system 1000 can be processed on board the data acqui
pixel array on the detector array (microbolometer array ) thatsition and processing module 1020 of the imaging system

are for example 250x250 pixels for each of the 12 channels.
employed . Similarly the number of channels be larger or1000 . One way to provide a smaller system 1000 is tomable gate arrays ( FPGA ) configured to execute methods

for a single channel may be larger or smaller than 250x250

system 1015 . In some embodiments , one or more Applica

Detector arrays having more or less pixels may beprocess the image data using one or more field -program

smaller than 12 and the detection area on the detector array 40 used in the analysis of the images captured by the optical

pixels. For example, the detection region may comprise tion Specific Integrated Circuits (ASICs) may be usedfrom between 100 -200 pixelsx100 -200 pixels per detection instead of, or in addition to , the FPGAs. For example, anregion . For example , the detection region may comprise ASICs chip may include a FPGA. The FPGA (s ) (and /orfrom between 100 - 200 pixelsx100 -200 pixels per detection 45 ASIC ( s )) can be mounted to and electrically coupled with
region , from between 200 - 300 pixelsx200 - 300 pixels per the substrate (s ) 1586 shown in FIG . 14C and can be physi
detection region , or from between 300 -400 pixelsx300 -400 cally located proximate the optical system . For example, thepixels or from between 400 -500 pixelsx400 -500 pixels. FPGA can include logic gates and read access memory
Likewise the detection region for a channel may measure(RAM ) blocks that are designed to quickly implement the
100 - 200 pixels on a side, 200 - 300 pixels on a side , 300 -400 50 computations used to detect the types of gases in a gas cloud .

pixels on a side , 400 -500 pixels on side or larger or smaller.

The small size /weight, and high performance characteristics

In some arrangements , the spectral band of the microboof the FPGA can enable on board computation and analysis

lometer can be about 7 . 5 microns to 14 microns or can bewithin the data acquisition and detection unit 1020 worn or

about 3 microns to 14 microns or 3 to 8 microns. The
The carried by the user. The use of FPGA (or similar electronics )microbolometer array can operate at a frame rate of about 30 55 on board the system 1000 can reduce costs associated with
Hz and can operate at operating temperatures of about - 40° using an off-site central server or larger computing device to
C . to + 70° C . In various embodiments , the microbolometer

array is an uncooled microbolometer that does not include acooler. The sensitivity of the microbolometer at F / 1 can be

conduct the image analysis computations. Advantageously ,the embodiments disclosed herein can enable on -board
computation even though it can be challenging to implement< about 40 mK . The systems 1000 disclosed herein can be 60 complex methods on the limited computing platform thatused to detect wavelengths in a range of about 1 micron toabout 20 microns. For example , the systems 1000 disclosed

herein can be used to detect wavelengths above about 6

microns , e. g ., in a range of about 6 microns to about 18

FPGAs provide .
In addition , enabling computation with one or more

FPGA devices on board the wearable system can also

prevent or reduce communication bottlenecks associatedmicrons, in a range of about 3 microns to about 14 microns, 65 with wirelessly transmitting large amounts of raw data fromor more particularly , in a range of about 7 microns to about
the system 1000 to a remote server or computer. For

14 microns or 3 to 8 microns. In various embodiments, theexample , the infrared optical system 1015 disclosed hereinUS 10 ,375 ,327 B2

52

51
may generate up to about 380 Mbps of raw image data at 30

motion detection and/ or compensation techniques to reduce

frames per second , and the visible sensor 1580 may generate

errors associated with the movements of the user.

about 425 Mbps of raw image data at 30 frames per second .
The resulting data rate of about 800 Mbps is faster than mostconventional wireless technologies. While data compression 5

IV . Additional Examples of a Mobile DAISI

and/ or pre -processing may reduce the raw data rates for thevisible and IR images , in some embodiments , the IR image

Additional examples of mobile divided -aperture infrareding calculations on board the system 1000 ( e .g ., on the dataacquisition and processing module 1020 ) can reduce theoccurrence of or avoid bottlenecks generated by wirelessly
communicating the raw image data to an off -site central
server.

DAISI systems 1000 shown in FIGS. 11A - 14C . Moreover,the imaging components used in FIGS. 15A - 24D may be
used in conjunction with any of the embodiments of FIGS.
1 - 10C . Beneficially, the systems 1000 disclosed herein can
provide various improvements that enable a multi-spectral,

Systemdata may only be compressed by a ratio of about 2: 1. The spectral imaging (DAISI) systems are provided in thisresulting overall data rate of about 192 Mbps may not be
section . For example , the systems 1000 shown in FIGS.
transmitted effectively by conventional wireless communi- 10 15A - 24D may be used with any of the embodiments dis
cations devices. Accordingly , performing the image process
closed above, including , e .g.,the embodiments of themobile

One challenge to implementing a mobile imaging system

snapshot mode imaging system to be worn or carried by ais the power requirements of each component of the system , person .
including, e . g ., the IR optical system 1015 , the visible sensor 20 . As with the above - referenced embodiments , the systems

1580, the processing electronics , the wireless communica tions modules , etc . Advantageously , the mobile infrared
imaging systems 1000 disclosed herein can be configured to1000 of FIGS. 15A -24D can comprise an optical focal planearray ( FPA ) and components that define at least two opticalchannels that are spatially and spectrally different from one

ion batteries, which have relatively high energy densities. In
addition , to help reduce power consumption within theelectronics can acquire multispectral image data represent
ing a target species from the received IR radiation . The

operate by battery power for long periods of time without another. The at least two optical channels can be positioned
recharging or replacing the batteries 1588 . In some arrange - 25 to transfer infrared ( IR ) radiation towards the FPA . A
ments the one or more batteries 1588 can comprise lithium processing unit comprising a processor and /or processing
system 1000, the FPGAs of the data acquisition and pro - optical system and the processing unit can be contained
cessing module 1020 can be advantageously programmed 30 together in a data acquisition and processing module con
such that power consumption is lower than that used for
figured to be worn or carried by a person . In some embodi

other types of processing electronics .
disclosed in this section , the imaging system may be
The systems 1000 disclosed herein can advantageously ments
fixed
ata desired location , such as at a petroleum refinery,
operate for between 8 hours and 36 hours without recharging
oil well site , etc .
or replacing the batteries, or more particularly between 35 anA . System
Overview
about 10 hours and 24 hours without recharging or replacing
FIG . 15A is a schematic perspective view of a system
the batteries. In some embodiments, the system 1000 can
1000 , according to various embodiments . FIG . 15B is a
operate for at least about 12 hours without recharging or
replacing the batteries. The components of the data acqui schematic rear perspective view of the system 1000 shown
sition and processing module 1020 (including the imaging 40 in FIG . 15A . The system 1000 can comprise a data acqui
optics , focal plane array, and on board processing electronics sition and processing module 1020 , which may be similar tomay ) can be configured to operate at relatively low electrical
power levels , e. g ., at power levels in a range of about 3 W
to about 10 W , or more particularly in a range of about 4 W

the data acquisition and processing module described above .
For example , the data acquisition and processing module1020 can comprise a housing 1640 within which the optical

to about 7 W , or in a range of about 4 W to about 6 W , e .g ., 45 components of the system 1000 are housed . The system
about 5 W in some embodiments . The components of the 1000 can include an optical window 1606 and a visible lightdata acquisition and processing module 1020 ( including the imaging system 1680. The window 1606 can be configured
imaging optics , focal plane array, and on board processing
electronics may ) can also be configured to operate at rela -to transmit infrared radiation from the object to the internal
optical components within the housing 1640 . In sometively low overall energy levels for a single charge of the 50 embodiments , the window 1606 comprises germanium . The
batteries 1588 , e . g ., at energy levels in a range of about 60

window 1606 and visible light imaging system 1680 may berange of about 80 Wh to about 95 Wh, or in a range of about

described above .

Watt-hours (Wh ) to about 100 Wh , or more particularly in a

the same as or similar to the window and visible light system
85 Wh to about 90 Wh .
As shown in FIG . 15B , the data acquisition and process
In addition , for each of the embodiments disclosed herein , 55 ing unit 1020 can comprise any suitable number of power
various motion detection and/ or compensation techniques and /or signal connections to a computing device . For
can be implemented to account for relatively large -scale example , the data acquisition and processing unit 1020 canmotions that are induced by the user moving his or her head comprise a data connector 1681 to provide data communi
during use . For example, when a user is visiting a well site cation between the data acquisition and processing unit 1020
or other installation , the user may be continuously walking 60 and a computing device . The data acquisition and processing

and looking in different directions ( e. g ., by rotating his orunit 1020 can also comprise a power connector 1682 toher head ). Additionally , vibration can be introduced by theprovide electrical power to the data acquisition and process

ously change the system 's field of view at a relatively rapid

and processing unit 1020 can comprise a communication

user ' s natural unsteadiness . Such movement can continu

ing unit 1020 . In some arrangements , the data acquisition

rate , which can affect the accuracy of the methods used to 65 module 1024 , which can provide wireless (and / or wired )determine the identity of species in a gas cloud or otherobject . Accordingly , it can be desirable to provide improved

data communication with an external computing device(such as a laptop computer, a tablet computer, a smartphone ,US 10 ,375 ,327 B2

5354etc.). In addition , the data acquisition and processing unit
1020 can comprise one or more batteries to provide power(e. g., an oil well site or other petroleum installation ) or canbe configured for mobile user (e .g ., worn or carried by ato the system 1000 .
The data acquisition and processing unit 1020 can beuser ) .

FIG . 15D is a schematic system diagram of a mobile
configured to be worn or carried by a person. The combi- 5 computing device 1600 having a first port 1602 configured

nation of components described herein can advantageously toto electrically and physically couple with a DAISI system
1000 , such as any of the mobile DAISI systems disclosed
enable the optical components and processing electronics to herein. The mobile computing device 1600 can be any
fit within a small form factor sufficient to be worn or carried
type of mobile computing device , e. g., a computing
by a person . For example , the data acquisition and process 10 suitableconfigured to be worn or carried by a person . For
ing unit 1020 can have dimensions and a weight (or mass ) device
example , the mobile computing device 1600 can comprise aselected so as to be easily worn or carried by a human user mobile, a tablet computing device , a laptop
to any suitable location , e .g ., for conducting infrared imag computersmartphone, etc .
ing and monitoring of potential gas leaks at a petroleum

The DAISI system 1000 can comprise a data acquisition

installation . As shown in FIG . 15A , the data acquisition and 15 and processing unit 1020 as described herein . The dataprocessing unit 1020 can be sized and shaped to fit within a acquisition and processing unit 1020 can be contained inbox- shaped boundary having dimensions length Xxheight and/or coupled with a housing 1640B . The DAISI system
Yxwidth Z . The volume of the data acquisition and pro
1000 can comprise an optical system 1610 contained in thecessing unit 1020 can be in a range of 5 cubic inches to 40 data acquisition and processing unit 1020 and /or the housing
cubic inches, in a range of 9 cubic inches to 30 cubic inches, 20 1640B . The optical system 1610 can include the various
in a range of 10 cubic inches to 30 cubic inches, in a range optical components of the DAISI system that cooperate toof 10 cubic inches to 25 cubic inches, in a range of 10 cubic acquire multispectral image data, including, e.g ., opticalinches to 20 cubic inches , or in a range of 10 cubic inches
filters, lenses, and the optical detector. For example , theto 15 cubic inches. In some embodiments, the volume of the

optical system 1610 can include a plurality of spectrally anddata acquisition and processing unit 1020 can be in a range 25 spatially different optical channels along which infraredof 15 cubic inches to 25 cubic inches, in a range of 17 cubic

inches to 24 cubic inches, or in a range of 19 cubic inches
to 23 cubic inches .
The length X can be in a range of 3 inches to 8 inches , inradiation can be transferred to the detector.

In some embodiments, the data acquisition and processing

unit 1020 and /or the housing 1640B can comprise a pro
cessing unit 1611 having processing circuitry configured toa range of 3 . 5 inches to 6 inches, in a range of 4 inches to 30 analyze the acquired image data to detect and / or identify the

6 inches, or in a range of 5 inches to 6 inches . The height Y

target species . In the illustrated embodiment, the processing

can be in a range of 1 inch to 5 inches, in a range of 1 inch

unit 1611 which analyzes the acquired image data is dis

to 3 inches , in a range of 1 . 5 inches to 2 . 5 inches, or in a

posed in and / or coupled with the data acquisition andrange of 2 inches to 2 .5 inches. The width Z can be in a range

processing unit 1020 and /or the housing 1640B . In otherof 1 inch to 5 inches, in a range of 1 inch to 3 inches, in a 35 embodiments , however, the processing unit 1611 may berange of 1 inch to 2.5 inches, or in a range of 1 inch to 2 disposed in and may form part of the mobile computing
inches . For example , the width Z can be in a range of 1 . 25
device 1600 .
inches to 2 inches, in a range of 1.5 inches to 2 inches, or in
The data acquisition and processing unit 1020 and /or the
housing 1640B can comprise a second port 1603 configured
a range of 1.6 inches to 1. 9 inches .
The weight of the data acquisition and processing unit 40 to mate with the first port 1602 of the mobile computing
1020 can be in a range of 0 .5 pounds to 5 pounds , in a range

device 1600 . The ports 1602 , 1603 can be any suitable typesystem 1000 according to various embodiments . The com -standards, such as the Universal Serial Bus (USB ) standards

ponents of the system 1000 of FIG . 15C may be the same as
the components of FIGS. 15A - 15B . However, in the(e. g ., USB Type- C , USB 3. 1 , etc .), available at usb .org . As
another example , ports 1602, 1603 may be wireless com

of 0 .5 pounds to 3 pounds , in a range of 0 . 75 pounds to 2 .5of data and/or power port. For example, the ports 1602 , 1603
pounds, in a range of 1 pound to 2 .5 pounds, in a range of may comprise ports used as conventional power supply
1 pound to 2 pounds, or in a range of 1.25 pounds to 1 .75 ports, audio ports, or other ports on mobile smartphones
pounds.
45 and / or tablet computing devices . In various embodiments,
FIG . 15C is a schematic front perspective view of a the ports 1602 , 1603 can comply with various industry
embodiment of FIG . 15C can comprise a housing 1640 A that 50 munication ports utilizing any desired wireless technology
is configured for use in conjunction with locations classified(e . g ., by Bluetooth , WiFi, etc . ) such the mobile computing
in Class 1, Division 1 of the National Electrical Code (NEC ), device 1600 and the DAISI system 1000 can communicate
available at necconnect. org . For example , the housing
even without physical connection .

1640A of FIG . 15C can be sufficiently sealed so as to prevent
Beneficially , the arrangement shown in FIG . 15D cangases from entering the housing 1640A . As another 55 enable the user to acquire a plug-and -play mobile DAISI
example , the housing 1640a of FIG . 15C can be of a typesystem 1000 , and can removably connect the system 1000
generally considered to be explosion proof. The processing with his or her personal mobile computing device 1600 . The
electronics and other components within the data acquisition
system 1000 can be pre -loaded with software instructions
and processing unit 1020 can be passively cooled without that cooperate with the operating system of the mobile
requiring external airflow into the data acquisition and 60 computing device 1600 to operate the optical and processing
processing unit 1020 from the outside environs ( e . g., ambicomponents of the mobile computing device 1600 . In otherent air ). In some embodiments , the data acquisition andarrangements , the user can download software to the mobile

processing unit 1020 can be filled with a gas to cool theinternal components . For example , in some embodiments ,computing device 1600 , and the downloaded software

instructions can control the operation of the DAISI systemdata acquisition and processing unit 1020 and the housing 65 1000 . In some embodiments , the DAISI system 1000 com

1640A can be filled with nitrogen gas . The system 1000

prises both the optical components and the processing

shown in FIG . 15C can be fixed in a permanent locationelectronics ( e.g ., the data acquisition and processing unitUS 10 ,375 ,327 B255561020 ), such that the system 1000 can perform image acqui-ticity of the user associated with the mobile computing

sition and data processing to detect and /or identify the target
species. The system 1000 can transmit data regarding thedetected and / or identified species to the mobile computing

device 1600 . If the mobile computing device 1600 is verified
by the electronic circuitry 1616 , the electronic circuitry 1616
can comprise switching circuitry that permits the acquired

device 1600, which can display the information to the user 5 image data to be transferred to themobile computing device
by way of a suitable user interface (e . g ., a display and/ or a1600 through the port. In some embodiments , the electronic
speaker ). In some embodiments , the DAISI system 1000
circuitry 1616 may be part of the processing unit 1611.

may include user interfaces ( e . g ., a display and/ or a speaker )system 1000 illustrated in FIG . 15D can accordingly
such that the system 1000 can directly alert the user to be The
sufficiently
miniaturized so as to be usable with small
detected and/or identified species, even when the mobile 10 mobile computing
devices, such as mobile smartphones andcomputing device 1600 is not coupled to the DAISI system
tabletcomputers.
In
various embodiments , for example , the1000 . As just one example , the DAISI system 1000 may
housing 1640B in which the optical system 1610 andinclude a display such as a strobe light and / or a speaker that
unit 1611 are disposed may have a volume in aalerts the user (i.e., provides an alarm for the user ) upon 5 processing
range
of
0
.
25
cubic inches to 10 cubic inches, in a range of
detection of one ormore target species and /or upon detection 15 range
0 .25 cubic inches to 8 cubic inches, in a range of 0 .5 cubicof one or more targets species at greater than a predeter
inches to 8 cubic inches, in a range of 0 .5 cubic inches to 5
mined threshold concentration .
In other embodiments , the DAISI system 1000 may
include only the optical components (e . g ., the optical win -cubic inches , in a range of 0 .5 cubic inches to 3 cubic inches ,or in a range of 0 . 5 cubic inches to 2 cubic inches .

dow , a plurality of optical filters, a plurality of lenses, and an 20 The system 1000 can be miniaturized in various ways. In
optical detector), and the processing electronics may be some embodiments , the optical system and/or the processing

housed in the mobile computing device 1600. In such anunit can be fabricated using wafer -scale or chip -scale pro

acquire image data from the scene (with or without pre -Section IV . E . 1 , a filter array of the optical system can bearrangement, the DAISI system 1000 can be configured to

cessing techniques. For example , as explained herein inprocessing techniques ), and can transmit the acquired image 25 patterned using semiconductor processing techniques, suchdata to the mobile computing device 1600. The processing
electronics of the mobile computing device 1600 can be

as deposition , lithography, and etching. In some embodi
ments, the lens array and the detector array may also be

configured with software instructions that, when executedmanufactured using such wafer - scale or chip - scale techdetected and/or identified target species can be transmitted

computing device 1600 , according to another embodiment.

to the user by way of a user interface, e. g., a display and /or

In FIG . 15E , the DAISI system 1000 is integrated within a

optical detector and optical components defining a pluralityof spectrally and spatially different optical channels (such asa plurality of filters and a plurality of lenses spaced from theherein . The mobile computing electronics 1601 can com
prise processing electronics configured to control the opera
tion of a conventionalmobile computing device 1600 . For

by the processing electronics , processes the acquired image niques .
data to detect and /or identify one or more target species . The 30 FIG . 15E is a schematic system diagram of a mobile

a speaker. In some embodiments , the housing can comprise housing 1640C that defines the body of the mobile comput
the optical system and a processing unit having processing ing device 1600 . The mobile computing device 1600 of FIG .
circuitry configured to analyze the acquired image data to 35 15E can comprise any suitable type of mobile computing
device , such as a mobile smartphone or a tablet computer.
detect and/or identify the target species.
Thus, in various embodiments, the DAISI system 1000 The DAISI system 1000 and mobile computing electronics
can comprise a housing 1640B in which the optical system
1601 may be disposed together within the housing 1640C of
1610 is disposed . The optical system 1610 can comprise the the mobile computing device 1600. The DAISI system 1000
optical components described herein , including, e. g., an 40 may comprise any of the mobile DAISI systems disclosed

filters). Each optical channel of the plurality of opticalexample , the mobile computing electronics 1601 can com

channels can be positioned to transfer IR radiation incident 45 prise various communications platforms, including circuitryon the optical system 1610 towards the optical detector, asconfigured to transmit and receive cellular data ( e . g ., voice

explained herein . The second port 1603 can be in data

data and /or multimedia data ), wireless data packets, etc . The

communication with the optical detector and configured tomobile computing electronics 1601 can comprise various

electrically and physically connect to the mobile computing

other applications used in mobile devices, such as mobile

device 1600 to transmit image data acquired by the optical 50 smartphones and /or tablet computers .

detector to the mobile computing device 1600 . In addition ,FIG . 16A is a schematic diagram of a DAISI system 1000

the housing 1640B can comprise electronic circuitry 1616 inthat can be used in accordance with any of the embodiments

1603, e. g., by way of the first port 1602 .

spatially different from one another, as explained herein . The
optical system 1610 can include a filter 1620, a lens 1622

communication with the second port 1603. The electronic
disclosed herein . The system 1000 of FIG . 16A can comprise
circuitry 1616 can be configured to receive an indication
the optical system 1610 in electrical communication with thefrom , or to transmit an indication to , the mobile computing 55 processing unit 1611 . FIG . 16A illustrates a single opticaldevice 1600 indicating that the mobile computing device
channel 1626 ; however, the system 1000 can include a
1600 is electrically and physically connected with the port plurality of optical channels 1626 that are spectrally and

The electronic circuitry 1616 of the housing can be

configured to verify an identifier transmitted from the 60 comprising a plurality of lens elements L1, L2 , L3 , anmobile computing device 1600 to authenticate that the optical window 1623 , and an optical detector 1624 . The filter
mobile computing device 1600 is authorized to receive the 1620 can comprise any of the filters described herein , which
acquired image data . For example, when the user connects may be infrared filters. Although only a single filter 1620 is
the second port 1603 with the first port 1602, corresponding
illustrated in FIG . 16A , the DAISI system 1000 can com
circuitry in the mobile computing device 1600 can send an 65 prise a plurality of spatially and spectrally distinct filters
identifier to the electronic circuitry of the housing to request

access to the captured image data and to verify the authen

which may be arranged in a two -dimensional array, as

explained herein .

US 10 ,375 ,327 B2

57

The lens 1622 of the illustrated optical channel 1626 can58
adjust the focal length (e .g., the magnification power) of thecomprise a plurality of lens elements L1, L2, L3 that aredisposed adjacent or with respect to one another along thelens in response to control signals ( generally locally by
circuitry in system 1000 or remotely by external devices andoptical axis , e .g ., between an object 1625 (e .g ., a gas cloud )received by system 1000 over a communications channel).

and the detector 1624 . As explained herein , the lens ele - 5
FIG . 16D is a schematic front perspective view of thements L1, L2 , L3 can be selectively dimensioned so as tooptical system 1610 . As shown in FIG . 16D , the opticalimprove the sensitivity of the optical system 1610 andsystem 1610 can comprise the shutter 1621, a support body

improve image quality. As with the filters 1620 , a pluralityof lenses 1622 can be arranged in a two - dimensional array

1626 , and the optical detector 1624. In FIG . 16D , the opticalcomponents such as the filter 1620 and the lens 1622 can be

and can be disposed with respect to or spaced from the filters 10 disposed in the support body 1626 . FIG . 16E is a schematic

1620 along the optical axis . The opticalwindow 1623 can bedisposed rear of the lens 1622 , and the detector 1624 can bedisposed rear of the optical window 1623 and can beperspective cross -sectional view of the optical system 1610 ,with the shutter omitted for illustration purposes. FIG . 16E

illustrates the array of filters 1620 and the lens elements L1,

configured to transduce acquired infrared image data into

L2, L3 of the lenses 1622 being supported by the support

1624 can comprise one or a plurality of microbolometers .

detail below .

electrical current. The detector 1624 can be any suitable type 15 body 1626 . As shown in FIG . 16E , the array of filters 1620
of detector including those disclosed herein , such as an
can be fitted within apertures of a lens holder 1627 . Addi
optical focal plane array (FPA ). As an example , the detector
tional features of the optical system 1610 are described in

The detector 1624 can be in electrical communication withAs shown in FIG . 16E , the lens elements L1 may gener
the processing unit 1611 . Variation in the optical design is 20 ally lie in a common plane . Similarly , the lens elements L2 ,possible . For example , additional elements may be included

L3 and the filters 1620 may generally lie in their own

such as baffles and/ or stops. Filters such as filters 1620 andother filters may be combined with the lenses and /or win -common planes . If desired , some or all of the opticalcomponents ( e .g ., lens elements L1, L2 , and L3 and filters
dow .
1620 ) associated with one or more of the spectral channels
FIG . 16B is a schematic front perspective view of the 25 may be offset from the optical components of the remaining
DAISI system 1000 with the housing removed for purposes spectral channels in a direction along the optical axis ofof illustration only . FIG . 16C is a schematic rear perspective
system 1000 (i.e ., in a direction normal to the common
view of the system 1000 of FIG . 16B . As shown in FIGS. planes ). In general, any of the channels may be offset in any
16B and 16C , a shutter 1621 can be disposed rear of an
direction ( towards or away from the detector ) and by any

optical window 1606 . As explained below , the shutter 1621 30 amount, as desired . As examples, the optical components of

can comprise a rotary shutter which rotates to switch
between one or more calibration modes and an operational
imaging mode. The optical system 1610 can be disposed rear

one or more channels may be offset closer to the detector
1624 by approximately 10 microns , by approximately 10 - 20
microns, approximately 20 microns, approximately 20 - 30of the shutter 1621 , and the processing unit 1611 can be

microns , approximately 30 microns , approximately 10 - 30

1610 can include the optical components described herein

10 - 100 microns, more than approximately 100 microns , lessdisposed rear of the optical system 1610 . The optical system 35 microns, approximately 10 - 50 microns, approximatelythat enable the acquisition of multispectral infrared image than 100 microns, less than 50 microns, less than 30
data . The processing unit 1611 comprises processing elec microns, more than 30 microns, more than 50 microns, etc .
tronics that can be configured to process the acquired
The optical components of one or more channels may also
multispectral infrared image data to detect and /or identify a 40 be shifted away from detector 1624 by similar amounts .
target species. For example , the processing unit 1611 can
In at least some arrangements, the position of filters 1620

comprise or be similar to the processing unit 1021 of FIG .
12 and the associated disclosure .

relative to the lens elements L1, L2, and L3 may also be

altered on a per -channel basis . As an example , a first set of

In the examples of FIG . 16B and also FIG . 15C , visible
filters 1620 may be behind one or more of lens elements L1,light imaging system 1680 is illustrated as being closely 45 L2 , and L3 for some channels and , in other channels , apositioned to ( e . g ., just above ) a divided -aperture infrared
second set of filters 1620 may be disposed in front of the lens

spectral imaging (DAISI) system . If desired , other suitableelements L2 , L2, and L3 .
arrangements may be provided . As an example , the visible
Shifting the optical elements of at least one spectral
light imaging system 1680 may be omitted entirely . As
channel closer to ( or farther from ) detector 1624 may
another example , housing 1640A (see FIG . 15C ) may be 50 facilitate imaging of a wider or particular range of infrared

divided into two or more sections, one ofwhich may containwavelengths . In some embodiments , the lenses of one ora visible light imaging system module and one of which may more spectral channels may be towards detector 1624 bycontain a DAISI system . Such an arrangement may facilitate
approximately 20 microns. A shift of lens position about 20
servicing of system 1000 , including replacing the visible microns may enable those channels to properly focus inci
light imaging system 1680 with another visible light imag - 55 dent IR radiation having wavelengths between 3 and 8
ing system depending on a user' s needs and desires . As an
microns. The remaining (i.e ., non - shifted ) lenses may prop

example , system 1000 may be provided to enable a user

erly focus incident IR radiation have longer wavelengths ofswap out at least part of the visible light imaging system

about 8 to 14 microns.

1680 for one having a zoom lens . System 1000 may facili1680 relatively separate from the DAISI system and /or

As an example, the lens elements L1, L2, and L3 of the
9 , and 12 in the FIG . 19 perspective ) may be offset from thetate such a swap by providing visible light imaging system 60 four channels in the corners of system 1000 (channels 1 , 4 ,contained in a separate section of housing 1640A .

other channels by approximately 20 microns towards the

Visible light imaging system 1680 may include any infrared detector 1624 . The offset of the four channels in thedesired focal length lens including zoom lenses with varying corners may enable the offset channels to image objects
focal lengths. A zoom lens in the visible light imaging 65 having different (e .g., shorter) wavelengths than the remain
system 1680 may include an actuator,motor, or other similar ing channels. In particular, the offset channels may propa
device that drives lens elements within the zoom lens to gate shorter wavelength light. The index of refraction of theUS 10 ,375 ,327 B2
59

60

material used in L1, L2 , L3, may vary with wavelength . As

infrared imaging aperture 1709 and to the optical elementsa result , the focal length of the imaging optics in thesechannels may be shorter. Without reducing the distance
between the imaging optics and the detector array, the image(e. g., the filters , lenses, etc .) of the system 1000 . The system
1000 can also include a visible imaging aperture 1711
through which at least visible light from the object passes .

will be out of focus. Likewise, by reducing this distance to 5 The visible imaging aperture 1711 can be transparent to at

the detector array, the image may be more in focus. Accord ingly , this distance may be reduce by moving the lenses( e .g ., L1, L2, L3 ) closer to the detector array and thereby

providing a better focus for shorter wavelengths such as

least visible light such that visible light from the object
passes through the aperture 1711 and to the visible light
imaging system 1680 , which may comprise a visible lightsensor to capture visible light image data from the object .

those extending from 8 microns down to 3 microns ( e . g ., in 10

Processing electronics can be provided in the processing

comparison to wavelength 8 to 14 microns ). Accordingly,

unit 1611 to control the operation of the drive system 1708 .

the offset along the optical axis may provide increase focus

The processing electronics can comprise one or more pro

for the different wavelengths of incident infrared radiation
cessors that are programmed to instruct the motor to rotate
onto detector 1624 . The offset along the optical axis may the shaft 1705 about its axis of rotation . Rotation of the shaft
thus reduce differences in focus for channels operating in 15 1705 and shutter body 1701 causes the regions 1702 , 1703,
different wavelengths.
1704 , 1710 to also rotate . To calibrate the system 1000 , thedrive system 1708 can rotate the shutter body 1701 such that
B . Rotary Shutter

As explained above with respect to FIGS . 1 -4 , it can be

the first reference region 1702 is approximately aligned withcan utilize one or more shutters that have a known and /ormeasured temperature . To calibrate the system , the one orregion 1702 can be actively maintained at a predetermined
temperature by one or more heating or cooling elements . In

more shutters (or other reference surface ( s )) can be placedsome embodiments , the first temperature of the first refer

important to provide one or more reference surfaces for the infrared imaging aperture 1709. The first reference
calibration of the DAISI system . For example , as explained 20 region 1702 can be at a known or measured first tempera
above, in some embodiments , the systems disclosed hereinture . For example , in some embodiments , the first referencealong the optical axis of the system , and the optical detector 25 ence region 1702 can be monitored (with or without activearray can acquire infrared image data of the shutter. The
measured value at the detector array can be used to estimate

the gain and/ or offset of the pixels so as to accurately

heating or cooling) by one or more temperature sensors ( e. g .,thermocouples , etc . ). Thus, the system 1000 can accurately

measure or otherwise store the approximate temperature ofestimate concentrations of objects ( such as a gas cloud ). In
the first reference region 1702 . When the first referencesome embodiments , as explained above , the system can 30 region 1702 is aligned with the infrared imaging aperture

utilize a plurality of shutters or surfaces that are at a1709, the optical detector can acquire first calibration image

corresponding plurality of known and / or measured tempera

data representative of the first temperature of the firsttures . The absolute difference in temperature between the
shutters or surfaces can be measured at the detector array,reference region 1702.
Similarly , the drive system 1708 can be activated to cause

and , as explained herein , the measured temperature differ - 35 the shutter body 1701 to rotate such that the second reference can be utilized to measure temperatures at the object.

ence region 1703 is approximately aligned with the infrared

FIG . 17A is a front plan view of the shutter 1621

imaging aperture 1709 . As with the first reference region

illustrated in FIGS. 16B and 16D . The illustrated shutter

1621 can comprise a rotary shutter assembly configured to1702 , the second reference region 1703 can be actively

maintained at a second predetermined temperature by one orrotate about an axis parallel to the optical axis of the system . 40 more heating or cooling elements . In some embodiments ,The shutter 1621 (or shutter assembly ) can comprise athe second temperature of the second reference region 1703

shutter frame 1706 and a shutter body 1701 rotatably
mounted to the shutter frame 1706 . For example , the shutter
1621 can comprise a shaft 1705 disposed within an apertureby one or more temperature sensors ( e .g ., thermocouples ,can bemonitored (with or without active heating or cooling)etc .). Thus, the system 1000 can accurately measure orof the shutter frame 1706 . A shutter drive system 1708 can 45 otherwise store the approximate temperature of the second
be activated to cause the shaft 1705 to rotate about an axis
reference region 1703 . When the second reference region

parallel to the optical axis of the system . The drive system

1703 is aligned with the infrared imaging aperture 1709 , the1708 can comprise any suitable drive components for

optical detector can acquire second calibration image data

imparting rotation to the shaft 1705 . For example , the drive

representative of the second temperature of the first refersystem 1708 can comprise a drive motor and one or more 50 ence region 1703, which may be different from the first

gears ( or other clutch mechanisms) to impart rotation to thetemperature of the first reference region 1702 by a known

shaft 1705 . The shaft 1705 can be secured to the shutter body and/or predetermined amount.
1701 such that rotation of the shaft 1705 imparts rotation toDuring operation (e . g ., when the calibration is complete
the shutter body 1701 .
and the user wishes to acquire image data of an object), theThe shutter body 1701 can comprise a plurality of sepa - 55 drive system 1708 can cause the shutter body 1701 to rotate

rate and distinct regions 1702, 1703 , 1704 , 1710 spaced
circumferentially from one another on the shutter body1701. In the illustrated embodiment, for example, the shutter

such that the infrared imaging region 1704 is approximatelyaligned with the infrared imaging aperture 1709 of the
DAISI system 1000 . The visible imaging region 1710 ofthebody 1701 can comprise a first reference region 1702, a
shutter body 1701 can be spaced relative to the infrared
second reference region 1703 , an infrared imaging region 60 imaging region 1704 of the shutter body 1701 such that,
1704 , and a visible imaging region 1710 . In some embodi- when the infrared imaging region 1704 is aligned with thements, the first and /or second reference regions 1702 , 1703 infrared imaging aperture 1709 of the system 1000 , themay be opaque to infrared radiation . The system 1000 can

include an infrared imaging aperture 1709, which can cor -visible imaging region 1710 is also aligned with the visible

imaging aperture 1711 of the system 1000 . When the infra

respond to the front aperture of the system 1000 . For 65 red imaging region 1704 and the visible imaging region

example , during operation of the system 1000, at least

infrared radiation from the object can pass through the1710 are aligned with the respective apertures 1709, 1711 ,infrared radiation from the object can pass through theUS 10 ,375 ,327 B2
61
infrared imaging region 1704 and the infrared imaging
aperture 1709 and to the infrared imaging optics. Similarly,
when the infrared imaging region 1704 and the visible
imaging region 1710 are aligned with the respective aper

62
Aswith the embodiment of FIG . 17A , in the embodimentof FIGS. 17B - 17D , the shutter 1621A can be used tocalibrate the DAISI system 1000 . For example , the first
shutter body 1701A can be at a known or measured firsttures 1709, 1711 , visible light radiation from the object can 5 temperature . For example , in some embodiments , the firstpass through the visible imaging region 1710 and the visible

shutter body 1701A can be actively maintained at a predeimaging aperture 1711 and to the visible light imaging

termined temperature by one or more heating or coolingelements . In some embodiments , the first temperature of thesystem 1680 .
The shutter body 1701 may comprise any suitable number
first shutter body 1701A can be monitored (with or withoutof reference regions, and the reference regions may be 10 active heating or cooling ) by one or more temperature

disposed at any suitable position on the body 1701 . Moreover, the shutter body 1701 may include embedded process

sensors (e. g., thermocouples, etc .). Thus , the system 1000
can accurately measure or otherwise store the approximate

components , such as temperature sensor(s ), the drive system

shutter body 1701A is aligned with an infrared imaging

ing electronics for controlling the operation of various

temperature of the first shutter body 1701A . When the first

1708 , active heating and /or cooling elements , etc . Advanta - 15 aperture 1709, the optical detector can acquire first calibra

geously, the embodiment of FIG . 17A enables the DAISI

systems 1000 disclosed herein to efficiently calibrate thetion image data representative of the first temperature of thefirst shutter body 1701A .
Similarly , the second shutter body 1701B can be at aa front view of the shutter 1621A in a closed configuration .

ormore heating or cooling elements . In some embodiments ,system by rotating a single rotary wheel shutter.
known or measured second temperature. For example , inC . Dual Shutters
FIG . 17B is a schematic perspective exploded view of a 20 some embodiments , the second shutter body 1701B can be
shutter 1621A according to some embodiments . FIG . 17C isactively maintained at a predetermined temperature by one

FIG . 17D is a front view of the shutter 1621A in an open

the second temperature of the second shutter body 1701B

configuration . The shutter 1621A can be used with any of thecan be monitored (with or without active heating or cooling )DAISI systems 1000 disclosed herein .
25 by one or more temperature sensors (e . g ., thermocouples,

The shutter 1621A can include a drive system 1708
The first and second drive elements 1708A , 1708B can

etc .). Thus, the system 1000 can accurately measure or
shutter body 1701B . When the second shutter body 1701B

comprising first and second drive elements 1708A , 1708B .

otherwise store the approximate temperature of the second

comprise a motor configured to impart rotation to corre -is aligned with an infrared imaging aperture 1709 , thesponding first and second shutter bodies 1701A , 1701B . The 30 optical detector can acquire second calibration image data

first and second drive elements 1708A , 1708B can be spaced

representative of the second temperature of the second

from one another along a lateral direction . The first andshutter body 1701B .

second drive elements 1708A , 1708B can have drive shaftsconnected to respective drive gears 1721A , 1721B , each of

In FIG . 17C , the shutter 1621A is illustrated in the closed
configuration , in which one or more of the shutter bodies(not shown ) of the motor ( to which the gears 1721A , 1721B
are connected ) can be disposed in corresponding recesses

ture 1709 . In the closed configuration , the shutter body1701 A can be disposed in a region laterally between the two

1725 of a frame 1720 . As shown in FIGS. 17C and 17D ,axes of rotation along the lateral direction. In the illustrated

frame 1720 .

bodies 1701A , 1701B with the aperture 1709 . For example ,which may have a plurality of gear teeth . The drive shafts 35 1701A , 1701B are aligned with the infrared imaging aper

drive gears 1721A , 1721B can be disposed above the shutter
arrangement, both shutter bodies 1701A , 1701B are aligned
bodies 1701A , 1701B . The drive gears 1721A , 1721B can be 40 with the aperture 1709 . In other arrangements , the drive
separated from the drive elements 1708A , 1708B by thesystem 1708 can independently align each of the shutter

Slip rings 1722A , 1722B can be disposed in correspondthe system 1000 can rotate the first shutter body 1701A to be

ing holes 1726 of the frame 1720 . The slip rings 1722A ,aligned with the aperture 1709 to acquire a first calibration
1722B can be configured to rotate within the holes 1726 in 45 measurement, as illustrated in FIG . 17D . At the same time,some embodiments . Respective gear shafts 1727A , 1727B

the system 1000 may rotate the second shutter body 1701B

can be mounted to corresponding flanges of the slip rings

into its closed position (i.e ., to be aligned with the aperture

1722A , 1722B . The first and second shutter bodies 1701A ,1709) or may rotate the second shutter body 170B into its

As shown in FIGS. 17C and 17D , the drive gears 1721A ,closed configuration , the shutter body 1701B can be dis

the drive elements 1708A , 1708B can be activated to cause

drive system 1708 can rotate both shutter bodies 1701A ,cause the shutter gears 1723A , 1723B to rotate . For

infrared imaging aperture 1709, as illustrated in FIG . 17D .

1701B can be secured to corresponding shutter gears 1723A ,open position . To acquire a second calibration measurement,
1723B . Retaining washers 1724A , 1724B can be provided to 50 the system 1000 can rotate the first shutter body 1701A tosecure the shutter bodies 1701A , 1701B and gears 1723A ,expose the aperture 1709 , and can rotate the second shutter
body 1701B to be aligned with the aperture 1709 . In its
1723B to the gear shafts 1727A , 1727B .
1721B can be operably engaged with the shutter gears posed in the region laterally between the two axes of rotation
1723A , 1723B . To rotate the shutter bodies 1701A , 1701B , 55 along the lateral direction . When calibration is complete , therotation of the drive gears 1721A , 1721B , which in turn can

example , gear teeth of the drive gears 1721A , 1721B can

1701B into their respective open positions to expose theAs explained above , infrared radiation from the object (suchmesh or interleave with corresponding gear teeth of the 60 as a gas cloud ) can enter the aperture 1709 and impinge upon

shutter gears 1723A , 1723B . Rotation of the shutter gears

the imaging optics, such as the filters 1620 , lenses, etc .

1723A , 1723B can cause the shutter bodies 1701A , 1701B

D . Lens Arrays

to rotate about respective axes which are parallel to the
The divided - aperture infrared spectral imaging (DAISI)
optical axis of the DAISI system 1000 . For example , rota systems described herein , including the DAISI systems
tion of the shutter bodies 1701A , 1701B can cause the slip 65 disclosed in Section II above and the mobile DAISI systems
rings 1722A , 1722B to rotate within the holes 1726 in some disclosed in Section III above , may include features such asarrangements .
arrays of lenses formed with monolithic lens substrates ,US 10 ,375 ,327 B2
63
arrays of lenses formed with individual lens substrates,

1000 is configured to detect and may be formed from glass

patterned optical filters , arrays of individual optical filters ,substances , crystal substances , and /or other suitable sub

and cooling modules coupled to components such as an

stances.

optical focal plane array (FPA ) unit and a lens assembly.

Lens substrate 2501 may be molded into desired shapes

assembly 1502 including a lens array 1002 . As disclosed inconnection with FIG . 18A , each lens of the lens array 1002
can at least partially define or be included in an opticalformed by molding processes ). Molding process may beparticularly suitable when lens substrate 2501 is formed

As described herein , DAISI systems may include a lens 5 (1.e ., individual lens portions 2502A , 2502B , etc . may bechannel to be imaged by the FPA unit 1008 .

from glass or other amorphous materials . Lens substrate

2501 may also be ground or cut into desired shapes (i.e .,individual lens portions 2502A , 2502B , etc . may be formed
In at least some embodiments, a baffle 2500 may be 10 bydiamond cutting or other methods ). Grinding and cutting
provided (e.g ., in mounting plate 1584 ) to reduce or block processes
may be particularly suitable when lens substratestray light. Baffle 2500 may reduce or block light that enters2501 is formed from crystalline or other similar substances.
via one optical channel (which may be associated with one
Ingeneral, combinations of molding , grinding , cutting , andlens) from exiting the lens assembly 1502 via another optical 15 othersimilar processes may be used to shape lens substratechannel (which may be associated with another lens). Baffle
2501. regardless of whether lens substrate 2501 is formed
2500 may be formed of any desired materials and using any
from amorphous , crystalline , or other substances .
jues. As one example , baffle 2500 may
2 . Individual Lens Substrates
include a metal sheet with lens openings formed by
As shown in FIG . 18C as well as FIGS . 18D - 18E , lensmechanical or laser cutting . If desired , baffle 2500 may be 20 array 1002 may be formed from an array of individual lensformed with a material having a coefficient of thermal

expansion (CTE ) that is similar to or thatmatches the CTEof substrate 2501 . By having similar or matching CTE ' s ,baffle 2500 and substrate 2501 may maintain optical per formance across a wide range of temperatures.

substrates such as lens substrates 2504A , 2504B , etc . ( also

referred to herein as individual lenses). By forming lensarray 1002 from an array of individual lenses, fabrication of
the lens array 1002 may be simplified (i.e ., in at least some
25 scenarios, it may be simpler to produce multiple individual

1. Monolithic Substrates for Lenses
As illustrated in FIGS. 18A and 18B , lens array 1002 may
be formed from one or more monolithic substrates 2501 . In

lenses than a monolithic substrate including multiple lensportions). The individual lenses 2504A , 2504B , etc . in lens

other words, multiple lenses ( i. e ., some or all of the lenses

including those described herein in connection with monoarray 1002 may be formed from any suitable materials

in lens array 1002 may share a single common substrate . A 30 lithic lens substrate 2501. The individual lenses 2504A ,monolithic substrate may be formed in such a manner as to2504B , etc . in lens array 1002 may be formed using any

provide lenses associated with multiple optical channels . As suitable techniques including those described herein in con
shown in FIG . 18B , all of the lenses of lens array 1002 may nection with monolithic lens substrate 2501.
be formed from a single monolithic substrate 2501. In thisLens array 1002 , whether formed from individual lensmanner, monolithic lens substrate 2501 may include por - 35 substrates or a monolithic lens substrates, may be mounted
tions corresponding to a lens for each of the optical channels

in lens holder 1584 ( also referred to herein as a mounting

in a DAISI system . For example , monolithic substrate 2501

plate ). Lens holder 1584 may be formed from any desired

While FIG . 18B illustrates monolithic lens substrate 2501
as having multiple lens portions formed from respective
shaped (e . g ., spherical) portions of the substrate, monolithic

some embodiments, lens holder 1584 may be formed with amaterial having a coefficient of thermal expansion (CTE )that is similar to or that matches the CTE of the lenses in lens

may include a lens portion 2502A corresponding to a first materials and using any desired techniques. As one example ,optical channel, lens portion 2502B corresponding to a lens holder 1584 may be formed from metal with lens
40 openings formed by mechanical or laser cutting . In at least
second optical channel, etc .
lens substrate 2501 may also be a gradient- index -basedarray 1002 . By having similar or matching CTE 's , lens

optical substrate (i. e ., lens substrate 2501 may form GRIN 45 holder 1584 and the lenses in lens array 1002 may maintainlenses ). In such arrangements , monolithic substrate 2501
may be formed with flat surfaces, but have variations ofrefractive index of the substrate material that forms thelenses , in a manner that focuses lights through each of the

optical performance across a wide range of temperatures. In
other words and by having similar or matching CTE 's , thelens holder is able to maintain optical alignment of lensportions 2502A , 2502B , etc . or individual lenses 2504A ,lens portions 2502A , 2502B , etc . in the same manner as 50 2504B , etc . even if the temperature of the overall system isconventionally shaped lens. Lens substrates such as mono varied . As a specific example , lens holder 1584 may belithic substrate 2501 may also be formed with a combination

formed from KOVAR® ( a nickel- cobalt ferrous alloy havingof lens- forming shaped portions and lens- forming variations

substantially similar CTE characteristics as germanium ).

KOVAR® may have a CTE of approximately 5 .5x10 - 6/of refractive index of the substrate material.
Lens substrate 2501 may be formed from any suitable 55 degree K ( at temperatures below 200 degrees C .), whereasmaterials including, but not limited to , silicon , germanium ,chalcogenide glass, calcium fluoride , zinc selenide , zincborosilicate glass may have a CTE of between approxi
mately 3 to 6x10 - /degree K ( at temperatures below 200

sulfide , gallium arsenide , cadmium telluride , BLACK DIA -degrees C .).

MOND - 2TM (a chalcogenidemade of an amorphousmixture
FIG . 18D shows an exploded perspective view of theof germanium , antimony, and selenium ), AMTIRTM ( amor - 60 imaging system of FIG . 18C . FIG . 18E shows a crossphous material transmitting infrared radiation ), thallium

bromoiodide, IR fused silica , sodium chloride , potassium

sectional view of the imaging system of FIG . 18C . As shownin FIGS. 18D and 18E , lens array 1002 may includemultiple

bromide, potassium chloride , sapphire , crystal quarts , UV optical layers such as front lenses 2504A , 2504B , etc .;fused silica , barium fluoride , calcium fluoride , magnesium
middle lenses 2506A , 2506B , etc . ; and rear lenses 2508a ,fluoride , lithium fluoride , etc . Lens substrate 2501 may 65 2508B , etc. Additionally , lens array 1002 may include
preferably be formed of materials that are transparent towashers or other mounting structures 2514 and 2516 that
infrared wavelengths and /or other wavelengths that system
hold the front, middle, and rear lenses together when lens

US 10 ,375 ,327 B2
65

66

array 1002 is assembled with lens holder 1584 . Furthermore , pass at least one wavelength orwavelength range or band or
the imaging system may include a filter housing 2510 set of wavelengths or set of wavelength ranges or bands inincluding an array of filters 2512A , 2512B , each of which the infrared range of approximately 1 to 20 microns wave
corresponds to a particular optical channel and respective set length , in the infrared range of approximately 7 - 14 microns ,of front, middle , and rear lenses . In at least some embodi- 5 or in the infrared range of approximately 3 - 14 microns or
ments , the front, middle , and rear lenses may be recessed 3 -8 .5 microns .As an example , one ofmore spectral channels
into the front of lens holder 1584 and secured by filter
system 1000 may have an infrared filter (which may behousing 2510 . The arrangement of FIG . 18D may reduce the informed
multiple filters ) that passes infrared light inpossibility of stray light (i. e ., light that enters a first optical both a 3 frommicronmicron range and a 6 to 8 micron range
channel and crosses over into a second optical channel). In 10 (or a 7 micron toto8.45 micron
range , or a 7 to 8 micron range ,other words, lens holder 1584 may operate as a stray lightorothersuitable
range
)
.
In
other words, the system 1000
blocking baffle when the lenses are recessed within lens may include a dual-notch infrared
filter in at least one
holder 1584 .
spectral channel. Such a dual-notch filter may be particularly
The middle and rear lenses 2506 and 2508 illustrated in
FIG . 18D may be formed using materials similar to those 15 useful in detecting a particular gas' s infrared signature ( suchdescribed herein in connection with lenses 2504 . In addition,
the middle and rear lenses 2506 and 2508 may be formed

as methane ) even without information from other spectral

channels in system 1000 . A notch filter may generallyusing manufacturing techniques similar to those describedattenuate wavelengths that fall outside their pass range . As

herein in connection with lenses 2504. In at least somean example, a dual-notch filter that passes infrared light infront and rear surfaces , while the front and rear lenses 2504
and 2508 have curved front and rear surfaces. In at least

attenuate wavelengths shorter than 3 microns, wavelengths
between 4 and 6 microns, and wavelengths longer than 8 . 5

some other embodiments some or all of the front, middle ,microns. Infrared blockingmaterial 2258 may help to reduce

embodiments , middle lenses 2506 may have relatively flat 20 both a 3 to 4 micron and a 6 to 8 .5 micron range may

and rear lenses are formed from GRIN lenses .
optical crosstalk or stray light, in which infrared light
E . Filter Arrays
25 entered a first optical channel but undesirably crosses overAs discussed herein , gas and chemical imaging systems to a second optical channel.
may include an array 2550 of optical filters, such as array
Individual optical filters 2512A , 2512B , etc . may be

2550 illustrated in FIG . 19 , that define spectrally -distinct formed on substrate 2501 using any suitable technique or
combination of techniques. As examples, the optical transwavelength or wavelength range or band or set of wave - 30 mission
characteristics of individual optical filters may be
sub - images. These optical filters may each pass a distinct

lengths or set of wavelength ranges or bands of incident
light. In at least some embodiments , some or all of thetuned by varying the type of material or materials depositedor set of wavelengths of incident light in an infrared range

material or materials formed at the location of each optical

optical filters comprise filters that pass a distinct wavelength

at the location of each optical filter, the thickness of theof layers of material or materials at the(e .g., extending generally from approximately 1 micron to 35 filter, theofnumber
each optical filter, etc . In at least some embodi
approximately 20 microns in wavelength ). Theoretical plots location
ments, the optical filters may be interference filters and mayof the transmission characteristics of optical filters usable ingas and chemical imaging systems of the type described

be bandpass , high -pass, low -pass, or band -rejection filters .
herein are shown and described in connection with FIGS.
The optical filters may, in at least some embodiments , be
6A , 6B , 6C , and 6D . The optical filters shown and described 40 formed from one or more thin film layers that determine thein connection with FIGS. 6A , 6B , 6C , and 6D are merely
optical transmission characteristics of the filters . Interfer
illustrative.

ence coating with different designs (e . g ., having different

While the filters and filter array 2550 are generally number or arrangement of layers, differentmaterials , differ
described herein as being separate from the optical lense nt thickness layers, etc . ) may be used . Forming the indiarray 1002 (and lenses 2502 , 2504, 2506 , or 2508), the filters 45 vidual optical filters 2512A , 2512B , etc . can involve pro
may, if desired , be incorporated into or on some or all of the cessing steps such as masking, etching, depositing ,
lenses of the optical lens array 1002 . In particular, the filter

planarizing, doping, stripping mask materials, etc . In thisarray 2550 may be provided as coatings on some or all themanner , one or more optical filters can be selectively pro

lenses of lens array 1002 . In arrangements in which lenscessed while one or more other optical filters are protected ).

array 1002 is formed from a monolithic substrate , the filter 50

array 2550 may be formed from a patterned filter array (asInfrared blocking material 2558 may serve as a baffle ,aperture stop , or field stop and may be patterned onto

described herein ) coated onto or integrated within themono

substrate 2501 in the spaces between the filters 2512 .

lithic substrate . In arrangements in which lens array 1002 is

Infrared blocking material 2558 may be formed from any

formed from individual lenses, the filter array 2550 may besuitable material, such as chrome, that blocks light including
formed from individual filters coated onto or integrated 55 stray light between the filters 2512 . In at least some embodi
within some or all of the individual lenses .
ments, infrared blocking material 2558 may be formed to

1 . Patterned Filter Arrays

implement apodization (i.e ., a smoothly varying transmis

As illustrated in FIG . 19 , a filter array 2550 may be sion profile, a transmission profile that smoothly varies as aprovided that includes a substrate 2501 patterned to form
function of position in the filter array, etc .). In particular,
individual optical filters 2512A , 2512B , etc . (also labeled 1, 60 infrared blocking material 2558 may provide a slowly
2 , . . . 12 in FIG . 19 ) and with infrared blocking material varying gradient baffle, aperture stop, or field stop that has
2558 disposed between the individual optical filters . Filter maximum transmissivity near the centers of the filters ,array 2550 may also be referred to herein as filter array 454 . minimal or zero transmissivity in the spaces between the
Each individual optical filter 2512A , 2512B , etc . may passfilters , and some intermediate transmissivity near the edges
only the desired infrared radiation for its respective optical 65 of the filters. Infrared blocking material 2258 may be formed
channel and for its respective infrared detector. In at least
some embodiments, the individual optical filters selectively

in such a manner using suitable patterning and processing
techniques .

US 10 ,375 , 327 B2
67
2 . Individual or Diced Filters
FIGS. 20A - 20C illustrate an alternative arrangement for

filter array 2550 in which the filter array 2550 is formed
from individual filters. In this arrangement, batches of filters

68
effect or using another cooling and/or heating device . TEC
device 2570 may be coupled to heat sinks 2572 and heat sinkfan 2574 . In operation , TEC device 2570 may convey

thermal energy from FPA 1508 to heat sink 2572 and heat

are created using suitable processing steps ( as described in 5 sink fan 2574 may transfer the thermal energy into theconnection with patterned filters herein ). Each batch may
include multiple copies of a particular filter (i. e ., one of filter

surrounding environment. If desired , heat sinks 2572 may becooled by liquid cooling in addition to or instead of heat sinkcopies of that particular filter may be separated , or diced, tosensor thermally coupled to FPA 1508 or TEC device 2570 .

2512A , 2512B , etc .). After forming a batch , the multiple

fan 2574 . The imaging system may include a temperature

create individual copies of that particular filter. Individual 10 The temperature sensor may be integrated into FPA 1508 ,copies of each of the filters that form filter array 2550 thathave been separated or diced from their respective batches

integrated into TEC device 2570 , or may be a separate
device . TEC device 2570 may be configured to monitor the

may then be assembled into filter array 2550 . With arrange -temperature of FPA 1508 using the temperature sensor and ,ments of this type, processing each batch may be somewhat in response , maintain FPA 1508 at a target temperature . By
simplified , as each substrate being processed includes only 15 holding the temperature of FPA 1508 relatively constant, thea single type of filter. The benefits of simplified batchprocessing may outweigh any additional complexity

involved in the separation, or dicing, and subsequent assem
bly of individual filters into filter array 2550 .

calibration of FPA 1508 can be improved or optimized . In

particular, FPA 1508 may be calibrated after TEC device

2570 cools FPA 1508 to a desired operating temperature , andthen TEC device 2570 may hold FPA 1508 at the operating

As shown in the rear views of FIGS. 20B and 20C , filter 20 temperature to maintain the calibration . TEC device 2570
housing 2510 may include alignment structures 2560A , may, alternatively, operate at a maximum or other preset

2560B , etc . in which individual filters 2512A , 2512B , etc .

are mounted and aligned . The alignment structures 2560A ,2560B may be formed from recesses, registration features ,cooling power to maintain as low a temperature of FPA 1508

as possible . TEC 2570 may , alternatively , maintain thetemperature of FPA 1508 in some desired range, e. g ., below

posts , other suitable elements , or a combination of these and 25 a first temperature , above a second temperature , etc . In someother elements in filter housing 2510 . In at least someembodiments, TEC 2570 may cryogenically cool FPA 1508 .

embodiments, individual filters may be secured to housing
2510 by pressure , when assembled onto mounting plate

In other embodiments , TEC 2570 may cool FPA 1508 to anon - cryogenic temperature such as ambient temperature , 101584 . If desired , individual filters may also or alternatively

degrees C . below ambient, 20 degrees C . below ambient, 30

be secured to housing 2510 by pressure (i.e ., by snapping 30 degrees C . below ambient, etc . or a temperature independent

into place in recessed portions of housing 2510 ), adhesive , of ambient such as – 10 degrees C ., - 5 degrees C ., 0 degrees
C ., 5 degrees C ., 10 degrees C ., 15 degrees C ., 20 degrees
screws, clips, or other fastening elements.
F . Detector Arrays
C ., 25 degrees C ., 30 degrees C ., etc. and any range within
As discussed herein , gas and chemical imaging systems any combination of these temperatures . TEC device 2570
may include a detector such as optical focal plane array 35 may be a single stage TEC cooler or may include multiple( FPA ) 1508 . The FPA 1508 may receive light from a stages (e.g ., a first TEC stage having a “hot side ” cooled byplurality of optical channels that are spatially separated anda larger second TEC stage, which itself has a hot side cooled
for example ,by virtue of filter array 2550 , and this lightmay by a radiator ). The temperature to which TEC unit 2570
be spectrally different. In at least some embodiments, FPA
cools FPA 1508 (whether an absolute temperature or a1508 may be formed from one or more arrays of microbo - 40 temperature relative to ambient may be preconfigured , may
lometers configured to detect infrared radiation , as discussed
be set by a user, or may be determined as part of a calibrationin more detail herein . In at least some embodiments, theindividual lenses 2502 , 2504, etc . and filters 2512 can belaterally spaced apart by a distance in a range of about 2 mmprocess. As an example, a calibration process may involve

determining that FPA 1508 needs to be cooled to a certain
temperature (whether an absolute temperature or a tempera

to about 20 mm , in a range of about 3 mm to about 10 mm , 45 ture relative to ambient ) for a desired level of performance .

in a range of about 4 mm to about 8 mm , about 4 . 3 mm , orIn response , a cooling controller in the imaging system maysome other suitable distance . Likewise , the spatially andspectrally spaced channels of FPA 1508 may be physicallyconfigure itself based on the results of the calibration tomaintain FPA 1508 at that temperature. In this manner, the2594 . FPGA board 2590 and the signal conditioning board

thermometers (i.e., temperature sensors ) coupled to ele

spaced about by 2 to 20 mm , 3 to 10 mm , 4 to 8 mm , about accuracy of the gas and chemical detection of FPA 1508 may
50 be improved .
4 .3 mm , etc .
FIG . 21 also illustrates that the imaging system may
The imaging system may include one or more controllers
include components such as an FPGA board 2590 , a signal that control the operation of cooling units such as TEC units
conditioning board 2592 , and a data communication board
2570 and 2580 . The controllers may receive inputs from2592 may be configured to execute methods used in the 55 ments being cooled , thermometers that determine the ambi
analysis of the images captured by the optical system as
ent temperature , other processors and controllers in thediscussed herein ( see , e. g ., the discussion of processing unit imaging system , feedback from the TEC units or other1021 of FIG . 12 ). The data communication board 2594 canbe configured to communication with at least one device

cooling units , etc . The controllers may adjust the operationof TEC units in real time, in order to maintain coolingphysically separate from the imaging system ( e . g ., over a 60 performance and desired temperatures of the elements being

wired or wireless connection ) as discussed herein (see , e . g .,the discussion of communication module 1024 of FIG . 12 ).
1. TEC Coolingcooled .
2 . TEC Cooling of Optics

If desired , lens assembly 1502 including elements such as
As shown in FIG . 21, FPA 1508 may be actively cooled , lens array 1002, mounting plate 1584 and filter housing 2510
heated , temperature- stabilized , and /or actively thermally 65 may be actively cooled and /or heated using a thermoelectric
controlled using a thermoelectric cooling ( TEC ) device 2570
cooling ( TEC ) device 2580 utilizing the Peltier effect or(which may also be operable as a heater ) utilizing the Peltier using another cooling and /or heating device . TEC deviceUS 10 ,375 ,327 B2
60

702580 may be coupled to heat sinks 2582 and heat sink fan
2584 . In operation , TEC device 2580 may convey thermalenergy from lens assembly 1502 to heat sink 2582 and heatsink fan 2584 may transfer the thermal energy into thedepicts 9 distinct optical channels 2602, any number (two,three , four, five , six , seven , eight , nine , twelve , or greater) ofoptical channels 2602 are possible .
Each optical channel 2602 is configured to collect lightsurrounding environment. If desired , heat sinks 2582 may be 5 from the object 2601 and transfer light along its correspondcooled by liquid cooling in addition to or instead of heat sinkfan 2584. TEC device 2580 may be provided with any of theing axis 2680 toward the optical detector 2610 ( represented

as light rays 2605 ). The optical detector 2610 may generatefeatures and operated using any of the techniques discussed

data representing an image corresponding to the lightherein in connection with TEC device 2570 . As examples,

received for each optical channel 2602 . However, as illus

TEC device 2580 may actively cool lens assembly 1502 to 10 trated in FIG . 22A , some of the lightmay cross between the
cryogenic or non -cryogenic temperatures , may utilize a neighboring optical channels because of the angle of inci

thermometer to monitor the temperature of lens assembly
1502, may be a single or multi -stage TEC device , may
facilitate calibration and maintenance of calibrated perfor -d ence of the light on the optical surfaces and the refractive
nature of the lenses . For example , light rays 2605A and
2605B are refracted by lenses 2504 into neighboring opticalmance, etc . By actively cooling lens assembly 1502 , the 15 channels and out of the desired optical channel 2605 (in theaccuracy of the gas and chemical detection of FPA 1508 may

FIG . 22A , the central optical channel) . Thus, a portion of thebe improved .

light incident on one optical channel may cross into neighimaging an object (such as a gas cloud ) by an opticaldetector while reducing the effects of stray light on the

As shown schematically by thermal connection 2586 , lens boring optical channels (e .g., optical channel 2602A ) and beassembly 1502 may optionally be actively cooled by TEC
added to the light from the object 2601 as transferred by thedevice 2570 . Thermal connection 2586 may be a heat pipe 20 neighboring optical channels to the optical detector 2610 .
2582 or other device . In other words , TEC device 2570 may
The additional light from a neighboring optical channelmay
provide primary cooling to FPA 1508 and secondary cooling
distort , corrupt , or otherwise interfere with the data corre
to lens assembly 1502 through a heat pipe 2586 , through the sponding to a given optical channel 2602 .
mounting of lens assembly 1502 to FPA 1508 and/ or TEC
Therefore , controlling stray light rays is important in a
25 DAISI system comprising a lens array of closely packed
device 2570 , or via other devices.
optical channels. Various embodiments disclosed herein
G . Reduction of Crosstalk
A DAISI system (whether installed at a fixed location or employ various techniques that can provide such control toa mobile DAIS ' system ) may include a lens array for increase , improve, or optimize the illumination ofthe opticaldetector. For example , as described herein in connection to 30 resulting image . For example , a DAISI system may be

FIGS. 18A - 18E , a DAISI system can comprise a lensassembly 1502 including lens arrays 2504, 2506 , and 2508

configured to provide vignetting of the image of the opticalchannel at the optical detector to remove or at least partiallythat at least partially define or are included in an optical

reduce optical crosstalk between the optical channels . The

channel to be imaged by an FPA unit 1008 . In some

DAISI system may induce the vignetting by at least a partial

implementations described throughout the present applica - 35 reduction of the brightness or illumination of the light at thetion, the DAISI system is configured as an infrared ( IR )imaging system for imaging an object. FPAs configured toperiphery or edges of an optical channel. For example , the
DAISI system may include one or more baffles or aperture

image IR radiation may be costly , thus to increase orelements configured to at least partially block stray lightmaximize the usable area of the FPA unit 1008 , it may befrom crossing between the optical channels, while permit

or possibly as close together as physically possible . How
ever, positioning the optical channels close together may

that optical channel. The one or more baffles or apertureelements may also be configured to at least partially block

result in undesired stray light rays from one optical channel
crossing over into a neighboring optical channel, also

stray light that has crossed between the optical channels
from reaching the optical detector. Reduction of opticaladvantageous to position the optical channels close together 40 ting the optical channels to transfer light that is incident onreferred hereinto as " optical crosstalk .” In various embodi- 45 crosstalk between the optical channels may be important inments, the lenses may be spaced apart edge -to - edge by adistance in a range of 0 mm to 2 mm , in a range of 0 mm

tightly packed lens array systems because , as the opticalchannels are placed closer together, the optical crosstalkto 1 mm , in a range of 0 mm to 0 .5 mm , or in a range of 0 . 05

between the optical channels may increase , thereby degrad

mm to 0 .5 mm , e g about 0 . 1 mm .
ing the quality of the data obtained .
For example , FIG . 22A is a ray trace diagram illustrating 50 In various embodiments , each of the systems disclosed
one example of optical crosstalk between the optical chan -herein can be used to monitor potential gas leaks in any

nels of lens assembly 1502 of FIG . 18D . Unless otherwise

suitable installation site , including, without limitation , drill

various optical elements described in connection to FIGS .

thermore , each of the systems disclosed herein can also be

noted , like reference numerals in FIG . 22A represent com - ing rigs , refineries , pipelines, transportations systems, ships
ponents that are the same as or similar to like numberedor other vessels (such as off- shore oil rigs, trains, tanker
components in FIGS . 18A - 18E . FIG . 22A illustrates the 55 trucks, petro -chemical plants , chemical plants , etc. ). Fur
18A - 18E as a collection of optical surfaces (represented as used with any mobile DAISI systems, including, withoutplanes in FIG . 22A ). For example , the lens assembly 1502 limitations, systems worn or carried by a user. In addition ,can include lenses 2504 , lenses 2506 , lenses 2508 , filters
each of the embodiments and aspects disclosed and illus
2512 , and an optical window 2607. ( FIG . 22A schematically 60 trated herein , e .g ., with respect to FIGS . 22A - 22G can beillustrated front and rear surfaces of each of lenses 2504 ,used in combination with any or any combination of the2506 , and 2508 as well as optical window 2607 .) The lensfeatures disclosed and illustrated through the present appli

assembly 1502 can be used to image an object 2601 that is

cation .

spaced from the lens assembly 1502 along an axis 2680 of

FIG . 22B is an exploded perspective view of a lensan optical detector 2610 . FIG . 22A depicts lenses 2504A , 65 assembly 2702 configured to at least partially reduce optical
2506A , and 2508A that correspond to an optical channel
crosstalk , which can be used in conjunction with a DAISI
2602A disposed along the axis 2680A . Although FIG . 22A system . The lens assembly 2702 is substantially similar toUS 10 ,375 ,327 B2
71

72

the lens assembly 1502 of FIGS. 18A - 18E . Unless otherwise
noted , like reference numerals in FIG . 22B represent com -otherwise be incident at the outer edge of the corresponding
optical channel. The openings 2622 can also be configured

ponents that are the same as or similar to like numbered

to permit light rays incident at a central region of the opticalcomponents in FIGS . 18A - 18E . Although the lens assembly

channel to be transferred to the optical detector ( not shownwith any other suitable type of optical system . For example ,stantially blocked such that stray light does not cross into ain FIG . 22B are described in connection to FIGS. 18A - 18E .

Although the plurality of openings 2622 are illustrated in

combination of lenses and optical elements, which maythat the openings 2622 may have any suitable shape ( e. g .,2702 is described in connection with lens assembly 1502, 5 in FIG . 22B ) via the optical channel on which the light isvarious features described herein can be used in conjunction
incident. Thus , the light rays are at least partially or sub
the various lenses and lens arrays and components illustrated

neighboring optical channel .

However, the lens assembly 2702 can include any number or 10 FIG . 22B as having a circular shape, it should be appreciatedcorrespond to a plurality of spatially and spectrally different
optical channels as described herein .
The lens assembly 2702 can be designed to block strayovular, rectangular, square , etc .) so as to vignette the imageat the optical detector. The shape, dimensions, and positionof the openings 2622 may be based on the optical properties

another optical channel. In some implementations, the lensFor example , the lens assembly 2702 may comprise an

assembly 2702 can also be configured to permit light rays

optical stop layer 2650 comprising a plurality of opticallight rays that have crossed between one optical channel into 15 and arrangement of the elements in the lens assembly 2702 .

incident on a given optical channel to be transferred by that
optical channel to the corresponding region of the opticalstops 2655a , 2655b , etc . corresponding to each opticalchannel. In one embodiment, the optical stop layer 2650

other embodiments, the optical detector can comprise a

within the lens assembly 2702 . For example , for the embodi

detector ( e . g ., a detection region as described in connection 20 may be disposed between the lens 2504 and 2506 . The
to FIG . 22D below ). In various embodiments , the optical dimensions of the plurality of openings 2622 may be based ,detector can comprise a single focal plane array . In various
at least in part, on the position of the optical stop layer 2650

plurality of focal plane arrays . For example , the lens assem
ment illustrated in FIG . 22B , each opening 2622 has a lateralbly 2702 may comprise at least one baffle 2630 , configured 25 size (e . g ., diameter, side , etc .) in a range of 3 mm to 6 mm ,to control stray light to provide at least partially vignetting
or in a range of 4 mm to 5 mm , e .g ., dimensions of about 4 . 4of the image at the optical detector. In some embodiments millimeters, with a tolerance of about + / - 0 .010 . A thickness
the lens assembly 2702 may include two baffles 2620 and of the baffles can be in a range of 0 .05 mm to 0 .5 mm , in a
2630. Unless otherwise stated , the baffles 2620 and 2630
range of 0 . 1 mm to 0 . 3 mm , e . g ., about 0 . 2 mm . Although
may be substantially similar to baffle 2500 of FIGS. 18A - 30 the openings 2622 are described herein as each having the
18E and configured to at least partially block light fromsame dimensions, it should be appreciated that this is notcrossing between the optical channels . The baffles 2620 andintended to be limiting and each opening 2622 may have2630 may be configured to at least partially block stray lightdifferent dimensions and /or shapes . In some embodiments ,that has crossed from neighboring optical channels fromthe structure and location of the baffles 2620 may be based

mentations, the baffles are configured to substantiallyvignette the image at optical detector array or portions

application .
In some embodiments , the baffle 2630 is provided whichbeing transferred to the optical detector. In various imple - 35 on an optical system thathas been optimized for any suitable

thereof.

For example , the baffle 2620 may be configured to reduce

may be similar to baffle 2620 and also configured to provide
at least partially vignetting of the image of the object. The

or at least partially block light that enters via one optical 40 baffle 2630 may be positioned at the back of the opticalchannel from exiting the lens assembly 2702 via anotheroptical channel. In some embodiments , the baffle 2620 isconfigured to substantially reduce light from crossing

channel closer to the optical detector array than to the front

element of the lens assembly . In some embodiments , thebaffle 2630 may be disposed adjacent to the lenses 2508 andbetween the optical channels. The baffle 2620 may be between the lenses 2508 and the optical detector. In anotherpositioned at the front of the optical channel 2602 . In some 45 embodiment, alternatively or in combination , the baffle 2630
embodiments, the baffle 2620 may be disposed adjacent to may be disposed between the lenses 2508 and the lens holder
the lenses 2504 and / or between the lenses 2504 and the1584 of FIG . 18D . In some embodiments , the baffle 2630

object (not shown in FIG . 22B ). In another embodiment,

may be formed as part of the lens holder 1584 or attachedalternatively or in combination , the baffle 2620 may be
therein . In one implementation , the baffle 2630 is disposed
disposed between the filter housing 2510 and the object. In 50 as close as possible to the optical detector, within manufac

some embodiments , the baffle 2620 may be formed as part turing tolerances.
of the filter housing 2510 or integrated into a recess of the
Similar to baffle 2620 , the baffle 2630 may comprise anfilter housing 2510 (illustrated in FIG . 18D ). In one imple light attenuating or light blocking surface such as a metal ormentation , the baffle 2620 is disposed as close as possible to plastic sheet or plate with a plurality of openings 2632
the filter housing 2510 , within manufacturing tolerances. 55 formed , for example , by mechanical or laser cutting . EachAs described in connection to FIGS . 18A - 18E , the baffle opening 2632a , 2632b , etc . (e. g., also referred to as field
2620 may comprise an light attenuating or light blocking stops) may be disposed along an axis of an optical channel
surface e . g ., a sheet or plate comprising light attenuating orof the lens assembly 2702 . The openings 2632 may beblocking material, e .g ., metal or plastic , with a plurality of configured to control light rays transferred through the
openings 2622 ( e . g ., also referred to as apertures ) formed , 60 optical channel by modifying the light path to the opticalfor example , by mechanical or laser cutting . Each opening

channel. For example , each opening 2632 may be configured

2622a , 2622b , etc . may be disposed along an axis ( e. g ., axis

to block stray light rays that have crossed between optical

2680 of FIG . 22A ) of a respective optical channel . The

openings 2622 may be configured to control light rays

channels such that these stray light rays are not transferredto the optical detector. The openings 2632 can also be

incident on the optical channel by modifying the light path 65 configured to permit light rays incident on a given opticalentering the optical channel. For example , each opening

2622 may be configured to block stray light rays that would

channel to be transferred by the given optical channel toreach the associated optical detector. For example, the baffleUS 10 ,375,327 B2
732630 may not affect light rays that are incident at a central
region of a given optical channel and /or have an angle of74

appreciated that the opening 2632 may have any suitablecrosstalk between neighboring optical channels , and ais transferred to the optical detector ( e.g ., as described below
in connection to FIG . 22G ). Although the lens assembly
incidence that permits the light ray to be transferred through 2702 is described as comprising two baffles 2620 and 2630 ,the given optical channel. Thus, the light rays are blocked it should be appreciated that the lens assembly 2702 cansuch that they do not interfere with the image formed by 5 comprise any number ofbafiles suitable to vignette an image
neighboring optical channels .
at the optical detector for a suitable application .
Although the plurality of openings 2632 are illustrated in
FIG . 22C is a forward facing schematic diagram of the
FIG . 22B as having a rectangular shape, it should be optical detector 2610 depicting another example of opticalshape ( e . g ., ovular, circular, square , etc .) so as to vignette the 10 potential resulting non -uniformity in usable image size due

image at the optical detector. As described above in con nection to baffle 2620 , the shape , dimensions, and position

to the crosstalk . The detector 2610 can comprise a pluralityof illumination regions 2616 , each of which may correspondof the openings 2632 may be based on the optical properties

to an optical channel 2602 and associated components (suchings 2632 may be based , at least in part, on the position andarea of the detector 2610 upon which light that enters thethe embodiment illustrated in FIG . 22B , each opening 2632
has a lateral dimension (e .g ., diameter, side, etc .) of 1 mm toincident. In some embodiments , the width of the opticalchannels 2602 at different locations (e .g ., the lenses )may be

to 4 mm , e .g ., about 3 .2 mm . The openings 2632 can beregion 2616 . In the arrangement shown in FIG . 22C , thepolygonal ( e.g ., square or rectangular) or rounded (e. g.,

optical channels 2602 ( including, e.g ., the lenses of the lensand arrangementof the optical elements in the lens assemblyas the lenses or lens elements 2504 , 2506 , 2508 ) . For
2702 . Accordingly, the dimensions of the plurality of open - 15 example , each illumination region 2616 can represent thedimensions of the optical stop layer 2650. For example , forfirst element of the associated optical channel 2602 is

5 mm , in a range of 2 mm to 5 mm , or in a range of 3 mm 20 smaller than the corresponding width of the illumination

elliptical or circular ), in various arrangements. Although the
openings 2632 are described herein as each having the samearray ) may be spaced in a two - dimensional array at a
generally uniform spacing. For example , the spacing

dimensions, this is not intended to be limiting and each 25 between adjacent optical channels in the vertical direction

opening 2632 may have different dimensions and/ or shapes.

may be approximately uniform , and the spacing between

In some embodiments, the baffles 2630 may be configured
for an optical system designed or optimized for any suitableapplication and have a design based on the components thatadjacent optical channels in the horizontal direction may
also be approximately uniform .
Due to the spacing of the optical channels in FIG . 22C , the30 illuminated regions 2616 may overlap , illustrated as overof the optical system .
The lens assembly 2702 can be used in conjunction with
an optical system that comprises any suitable opticalarrangement, such as one or more lenses ( e . g ., a plurality oflenses ) and/or one or more filters (e .g ., a plurality of filters )lapping regions 2618 in FIG . 22C . The overlapping regions
2618 may occur since the image produced by the lenses in
the illumination regions 2616 is typically larger than thecorresponding area of the associated lenses and other opticalthat transfer light to the optical detector. The lens assembly 35 elements of the optical channels. The overlapping regions

2702 is one embodiment of a design described in connection

with various DAISI systems that may vary in design char-

2618 may be indicative of the optical crosstalk between

neighboring optical channels, and may introduce non - uni

acteristics ( e . g ., the DAISI system may be mobile or fixed ).

form image regions that reduce the effective size of the

However, the optical components and the positions within

usable image that is not contaminated by cross -talk fromsuitable type of infrared imaging system or camera toregions may define a usable image region 2615 for imaging

control stray lightto maintain the optical performance of the

an object (such as a gas cloud ).

the lens assembly 2702 can be modified as desired in 40 other channels. For example , FIG . 22C depicts rectangularconjunction with any suitable type of imaging application
regions of different sizes, with the overlapping regions 2618
For example, the lens assembly 2702 can be used with any
disposed about each rectangular region . The rectangularsystem . Based on the desired application , the lens assembly 45

For example , a first optical channel transfers light to a2702 may be optimized for any particular application having
any combination or arrangement of elements . Accordingly,

portion of the optical detector 2610 corresponding to theillumination region 2616A . The neighboring optical chan

the various optical elements of the lens assembly 2702 maynels also transfer light within the corresponding illumination

be modified , moved , removed , etc , for any suitable appli -regions 2616B , 2616C , 2616D . However, because the opti

may be changed or the optical powers and /or position of thelenses 2504 , 2506 , and /or 2508 may be modified , for

the illumination regions 2616B and 2616D may enter theneighboring illumination region 2616A , and vice versa . This

cation . For example , the position of the optical stop 2650 50 cal channels are spaced close together, the light of at least
produces the plurality of overlapping regions 2618 shown inexample , for a particular application .
In some embodiments , controlling the stray light and FIG . 22C .
increasing the sensitivity of the lens assembly 2702 for a 55 In the arrangement illustrated in FIG . 22C , each opticalgiven application may be inversely related (e.g., blocking channel 2602 also defines a detection region 2612 of thelight beams may inversely affect the overall amount of light optical detector 2610 . Each of the detections regions 2612

received at the optical detector ). Accordingly , in somecomprises a square that may have its center coincident with
implementations it may be advantageous to design the lens
the optical axis or central axis through the lens assembly
assembly 2702 such that the baffles are configured to block 60 corresponding to the optical channel. The detection region

or reduce the light at the edges of an image to approximately

2612 can comprise a plurality of pixels and can be spatiallygeous to configure the lens assembly 2702 such that at least

regions 2616 can have a diameter of 6 .01 millimeters inabout 50 % or at least about 60 % of the light from the object

some embodiments .

0 . 1 % of the amount of light incident on the optical detector separate from one another. For example, in the illustrated
at the center of an image (e. g., as described below in arrangement, the detection regions 2612 can be separated byconnection to FIGS. 22F and 22G ). In another implemen approximately 0 . 136 millimeters and can have dimensions
tation, alternatively or in combination , it may be advanta - 65 of 4 .25 millimeters by 4 .25 millimeters . The illumination