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OSAC 2021-N-0035

Standard Guide for 

Scanning Facial Images

Facial Identification Subcommittee

Digital Evidence/Multimedia Scientific Area Committee

Organization of Scientific Area Committees (OSAC) for Forensic Science
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Draft OSAC Proposed Standard

OSAC 2021-N-0035

Standard Guide for Scanning

Facial Images

Prepared by 

Facial Identification Subcommittee

Version: 1.0

September 2021

Disclaimer:

This OSAC Proposed Standard was written by the (subcommittee) of the Organization of Scientific Area 

Committees (OSAC) for Forensic Science following a process that includes an open comment period. 

This Proposed Standard will be submitted to a standards developing organization and is subject to 

change.

There may be references in an OSAC Proposed Standard to other publications under development by 

OSAC. The information in the Proposed Standard, and underlying concepts and methodologies, may be 

used by the forensic-science community before the completion of such companion publications.

Any identification of commercial equipment, instruments, or materials in the Proposed Standard is not a 

recommendation or endorsement by the U.S. Government and does not imply that the equipment, 

instruments, or materials are necessarily the best available for the purpose.

To be placed on the OSAC Registry, certain types of standards first must be reviewed by a Scientific and 

Technical Review Panel (STRP). The STRP process is vital to OSAC’s mission of generating and 

recognizing scientifically sound standards for producing and interpreting forensic science results. The 

STRP shall provide critical and knowledgeable reviews of draft standards or of proposed revisions of 

standards previously published by standards developing organizations (SDOs) to ensure that the 

published methods that practitioners employ are scientifically valid, and the resulting claims are 

trustworthy.

The STRP panel will consist of an independent and diverse panel, including subject matter experts, 

human factors scientists, quality assurance personnel, and legal experts, which will be tasked with 

evaluating the proposed standard based on a comprehensive list of science-based criteria.

For more information about this important process, please visit our website 

at: https://www.nist.gov/topics/organization-scientific-area-committees-forensic-science/scientifictechnical-review-panels. 
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1. Scope

1.1 This guideline provides best practices for scanning documents containing images 

for Facial Recognition enrollment or Facial Image Comparisons. 

1.2 This guide is for instances in which a printed image requires capture for 

enrollment into a Facial Recognition system or by facial examiners undertaking a facial 

image comparison.

1.3 This guide will not provide information on original image capture, printing 

resolution, image enhancements that may have occurred prior to a facial image being 

printed, or during preparation of a facial image for the creation of identity documents. 

1.4 This guide acknowledges that in Appendix F of IAFIS-DOC-01078-9.31the 

minimum scanner testing requirements are provided, and notes that whilst the core 

capabilities and attributes for a fingerprint scanner are similar, there are crucial 

differences for scanning an optimal facial image. 

1.5 This guide also acknowledges that there is a list of certified fingerprint scanners on the 

Criminal Justice Information Services (CJIS) website2, and notes that some of these 

scanners are capable of gray scale and full color scanning. 

2. Summary of Practice

2.1 Generally, modern facial images are color or black and white. These images can 

also be found in historical documents, newspapers, Closed Circuit Television (CCTV) 

extracts, and some security documents that print to a polycarbonate substrate. Standards 

for scanning facial images need to reflect the variety of sources that may be encountered.

2.2 This guideline provides best practice for scanning documents containing facial 

images for:

2.2.1 Facial Recognition enrollment, or 

2.2.2 Facial Image Comparison. 

2.3 A facial image scanner must be capable of producing images that exhibit good geometric 

fidelity, sharpness, and detail rendition, with low noise characteristics. The images must 

be true color representations of the printed facial image without creating any significant 

artifacts, anomalies, false detail, or cosmetic image restoration effects.

2.4 It may be necessary to consult an Image Specialist to provide advice on the best method 

of scanning a facial image in a document, which may have other impacting features. 

Examples include mass produced documents (newspapers, magazines etc.) where a halftone or similar process has been used.

1

IAFIS-DOC-01078-9.3 Electronic Biometric Transmissions Specification https://www.fbibiospecs.cjis.gov/

2 https://www.fbibiospecs.cjis.gov/certifications
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3. Referenced Documents

3.1 ISO 12641 - 1: 2016 Graphic technology - Prepress digital data exchange - Color 

targets for input scanner calibration - Part 1: Color targets for input scanner calibration

3.2 ISO 12641 - 2: 2016 Graphic technology - Prepress digital data exchange - Part 2: 

Advanced color targets for input scanner calibration

3.3 ISO 22028-1:2016 - Photography and graphic technology - Extended color 

encodings for digital image storage, manipulation and interchange - Part 1: Architecture 

and requirements

3.4 ANSI IT8/4-2005 Graphic Technology - Input data for characterization of 4-

colour process printing 

3.5 IAFIS-DOC-01078-9.3: Electronic Biometric Transmissions Specification 

3.6 ASTM E2825-12: Standard Guide for Forensic Image Processing

3.7 ISO 21043-2-2018 Forensic sciences - Part 2- Recognition recording collecting 

transport and storage of items

4. Terminology

4.1 Definitions:

4.1.1 Color depth: is the bit scale of the image, e.g., 8 bit grayscale and 24 or 48 bit 

RGB (Red, Green, Blue).

4.1.2 CMYK: is a color gamut spectrum widely used in printing. CMYK stands for 

Cyan, Magenta, Yellow, and Black. 

4.1.3 Descreen: The array of dots used in the halftone or desktop printing processes are 

called a “screen” where the color dots are placed at different angles, and a 

scanning software option can be used to minimize the screen pattern by use of a 

screen frequency filter algorithm. This filter is called a Descreen option setting. 
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Examples of screening angles in CMYK printing:

 Descreen not used (image magnified) Descreen used (image magnified)

4.1.4 Dots per inch (DPI): In printing, DPI refers to the resolution setting of the printer 

and resolution capture for printed media. For example, a 1200 DPI resolution 

printer will deposit a much higher density of ink per inch than a 300 DPI printer. 

Use of DPI as a resolution term when scanning printed media will enable the use 

of post-scanning descreen software enhancement to more accurately reproduce the 

original artwork or image.

4.1.5 Lamina: A clear/low opacity sheet of film or security designed film that is sealed 

onto a substrate by cold or hot adhesion.

4.1.6 Lines per inch (LPI). A term in the resolution setting of scanner software 

used for scanning original artwork for printing.

4.1.7 Moiré: A moiré pattern occurs when a scene or an object that is being 

scanned contains repetitive details (such as lines, circles, dots, etc.) that exceed 

the sensor resolution. As a result, many scanners produce a moiré pattern that is 

not visible in the physical item being scanned. 
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The illustrations above show a number of concentric circles plotted with a 

range of uniform spacing. Note the phantom lines and curves that appear3. 

4.1.8 Pixels per inch (PPI): Measurements of the pixel density of an electronic 

image device, such as a computer monitor or camera. For example, a 1200 PPI 

image will produce a higher quality image than a 300 PPI image. Use of PPI as a 

resolution term is generally used with digitally captured images (i.e., 

photography). 

4.1.9 Printed Image: A printed image is the production of a digital image onto 

a substrate by a direct or indirect printing process.

4.1.10 RGB: A color gamut spectrum that stands for the color channels red, green, and 

blue. An example of the use of RGB is in the bit depth range where 48-bit refers 

to 16-bits per color channel, i.e., 16 Red, 16 Green, 16 Blue.

4.1.11 Samples per inch (SPI): A generic term that can include of DPI, LPI, and PPI. 

SPI is the measurement of the resolution, in particular the number of individual 

samples that are taken in the space of one linear inch. Scanner software may not 

allow for the use of SPI during image capture.

4.1.12 Substrate: A substrate in printing terms is a form of media on which a printed 

image is produced. A substrate, as referred to in this guideline includes gloss or 

matte paper, plastic, sensitized material, or polycarbonate. 

5. Scanning Overview

5.1 There are various scanning devices (auto-feed, sheet feed, flatbeds), software, physical 

media type, color calibration targets, calibrated reference target, and other processes that 

can be used to produce a digital facial image from physical media. 

5.2 Be cautious using fingerprint scanners for scanning color images avoiding:

5.2.1 Having to recalibrate the scanner from a grayscale calibration target for 

fingerprints to color calibration target for facial images.

5.2.2 Incorrectly scanning a facial image with fingerprint scanner settings, such as 

scanning in grayscale instead of color.

3 http://mathworld.wolfram.com/MoirePattern.html
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5.3 To achieve optimal results, the scanner selected should be:

5.3.1 A flatbed device in order to minimize target item movement. Scanners with autofeed trays should not be considered unless there is a mechanism for securing and 

flattening an item in situ on the scanning bed.

5.3.2 Calibrated regularly.

5.3.3 Have optional scanner settings, such as descreen turned off to prevent unwanted 

and unnecessary image processing.

6. Scanner Testing and Calibration 

6.1 To assess whether a scanner is capable of producing good quality images, the 

following scanner attributes and capabilities should be considered: 

6.1.1 Good geometric fidelity (linearity and geometric accuracy) 

6.1.2 Sharpness

6.1.3 Detail rendition

6.1.4 Gray-level and color uniformity

6.1.5 Gray-scale and color dynamic range

6.1.6 Low noise characteristics (signal-to-noise ratio)

6.1.7 The output images are true representations of the item being scanned without 

creating any significant artifacts, anomalies, false detail, or cosmetic image 

restoration effects.

6.2 In Appendix F of IAFIS-DOC-01078-9.3 there is guidance on the testing 

parameters and requirements for the following tests for fingerprint scanners that are also 

applicable for testing color image scanners:

6.3 Linearity

6.4 Geometric accuracy

6.5 Spatial frequency response

6.6 Signal-to-noise ratio

6.6.1 It is important to note that section 2.5 Gray-Level Uniformity of Appendix F in 

IAFIS-DOC-01078-9.3 is not relevant for testing parameters for color image 

scanners. For more information on Appendix F of IAFIS-DOC-01078-9.3 see 

Appendix 2: IQS Appendix F Summary.

6.7 For testing color image scanners, a Color Calibration Target card is the initial step 

in identifying and managing a scanners capability for color management and output 

accuracy. As facial images are generally produced in color, the calibration target should 
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incorporate color scales, a gray scale, and a calibrated measurement area. The 

recommended content of a color calibration target is outlined in ANSI IT8/4-20054, 

which is compliant with ISO standard 12641 parts 1 and 2.5

6.8 The minimum testing parameters in an IT8 calibration target card for reflection 

scanning are: 

6.8.1 264 color patches including rows for hue, chroma, and lightness, and columns for 

RGB and CMYK

6.8.2 24 stepped gray scale

Example of an IT8 calibration target

6.9 Scanner systems may incorporate calibration software and target reference 

profiles, or have automated calibration, and if not, calibration software can be purchased 

commercially. Scanner calibration software also typically includes measurement targets 

for the scanner attributes outlined in point 5.2.

6.10 Whilst use of a calibration target card will assist in determining the scanner capabilities 

and limitations, the target cards can also assist in routinely determining a scanners 

performance and color management. 

7. Scanner Calibration

7.1 Scanner calibration is different to camera calibration in that scanners generally 

operate with:

4 ANSI IT8/4-2005 Graphic Technology - Input data for characterization of 4-colour process printing

5

ISO 12641 - 1: 2016 Graphic technology - Prepress digital data exchange - Color targets for input scanner 

calibration, Part 1: Color targets for input scanner calibration and Part 2: Advanced color targets for input scanner 

calibration
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7.1.1 Almost constant conditions

7.1.2 Constant light source

7.1.3 A fixed color temperature

7.1.4 A relatively constant distance between the object and the sensor; as well as 

absolutes between the object and sensor.

7.2 Depending on the scanning device and calibration software, there may be a choice 

of different color gamut spectrums such as RGB, CMYK, Adobe RGB, sRGB, etc. for 

color management or color sync workflow. 

7.3 The following image is an example of the differences between color gamut 

spectrums with LAB being relative to the color spectrum visible by the human eye.

Example of differences between color gamuts

7.4 After running the scanner calibration process, the software will compare the result 

with the system calibration profile and will either make or suggest recommended 

corrections.

7.5 A Scanner Calibration Profile will be then be generated, which can be used as an 

image collection reference for the scanned image. It can also be used for comparative 

assessment purposes over the life of the scanner, and against other devices where color 

management or color syncing is required, such as monitors, printers, and imaging 

software.
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7.6 The use of a calibration target and calibration profile will not improve the 

accuracy of low range scanner products. 

7.7 It is essential that in testing the output of scanning products that there is a human 

assessment of the scanner output for color and image accuracy. 

7.8 For more information on scanner calibration and testing see Appendix 1: 

Scanning Procedures.

8. Recommended Scanning Process 

8.1 Once it has been determined that the scanner is accurately reproducing the color 

calibration target card and reference facial image, the scanner can now be used 

operationally.

8.2 The following scanner settings should be applied for all image capture:

8.2.1 Following scanner adjustment or enhancement options should not be selected as 

any enhancements should occur after scanning:

8.2.1.1 Auto photo orientation

8.2.1.2 Unsharp Mask

8.2.1.3 Descreening (unless print screening angle can be identified)

8.2.1.4 Color Restoration

8.2.1.5 Brightness

8.2.1.6 Contrast

8.2.1.7 Backlight Correction

8.2.1.8 Optical Character Recognition, including text enhancement

8.2.2 100% scan with ratio setting 1:1

8.2.3 Lossless output format (TIFF, PNG, etc.) 
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9. Calibrated Reference Targets

9.1 A calibrated reference target (IEEE Standard 167A-1995) includes measurements 

to accurately reflect the dimensions of the item being scanned. Reference targets should 

border the item being scanned without encroaching into the area of the item being 

scanned. 

Examples of reference target cards

9.2 In the scanner preview, use the marquee tool or similar tool to select the target 

item and the reference target card for scanning. Scanning of the complete item with 

reference card to create a master image file is generally required for evidentiary purposes 

and chain of custody requirements.
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10. Facial Recognition Minimum Recommended Scanning Resolution Settings

In addition to the above settings, the minimum recommended scanning practices for 

Facial Recognition enrollment are: 

ITEM TO BE 

SCANNED

BIT DEPTH 

MINIMUM

DPI MINIMUM COLOR CHANNEL

Colored prints 24 bit 300 RGB 

Black and White 

prints

16 bit 300 Grayscale

24 bit 300 RGB 

10.2 If image is to be scanned for the purposes of both Face Recognition and Facial 

Comparison, it is recommended that the minimum recommended scanning practices for 

Facial Comparison are used.

11. Facial Comparison Minimum Recommended Scanning Resolution Settings

11.2 To capture images suitable for facial comparison, the following additional scanning 

practices should be used:

ITEM TO BE 

SCANNED

BIT DEPTH 

MINIMUM

DPI MINIMUM COLOR CHANNEL

Colored prints 24 bit 600 

1200 recommended

RGB 

Black and White 

prints

16 bit Grayscale

(May not capture all 

gray tones)

24 bit RGB (Use of RGB 

enables all gray tones 

to be captured) 

12. Image Recording and Processing

12.2 It is recommended best practice that any image processing occur after scanning. 

12.3 There are guidelines and recommended best practices for recording of images and 

image processing such as:

12.3.1 ISO 21043-1-2018, Part 2 6

12.3.2 ASTM E2825-12 7

6

ISO 21043-2-2018 Forensic sciences - Part 2- Recognition recording collecting transport and storage of items

7 ASTM E2825-12: Standard Guide for Forensic Image Processing
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12.3.3 Documents published by the Scientific Working Group Imaging 

Technology (SWGIT)8, 9, 10

12.3.4 The basic image enhancement techniques for facial images after scanning 

as per SWGIT document Section 11, include: 

12.3.4.1 Cropping 

12.3.4.2 Brightness and contrast adjustment, including dodging and burning

12.4 Resizing

12.4.1 Image rotation/inversion (normalization)

12.4.2 Color balancing or color correction

12.5 For images to be used for enrollment into Facial Recognition, refer to FISWG 

Standard Practice/Guide for Image Processing to Improve Automated Facial 

Recognition Search Performance, which provides information on the recommended 

image processing techniques and procedural steps for Facial recognition searches.11

12.6 Additional image enhancement techniques, using software such as Adobe 

Photoshop and PaintShop Pro, include but not limited to:

12.6.1 Descreen12

12.6.2 Remove moiré

13. Obtaining a Facial Image from an Identity Document 

13.1. Identity documents such as passports and identity cards issued since 2005 may 

contain a chip with details of the document or biometrics such as a digital record of 

the facial image or fingerprint. 

13.2. When the facial image needs to be captured from the identity document containing 

a chip, it is highly recommended the digital image record be extracted from the chip 

by specialized equipment and software (passport/identity reader or Mobile APP) 

that is compliant with International Civil Aviation Organization (ICAO) document 

9303 Machine Readable Travel Documents.

8 SWGIT Section 5 Guidelines for Image Processing.pdf

9 SWGIT Section 11 Best Practices for Documenting Image Enhancement.pdf

10 SWGIT Section 13 Best Practices for Maintaining the Integrity of Digital Images and Digital Video

11 FISWG Standard Practice/Guide for Image Processing to Improve Automated Facial Recognition Search 

Performance 

12 http://www.descreen.net/eng/help/descreen/home/descreen_manual.htm
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Examples of Passport/identity 

reader and Mobile applications

13.3. Where there is no chip within the document or if equipment and software is not 

available to extract the digital image record, the printed facial image in the security 

document will need to be scanned.

13.4. The initial step to scanning a printed facial image from a security document is to 

determine whether there is a security lamina or clear/low opacity film over the 

facial image. 

13.4.1. If there is no lamina/film or if there is only a clear film present, the 

scanning processes described in section 6 should be undertaken.

13.4.2. If there is a low opacity film present, there is little that can be done to 

minimize the effects of the film opacity. The scanning processes described 

in section 6 should be undertaken and the scanning operator may need to 

consider image processing to mitigate the opacity effect.

13.4.3. If there is a security lamina present, in addition to the scanning processes 

described in section 6, the insertion of clear plastic film(s) (such as 

overhead projector sheets) between the glass scanning bed and the 

document can assist in preventing the diffraction of security feature(s), and 

will enable a cleaner/more accurate scan of the facial image. If diffractive 

or moiré patterns appear in the scan and output image, it may be necessary 

to increase the amount of clear plastic film(s) being used or offset their 

position. It should be noted that depending on the location of the security 

features, it may not be possible to totally prevent the security features 

diffraction from obscuring part of the face.
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Appendix 1

Scanning Procedures

The frequency of scanner calibration is dependent on laboratory accreditation requirements, 

frequency of use, scanner location and maintenance, use of optional settings, and the level of 

output quality required. 

Whilst it is preferable that a scanner is calibrated prior to every scan, it is not always practicable. 

If a scanner is well maintained, kept dust-free, is installed in a room with regulated temperature, 

and all pre-scan options such as descreen or unsharp mask are turned off, the scanner may only 

need yearly calibration or calibrated on a regular basis consistent with laboratory accreditation 

requirements.

The following steps for scanner calibration describe the basic process: 

1. Reset scanner settings to factory default, e.g., all scanner adjustment and enhancement 

options are de-selected.

2. Clean glass scanning bed/platen with a soft, lint-free cloth and a small amount of fluid 

using a mixture of 1-part vinegar to 3-parts water, or other agency approved solution.

3. Once glass scanning bed/platen is dry, place IT8 calibration target card on glass scanning 

bed/platen.

4. Locate the scanner software tool for scanner calibration.

5. Run the scanner calibration process.

6. The software will automatically generate and update scanner calibration profile.

7. Scan the IT8 target card at 600 DPI with a 100% 1:1 scan ratio to produce an output 

image for assessment.

8. Compare the scanner output image to the physical IT8 calibration target card to identify 

whether there are any image quality issues present to determine whether the scanner has 

been able to accurately reproduce the color, grayscale, or brightness/contrast of the 

content, size, and measurements within the target card. 

9. Scan a printed reference facial image at 600 DPI with a 100% 1:1 scan ratio to produce a 

real-life output image for assessment.

10.Compare the new scanner output image to the physical printed reference facial image to 

identify whether there are any image quality issues present to determine whether the 

scanner has been able to accurately reproduce the printed reference. 

11.It should be noted that depending on the printing process used to produce the reference 

facial image, there may appear to be image quality issues, when in fact the scanner has 

reproduced evidence of the printing process. For example, if the printed reference facial 

image is produced using a four-color inkjet printer, the output image may have the 
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appearance of pixilation when it is actually the individual color droplets from the inkjet 

printing visible when the image is viewed at 100%. For more information on potential 

printing effects in a scanned image, refer to FISWG Guide to the Effects of Printing 

Methods on Facial Images used for Comparisons.

12.Undertake agency approved image recording procedures and image processing 

techniques.

The following URL references show examples of commercial solutions for scanner calibration. 

These are included as references only and not any endorsement of any commercial product for 

scanner calibration. 

● https://www.silverfast.com/PDF/printer_calibration_review_en.pdf

● https://www.silverfast.com/download/docs/SF-IT8-en.pdf

● https://www.silverfast.com/PDF/Epson_V800_long_en.pdf

● https://www.silverfast.com/download/docu/manual,complete_en_2006-11-27.pdf
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Appendix 2

IQS Appendix F Summary: As NIST has evolved the Electronic Biometric Transmission 

Standard (EBTS) they have included guidelines for fingerprint scanners. All sections are 

extracted from IAFIS-DOC-01078-9.3: Electronic Biometric Transmissions Specification13

IQS Appendix F

These test procedures will be used by the FBI principally for certification of fingerprint 

systems; they may also be used in acceptance testing and in performance capability 

demonstrations as an indication of capability to perform. Equipment shall be tested to 

meet the requirements in normal operating modes, e.g., scanners shall not be tested at 

slower-than-normal operating speeds in an attempt to meet geometric accuracy 

specifications. A vendor may recommend alternate testing methods if the test 

procedures given in this appendix are not applicable or cannot be applied to the 

particular system under test.14

For the purpose of this document, the key section in Appendix F is this: “they may also be used 

in acceptance testing and in performance capability demonstrations as an indication of 

capability to perform.” It is acknowledged that scanning black and white fingerprint images is 

different than scanning color facial images, the core and basic capabilities of the scanner are still

critical to scan a quality resultant facial image. 

Scope and Purpose

The fingerprint scanner must be capable of producing images that exhibit good geometric 

fidelity, sharpness, detail rendition, gray-level uniformity, and gray-scale dynamic range, 

with low noise characteristics. The images must be true representations of the input 

fingerprints without creating any significant artifacts, anomalies, false detail, or cosmetic 

image restoration effects.

2.1Linearity

Requirement:

When measuring a stepped series of uniform target reflectance patches (e.g., step tablet) 

that substantially cover the scanner‘s gray range, the average value of each patch shall be 

within 7.65 gray-levels of a linear, least squares regression line fitted between target 

reflectance patch values (independent variable) and scanner output gray-levels (dependent 

variable).

2.2Geometric Accuracy

Requirement (across-bar):

When scanning a multiple, parallel bar target, in both vertical bar and horizontal bar 

orientations, the absolute value of the difference between the actual distance across parallel 

target bars and the corresponding distance measured in the image shall not exceed the 

following values for at least 99% of the tested cases in each print block measurement area 

and in each of the two orthogonal directions.

13 https://www.fbibiospecs.cjis.gov/Document/Get?fileName=EBTS_v9.1_Final.pdf

14 https://www.fbibiospecs.cjis.gov/Document/Get?fileName=EBTS_v9.1_Final.pdf
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2.3Spatial Frequency Response

Requirements:

The spatial frequency response shall be measured using a continuous tone sine wave target 

denoted as Modulation Transfer Function (MTF) measurement unless the scanner cannot 

obtain adequate tonal response from this target, in which case a bi-tonal bar target shall be 

used to measure the spatial frequency response, denoted as Contrast Transfer Function 

(CTF) measurement. When measuring the sine wave MTF, it shall meet or exceed the 

minimum modulation values given in Table F-2 in both the detector row and detector 

column directions and over any region of the scanner‘s field of view. When measuring the 

bar CTF, it shall meet or exceed the minimum modulation values defined by equation 2-1 

or equation 2-2 (whichever applies) in both the detector row and detector column 

directions and over any region of the scanner‘s field of view. CTF values computed from 

equations 2-1 and 2-2 for nominal test frequencies are given in Table F-3. None of the 

MTF or CTF modulation values measured at specification spatial frequencies shall exceed 

1.05.

2.4Signal-to-Noise Ratio

Requirement:

The white signal-to-noise ratio and black signal-to-noise ratio shall each be greater than or 

equal to 125 in at least 97% of respective cases within each print block measurement area.

2.5Gray-Level Uniformity

Requirement – adjacent row, column uniformity:

At least 99% of the average gray-levels between every two adjacent quarter-inch-long 

rows and 99% between every two adjacent quarter-inch-long columns within each imaged 

print block area shall not differ by more than 1.0 gray-levels when scanning a uniform

low-reflectance target and shall not differ by more than 2.0 gray-levels when scanning a 

uniform high-reflectance target.

Requirement – pixel-to-pixel uniformity:

For at least 99.9% of all pixels within every independent 0.25 by 0.25 inch area located 

within each imaged print block area, no individual pixel‘s gray-level shall vary from the 

average by more than 22.0 gray-levels when scanning a uniform high-reflectance target 

and shall not vary from the average by more than 8.0 gray-levels when scanning a uniform 

low-reflectance target.

Requirement – small area uniformity:

For every two independent 0.25 by 0.25 inch areas located within each imaged print block 

area, the average gray-levels of the two areas shall not differ by more than 12 gray-levels 

when scanning a uniform high-reflectance target and shall not differ by more than 3.0 

gray-levels when scanning a uniform low-reflectance target.
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All of these tests utilize a specific target which is placed on the scanner after which the specific 

tests are run on the resultant scanned images:15

Catalog Part No: QA-74-P-RM

Product Name: FBI Mitre Scanner Image Quality Test (SIQT) Chart

Drawing / Photo of part:

The above image is an approximate representation of the actual product.

Specifications are subject to change without 

notice.

General Description: This chart is used for evaluation of reflective fingerprint scanners. 

Test elements contained on this chart can be used for tests as described in, Test Procedures 

for Verifying IAFIS Image Quality Requirements for Fingerprint Scanners and Printers. 13

Image Description: The test chart includes the following items.

15 https://www.appliedimage.com/files/VCX2do/QA-74 FBI Mitre Fingerprint Scanner Test QA-74_spec_v1-

04.pdf 
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● Sixteen stepped density patches (7 x 11 mm each)

● Resolution bar patterns ranging in frequency from 1.0 to 19.6 

cycle per mm, one each in horizontal and vertical orientation

● Reference bars 2.5 x 10 mm (horizontal and vertical, adjacent to 

resolution groups for geometric accuracy)

● Horizontal and vertical Ronchi patterns (1 cycle per mm for 

geometric accuracy)

● Mid-scale density patches along each chart-edge (grey areas for 

uniformity)

● Large mid-scale patch, 75 x 80 mm (grey area for uniformity)

This guideline does not assume that an agency would actually attempt to execute the Appendix F 

tests, but is included to show the applicability and usage of selecting and using a scanner which 

has passed Appendix F. 

All scanners which have passed Appendix F and been certified by CJIS can be found at: 

https://www.fbibiospecs.cjis.gov/Certifications