Patent Application: US-201514840013-A

Abstract:
there is disclosed a novel system and method for multiview , multispectral , polarimetric , light - field , and high dynamic range imaging in a concurrent manner specifically capturing information at different spectral bands and light polarizations simultaneously . the present system and method is capable of concurrent imaging of multiple spectral bands , proportional or greater than the number of filters used in the device , concurrent imaging of multiple light polarizations , acquiring images at different point - of - view of the same scene and / or object that allow for topographical reconstruction , concurrent imaging of the multiple depth of fields that allow for light - field imaging , and concurrent imaging of multiple simulated exposures of the detector that allow for high dynamic range imaging , all at the same time using a single sensor in the same imaging system enclosure .

Description:
as noted above , the present disclosure relates to an improved system and method for capturing multispectral ( ms ) images . in an embodiment , the system and method simultaneously captures multiview images at multiple discrete spectral bands , in the visible and nir , and light polarizations concurrently utilizing improved imaging technologies and image processing techniques . a term is used herein which refers to concurrent multiview , spectral - polarimetric , light - field , hdr imaging ( cmslhi ). it will be appreciated that , for simplicity and clarity of illustration , where considered appropriate , reference numerals may be repeated among the figures to indicate corresponding or analogous elements or steps . in addition , numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein . however , it will be understood that the embodiments described herein may be practiced without these specific details . in other instances , well - known methods , procedures and components have not been described in detail , so as not to obscure the embodiments described herein . furthermore , this description is not to be considered as limiting the scope of the embodiments described herein in any way , but rather as merely describing the implementation of the various embodiments described herein . finally , while all of the embodiments described herein are described to provide nine views that are concurrently imaged for illustration purposes , the invention is not limited to providing nine views and other embodiments of this invention may provide less than nine views or more than nine views that are concurrently imaged . with reference to fig1 , 1 a , 2 , 2 a , 3 , and 3 a , a detector 100 and an imaging lens system 200 are shared between all embodiments presented , and can be combined to perform as a “ camera ”. a person skilled in the art will understand that any detector 100 - lens 200 combination may be used as the image capturing ( camera ) portion of the system and method without limiting the scope of the embodiments described herein . with reference to fig1 , a concurrent multiview , ms , polarimetric , hdr imaging embodiment of the present system and method is illustrated . the field multiplying element 600 houses a plurality of reflective surfaces , i . e . mirrors , 601 , 602 , 603 , 604 , 606 , 607 , 608 , 609 . in this illustrative embodiment , there exists no mirror for the “ zenith ” view which passes straight through element 600 without reflecting off any mirror . each of the mirrors 601 - 609 are adapted to present light entering from the fov from an independent , mutually exclusive perspective of the fov . in this illustrative embodiment , a total of nine perspective views then encounter a filter housing element 300 which in this illustrative example includes nine independent permutations of spectral bandpass filters and / or polarizing filters and / or nd filters 301 through 309 . following the filtering phase , the nine perspective views are then concurrently imaged by the camera . it will be appreciated that the reflecting surfaces , 601 - 609 , need not to be a planar mirror and instead can be any planar reflective surfaces or non - planar ( focusing ) reflective surfaces negating the need for the imaging lens system 200 . referring to fig1 a , concurrent multiview , ms , polarimetric , and hdr embodiments of the system and are shown , while illustrating a select few light beam paths through the optical elements by way of example . in this illustration , a subject 700 scatters light that is shown onto it in all directions . it will be appreciated that an illumination source with prescribed spectral and polarization characteristics , external or internal to the embodiment , can be used to illuminate the subject 700 in preparation for imaging , additionally , the subject 700 can be imaged in an ambient lighting condition . a number of beams 802 , 805 , and 808 of light are a selection of three of many beams of light that can be observed scattered by the subject 700 . these beams 802 , 805 , and 808 are also a selection of three of the nine beams that are observed by the system and method . the beams 802 and 808 are each reflected and redirected off of their corresponding mirrors , 602 and 608 housed in the field multiplying element 600 . the beam 805 is the “ zenith ” view , and hence does not encounter a mirror in the field multiplying element 600 . each of the beams 802 , 805 , and 808 then encounters a permutation of spectral bandpass filters and / or polarization filters and / or nd filters in the filter housing element 300 , as illustrated in fig1 , and are accordingly filtered . the beams then continue to the camera ( 100 , 200 ) and the filtered images of subject 700 from each of the beams 802 , 805 , and 808 are then focussed at different positions 102 , 105 , and 108 on a sensor 150 located in the detector 100 . the sensor 150 may be any type of sensor technology ( e . g . charge - coupled devices ccd , complementary metal - oxide - semiconductor cmos , indium gallium arsenide ingaas ) suitable for capturing the filtered images of subject 700 as a composite image file is then stored on a non - volatile memory , such as a flash memory card 170 . the camera may alternatively be tethered by cable or linked wirelessly to a computer , as represented for example by a generic computing device 1000 described further below with reference to fig4 , such that the composite image file can be stored directly into storage of the computing device 1000 . now referring to fig2 , another embodiment of the present system and method is illustrated . in this embodiment , the field multiplying element 600 houses a plurality of planar reflective surfaces , such as mirrors 601 , 602 , 603 , 604 , 606 , 607 , 608 , 609 . there exists no mirror for the zenith view passing straight through element 600 . each of the mirrors presents the light of the fov from an independent mutually exclusive perspective of the fov . each of the nine perspective views encounter their respective field lens , 501 through 509 , contained in the lens housing element 500 . the lenses in this element can have the same or different na , and therefore focal length . the total of nine perspective views then encounter the filter housing element 300 which comprise of nine independent permutations of spectral bandpass filters and / or polarizing filters and / or nd filters 301 through 309 . following the filtering phase , the nine perspective views are then concurrently imaged by the camera . as will be appreciated , the reflecting surfaces need not be planar mirror , and can be any planar reflective surfaces or non - planar ( focusing ) reflective surfaces , negating the need for the lens housing element 500 or the imaging lens system 200 . referring to fig2 a , a concurrent multiview , ms , polarimetric , light - field , and hdr imaging embodiment of the system and method is illustrated while illustrating a select few light beam paths through the optical elements of the system and method . the subject 700 scatters light that is reflected off of it in all directions . the beams 802 , 805 , and 808 are a selection of three of many beams of light that can be observed scattered by the subject 700 . they are also a selection of three of the nine beams that are observed by the system and method . the beams 802 and 808 are each reflected and redirected off of their corresponding mirrors , 602 and 608 housed in the field multiplying element 600 . the beam 805 is the zenith view hence does not encounter a mirror in the field multiplying element 600 . each of the beams 802 , 805 , and 808 will then encounter their respective field lens 502 , 505 , and 508 in the lens housing element 500 . depending on the na of the field lens , only the light scattered from a specific depth , 705 , 702 , and 708 in this case , in the fov will be collimated toward the filter housing element 300 . each one of the beams will then encounter their respective permutations of spectral bandpass filters and / or polarization filters and / or nd filters in the filter housing element 300 , then are accordingly filtered . the beams then continue to the camera and their images are formed at positions 102 , 105 , and 108 on sensor 150 located in the detector 100 . the images are then stored in a memory card 170 or transferred to a tethered computing device for storage . it will be apparent that the notion of imaging within the depth of the subject 700 is only possible with the correct combination of the field lenses 501 through 509 and spectral filters and polarizations filters 301 through 309 . thus , it will be appreciated that an illumination source with prescribed spectral and polarization characteristics , external or internal to the embodiment , can be used to illuminate the subject 700 in preparation for imaging , additionally , the subject 700 can be imaged in ambient lighting condition and the imaging lens system 200 can alternatively be removed from the embodiment without affecting the function of the embodiment . with reference to fig3 , another embodiment of the system and method is illustrated . in this embodiment , a parabolic field lens housing element 400 is used to contain nine lenses , 401 through 409 , of similar or different na , and therefore focal length . the parabolic nature of element 400 is to enable all nine lenses , contained within , to observe the same fov all from independent mutually exclusive perspectives . each of the nine perspective views then encounter the filter housing element 300 which comprise nine independent permutations of spectral bandpass filters and / or polarizing filters and / or nd filters 301 through 309 . following the filtering phase the nine perspective views are then concurrently imaged by the camera . referring to fig3 a , the concurrent multiview , ms , polarimetric , light - field , and hdr imaging embodiment of the system and method is illustrated while illustrating a select few light beam paths through the optical elements of the system and method . the subject 700 scatters light that is shown onto it in all directions . the beams 802 , 805 , and 808 are a selection of three of many beams of light that can be observed scattered by the subject 700 . they are also a selection of three of the nine beams that are observed by the system and method . the beams 802 , 805 , and 808 each encounter their corresponding lens , 402 , 405 , and 408 , housed in the parabolic field lens housing element 400 . the beams emerging from the field lenses then encounter their respective permutations of spectral bandpass filters and / or polarization filters and / or nd filters , 302 , 305 , and 308 contained in the filter housing element 300 . the filtered beams then continue to the camera and their images are formed at positions 102 , 105 , and 108 on a sensor 150 in the detector 100 , and stored as previously described . it will be appreciated that by using similar spectral bandpass filters or polarizing filters or nd filters in 300 s , while using lenses of differing nas 400 s this embodiment can be used for light - field imaging . if the lenses where to have the similar na , with correct combination of nd filters , hdr imaging would be enabled in this embodiment . it will be apparent that the notion of imaging within the depth of the subject 700 is only possible with the correct combination of the field lenses 401 through 409 and spectral filters and / or polarizations filters 301 through 309 . it will also be appreciated that and illumination source with prescribed spectral and polarization characteristics , external or internal to the embodiment , can be used to illuminate the subject 700 for imaging , additionally , the subject 700 can be imaged in ambient lighting condition . moreover , the imaging lens system 200 can alternatively be removed from the embodiment without affecting the function of the embodiment . in all embodiments the captured image is stored in the storage device 170 or in storage of a tethered computing device may be retrieved , processed and displayed , thereby making the captured image available for interpretation . a single image per acquisition is stored which contain information about all povs as well as all spectral bands and polarization states . as a specific pov is recorded to a specific area of the sensor 150 , it will be appreciated that parts of the captured image may be predefined and identified as having a particular pov with particular type of multispectral and polarimetric filtering applied . the image that has been stored can be later retrieved from the storage device and may be processed to obtain the ms and polarimetric properties of the subject 700 . the image that has been stored can be later retrieved from the storage device and may be processed to produce a multispectral or a hyperspectral image cube where the number of spectral channels is proportional or greater than the number of filters used in the device . as an example , additional channels in the spectral image cube can be produced by the present invention using numerical spectral disassociation methods such as those based on wiener estimation and regression modeling , although other methods can be used in other embodiments . the image that has been stored can also be later retrieved from the storage device and may be processed to produce a 3d image / topographical map of the subject 700 . the image may also be processed to produce a depth image and light - field information of the subject 700 or the fov , and may also be processed to obtain hdr information corresponding to the subject 700 or the fov . now referring to fig4 , shown is a schematic block diagram of a generic computing device . a suitably configured computer device , and associated communications networks , devices , software and firmware may provide a platform for enabling one or more embodiments as described above . by way of example , fig4 shows a generic computer device 1000 that may include a central processing unit (“ cpu ”) 1002 connected to a storage unit 1004 and to a random access memory 1006 . the cpu 1002 may process an operating system 1001 , application program 1003 , and data 1023 . the operating system 1001 , application program 1003 , and data 1023 may be stored in storage unit 1004 and loaded into memory 1006 , as may be required . computer device 1000 may further include a graphics processing unit ( gpu ) 1022 which is operatively connected to cpu 1002 and to memory 1006 to offload intensive image processing calculations from cpu 1002 and run these calculations in parallel with cpu 1002 . an operator 1010 may interact with the computer device 1000 using a video display 1008 connected by a video interface 1005 , and various input / output devices such as a keyboard 1010 , pointer 1012 , and storage 1014 connected by an i / o interface 1009 . in known manner , the pointer 1012 may be configured to control movement of a cursor or pointer icon in the video display 1008 , and to operate various graphical user interface ( gui ) controls appearing in the video display 1008 . the computer device 1200 may form part of a network via a network interface 1017 , allowing the computer device 1200 to communicate with other suitably configured data processing systems or circuits . one or more different types of sensors 1030 connected via a sensor interface 1032 may be used to search for and sense input from various sources . the sensors 1030 may be built directly into the generic computer device 1000 , or optionally configured as an attachment or accessory to the generic computer device 1000 . thus , in an aspect , there is provided a system for capturing a multiview , multispectral image of a subject , comprising : a field multiplying element housing a plurality of reflective surfaces for obtaining multiple point - of - view ( pov ) images of a subject , and directing each pov image along one of a plurality of different beam paths ; and a filter housing element adapted to receive a plurality of independent filters , each filter adapted to receive one pov image along one of the plurality of different beam paths ; wherein the multiple pov images are directed to different areas of a sensor for capturing the multiple pov images simultaneously in an image file . in an embodiment , the field multiplying element is adapted to provide a zenith view of the subject through its center , and a plurality of reflected views of the subject via the plurality of reflective surfaces arranged in a ring around the center of the field multiplying element . in another embodiment , the plurality of reflective surfaces are substantially equal in size and arranged circularly around an inner surface of the ring around the center of the field multiplying element . in another embodiment , the plurality of reflective surfaces are substantially flat . in another embodiment , the filter housing element is adapted to receive the plurality of independent filters in an array , each filter of the array adapted to receive one pov image along one of the plurality of different beam paths . in another embodiment , the filter housing element includes one or more polarizing filters for concurrent imaging of multiple light polarizations . in another embodiment , the filter housing element includes one or more spectral bandpass filters and / or neutral density filters for concurrent imaging of a high dynamic range of light intensities . in another embodiment , the system further comprises a lens housing element adapted to receive a plurality of field lenses , each field lens adapted to align with one of the plurality of different beam paths of the field multiplying element and one of the plurality of independent filters in the filter housing element . in another embodiment , the plurality of field lenses in the lens housing element are adapted to perform light - field imaging for capturing information pertaining to light intensity going through each point in space at different directions . in another embodiment , the plurality of field lenses in the lens housing element are adapted to be directed and focussed independently , thereby allowing all multiview , multispectral images of the subject to be captured simultaneously . in another aspect , there is provided a system for capturing a multiview , multispectral image of a subject , comprising : a lens housing element including a plurality of lenses for obtaining multiple points - of - view ( pov ) images of a subject , and directing each pov image along one of a plurality of different beam paths ; and a filter housing element adapted to include a plurality of independent filters , each filter adapted to receive one pov image along one of the plurality of different beam paths ; wherein the multiple pov images are directed to different areas of a sensor for capturing the multiple pov images simultaneously in an image file . in an embodiment , the plurality of lenses in the lens housing element are arranged in a parabolic dish configuration to produce a series of images of the subject . in another embodiment , the filter housing element is adapted to receive the plurality of independent filters in an array , each filter of the array adapted to receive one pov image along one of the plurality of different beam paths . in another embodiment , the filter housing element includes one or more polarizing filters for concurrent imaging of multiple light polarizations . in another embodiment , the filter housing element includes one or more spectral bandpass filters and / or neutral density filters for concurrent imaging of a high dynamic range of light intensities . in another embodiment , the plurality of field lenses in the lens housing element are each adapted to align with one of the plurality of different beam paths of the field multiplying element and one of the plurality of independent filters in the filter housing element . in another embodiment , the plurality of field lenses in the lens housing element are adapted to perform light - 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