SPECTRAL IMAGING SYSTEM FOR REMOTE AND NONINVASIVE DETECTION OF TARGET SUBSTANCES USING SPECTRAL FILTER ARRAYS AND IMAGE CAPTURE ARRAYS

• US 20160069743A1
• Filed: 06/17/2015
• Published: 03/10/2016
• Est. Priority Date: 06/18/2014
• Status: Active Grant

• Current Assignee: Innopix Incorporated
• Original Assignee: Innopix Incorporated
• Inventors: McQuilkin, Gary L., Engelke, Gregory L.
• Granted Patent: US 9,551,616 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A22B 5/007 Non-invasive scanning of carcasses, e.g. using image recognition, tomography, X-rays, ultrasound analysing meat, e.g. search for foreign embedded objects G01N33/12; image analysis G06T7/00
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/14507 specially adapted for measuring characteristics of body fluids other than blood devices for taking samples of body liquids A61B10/0045
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: G01J 2003/1213 Filters in general, e.g. dichroic, band
• CPC Class Codes: G01J 2003/123 Indexed discrete filters
• CPC Class Codes: G01J 2003/1239 and separate detectors
• CPC Class Codes: G01J 2003/2826 Multispectral imaging, e.g. filter imaging
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/0297 Constructional arrangements for removing other types of optical noise or for performing calibration
• CPC Class Codes: G01J 3/12 Generating the spectrum; Monochromators
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01N 2021/1793 Remote sensing
• CPC Class Codes: G01N 2021/3137 with selection of wavelengths after the sample
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/31 : Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 2201/129 : Using chemometrical methods
• CPC Class Codes: G02B 5/201 : in the form of arrays
• CPC Class Codes: G16H 30/40 : for processing medical images, e.g. editing

Abstract

An approach to noninvasively and remotely detect the presence, location, and/or quantity of a target substance in a scene via a spectral imaging system comprising a spectral filter array and image capture array. For a chosen target substance, a spectral filter array is provided that is sensitive to selected wavelengths characterizing the electromagnetic spectrum of the target substance. Elements of the image capture array are optically aligned with elements of the spectral filter array to simultaneously capture spectrally filtered images. These filtered images identify the spectrum of the target substance. Program instructions analyze the acquired images to compute information about the target substance throughout the scene. A color-coded output image may be displayed on a smartphone or computing device to indicate spatial and quantitative information about the detected target substance. The system desirably includes a library of interchangeable spectral filter arrays, each sensitive to one or more target substances.

Claims

1. A spectral imaging system for remotely and noninvasively detecting the presence and location of one or more target substances in a scene, said system comprising:

a) an image capture array comprising a plurality of image capturing elements;

b) a plurality of spectral filter arrays, wherein;

(i) each spectral filter array is pre-associated with at least one corresponding target substance;

(ii) each spectral filter array includes a plurality of spectral filtering elements, wherein each spectral filtering element of said plurality of spectral filtering elements selectively passes a pre-selected bandwidth portion of the electromagnetic spectrum that is pre-associated with a spectral characteristic of the corresponding target substance;

(iii) each of the plurality of spectral filter arrays is selectable and positionable on demand to be aligned with the image capture array such that each of at least two or more of the image capturing elements is optically aligned with at least one corresponding spectral filtering element in a manner effective to capture spectrally filtered image information comprising image pixels; and

c) program instructions that use the spectrally filtered image information to determine if image pixels are associated with spectral responses matching the target substance and to determine and output information indicative of the presence and location of the at least one associated target substance in the scene.

2. A method of remotely and noninvasively detecting at least one target substance in a scene, comprising the steps of:

a) providing an image capture array comprising a plurality of image capturing elements;

b) providing a spectral filter array, wherein;

(i) the spectral filter array is associated with at least one corresponding target substance;

(ii) the spectral filter array includes a plurality of spectral filtering elements, wherein at least two spectral filtering elements of said plurality each selectively passes a pre-selected bandwidth portion of the electromagnetic spectrum that is pre-associated with a spectral characteristic of the corresponding target substance;

(iii) the spectral filter array is aligned with the image capture array such that each of at least two or more of the image capturing elements is optically aligned with at least one corresponding spectral filtering element in a manner effective to capture spectrally filtered image information comprising image pixels;

c) aiming the image capturing elements of the image capture array at the scene;

d) using the image capture array and the spectral filter array to capture a plurality of filtered images of the scene; and

e) using information comprising the filtered, captured images to determine if image pixels are associated with spectral responses matching the target substance and to determine and output information indicative of the presence and location of the at least one associated target substance in the scene.

3. A method of providing a spectral imaging system, comprising the steps of:

a) providing spectral information for a target substance;

b) using the spectral information to associate at least first and second bandwidth portions of the electromagnetic spectrum with spectral characteristics of the target substance;

c) providing a spectral filter array comprising a plurality of spectral filtering elements, wherein a first spectral filtering element selectively passes the first bandwidth portion of the electromagnetic spectrum and a second spectral filtering element selectively passes a second bandwidth portion of the electromagnetic spectrum; and

d) causing an image capture array comprising a plurality of image capturing elements to be aligned with the spectral filter array in a manner effective to capture first and second, filtered images through the first and second spectral filtering elements in a manner such that image pixels of the filtered images that match the spectral characteristics of the target substance indicate the presence and location of the target substance in a scene.

4. A method of processing image information, comprising the steps of:

a) capturing a first filtered, spectral image of at least a portion of a scene wherein the first filtered spectral image is obtained using a first spectral filter element that selectively transmits a first bandwidth portion of the electromagnetic spectrum within which a target substance has a first pre-determined spectral response;

b) simultaneously capturing a second filtered, spectral image of at least a portion of the scene, wherein the second filtered spectral image is obtained using a second spectral filter element that selectively transmits a second bandwidth portion of the electromagnetic spectrum within which the target substance has a second pre-determined spectral response, and wherein the first and second filtered, spectral images comprise image pixels; and

c) using information comprising the first and second filtered, spectral images to determine if image pixels are associated with spectral responses matching the target substance and to determine and output information indicative of the presence and location of the at least one associated target substance in the scene;

5. A spectral imaging system, comprising:

a) an image capture array comprising a plurality of image capturing elements;

b) a plurality of spectral filter arrays, wherein;

(i) each spectral filter array is pre-associated with at least one corresponding target substance; and

(ii) each spectral filter array includes a plurality of spectral filtering elements, wherein each spectral filtering element of said plurality of spectral filtering elements selectively passes a pre-selected bandwidth portion of the electromagnetic spectrum that is pre-associated with a spectral characteristic of the corresponding target substance;

(iii) each of the plurality of spectral filter arrays is selectable and positionable on demand to be aligned with the image capture array such that each of at least two or more of the image capturing elements is optically aligned with at least one corresponding spectral filtering element in a manner effective to capture spectrally filtered image information in a manner such that image pixels of the filtered images that match the spectral characteristics of the target substance indicate the presence and location of the target substance in a scene.

6. A method of providing an imaging system for detecting a target substance in a scene, comprising the steps of:

a) providing spectral information for a target substance;

b) using the spectral information to associate a plurality of specific bandwidth portions of the electromagnetic spectrum with spectral characteristics of the target substance;

c) using the selected bandwidth portions to provide a spectral imaging system comprising;

i) an image capture array comprising at least two image capturing elements, each image capturing element capable of independently capturing an image of the scene;

ii) a filter array comprising a plurality of filter elements, each sensitive to a pre-determined specific bandwidth portion, and wherein the filter elements are each aligned with a corresponding camera element of the image capture array in a manner such that the image capture array captures image information for a plurality of independent spectrally filtered images;

iii) program instructions that use the captured image information to identify at least one spatial location of the target substance in the scene.

7. The method of claim 6, wherein the programming instructions align captured image information corresponding to the spatial position of objects in the scene.

8. The method of claim 6, wherein the program instructions perform an illumination calibration.

9. The method of claim 6, wherein image information corresponding to at least one captured image is calibrated to account for a variation in a sensor sensitivity.

10. The method of claim 6, wherein image information corresponding to at least one captured image is calibrated to account for a variation in filter transmission efficiency.

11. The method of claim 6, wherein the filter array comprises a plurality of spectral filter elements incorporated into a card.

12. The method of claim 6, wherein the system comprises a plurality of filter arrays, and wherein the filter arrays are independently selectable and alignable on demand with the image capture array to allow the system to capture filtered spectral information for one or more target substances pre-associated with a selected and aligned filter array.

13. The method of claim 12, wherein using a selected and aligned filter array automatically causes the system to choose program instructions to detect a pre-associated target substance corresponding to the filter array being used.

14. The method of claim 6, wherein the program instructions use the captured image information to generate an output that comprises information indicative of a quantity of the target substance.

15. The method of claim 6, further comprising the step of providing at least one of a smartphone, tablet computer, laptop computer, desktop computer, head-mounted computer, mobile computing device, communicatively coupled to the image capture array.

16. The method of claim 6, comprising using an in-frame reference that provides image information indicative of an intensity of an illumination source.

17. The methods of claim 6, comprising using an in-frame reference that provides image information to calibrate the spectral imaging system.

18. The method of claim 14, further comprising using a colormap to compute a color intensity indicative of a quantity of the target substance at a given location in an output image.

19. An imaging system for detecting a target substance within a scene, comprising:

a) an image capture array with at least two image capturing elements, each image capturing element capable of independently capturing an image of a scene;

b) a spectral filter array comprising a plurality of spectral filtering elements that are each optically aligned with a corresponding image capturing element of the image capture array in a manner such that the image capturing array captures a plurality of independently, selectively, and spectrally filtered images, and wherein each spectral filtering element of said plurality of spectral filtering elements selectively passes a pre-selected bandwidth portion of the electromagnetic spectrum that is pre-associated with a spectral characteristic of the corresponding target substance;

c) program instructions that use a plurality of captured images to provide an output indicative of the presence and location of the target substance is in the scene.

20. The system of claim 19, wherein the system comprises a plurality of interchangeable filter cards, wherein each filter card comprises a spectral filter array, wherein each spectral filter array comprises a plurality of spectral filtering elements and wherein each filter card is pre-associated with at least one corresponding target substance.

21. The imaging system of claim 20, wherein at least one filter card is pre-associated with two or more corresponding target substances.

22. The imaging system of claim 19, wherein the program instructions use captured image information to compute at least one of the following:

a) information indicative of at least one ratio of spectral amplitude information at two or more wavelengths;

b) information indicative of at least one difference of spectral amplitude information at two or more wavelengths;

c) information indicative of at least one area associated with spectral information; and

/or

d) a computation, using spectral image information, wherein the computation is selected from one or more of the following;

eigenvector, basis function, least squares, principle component analysis, matched filter, neural networks, cross-correlation, multivariate analysis;

23. The imaging system of claim 19, wherein the program instructions compute an illumination calibration.

24. The imaging system of claim 23, wherein the program instructions comprise information indicative of a listing comprising a plurality of predetermined calibration curves for a plurality of light sources.

25. The imaging system of claim 24, wherein the light sources include at least one sunlight, incandescent light, fluorescent light, mercury vapor light, ultraviolet light, and an LED source.

26. A method of detecting a target substance in a scene, comprising the steps of:

a) using an image capture array and a spectral filter array, to simultaneously capture a plurality of spectrally filtered images of the scene, wherein the spectral filter array is sensitive to at least two bandwidth portions of the electromagnetic spectrum which provide spectral information effective to identify the target substance; and

b) using the spectrally filtered images to generate an output indicative of the presence and the one or more locations of the target substance in the scene.

27. The method of claim 26, wherein the output comprises an image of the scene comprising color information to indicate the presence and location of the target substance in the image.

28. The method of claim 27, wherein portions of the image at which the target substance is not located are shown in grayscale.

29. The method of claim 26, wherein a non-natural color is assigned to pixels of the image that correspond to locations of the target substance in the scene.

30. The method of claim 26, comprising using an in-frame reference that provides image information indicative of a known amount of a detected target substance.

31. The method of claim 26, comprising capturing reflected image information from the scene.

32. The method of claim 26, comprising capturing transmission image information from the scene.

33. A spectral filter system, comprising a plurality spectral filter arrays, wherein each spectral filter array comprises a plurality of spectral filtering elements, and wherein each spectral filter array is pre-associated with at least one target substance, and wherein each spectral filtering element of said plurality of spectral filtering elements selectively passes a pre-selected bandwidth portion of the electromagnetic spectrum that is pre-associated with a spectral characteristic of the corresponding target substance.

34. The system of claim 33, further comprising information indicative of a spectral characteristic of a target substance within each of a plurality of distinct bandwidth portions of the electromagnetic spectrum, each of said bandwidth portions having a wavelength span of up to about 30 nm.

35. The system of claim 34, wherein each wavelength span is up to about 10 nm.

36. The system of claim 33, wherein the spectral filter system is an interchangeable spectral filter card.

37. The system of claim 33, wherein the spectral filter system comprises program instructions that control a filtering bandwidth for two or more electronic filter elements.