SWIR targeted agile raman (STAR) system for on-the-move detection of emplace explosives

• US 8,379,193 B2
• Filed: 06/17/2010
• Issued: 02/19/2013
• Est. Priority Date: 08/27/2008
• Status: Active Grant

• Current Assignee: Chemimage Corporation
• Original Assignee: Chemimage Corporation
• Inventors: Gardner, Charles W. Jr., Nelson, Matthew
• Primary Examiner(s): Geisel, Kara E
• Application Number:
  US12/802,994
• Publication Number:
  US 20120147358A1
• Time in Patent Office: 978 Days
• Field of Search: 356/301, 356 72- 73, 250/332
• US Class Current: 356/73
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0221 the fibers defining an entry slit
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• 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: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 2021/1738 Optionally different kinds of measurements; Method being valid for different kinds of measurement
• CPC Class Codes: G01N 2021/174 either absorption-reflection or emission-fluorescence
• CPC Class Codes: G01N 2021/1744 either absorption or scatter
• CPC Class Codes: G01N 21/6456 Spatial resolved fluorescence measurements; Imaging
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

The present disclosure provides for a system and method for detecting explosives and other materials in a sample scene. First interacted photons are produced from a target area wherein the first interacted photons are generated via solar radiation. The first interacted photons are assessed to thereby generate a SWIR hyperspectral image. The SWIR hyperspectral image is analyzed to identify an area of interest likely of comprising an explosive material. The area of interest is illuminated using laser light illumination to generate second interacted photons from the area of interest. These second interacted photons are assessed to determine whether it not an explosive material is present in the area of interest. The system and method may be configured in standoff, OTM, static and UGV configurations.

Claims

1. A method comprising:

illuminating a target area comprising at least one unknown sample to thereby generate a plurality of first interacted photons wherein said first interacted photons are selected from the group consisting of;

photons absorbed by said target area, photons reflected by said target area, photons scattered by said target area, photons emitted by said target area, and combinations thereof;

assessing said plurality of first interacted photons using a spectroscopic device wherein said assessing comprises obtaining a test SWIR data set representative of said target area;

analyzing said test SWIR data set to thereby identify an area of interest in said target area;

illuminating said area of interest using a laser light source to thereby generate a plurality of second interacted photons wherein said second interacted photons are selected from the group consisting of;

photons absorbed by said area of interest, photons reflected by said area of interest, photons scattered by said area of interest, photons emitted by said area of interest, and combinations thereof;

assessing said plurality of second interacted photons using a spectroscopic device wherein said assessing comprises obtaining a test Raman data set representative of said area of interest;

analyzing said test Raman data set to thereby identify said area of interest as comprising at least one of;

an explosive material, a concealment material, a formulation additive of an explosive material, a binder of an explosive material, a non-explosive material, and combinations thereof.

2. The method of claim 1 further comprising surveying a sample scene using a video capture device to thereby identify a target area based on at least one of size of said target area, shape of said target area, color of said target area, and combinations thereof.

3. The method of claim 1 wherein said analyzing of said test SWIR data set comprises searching a reference SWIR database in accordance with the test SWIR data set in order to identify a known SWIR data set from said reference SWIR database, wherein said reference SWIR database contains a plurality of known SWIR data sets, and wherein each known SWIR data set is associated with a known material.

4. The method of claim 1 wherein said test SWIR data set comprises at least one of:

a plurality of spatially resolved SWIR spectra representative of said target SWIR image representative of said target area, and combinations thereof.

5. The method of claim 1 wherein said test SWIR data set comprises a SWIR hyperspectral image representative of said target area wherein said SWIR hyperspectral image comprises an image and a fully resolved spectrum unique to the material for each pixel location in said image.

6. The method of claim 5 wherein said image comprises a spatially accurate wavelength resolved image.

8. The method of claim 1 wherein said test Raman data set comprises at least one of:

a plurality of spatially resolved Raman spectra representative of an area of interest and a Raman image representative of said area of interest.

9. The method of claim 1 wherein said target area is illuminated using solar radiation.

10. The method of claim 1 further comprising passing said second interacted photons through a fiber array spectral translator device.

11. The method of claim 1 further comprising passing at least one of said first interacted photons and said second interacted photons through a filter wherein said filter is selected from the group consisting of:

a multi-conjugate tunable filter, a liquid crystal tunable filter, acousto-optical tunable filters, Lyot liquid crystal tunable filter, Evans Split-Element liquid crystal tunable filter, Solc liquid crystal tunable filter, Ferroelectric liquid crystal tunable filter, Fabry Perot liquid crystal tunable filter, and combinations thereof.

12. The method of claim 1 wherein said area of interest is illuminated using pulsed laser excitation.

13. The method of claim 1 wherein said second interacted photons are assessed using time gated detection.

14. The method of claim 1 further comprising applying a fusion algorithm to at least one of said Raman data set, said SWIR data set, and combinations thereof.

15. The method of claim 1 wherein at least one of said test SWIR data set and said test Raman data set comprises a dynamic chemical image.

7. The method of claim wherein said analyzing of said test Raman data set comprises searching a reference Raman database in accordance with the test Raman data set in order to identify a known Raman data set from said reference Raman database, wherein said reference Raman database contains a plurality of known Raman data sets, and wherein each know Raman data set is associated with a known material.

16. A system comprising:

a first two-dimensional array of detection elements;

a laser light source configured to illuminate an area of interest in a target area;

a second two-dimensional array of detection elements;

a first optical system coupled to said laser light source to direct light to said area of interest;

a second optical system wherein said second optical system;

collects a first plurality of interacted photons wherein said first plurality of interacted photons are generated by illuminating a target area, directs said first plurality of interacted photons to a first two-dimensional array of detection elements to thereby generate at least one of;

a plurality of spatially resolved SWIR spectra representative of said target area, a SWIR image representative of said target area, and combinations thereof, collects a second plurality of interacted photons wherein said second plurality of interacted photons are generated by illuminating an area of interest in said target area with said laser light source, and directing said second plurality of interacted photons to a fiber array spectral translator device, wherein said fiber array spectral translator device comprises;

a two-dimensional array of optical fibers drawn into a one-dimensional fiber stack so as to effectively convert a two-dimensional field of view into a curvilinear field of view;

a spectrometer coupled to said one-dimensional fiber stack of said fiber array spectral translator device, wherein an entrance slit of the spectrometer is coupled to said one-dimensional fiber stack to generate a plurality of spatially resolved Raman spectra; and

wherein said second two-dimensional array of detection elements coupled to said spectrometer detects said spatially resolved Raman spectra to thereby generate at least one of;

a plurality of spatially resolved Raman spectra representative of said area of interest and a Raman image representative of said area of interest.

17. The system of claim 16 further comprising a filter for sequentially filtering at least one of said first plurality of interacted photons and said second plurality of interacted photons in each of a plurality of predetermined wavelength bands.

18. The system of claim 17 wherein said filter is a filter selected from the group consisting of:

a multi-conjugate tunable filter, a liquid crystal tunable filter, acousto-optical tunable filters, Lyot liquid crystal tunable filter, Evans Split-Element liquid crystal tunable filter, Solc liquid crystal tunable filter, Ferroelectric liquid crystal tunable filter, Fabry Perot liquid crystal tunable filter, and combinations thereof.

19. The system of claim 16 wherein said laser light source comprises a Nd:

YLF laser.

20. The system of claim 16 further comprising a telescope used to locate and focus on at least one of a sample scene, the target area, the area of interest, and combinations thereof, and wherein said telescope is coupled to at least one of:

said first two-dimensional array of detection elements and said second two-dimensional array of detection elements.

21. The system of claim 16 further comprising:

instructions executable by at least one processor that apply a fusion algorithm to one or more of;

a plurality of spatially resolved SWIR spectra, a plurality of spatially resolved Raman spectra, and combinations thereof.

22. The system of claim 16 further comprising a video capture device that outputs a dynamic image of at least one of:

a the sample scene, the target area, the area of interest, and combinations thereof.

23. The system of claim 16 wherein said laser light source is configured for pulsed laser excitation of said area of interest and said second two-dimensional array of detection elements are configured for time-gated detection of said second plurality of interacted photons.

24. The system of claim 16 wherein said system is configured to operate in one or more of the following modalities:

a static modality, an on-the-move modality, a standoff modality, an unmanned ground vehicle modality, and combinations thereof.

25. A method comprising:

illuminating a target area comprising at least one unknown sample to thereby generate a plurality of first interacted photons wherein said first interacted photons are selected from the group consisting of;

photons absorbed by said target area, photons reflected by said target area, photons scattered by said target area, photons emitted by said target area, and combinations thereof;

assessing said first interacted photons to thereby generate a SWIR hyperspectral image representative of said target area;

analyzing said SWIR hyperspectral image representative of said target area to thereby identify an area f interest;

illuminating said area of interest to thereby generate a plurality of second interacted photons wherein said second interacted photons are selected from the group consisting of photons absorbed by said area of interest, photons reflected by said area of interest, photons scattered by said area of interest, photons emitted by said area of interest, and combinations thereof;

assessing said second interacted photons to thereby generate a plurality of spatially resolved Raman spectra representative of said area of interest;

analyzing said Raman spectra to thereby identify said area of interest comprising at least one of;

an explosive material, a concealment material, a formulation additive of an explosive material, a binder of an explosive material, a non-explosive material, and combinations thereof.

26. The method of claim 25 wherein said target area is illuminated using a solar radiation source.

27. The method of claim 25 wherein said area of interest is illuminated using a laser light source.

28. The method of claim 25 further comprising passing at least one of said first interacted photons and said second interacted photons through a filter, wherein said filter is selected from the group consisting of:

a multi-conjugate tunable filter, a liquid crystal tunable filter, acousto-optical tunable filters, Lyot liquid crystal tunable filter, Evans Split-Element liquid crystal tunable filter, Solc liquid crystal tunable filter, Ferroelectric liquid crystal tunable filter, Fabry Perot liquid crystal tunable filter, and combinations thereof.

29. The method of claim 25 further comprising passing said second interacted photons through a fiber array spectral translator device.

30. The method of claim 25 further comprising fusing the results of said analyzing said SWIR image and said analyzing said Raman spectra.

31. The method of claim 25 wherein said SWIR hyperspectral image comprises an image and a fully resolved spectrum unique to the material for each pixel location in said image.

32. The method of claim 25 wherein said area of interest is illuminated using pulsed laser excitation.

33. The method of claim 25 wherein said second interacted photons are assessed using time-gated detection.

34. The method of claim 25 further comprising generating a dynamic chemical image of at least one of:

a target area, an area of interest, and combinations thereof.