Stand-off chemical detector

• US 8,124,936 B1
• Filed: 12/13/2007
• Issued: 02/28/2012
• Est. Priority Date: 12/13/2007
• Status: Expired due to Fees

• Current Assignee: Government of the United States of America
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Lagna, William M.
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Malevic, Djura
• Application Number:
  US11/955,674
• Time in Patent Office: 1,538 Days
• Field of Search: 250/339.1, 250/339, 250/372
• US Class Current: 250/339.01
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 3/00 Spectrometry; Spectrophotometry; Monochromators; Measuring colours
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 5/025 Interfacing a pyrometer to an external device or network; User interface
• CPC Class Codes: G01N 2021/1793 Remote sensing
• CPC Class Codes: G01N 21/00 Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light G01N3/00 - G01N19/00 take precedence
• CPC Class Codes: G01N 21/35 using infrared light G01N21/39 takes precedence
• CPC Class Codes: G01N 33/22 Fuels, explosives liquid hydrocarbons G01N33/28

Abstract

A stand-off chemical detector has an array of charge-coupled-device electromagnetic radiation sensing elements. One or more first charge-coupled-device electromagnetic radiation sensing elements of the array are selectively responsive to non-visible electromagnetic radiation having at least a first wavelength, and one or more second charge-coupled-device electromagnetic radiation sensing elements of the array are selectively responsive to non-visible electromagnetic radiation having at least a second wavelength that is different that the at least first wavelength.

Claims

1. A stand-off chemical detector, comprising:

an array of charge-coupled-device electromagnetic radiation sensing elements;

wherein one or more first charge-coupled-device electromagnetic radiation sensing elements of the array are each selectively responsive to a first range of non-visible electromagnetic radiation wavelengths; and

wherein one or more second charge-coupled-device electromagnetic radiation sensing elements of the array are each selectively responsive to a second range of non-visible electromagnetic radiation wavelengths different than the first range of non-visible electromagnetic radiation wavelengths.

2. The stand-off detector of claim 1, wherein a plurality of third charge-coupled-device electromagnetic radiation sensing elements of the array is selectively responsive to a third range of non-visible electromagnetic radiation wavelengths that is different than the first range of non-visible wavelengths and different than the second range of non-visible wavelengths or is selectively responsive to non-visible electromagnetic radiation having the third range of non-visible wavelengths and a fourth range of non-visible wavelengths, the fourth range of non-visible wavelengths being different than the first range of non-visible wavelengths, the second range anon-visible wavelengths, and the third range of non-visible wavelengths.

3. The stand-off detector of claim 1, wherein a silicon substrate on which the charge-coupled-device electromagnetic radiation sensing elements are formed is doped so that the silicon substrate can pass electromagnetic radiation having a wavelength of about 0.35 to about 15 microns.

4. The stand-off detector of claim 3, wherein the silicon substrate is doped so that the silicon substrate can pass electromagnetic radiation having a wavelength of about 0.35 to about 4 microns.

5. The stand-off detector of claim 1, further comprising a processor coupled to the array of charge-coupled-device electromagnetic radiation sensing elements, the processor configured to demosaic outputs of the one or more first charge-coupled-device electromagnetic radiation sensing elements and the one or more second charge-coupled-device electromagnetic radiation sensing elements so that pixel data of pixels of an image field of the detector respectively corresponding to the one or more first charge-coupled-device electromagnetic radiation sensing elements and the one or more second charge-coupled-device electromagnetic radiation sensing elements contains contributions from the first range of non-visible electromagnetic radiation wavelengths and the second range of non-visible electromagnetic radiation wavelengths.

6. The stand-off detector of claim 5, wherein the pixel data of each pixel corresponds to a spectral chemical signature of a chemical present at a location in the image field of the detector that corresponds to the charge-coupled-device electromagnetic radiation sensing element corresponding to that pixel.

7. The stand-off detector of claim 6, wherein the processor is further configured to compare the spectral signature of the chemical compound to spectral signatures of a plurality of target chemical compounds to determine whether the chemical compound is a target chemical compound.

8. The stand-off detector of claim 7, wherein the processor is further configured to assign a certain color to the pixels respectively corresponding to the one or more first charge-coupled-device electromagnetic radiation sensing elements and the one or more second charge-coupled-device electromagnetic radiation sensing elements when the chemical compound is determined to be a target chemical compound.

9. The stand-off detector of claim 8, wherein the stand-off detector is configured to display the certain color on portions of a display of the stand-off detector that correspond to the pixels respectively corresponding to the one or more first charge-coupled-device electromagnetic radiation sensing elements and the one or more second charge-coupled-device electromagnetic radiation sensing elements.

10. The stand-off detector of claim 1, wherein a plurality of third charge-coupled-device electromagnetic radiation sensing elements of the array is selectively responsive to visible electromagnetic radiation.

11. The stand-off detector of claim 10, wherein first, second, and third portions of the plurality of third charge-coupled-device electromagnetic radiation sensing elements are respectively selectively responsive to red;

green, and blue visible electromagnetic radiation.

12. The stand-off detector of claim 1, wherein the non-visible electromagnetic radiation having the first range and second range of wavelengths is infrared or ultraviolet electromagnetic radiation.

13. The stand-off detector of claim 1, wherein the one or more first charge-coupled-device electromagnetic radiation sensing elements are coated with first filters that can pass the electromagnetic radiation having the first range of wavelengths and the one or more second charge-coupled-device electromagnetic radiation sensing elements are coated with second filters that can pass the electromagnetic radiation having the second range of wavelengths.

14. The stand-off detector of claim 13, wherein the first and second filters are infrared filters or ultraviolet filters.

15. A chemical detection method, comprising:

selectively receiving first non-visible radiation having a first range of wavelengths at a plurality of first charge-coupled-device radiation sensing elements of an array of charge-coupled-device radiation sensing elements of a stand-off sensor;

selectively receiving second non-visible radiation having a second range of wavelengths different than the first range of wavelengths at a plurality of second charge-coupled-device radiation sensing elements of the array of charge-coupled-device radiation sensing elements;

outputting a first electrical signal from each of the first charge-coupled-device radiation sensing elements in response to receiving the first range of non-visible radiation thereat;

outputting a second electrical signal from each of the second charge-coupled-device radiation sensing elements in response to receiving the second range of non-visible radiation thereat; and

demosaicing the first and second electrical signals so that data of first pixels of an image field of the detector respectively corresponding to the first charge-coupled-device electromagnetic radiation sensing elements and data of second pixels of the image field of the detector respectively corresponding to the second charge-coupled-device electromagnetic radiation sensing elements contain contributions from the first and second electrical signals and thus from the first range and second range of non-visible radiation.

16. The method of claim 15, further comprising digitizing the first and second electrical signals before demosaicing the first and second electrical signals.

17. The method of claim 15, further comprising:

selectively receiving visible radiation at a plurality of third charge-coupled-device radiation sensing elements of the array of charge-coupled-device radiation sensing elements;

outputting a third electrical signal from each of the third charge-coupled-device radiation sensing elements in response to receiving the visible radiation thereat; and

demosaicing the third electrical signals along with the first and second electrical signals so that the data of the first and second pixels further contain contributions from the third electrical signals and thus the visible radiation and so that data of third pixels of the image field respectively corresponding to the third charge-coupled-device radiation sensing elements contain contributions from the first, second, and third electrical signals and thus from the first range and second range of non-visible radiation and the visible radiation.

18. The method of claim 17, wherein the visible radiation comprises red, green, and blue radiation.

19. The method of claim 15, wherein the data of each of the first and second pixels corresponds to a spectral signature of a chemical compound that is present in the image field.

20. The method of claim 19, further comprising comparing the spectral signature of the chemical compound to spectral signatures of a plurality of target chemical compounds to determine whether the chemical compound is a target chemical compound.

21. The method of claim 20, wherein comparing the spectral signature of the chemical compound to spectral signatures of the plurality of target chemical compounds comprises inputting the spectral signature of the chemical compound into a look-up table of the stand-off detector that contains the plurality of target chemical compounds.

22. The method of claim 20, further comprising assigning a certain color to the first and second pixels when the chemical compound is determined to be a target chemical compound.

23. The method of claim 22, further comprising displaying the certain color on portions of a display of the stand-off detector that correspond to the first and second pixels.

24. The method of claim 15, further comprising:

selectively receiving third non-visible radiation having a third range of wavelengths that are different than the first range of wavelengths and the second range of wavelengths at a plurality of third charge-coupled-device radiation sensing elements of the array of charge-coupled-device radiation sensing elements;

outputting a third electrical signal from each of the third charge-coupled-device radiation sensing elements in response to receiving the third range of non-visible radiation thereat; and

demosaicing the third electrical signals along with the first and second electrical signals so that the data of the first and second pixels further contain contributions from the third electrical signals and this the third range of non-visible radiation and so that data of third pixels of the image field respectively corresponding to the third charge-coupled-device radiation sensing elements contain contributions from the first, second, and third electrical signals and thus from the first range, second range, and third range of non-visible radiation.

25. A stand-off chemical detector, comprising:

an array comprising at least a plurality of first charge-coupled-device radiation sensing elements and a plurality of second charge-coupled-device radiation sensing elements, wherein the first charge-coupled-device radiation sensing elements respectively correspond to first pixels of an image field of the detector and the second charge-coupled-device radiation sensing elements respectively correspond to second pixels of the image field;

a plurality of first filters, each of the first filters configured to pass first non-visible radiation having a first range of wavelengths to a respective one of the first charge-coupled-device radiation sensing elements;

a plurality of second filters, each of the second filters configured to pass second non-visible radiation having a second range of wavelengths different from the first range of wavelengths to a respective one of the second charge-coupled-device radiation sensing elements;

a processor electrically coupled to the array;

wherein the processor is configured to demosaic outputs of the first charge-coupled-device electromagnetic radiation sensing elements corresponding to the first range of non-visible radiation and the second charge-coupled-device electromagnetic radiation sensing elements corresponding to the second range of non-visible radiation so that first pixel data of the first pixels and second pixel data of the second pixels contain contributions from the first range of non-visible radiation and the second range of non-visible radiation.