ACTIVE HYPERSPECTRAL IMAGING SYSTEM

• US 20170205344A1
• Filed: 01/15/2016
• Published: 07/20/2017
• Est. Priority Date: 01/15/2016
• Status: Active Grant

• Current Assignee: Mitre Corporation
• Original Assignee: Mitre Corporation
• Inventors: GEMP, Kevin, SCHLAMM, Ariel, MILLER, Christopher, JORDAN, Shannon, HALPER, Marin, BARTLETT, Brent
• Granted Patent: US 10,451,548 B2
• Time in Patent Office: Days
• CPC Class Codes: G01N 21/27 using photo-electric detection G01N21/31 takes precedence; circuits for computing concentration logarithmic circuits G06G7/24; photometric circuits in general G01J
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 2201/0612 Laser diodes
• CPC Class Codes: G01N 2201/0621 Supply

Abstract

A system for generating reflectance values for a target that includes a plurality of electromagnetic radiation sources for irradiating the target, an imager for generating a plurality of digital representations of the target that includes an array of filter elements for filtering electromagnetic radiation reflected by the target through an array of filter elements, and a detector for detecting the filtered electromagnetic radiation at an array of detection elements. The system includes processors for determining a set of reflectance values for a portion of the target based on a first digital representation of the target generated in response to irradiation of the target with radiation of a first wavelength band and a second digital representation of the target generated in response to irradiation of the target with radiation of a second wavelength band.

Claims

1. A system for generating reflectance values for a target comprising:

a plurality of electromagnetic radiation sources for irradiating the target;

an imager for generating a plurality of digital representations of the target comprising;

an array of filter elements for filtering electromagnetic radiation reflected by the target through an array of filter elements; and

a detector for detecting the filtered electromagnetic radiation at an array of detection elements;

one or more processors for determining a set of reflectance values for a portion of the target based on a first digital representation of the target generated in response to irradiation of the target with radiation of a first wavelength band and a second digital representation of the target generated in response to irradiation of the target with radiation of a second wavelength band, wherein each reflectance value in the set of reflectance values corresponds to the reflectance of the portion of the target at a different wavelength band; and

memory for storing the set of reflectance values.

2. The system of claim 1, wherein the first wavelength band overlaps the second wavelength band.

3. The system of claim 1, wherein the first wavelength band does not overlap the second wavelength band.

4. The system of claim 1, wherein the array of filter elements comprises filter elements of a first type for passing electromagnetic radiation in a first filtering wavelength band and filter elements of a second type for passing electromagnetic radiation in a second filtering wavelength band.

5. The system of claim 4, wherein the filter elements of the first type are interspersed with the filter elements of the second type.

6. The system of claim 4, wherein the first filtering wavelength band and the second filtering wavelength band are each different from the first wavelength band and the second wavelength band.

7. The system of claim 4, wherein the first filtering wavelength band overlaps one or more of the second filtering wavelength band, the first wavelength band, and the second wavelength band.

8. The system of claim 1, wherein each filter element in the array of filter elements corresponds to a detection element in the array of detection elements.

9. The system of claim 1, wherein radiation reflected by the target passes through an aperture prior to reaching the array of filter elements and the aperture is fixed relative to the array of filter elements.

10. The system of claim 1, wherein the first electromagnetic radiation source comprises an array of light emitting diodes or an array of laser diodes.

11. The system of claim 1, wherein the first digital representation comprises an array of intensity values, each intensity value corresponding to an intensity of total electromagnetic radiation detected at the respective detection element of the array of detection elements, and the total electromagnetic radiation includes electromagnetic radiation from sources other than the first electromagnetic radiation source.

12. The system of claim 1, wherein the filter array comprises M filter types, the processing unit is configured to determine a set of M×

N reflectance values for a portion of the target based on N digital representation of the target, each digital representation generated based on irradiation of the target by a respective one of N electromagnetic radiation sources, and each reflectance value in the set of reflectance values corresponds to the reflectance of the portion of the target at a discrete wavelength band.

13. A method for generating reflectance values for a target comprising:

irradiating the target with radiation of a first wavelength band, wherein the radiation of the first wavelength band is generated by a first electromagnetic radiation source;

filtering the electromagnetic radiation of the first wavelength band reflected by the target through an array of filter elements;

detecting the filtered electromagnetic radiation of the first wavelength band reflected by the target at an array of detection elements;

generating a first digital representation of the target based on the detected filtered electromagnetic radiation of the first wavelength band reflected by the target;

irradiating the target with radiation of a second wavelength band, wherein the radiation of the second wavelength band is generated by a second electromagnetic radiation source;

filtering the electromagnetic radiation of the second wavelength band reflected by the target through the array of filter elements;

detecting the filtered electromagnetic radiation of the second wavelength band reflected by the target at the array of detection elements;

generating a second digital representation of the target based on the detected filtered electromagnetic radiation of the second wavelength band reflected by the target; and

determining a set of reflectance values for a portion of the target based on the first digital representation and the second digital representation, wherein each reflectance value in the set of reflectance values corresponds to the reflectance of the portion of the target at a different wavelength band.

14. The method of claim 13, wherein the first wavelength band overlaps the second wavelength band.

15. The method of claim 13, wherein the first wavelength band does not overlap the second wavelength band.

16. The method of claim 13, wherein the array of filter elements comprises filter elements of a first type for passing electromagnetic radiation in a first filtering wavelength band and filter elements of a second type for passing electromagnetic radiation in a second filtering wavelength band.

17. The method of claim 16, wherein the filter elements of the first type are interspersed with the filter elements of the second type.

18. The method of claim 16, wherein the first filtering wavelength band and the second filtering wavelength band are each different from the first wavelength band and the second wavelength band.

19. The method of claim 16, wherein the first filtering wavelength band overlaps one or more of the second filtering wavelength band, the first wavelength band, and the second wavelength band.

20. The method of claim 13, wherein each filter element in the array of filter elements corresponds to a detection element in the array of detection elements.

21. The method of claim 13, wherein radiation reflected by the target passes through an aperture prior to reaching the array of filter elements and the aperture is fixed relative to the array of filter elements.

22. The method of claim 13, wherein the first electromagnetic radiation source comprises an array of light emitting diodes or an array of laser diodes.

23. The method of claim 13, wherein the first digital representation comprises an array of intensity values, each intensity value corresponding to an intensity of total electromagnetic radiation detected at the respective detection element of the array of detection elements, and the total electromagnetic radiation includes electromagnetic radiation from sources other than the first electromagnetic radiation source.

24. The method of claim 13, wherein the filter array comprises M filter types, the method comprising:

generating N digital representation of the target, each digital representation generated based on irradiation of the target by a respective one of N electromagnetic radiation sources; and

determining a set of M×

N reflectance values for a portion of the target based on the N digital images, wherein each reflectance value in the set of reflectance values corresponds to the reflectance of the portion of the target at a discrete wavelength band.

25. A handheld electronic device for collecting digital representations of a target comprising:

a plurality of electromagnetic radiation sources for irradiating the target;

an imager for generating a plurality of digital representations of the target, the imager comprising;

an array of filter elements for filtering electromagnetic radiation reflected by the target through an array of filter elements; and

a detector for detecting the filtered electromagnetic radiation at an array of detection elements;

one or more processors;

memory; and

one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for;

activating a first electromagnetic radiation source of the plurality of electromagnetic radiation sources to irradiate the target with radiation of a first wavelength band generated by the first electromagnetic radiation source;

triggering the imager to collect a first digital representation of the target, wherein the first digital representation of the target is based on the radiation of the first wavelength band that is reflected by the target and filtered through the array of filter elements;

activating a second electromagnetic radiation source of the plurality of electromagnetic radiation sources to irradiate the target with radiation of a second wavelength band generated by the second electromagnetic radiation source; and

triggering the imager to collect a second digital representation of the target, wherein the second digital representation of the target is based on the radiation of the second wavelength band that is reflected by the target and filtered through the array of filter elements.

26. The device of claim 25, wherein the first wavelength band overlaps the second wavelength band.

27. The device of claim 25, wherein the first wavelength band does not overlap the second wavelength band.

28. The device of claim 25, wherein the array of filter elements comprises filter elements of a first type for passing electromagnetic radiation in a first filtering wavelength band and filter elements of a second type for passing electromagnetic radiation in a second filtering wavelength band.

29. The device of claim 28, wherein the filter elements of the first type are interspersed with the filter elements of the second type.

30. The device of claim 28, wherein the first filtering wavelength band and the second filtering wavelength band are each different from the first wavelength band and the second wavelength band.

31. The device of claim 28, wherein the first filtering wavelength band overlaps one or more of the second filtering wavelength band, the first wavelength band, and the second wavelength band.

32. The device of claim 25, wherein each filter element in the array of filter elements corresponds to a detection element in the array of detection elements.

33. The device of claim 25, wherein radiation reflected by the target passes through an aperture prior to reaching the array of filter elements and the aperture is fixed relative to the array of filter elements.

34. The device of claim 25, wherein the first electromagnetic radiation source comprises an array of light emitting diodes or an array of laser diodes.

35. The device of claim 25, wherein the first digital representation comprises an array of intensity values, each intensity value corresponding to an intensity of total electromagnetic radiation detected at the respective detection element of the array of detection elements, and the total electromagnetic radiation includes electromagnetic radiation from sources other than the first electromagnetic radiation source.

36. The device of claim 25, wherein the filter array comprises M filter types, the one or more programs include instructions for:

generating N digital representation of the target, each digital representation generated based on irradiation of the target by a respective one of N electromagnetic radiation sources; and

determining a set of M×

N reflectance values for a portion of the target based on the N digital images, wherein each reflectance value in the set of reflectance values corresponds to the reflectance of the portion of the target at a discrete wavelength band.