Divided-aperture infra-red spectral imaging system

• US 10,267,686 B2
• Filed: 01/27/2017
• Issued: 04/23/2019
• Est. Priority Date: 11/12/2013
• Status: Active Grant

• Current Assignee: Rebellion Photonics, Inc. (Honeywell International Inc.)
• Original Assignee: Rebellion Photonics, Inc. (Honeywell International Inc.)
• Inventors: Kester, Robert Timothy, Hagen, Nathan Adrian
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US15/418,532
• Publication Number:
  US 20170205290A1
• Time in Patent Office: 816 Days
• CPC Class Codes: G01J 2003/2826 Multispectral imaging, e.g. filter imaging
• CPC Class Codes: G01J 2003/283 computer-interfaced
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0232 using shutters
• CPC Class Codes: G01J 3/0256 Compact construction
• 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 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• 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 5/0014 for sensing the radiation from gases, flames
• CPC Class Codes: G01J 5/0802 Optical filters
• CPC Class Codes: G01J 5/0804 Shutters
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52
• CPC Class Codes: G01N 2021/1793 Remote sensing
• CPC Class Codes: G01N 2021/3531 : without instrumental source, i.e. radiometric
• CPC Class Codes: G01N 21/3504 : for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 2201/06106 : Plural sources used for calibration
• CPC Class Codes: G01N 2201/068 : Optics, miscellaneous
• CPC Class Codes: G01N 2201/127 : Calibration; base line adjustment; drift compensation
• CPC Class Codes: H04N 23/11 : for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 25/21 : for transforming thermal infrared radiation into image signals
• CPC Class Codes: H04N 25/67 : applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 25/671 : for non-uniformity detection or correction
• CPC Class Codes: H04N 25/673 : by using reference sources
• CPC Class Codes: H04N 3/09 : for electromagnetic radiation in the invisible region, e.g. infrared
• CPC Class Codes: H04N 5/33 : Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

Various embodiments disclosed herein describe a divided-aperture infrared spectral imaging (DAISI) system that is adapted to acquire multiple IR images of a scene with a single-shot (also referred to as a snapshot). The plurality of acquired images having different wavelength compositions that are obtained generally simultaneously. The system includes at least two optical channels that are spatially and spectrally different from one another. Each of the at least two optical channels are configured to transfer IR radiation incident on the optical system towards an optical FPA unit comprising at least two detector arrays disposed in the focal plane of two corresponding focusing lenses. The system further comprises at least one temperature reference source or surface that is used to dynamically calibrate the two detector arrays and compensate for a temperature difference between the two detector arrays.

Claims

1. An infrared (IR) imaging system, the imaging system comprising:

an optical system comprising an optical focal plane array (FPA) unit, the optical system including components associated with at least two optical channels, said at least two optical channels being spatially and spectrally different from one another, the at least two optical channels positioned to transfer IR radiation incident on the optical system towards the optical FPA unit, the optical FPA unit comprising at least two groups of detector pixels disposed at a distance from at least two corresponding focusing lenses;

a first thermal reference at a first temperature;

a second thermal reference at a second temperature different from the first temperature, wherein radiation emitted from the first and the second thermal references is directed to at least one of the at least two groups of detector pixels simultaneously with radiation emitted from a scene viewed by the imaging system; and

electronics configured to;

dynamically calibrate the at least two groups of detector pixels to reduce a difference in measurements obtained using light from the first and the second thermal references received by at least one of the at least two groups of detector pixels.

2. The system of claim 1, wherein at least one of the first or the second thermal references has a known spectrum.

3. The system of claim 1, wherein at least one of the first or the second temperatures is unknown.

4. The system of claim 1, wherein at least one of the first or the second thermal references is displaced away from a conjugate image plane of optical FPA unit such that an image of at least one of the first or the second thermal references on at least one of the at least two groups of detector pixels is blurred.

5. The system of claim 1, wherein at least one of the first or the second thermal references is positioned at a conjugate image plane of the optical FPA unit.

6. The system of claim 1, wherein at least one of the first or the second thermal references is disposed outside a central field of view of the optical FPA unit.

7. The system of claim 1, further comprising at least one shutter removably positioned to block IR radiation incident on the system from reaching the optical FPA unit.

8. The system of claim 1, wherein the optical system includes at least three optical channels.

9. The system of claim 1, wherein the optical system includes at least four optical channels.

10. The system of claim 1, wherein the measurements obtained by the at least two groups of detector pixels using the light received from the thermal references are temperature measurements of the first and second thermal references.

11. The system of claim 1, wherein one of the at least two groups of detector pixels comprises a first focal plane array and another of the at least two groups of detector pixels comprises a second focal plane array.

12. An infrared (IR) imaging system, the imaging system comprising:

an optical system including an optical focal plane array (FPA) unit, the optical system including components associated with at least two optical channels, said at least two optical channels being spatially and spectrally different from one another, the at least two optical channels positioned to transfer IR radiation incident on the optical system towards the optical FPA unit, the optical FPA unit comprising at least two groups of detector pixels disposed at a distance from at least two corresponding focusing lenses;

a thermal reference comprising a first portion at a first temperature and a second portion at a second temperature different from the first temperature, wherein radiation emitted from the first and the second portions of the thermal reference is directed to at least one of the at least two groups of detector pixels simultaneously with radiation emitted from a scene viewed by the imaging system; and

a data-processing system, said data-processing system configured to;

dynamically calibrate the at least two groups of detector pixels to reduce a difference in measurements obtained using light from of the first and the second portions of the thermal reference obtained by at least one of the at least two groups of detector pixels.

13. The system of claim 12, wherein the first or the second temperatures is unknown.

14. The system of claim 12, wherein the thermal reference is displaced away from a conjugate image plane of the optical FPA unit such that an image of at least one of the first or the second portions of the thermal reference is blurred.

15. The system of claim 12, wherein the thermal reference is positioned at a conjugate image plane of the optical FPA unit.

16. The system of claim 12, wherein the first or the second portion of the thermal reference is disposed outside a central field of view of the optical FPA unit.

17. The system of claim 12, further comprising at least one shutter removably positioned to block IR radiation incident on the system from reaching the optical FPA unit.

18. The system of claim 12, wherein the optical system includes at least three optical channels.

19. The system of claim 12, wherein the optical system includes at least four optical channels.

20. The system of claim 12, wherein the optical system includes at least five optical channels.

21. The system of claim 12, wherein the measurements obtained by the at least two groups of detector pixels using the light received from the first and second portions of the thermal reference are temperature measurements of the first and second portions of the thermal reference.

22. The system of claim 12, wherein one of the at least two groups of detector pixels comprises a first focal plane array and another of the at least two groups of detector pixels comprises a second focal plane array.