DIVIDED-APERTURE INFRA-RED SPECTRAL IMAGING SYSTEM

• US 20150136982A1
• Filed: 11/12/2014
• Published: 05/21/2015
• 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 T., Hagan, Nathan A.
• Granted Patent: US 9,562,849 B2
• Time in Patent Office: Days
• US Class Current: 250/332
• 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 25/67 : 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:

a plurality of cameras;

at least one thermal reference source having a known temperature placed in front of the plurality of cameras and configured to be imaged by the plurality of cameras; and

a data-processing unit comprising a processor, the imaging system configured to;

acquire with the plurality of cameras a plurality of frames having regions that correspond to the image of the reference source; and

apply a dynamic calibration correction to the plurality of cameras to allow every camera in the plurality of cameras to be calibrated to agree with every other camera in the plurality imaging the reference source.

2. The system of claim 1, wherein the plurality of cameras comprises an FPA unit and a plurality of lenses.

3. The system of claim 2, wherein the FPA unit comprises one FPA or a plurality of FPAs.

4. The system of claim 1, wherein the at least one thermal reference source has a known spectrum.

5. The system of claim 4, further comprising an additional thermal reference source imaged by the plurality of cameras.

6. The system of claim 5, wherein the additional reference source has a temperature and a spectrum different from the known temperature and the known spectrum of the at least one reference source.

7. The system of claim 6, wherein the temperature of the additional thermal reference source is less than the known temperature.

8. The system of claim 6, wherein the temperature of the additional thermal reference source is greater than the known temperature.

9. The system of claim 1, wherein the at least one reference source is displaced away from a conjugate image plane of the plurality of cameras such that the image of the at least one reference source captured by the plurality of cameras is blurred.

10. The system of claim 1, wherein the at least one reference source is positioned at a conjugate image plane of the plurality of cameras.

11. The system of claim 1, further comprising a plurality of mirrors configured to image the at least one reference source onto the plurality of cameras.

12. The system of claim 11, wherein the plurality of mirrors are disposed outside a central field of view of the plurality of cameras.

13. The system of claim 1, further comprising a first and a second temperature-controlled shutter removably positioned to block IR radiation incident on the system from reaching the plurality of cameras.

14. The system of claim 1, wherein the system includes at least two spatially and spectrally different optical channels.

15. The system of claim 14, wherein the system includes at least three optical channels.

16. The system of claim 14, wherein the system includes at least four optical channels.

17. The system of claim 14, wherein the system includes at least five optical channels.

18. The system of claim 14, wherein the system includes at least six optical channels.

19-27. -27. (canceled)

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

a plurality of cameras;

a first temperature-controlled reference source imaged by the plurality of cameras;

a second temperature-controlled reference source imaged by the plurality of cameras; and

a data-processing unit comprising a processor, said data-processing unit configured to;

acquire with the plurality of cameras a plurality of frames having regions that correspond to the image of the reference source; and

dynamically calibrate the plurality of cameras so that various cameras imaging a scene agree on a temperature estimate of the first and second reference sources.

29-47. -47. (canceled)

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

a plurality of cameras;

a reference having an unknown temperature configured to be imaged by the plurality of cameras; and

a data-processing unit comprising a processor, the imaging system configured to;

acquire with the plurality of cameras a plurality of frames having regions that correspond to the image of the reference;

calculate a dynamic calibration correction using a temperature measured by one of the cameras in the plurality of cameras as a reference temperature; and

apply the calibration correction to the other cameras in the plurality of cameras to match the temperature estimate of the other cameras in the plurality of cameras with the reference temperature.

49-65. -65. (canceled)