Multiband camera system

• US 7,646,419 B2
• Filed: 11/02/2006
• Issued: 01/12/2010
• Est. Priority Date: 11/02/2006
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cernasov, Andrei
• Primary Examiner(s): Henn; Timothy J
• Assistant Examiner(s): Vieaux; Gary C
• Application Number:
  US11/591,633
• Publication Number:
  US 20080106727A1
• Time in Patent Office: 1,167 Days
• Field of Search: 348/343, 348/344
• US Class Current: 348/344
• CPC Class Codes: G02B 13/146 with corrections for use in multiple wavelength bands, such as infrared and visible light, e.g. FLIR systems
• CPC Class Codes: G02B 27/1013 for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors spectral imaging systems G01J
• CPC Class Codes: G02B 27/143 using macroscopically faceted or segmented reflective surfaces
• CPC Class Codes: G02B 27/32 Fiducial marks and measuring scales within the optical system
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/15 Image signal generation with circuitry for avoiding or correcting image misregistration
• 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

A multiband camera system includes: a first sensor for generating a first object image and a first alignment image in a first frequency band; a second sensor for generating a second object image and a second alignment image in a second frequency band; and an internal alignment assembly. A splitter directs radiation in the first frequency band from the object to the first sensor to form the first object image, directs radiation in the second frequency band from the object to the second sensor to form the second object image, directs radiation in the first frequency band from the internal alignment assembly to the first sensor to form the first alignment image, and directs radiation in the second frequency band from the internal alignment assembly to the second sensor to form the second alignment image. The first alignment image and the second alignment image establish a reference for aligning the first and second object images.

Claims

1. A multiband camera system, said system comprising:

a first sensor for generating a first object image and a first alignment image in a first frequency band;

a second sensor for generating a second object image and a second alignment image in a second frequency band;

an internal alignment assembly; and

a splitter for directing radiation in said first frequency band from said object to said first sensor to form said first object image, directing radiation in said second frequency band from said object to said second sensor to form said second object image, directing radiation in said first frequency band from said internal alignment assembly to said first sensor to form said first alignment image, and directing radiation in said second frequency band from said internal alignment assembly to said second sensor to form said second alignment image

wherein said first alignment image and said second alignment image establish a reference for aligning the first and second object images.

2. The multiband camera system according to claim 1, wherein

said internal alignment assembly is sequentially turned on and off,

said first alignment image is located by comparing successive images formed on said first sensor, and

said second alignment image is located by comparing successive images formed on said second sensor.

3. The multiband camera system according to claim 2, wherein the internal alignment assembly is turned on and off in synchronized fashion with a read-out timing of said first and second sensors.

4. The multiband camera system according to claim 1, wherein

said first and second sensors are two-dimensional sensor arrays, and

read-out from said first and second sensors is adjusted as a function of said first and second alignment images to automatically align said first object image with said second object image.

5. The multiband camera system according to claim 1, wherein said splitter device includes at least one of a dichroic region and an annular mirror.

6. The multiband camera system according to claim 1, wherein said splitter device includes

an image splitter for directing radiation in said first frequency band from said object to said first sensor, and directing radiation in said second frequency band from said object to said second sensor, and

an alignment image splitter for directing radiation in said first frequency band from said internal alignment assembly to said first sensor, and directing radiation in said second frequency band from said internal alignment assembly to said second sensor.

7. The multiband camera system according to claim 6, wherein

said image splitter includes at least one of a dichroic region and an annular mirror, and

said alignment image splitter includes at least one of a dichroic region and an annular mirror.

8. The multiband camera system according to claim 1, further comprising:

an optical front end for processing said radiation from said object, before said radiation from said object reaches said splitter device.

9. The multiband camera system according to claim 1, further comprising:

a corrective optics system for modifying optical paths for said radiation in said second frequency band from said internal alignment assembly and said radiation in said second frequency band from said object, before said radiation in said second frequency band from said internal alignment assembly and said radiation in said second frequency band from said object reach said second sensor.

10. The multiband camera system according to claim 1, wherein

said first frequency band is a visible frequency band, and

said second frequency band is an infrared frequency band.

11. The multiband camera system according to claim 1, wherein said internal alignment assembly comprises an alignment image array.

12. The multiband camera system according to claim 11, wherein said alignment image array comprises an array of LEDs.

13. The multiband camera system according to claim 11, wherein said alignment image array includes a plurality of pixels co-located, adjacently located, or grouped, each pixel in said plurality of pixels emitting radiation across only one of a bandwidth of said first sensor and a bandwidth of said second sensor.

14. The multiband camera system according to claim 11, wherein

said alignment image array includes a plurality of interleaved visible and infrared LEDs.

15. The multiband camera system according to claim 1, wherein

said internal alignment assembly comprises at least one laser diode emitting in said first frequency band and at least one laser diode emitting in said second frequency band.

16. A multiband camera system according to claim 1, wherein

said alignment assembly includes:

at least one alignment element positioned on said first sensor and at least one alignment element positioned on said second sensor.

17. A method for multiband operation of a camera system, said method comprising:

directing radiation in a first frequency band from an object and an internal alignment assembly to a first sensor;

directing radiation in a second frequency band from said object and said internal alignment assembly to a second sensor;

generating a first object image and a first alignment image in said first frequency band on said first sensor;

generating a second object image and a second alignment image in said second frequency band on said second sensor; and

aligning said first and second object images using said first and second alignment images.

18. The method for multiband operation of a camera system as recited in claim 17, further comprising:

sequentially turned on and off said internal alignment assembly;

comparing successive images formed on said first sensor to locate said first alignment image; and

comparing successive images formed on said second sensor to locate said second alignment image.

19. The method for multiband operation of a camera system as recited in claim 17, further comprising:

adjusting read-out from said first and second sensors as a function of said first and second alignment images to automatically align said first object image with said second object image.

20. The method for multiband operation of a camera system as recited in claim 18, wherein the internal alignment assembly is turned on and off in synchronized fashion with a read-out timing of said first and second sensors.