Multi-mode optical imager

• US 7,049,597 B2
• Filed: 12/20/2002
• Issued: 05/23/2006
• Est. Priority Date: 12/21/2001
• Status: Expired due to Fees

• Current Assignee: Bodkin Design and Engineering LLC
• Original Assignee: Bodkin Design and Engineering LLC
• Inventors: Bodkin, Andrew
• Primary Examiner(s): Gabor, Otilia
• Assistant Examiner(s): Sung, Christine
• Application Number:
  US10/325,129
• Publication Number:
  US 20040119020A1
• Time in Patent Office: 1,250 Days
• Field of Search: 250/338.1, 250/336.1, 250/214.VT, 250/353, 250/214
• US Class Current: 250/353
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/0278 Control or determination of height or angle information for sensors or receivers
• CPC Class Codes: G01J 3/0289 Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 5/06 Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity for adjusting of solid angle of collected radiation G01J5/07; means for wavelength selection G01J5/0801
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4812 transmitted and received beams following a coaxial path
• CPC Class Codes: G02B 17/0808 on-axis systems with at least one of the mirrors having a central aperture
• CPC Class Codes: G02B 17/0852 having a field corrector only
• CPC Class Codes: G02B 17/0896 with variable magnification or multiple imaging planes, including multispectral systems systems with only refractive elements G02B15/14
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/23 from thermal infrared radiation
• 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 common aperture, multi-mode optical imager for imaging electromagnetic radiation bands from a field of two or more different wavelengths is described. Fore-optics are provided to gather and direct electromagnetic radiation bands forming an image into an aperture of the multi-mode optical imager. The image is divided into two different wavelength bands, such as visible light and long-wave infrared. The first wavelength band (e.g., visible light) is detected by a first detector, such as a CCD array, for imaging thereof. The second wavelength band (e.g., long-wave infrared) is detected by a second detector, such as an uncooled microbolometer array, for imaging thereof. Additional optics may be provided for conditioning of the first and second wavelength bands, such as such as for changing the magnification, providing cold shielding, filtering, and/or further spectral separation.

Claims

1. A common aperture multi-mode optical system, comprising:

reflective first fore-optics for imaging electromagnetic radiation through a common aperture to an intermediate image plane;

a first imaging module having

(a) a first beam-splitter located after the common aperture, for dividing the electromagnetic radiation between a first wavelength band and one or more second wavelength bands,

(b) a first detector for detecting the first wavelength band,

(c) one or more second detectors for detecting the second wavelength bands; and

an interface for attaching the first imaging module to the first fore-optics and alternatively detaching the first imaging module from the first fore-optics.

2. The system of claim 1, further comprising a second imaging module, the first imaging module being removable from the first fore-optics via the interface, the second imaging module being attachable to the first fore-optics via the interface, for providing imaging of one or more third wavelength bands.

3. The system of claim 2, the first wavelength band comprising visible light, the one or more second wavelength bands comprising long-wave infrared radiation, the one or more third wavelength bands comprising mid-wave infrared radiation.

4. The system of claim 1, further comprising second fore-optics, the first fore-optics module being removable from the first imaging module via the interface, the second fore-optics being attachable to the first imaging module via the interface, for providing different optical imaging of the electromagnetic radiation into the first imaging module.

5. The system of claim 1, wherein the beam-splitter is a dichroic beam-splitter.

6. The system of claim 1, wherein the first wavelength band is visible light electromagnetic radiation.

7. The system of claim 6, wherein the first detector comprises one of a CCD array or a CMOS array.

8. The system of claim 6, further comprising a field lens and one or more magnifying lenses positioned between the beam-splitter and the first detector, to provide for zooming in and out of the first wavelength band.

9. The system of claim 1, wherein the one or more second wavelength bands comprise a long-wave infrared band.

10. The system of claim 9, wherein the one or more second detectors comprise an uncooled microbolometer array.

11. The system of claim 10, further comprising micro-optics disposed proximal to the uncooled microbolometer array to reduce the f-number of the long-wave infrared band incident to the uncooled microbolometer array.

12. The system of claim 11, the micro-optics comprising a plurality of reflective concentrators, each of the concentrators being adjacent to one bolometer of the microbolometer array.

13. The system of claim 12, the concentrators comprising compound parabolic shapes.

14. The system of claim 12, the concentrators comprising one or more reflective elements transmissive to the long-wave infrared band, each of the elements being adjacent to one bolometer of the microbolometer array.

15. The system of claim 11, the micro-optics comprising one or more refractive elements transmissive to the long-wave infrared band, each of the elements being adjacent to one bolometer of the microbolometer array.

16. The system of claim 11, further comprising a piezo-electric element responsive to a command signal to displace the micro-optics further from, and alternatively closer to, the microbolometer array.

17. The system of claim 11, wherein the micro-optics comprise an array of hallow tapered capillaries.

18. The system of claim 1, wherein the one or more second wavelength bands comprises a mid-wave infrared band and a long-wave infrared band, and further comprising a second beam-splitter for dividing the one or more second wavelength bands between the mid-wave infrared band and the long-wave infrared band, the one or more second detectors comprising a first infrared detector and a second infrared detector.

19. The system of claim 18, the first infrared detector comprising a microbolometer array, the second infrared detector comprising a MWIR detector.

20. The system of claim 19, the MWIR detector comprising one of PtSi, InSb and HgCdTe.

21. The system of claim 1, wherein the first imaging module further comprises optics for reducing the f-number of at least one of the one or more second wavelength bands.

22. The system of claim 21, wherein the optics comprises one or more of a fiber optic taper, one or more refractive lens elements, and reflective elements.

23. The system of claim 1, further comprising one or more magnifying lenses positioned between the first beam-splitter and at least one of the one or more second detectors, to provide for zooming in and out of at least one of the one or more second wavelength bands.

24. The system of claim 1, further comprising a housing encasing at least the first imaging module, except for a region of the common aperture.

25. The system of claim 1, wherein the first fore-optics comprises a Cassegrain mirrored telescope.

26. The system of claim 1, wherein the first fore-optics comprises a Newtonian mirrored telescope.

27. The system of claim 1, wherein the first imaging module further comprises a first post processor coupled with the first detector and the one or more second detectors to process the first wavelength band and the one or more second wavelength bands to form an assembled image.

28. The system of claim 27, further comprising a second imaging module, the first imaging module being removable from the first fore-optics via the interface, the second imaging module being attachable to the first fore-optics via the interface, for providing imaging one or more third wavelength bands via one or more third detectors within the second imaging module, the second imaging module comprising a second post processor coupled with the third detectors for detecting the third wavelength bands, the second post-processor coupled with the third detectors to form an assembled image.

29. The system of claim 1, wherein the first imaging module further comprises a post processor coupled with the first detector and one or more second detectors to process the first wavelength band and the one or more second wavelength bands to automatically identify and detect target objects in the field of view of the system.

30. The system of claim 1, wherein the first imaging module further comprises a distance finder for transmitting a signal through the first fore-optics to determine a distance from the optical system to a target object.

31. The system of claim 1, wherein the first imaging module further comprises a targeting laser for transmitting a laser through the first fore-optics to a target object.

32. The system of claim 1, wherein the first imaging module further comprises a global positioning system for determining earth location of the optical system.

33. The system of claim 32, wherein the first imaging module further comprises a distance finder and one or more orientation sensors, to determine the location of a target object by determining:

(a) the location of the optical system determined by the global positioning system;

(b) a distance from the optical system to the target object determined by the distance finder; and

(c) a direction the first fore-optics are aimed as determined by the one or more orientation sensors.

34. The system of claim 1, wherein the first imaging module further comprises one or more rate sensors to measure movement of the optical system for image stabilization.

35. The system of claim 1, further comprising a housing for encasing at least the first imaging module, except for a region of the common aperture, and wherein the first wavelength band comprises a first optical channel within the housing that is modularized to be mechanically swappable with another channel to provide one of (a) repair of the first channel and (b) imaging in another wavelength band.

36. The system of claim 35, wherein the first imaging module further comprises a first post processor coupled with the first detector and the one or more second detectors to process the first wavelength band and the one or more second wavelength bands to form an assembled image, the post-processor being configured to accommodate processing of the another wavelength band automatically after swapping the first optical channel with the another channel.

37. The system of claim 1, further comprising a hyperspectral imager for processing any of the first wavelength band and one or more second wavelength bands.

38. The system of claim 1, further comprising a housing for encasing at least the first imaging module, except for a region of the common aperture, and wherein at least one of the one or more second wavelength bands comprises a second optical channel within the housing that is modularized to be mechanically swappable with another channel to provide one of (a) repair of the second channel and (b) imaging in another wavelength band.

39. The system of claim 38, wherein the first imaging module further comprises a first post processor coupled with the first detector and the one or more second detectors to process the first wavelength band and the one or more second wavelength bands to form an assembled image, the post-processor being configured to accommodate processing of the another wavelength band automatically after swapping the second optical channel with the another channel.

40. A common aperture multi-mode optical system, comprising:

reflective first fore-optics for imaging electromagnetic radiation through a common aperture to an intermediate image plane;

a removably-attachable first imaging module configured for attachment to the reflective first fore optics, the first imaging module having;

(a) a first beam-splitter for dividing the electromagnetic radiation through the common aperture between a first wavelength band and one or more second wavelength bands,

(b) a first detector for detecting the first wavelength band,

(c) one or more second detectors for detecting the second wavelength bands; and

(d) one or more refractive elements transmissive to the second wavelength bands, for imaging the second wavelength bands to the second detectors.

41. The system of claim 40, further comprising a second imaging module for providing imaging of one or more third wavelength bands, the second imaging module being swappable with the first imaging module and removably-attachable to the first fore-optics, the second imaging module having:

(a) a second beam-splitter for dividing the electromagnetic radiation through the common aperture between a third wavelength band and one or more fourth wavelength bands,

(b) a third detector for detecting the third wavelength band,

(c) one or more fourth detectors for detecting the fourth wavelength bands; and

(d) one or more refractive elements transmissive to the fourth wavelength bands, for imaging the second wavelength bands to the second detectors.