Resolution on demand

• US 8,577,183 B2
• Filed: 08/05/2009
• Issued: 11/05/2013
• Est. Priority Date: 08/05/2009
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Robinson, Ian S.
• Primary Examiner(s): Bali, Vikkram
• Assistant Examiner(s): TORRES, JOSE
• Application Number:
  US12/536,434
• Publication Number:
  US 20110033129A1
• Time in Patent Office: 1,553 Days
• Field of Search: 382/270, 382/272, 382/276, 382/284, 382/299, 348/162
• US Class Current: 382/299
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01S 17/90 using synthetic aperture techniques
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/84 for processing colour signals
• CPC Class Codes: H04N 23/951 by using two or more images to influence resolution, frame rate or aspect ratio

Abstract

A method samples a first spectral band to obtain an initial image frame, determines at least one region of interest of the scene from the initial image frame, each of the at least one region of interest associated with a mean signal level, illuminates the at least one region of interest with at least one illuminator when the mean signal level of the at least one region of interest is at or below a respective threshold of a first plurality of thresholds, the at least one region of interest being illuminated in accordance with a power threshold indicating a minimum illuminator power and agility necessary to illuminate the at least one region of interest, collects at least one image frame in at least one sub-band of a second spectral band, and generates at least one image to be displayed from at least the at least one image frame.

Claims

1. A method of providing an image of a scene utilizing imaging optics, wherein radiation from the scene impinges on at least one focal plane, the method comprising:

sampling a first spectral band to obtain an initial image frame;

determining at least one region of interest of the scene from the initial image frame, each of the at least one region of interest associated with a mean signal level;

illuminating the at least one region of interest with at least one illuminator when the mean signal level of the at least one region of interest is at or below a respective threshold of a first plurality of thresholds to increase spatial resolution in the at least one region of interest, the at least one region of interest being illuminated in accordance with the mean signal level and one or more of an illuminator power and an illuminator agility;

collecting at least one illuminated image frame in at least a second spectral band; and

generating at least one image to be displayed from at least the at least one illuminated image frame.

2. The method of claim 1, wherein the at least one illuminated image frame is collected over the at least one region of interest.

3. The method of claim 1, wherein the first spectral band comprises a medium-wave infrared spectral band.

4. The method of claim 1, wherein the first spectral band comprises an upper short-wave infrared spectral band.

5. The method of claim 1, wherein the at least one image is generated by combining at least two image frames.

6. The method of claim 5, wherein the image to be displayed is a composite image.

7. The method of claim 5, wherein the image to be displayed is a band ratio image.

8. The method of claim 5, further comprising:

determining a first band mean signal level from the initial image frame;

when the first band mean signal level is above a first threshold;

sampling sub-bands in a first plurality of sub-bands to obtain mean signal levels for each of the sub-bands; and

collecting at least one image frame in each of the sampled sub-bands for which a corresponding mean signal level is above a second threshold.

9. The method of claim 5, further comprising:

sampling the second spectral band to obtain a second band mean signal level;

collecting at least one second band image frame when the second band mean signal level is at or below a third threshold;

when the second band mean signal level is above the third threshold;

sampling sub-bands in the second spectral band to obtain mean signal levels for each of the sub-bands;

collecting at least one image frame in each of the sampled sub-bands for which a corresponding mean signal level is above a fourth threshold.

10. The method of claim 5, further comprising:

determining a first band mean signal level from the initial image frame;

when the first band mean signal level is above a first threshold;

sampling successively narrower sub-bands in the first spectral band to obtain mean signal levels for the successively narrower sub-bands, each of the mean signal levels corresponding to a respective one of the successively narrower sub-bands, until at least one of the mean signal levels is at or below a respective threshold of a second plurality of thresholds; and

collecting at least one image frame in each of the sampled sub-bands for which the corresponding mean signal level is above the respective threshold of the second plurality of thresholds.

11. The method of claim 10, wherein the successively narrower sub-bands comprise at least a portion of a long-wave infrared sub-band.

12. The method of claim 10, wherein the successively narrower sub-bands in the first spectral band comprises at least a portion of a short-wave infrared sub-band.

13. The method of claim 10, further comprising:

determining a minimum integration time to collect the at least one image frame in the sampled sub-bands from the corresponding one of the mean signal levels.

14. The method of claim 10, further comprising:

when the first band mean signal level is at or below the first threshold;

collecting at least one image frame in the first spectral band.

15. The method of claim 10, further comprising:

determining a first band minimum integration time to obtain the at least one image frame in the first spectral band from the first band mean signal level.

16. The method of claim 1, further comprising:

adjusting the imaging optics until a threshold signal level or a threshold edge contrast ratio has been reached.

17. The method of claim 16, wherein the imaging optics is adjusted until the threshold signal level or the threshold edge contrast ratio has been reached with respect to at least one sub-band of the first and second spectral bands.

18. The method of claim 16, wherein the imaging optics is adjusted by increasing or decreasing a focal length of a telescope of the imaging optics to increase effective Q, where

19. The method of claim 18, further comprising:

correcting geometric aberrations caused by telescope errors or pointing motion when Q is greater than 2.

20. The method of claim 1, wherein the at least one region of interest is determined by shapes of objects, spectral signatures, temperature, motion, previously obtained image frames, external cues, or a combination thereof.

21. The method of claim 1, wherein the at least one focal plane comprises two focal planes, one of the focal planes corresponding to a range of frequencies of about the first spectral band.

22. The method of claim 1, wherein the at least one focal plane comprises two focal planes, one of the focal planes corresponding to a range of frequencies of about the second spectral band.

23. The method of claim 1, wherein at least one sub-band of a second plurality of sub-bands comprises at least portions of red, green and blue sub-bands.

24. The method of claim 1, further comprising:

generating a series of images to be displayed during corresponding frame times in accordance with a frame rate.

25. The method of claim 1, wherein the at least one illuminator comprises at least one laser.

26. The method of claim 25, wherein the at least one laser is a coherent laser, and collects synthetic aperture data.

27. The method of claim 1, wherein the at least one illuminated image frame comprises three-dimensional image data.

28. The method of claim 1, further comprising:

determining at least one sub-region of the at least one region of interest to be illuminated from the at least one image frame collected in the second spectral band when the at least one image frame collected in the second spectral band has been illuminated using a first illuminator of the at least one illuminator;

illuminating the at least one sub-region with at least one illuminator other than the first illuminator, wherein the at least one illuminator other than the first illuminator operates at a wavelength smaller than the first illuminator; and

collecting at least one image frame in the at least one sub-region in at least a sub-band of the second spectral band.

29. The method of claim 1, wherein the illuminating the at least one region of interest further comprises balancing an available collection time and the illuminator power according to an ambient light level.

30. A method of providing an image of a scene utilizing imaging optics, wherein radiation from the scene impinges on at least one focal plane, the method comprising:

sampling a first spectral band to obtain an initial image frame;

determining at least one region of interest of the scene from the initial image frame, each of the at least one region of interest associated with a mean signal level;

illuminating the at least one region of interest with at least one illuminator when the mean signal level of the at least one region of interest is at or below a respective threshold of a first plurality of thresholds, the at least one region of interest being illuminated in accordance a power threshold indicating a minimum illuminator power and agility necessary to illuminate the at least one region of interest;

collecting at least one illuminated image frame in at least a second spectral band;

generating at least one image to be displayed from at least the at least one illuminated image frame;

determining an optimal path to illuminate the at least one region of interest based on a prioritized scheduling algorithm; and

illuminating the at least one region of interest in accordance with the optimal path.

31. The method of claim 30, wherein the prioritized scheduling algorithm determines a minimum integration time to collect the at least one illuminated image frame.

32. An imaging system comprising:

at least one focal plane for providing images of a scene;

a spectral selector for transmitting a first spectral band, a second spectral band or portions thereof to the at least one focal plane;

at least one illuminator for illuminating at least one region of interest of the scene;

a cueing controller for sampling a first spectral band to obtain an initial image frame, determining at least one region of interest of the scene from the initial image frame, each of the at least one region of interest associated with a mean signal level, illuminating the at least one region of interest with at least one illuminator when the mean signal level of the at least one region of interest is at or below a respective threshold of a first plurality of thresholds to increase spatial resolution in the at least one region of interest, the at least one region of interest being illuminated in accordance with the mean signal level and one or more of an illuminator power and an illuminator agility, collecting at least one illuminated image frame in at least a second spectral band; and

a data combiner for generating at least one image to be displayed from at least the at least one illuminated image frame.

33. The imaging system of claim 32, wherein the at least one illuminated image frame is collected over the at least one region of interest.

34. The imaging system of claim 32, wherein the imaging optics is adjusted until a threshold signal level or a threshold edge contrast ratio has been reached.

35. The imaging system of claim 34, wherein the imaging optics is adjusted until the threshold signal level or the threshold edge contrast ratio has been reached with respect to at least one sub-band of the first and second spectral bands.

36. The imaging system of claim 34, wherein the imaging optics is adjusted by increasing or decreasing a focal length of a telescope of the imaging optics to increase effective Q, where

37. The imaging system of claim 36, wherein the data combiner corrects geometric aberrations caused by telescope errors or pointing motion when Q is greater than 2.

38. The imaging system of claim 32, wherein the at least one image is generated by combining at least two image frames.

39. The imaging system of claim 38, wherein the cueing controller further collects at least two image frames in at least two sub-bands of the second spectral band.

40. The imaging system of claim 38, wherein the cueing controller further determines a first band mean signal level from the initial image frame, and when the first band mean signal level is above a second threshold:

samples sub-bands in a first plurality of sub-bands to obtain mean signal levels for each of the sub-bands, and collects at least one image frame in each of the sampled sub-bands for which a corresponding mean signal level is above a third threshold.

41. The imaging system of claim 38, wherein the cueing controller further samples the second spectral band to obtain a second band mean signal level, collects at least one second band image frame when the second band mean signal level is at or below a third threshold, when the second band mean signal level is above the third threshold:

samples sub-bands in the second spectral band to obtain mean signal levels for each of the sub-bands, and collects at least one image frame in each of the sampled sub-bands for which a corresponding mean signal level is above a fourth threshold.

42. The imaging system of claim 38, wherein the cueing controller further determines a first band mean signal level from the initial image frame, and when the first band mean signal level is above a first threshold:

samples successively narrower sub-bands in the first spectral band to obtain mean signal levels for each of the successively narrower sub-bands until at least one of the mean signal levels each corresponding to one of the successively narrower sub-bands is at or below a respective threshold of a second plurality of thresholds, and collects at least one image frame in each of the sampled sub-bands for which a corresponding mean signal level is above the respective threshold of the second plurality of thresholds.

43. The imaging system of claim 38, wherein the cueing controller further determines an optimal path to illuminate the at least one region of interest based on a prioritized scheduling algorithm, and commands the at least one illuminator to illuminate the at least one region of interest in accordance with the optimal path.

44. The imaging system of claim 32, wherein the at least one focal plane comprises two focal planes, one of the focal planes corresponding to a range of frequencies substantially equivalent to the first spectral band.

45. The imaging system of claim 32, wherein the at least one focal plane comprises two focal planes, one of the focal planes corresponding to a range of frequencies substantially equivalent to the second spectral band.

46. The imaging system of claim 32, wherein the cueing controller further generates a series of images to be displayed during corresponding frame times in accordance with a frame rate.

47. The imaging system of claim 32, wherein the at least one illuminator comprises at least one laser.

48. The imaging system of claim 47, wherein the at least one laser is a coherent laser, and collects synthetic aperture data.

49. The imaging system of claim 32, wherein the at least one illuminated image frame comprises three-dimensional image data.

50. The imaging system of claim 32, wherein the cueing controller further determines at least one sub-region of the at least one region of interest to be illuminated from the at least one image frame collected in the second spectral band when the at least one image frame collected in the second spectral band has been illuminated using a first illuminator of the at least one illuminator, illuminates the at least one sub-region with at least one other illuminator other than the first illuminator, wherein the at least one other illuminator other than the first illuminator operates at a wavelength smaller than the first illuminator, and collects at least one image frame in the at least one sub-region in at least a sub-band of the second spectral band.

51. The imaging system of claim 32, wherein the cue controller balances an available collection time and the illuminator power according to an ambient light level.