Imager with array of multiple infrared imaging modules

• US 10,091,439 B2
• Filed: 12/20/2013
• Issued: 10/02/2018
• Est. Priority Date: 06/03/2009
• Status: Active Grant

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: Hogasten, Nicholas, Nussmeier, Mark, Kurth, Eric A., Hoelter, Theodore R., Strandemar, Katrin, Boulanger, Pierre, Sharp, Barbara
• Primary Examiner(s): Senfi, Behrooz
• Assistant Examiner(s): Picon-Feliciano, Ana
• Application Number:
  US14/137,573
• Publication Number:
  US 20140139643A1
• Time in Patent Office: 1,747 Days
• Field of Search: 348 48, 348164, 348166, 348139, 348274, 348275
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H04N 13/218 using spatial multiplexing
• CPC Class Codes: H04N 13/243 using three or more 2D image sensors
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction
• CPC Class Codes: H04N 25/674 based on the scene itself, e.g. defocusing
• CPC Class Codes: H04N 25/68 applied to defects
• 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

An imager array may be provided as part of an imaging system. The imager array may include a plurality of infrared imaging modules. Each infrared imaging module may include a plurality of infrared sensors associated with an optical element. The infrared imaging modules may be oriented, for example, substantially in a plane facing the same direction and configured to detect images from the same scene. Such images may be processed in accordance with various techniques to provide images of infrared radiation. The infrared imaging modules may include filters or lens coatings to selectively detect desired ranges of infrared radiation. Such arrangements of infrared imaging modules in an imager array may be used to advantageous effect in a variety of different applications.

Claims

1. An imaging system comprising:

a system housing;

an imager array disposed in the system housing and adapted to image a scene, wherein the imager array comprises a base and a plurality of infrared imaging modules arranged in an array comprising a plurality of rows and a plurality of columns, wherein each infrared imaging module comprises;

a module housing,

an optical element fixed relative to the module housing and adapted to receive infrared radiation from the scene, and

a plurality of infrared sensors in a focal plane array (FPA) adapted to capture an image of the scene based on the infrared radiation received through the optical element; and

wherein the infrared imaging modules are arranged within the system housing in a multi-level staggered configuration such that first and second levels of the infrared imaging modules including the plurality of infrared sensors are disposed at corresponding first and second distances from the base, wherein the first distance is different than the second distance.

2. The imaging system of claim 1, wherein the multi-level staggered configuration increases a packing ratio of the imager array and reduces parallax associated with at least two of the infrared imaging modules.

3. The imaging system of claim 1, wherein:

a first one of the infrared imaging modules comprises a first filter adapted to limit the infrared radiation received by the first infrared imaging module to a first spectral range; and

a second one of the infrared imaging modules comprises a second filter adapted to limit the infrared radiation received by the second infrared imaging module to a second spectral range.

4. The imaging system of claim 1, wherein:

at least a first one of the infrared imaging modules is greater in size than a second one of the infrared imaging modules; and

the first infrared imaging module is adapted to capture an image of the scene with a higher resolution and a narrower field of view than the second infrared imaging module.

5. The imaging system of claim 1, wherein at least one of the infrared imaging modules is adapted to block infrared radiation outside a desired field of view of its infrared sensors.

6. The imaging system of claim 1, wherein at least two of the infrared imaging modules exhibit parallax relative to each other and are adapted to provide stereo images of the scene, wherein the system is configured to selectively compensate for the parallax.

7. The imaging system of claim 1, wherein:

each infrared imaging module comprises an optical axis extending from its infrared sensors through its optical element;

the optical axes of at least two of the infrared imaging modules exhibit phase shifts relative to each other;

images provided by the at least two infrared imaging modules are phase shifted relative to each other; and

the imaging system further comprises a processor adapted to perform super resolution processing of the phase shifted images to provide a result image of the scene with a resolution greater than the resolution of the at least two infrared imaging modules.

8. The imaging system of claim 1, wherein:

the imager array is adapted to capture a first image of the scene using at least a first one of the infrared imaging modules;

the imager array is adapted to capture a second image of the scene using at least a second one of the infrared imaging modules substantially simultaneously with the first image, wherein the second image has a higher resolution than the first image; and

the imaging system further comprises;

a database comprising a mapping from the first image to the second image, and

a processor adapted to;

map a third image provided by the imager array to the first image, wherein the third image has a resolution substantially equal to the first image, and

replace the third image with the second image to provide a high resolution result image.

9. The imaging system of claim 1, wherein:

one of the infrared sensors in a first one of the infrared imaging modules is defective; and

the imaging system further comprises a processor adapted to replace image data associated with the defective infrared sensor with image data associated with a corresponding one of the infrared sensors in a second one of the infrared imaging modules.

10. The imaging system of claim 1, further comprising a processor adapted to:

map the infrared sensors of at least two of the infrared imaging modules to a grid comprising a plurality of pixels;

accumulate signals from the at least two infrared imaging modules for each of the grid pixels; and

provide a result image of the scene from the grid pixels, wherein the result image has a signal to noise ratio higher than signal to noise ratios of the images captured by the infrared imaging modules.

11. The imaging system of claim 1, wherein the imager array further comprises:

a plurality of visible light sensor arrays, wherein each visible light sensor array comprises;

a lens adapted to receive visible light radiation from the scene; and

a plurality of visible light sensors adapted to capture an image of the scene based on the visible light radiation received through the lens.

12. The imaging system of claim 1, wherein:

a first one of the infrared imaging modules is adapted to capture a first image of a first wavelength range of the infrared radiation;

a second one of the infrared imaging modules is adapted to capture a second image of a second wavelength range of the infrared radiation;

the second wavelength range is a subset of the first wavelength range and substantially corresponds to an absorption band of a gas; and

the imaging system further comprises a processor adapted to compare the first and second images to determine a presence of the gas in the scene.

13. The imaging system of claim 12, wherein:

a third one of the infrared imaging modules is adapted to capture a third image of a third wavelength range of the infrared radiation;

the third wavelength range substantially corresponds to another absorption band of the gas; and

the processor is adapted to compare the first or second images to the third image to determine the presence of the gas in the scene.

14. The imaging system of claim 1, wherein each infrared imaging module further comprises a processor adapted to:

receive a plurality of pixel values associated with the images captured by the infrared sensors of the infrared imaging modules;

map the infrared sensors to a coordinate space, wherein at least one infrared sensor of each infrared imaging module is mapped to each coordinate of the coordinate space; and

calculate an offset correction term for each infrared sensor based on the pixel values of all infrared sensors mapped to the same coordinate.

15. The imaging system of claim 1, wherein the FPA of each infrared imaging module comprises an array of microbolometers adapted to receive a bias voltage selected from a range of approximately 0.2 volts to approximately 0.7 volts.

16. The imaging system of claim 15, wherein:

a size of the array of microbolometers is approximately 80 by 60; and

each infrared imaging module is adapted to be inserted into a socket having dimensions less than approximately 8.5 mm by 8.5 mm.

17. The imaging system of claim 1, wherein:

the images are unblurred infrared images of the scene;

at least one of the infrared imaging modules is configured to capture an intentionally blurred infrared image of the scene; and

the imaging system further comprises a processor adapted to determine a plurality of non-uniform correction (NUC) terms based on the intentionally blurred infrared image and apply the NUC terms to a corresponding unblurred infrared image to remove noise from the unblurred infrared image.

35. The system of claim 1, wherein the rows of the array of infrared imaging modules extend in a first direction and the columns of the array of infrared imaging modules extend in a second direction, and

wherein the first level and the second level are displaced relative to each other along a third direction normal to a plane formed by the first direction and the second direction.

18. A method of imaging, the method comprising:

receiving infrared radiation from a scene at an imager array disposed in a system housing of an imaging system, wherein the imager array comprises a base and a plurality of infrared imaging modules arranged in an array comprising a plurality of rows and a plurality of columns, wherein each infrared imaging module comprises a module housing, an optical element fixed relative to the module housing and adapted to receive the infrared radiation from the scene, and a plurality of infrared sensors in a focal plane array (FPA) adapted to capture an image of the scene based on the infrared radiation received through the optical element;

capturing a plurality of images of the scene substantially simultaneously using the infrared sensors of the infrared imaging modules; and

wherein the infrared imaging modules are arranged within the system housing in a multi-level staggered configuration such that first and second levels of the infrared imaging modules including the plurality of infrared sensors are disposed at corresponding first and second distances from the base, wherein the first distance is different than the second distance.

19. The method of claim 18, wherein the multi-level staggered configuration increases a packing ratio of the imager array and reduces parallax associated with at least two of the infrared imaging modules.

20. The method of claim 18, further comprising:

filtering the infrared radiation received by a first one of the infrared imaging modules to a first spectral range; and

filtering the infrared radiation received by a second one of the infrared imaging modules to a second spectral range.

21. The method of claim 18, wherein:

at least a first one of the infrared imaging modules is greater in size than a second one of the infrared imaging modules; and

the image captured by the first infrared imaging module has a higher resolution and a narrower field of view than the image captured by the second infrared imaging modules.

22. The method of claim 18, wherein at least one of the infrared imaging modules is adapted to block infrared radiation outside a desired field of view of its infrared sensors.

23. The method of claim 18, wherein at least two of the infrared imaging modules exhibit parallax relative to each other and their captured images are stereo images of the scene, wherein the system is configured to selectively compensate for the parallax.

24. The method of claim 18, wherein:

each infrared imaging module comprises an optical axis extending from its infrared sensors through its optical element;

the optical axes of at least two of the infrared imaging modules exhibit phase shifts relative to each other;

images provided by the at least two infrared imaging modules are phase shifted relative to each other; and

the method further comprises performing super resolution processing of the phase shifted images to provide a result image of the scene with a resolution greater than the resolution of the at least two infrared imaging modules.

25. The method of claim 18, wherein the capturing comprises:

capturing a first image of the scene using at least a first one of the infrared imaging modules;

capturing a second image of the scene using at least a second one of the infrared imaging modules substantially simultaneously with the first image, wherein the second image has a higher resolution than the first image;

mapping the first image to the second image;

mapping a third image provided by the imager array to the first image, wherein the third image has a resolution substantially equal to the first image; and

replacing the third image with the second image to provide a high resolution result image.

26. The method of claim 18, wherein:

one of the infrared sensors in a first one of the infrared imaging modules is defective; and

the method further comprises replacing image data associated with the defective infrared sensor with image data associated with a corresponding one of the infrared sensors in a second one of the infrared imaging modules.

27. The method of claim 18, further comprising:

mapping the infrared sensors of at least two of the infrared imaging modules to a grid comprising a plurality of pixels;

accumulating signals from the at least two infrared imaging modules for each of the grid pixels; and

providing a result image of the scene from the grid pixels, wherein the result image has a signal to noise ratio higher than signal to noise ratios of the images captured by the infrared imaging modules.

28. The method of claim 18, wherein the imager array further comprises a plurality of visible light sensor arrays, wherein each visible light sensor array comprises a lens adapted to receive visible light radiation from the scene and a plurality of visible light sensors adapted to capture an image of the scene based on the visible light radiation received through the lens.

29. The method of claim 18, further comprising:

capturing a first image of a first wavelength range of the infrared radiation;

capturing a second image of a second wavelength range of the infrared radiation, wherein the second wavelength range is a subset of the first wavelength range and substantially corresponds to an absorption band of a gas; and

comparing the first and second images to determine a presence of the gas in the scene.

30. The method of claim 29, further comprising:

capturing a third image of a third wavelength range of the infrared radiation, wherein the third wavelength range substantially corresponds to another absorption band of the gas; and

comparing the first or second images to the third image to determine the presence of the gas in the scene.

31. The method of claim 18, further comprising:

receiving a plurality of pixel values associated with the images captured by the infrared sensors of the infrared imaging modules;

mapping the infrared sensors to a coordinate space, wherein at least one infrared sensor of infrared imaging module is mapped to each coordinate of the coordinate space; and

calculating an offset correction term for each infrared sensor based on the pixel values of all infrared sensors mapped to the same coordinate.

32. The method of claim 18, wherein the FPA of each infrared imaging module comprises an array of microbolometers adapted to receive a bias voltage selected from a range of approximately 0.2 volts to approximately 0.7 volts.

33. The method of claim 32, wherein:

a size of the array of microbolometers is approximately 80 by 60; and

each infrared imaging module is adapted to be inserted into a socket having dimensions less than approximately 8.5 mm by 8.5 mm.

34. The method of claim 18, wherein the images are unblurred infrared images of the scene, the method further comprising:

capturing, by at least one of the infrared imaging modules, an intentionally blurred infrared image of the scene; and

determining a plurality of non-uniform correction (NUC) terms based on the intentionally blurred infrared image and applying the NUC terms to a corresponding unblurred infrared image to remove noise from the unblurred infrared image.

36. The method of claim 18, wherein the rows of the array of infrared imaging modules extend in a first direction and the columns of the array of infrared imaging modules extend in a second direction, and

wherein the first level and the second level are displaced relative to each other along a third direction normal to a plane formed by the first direction and the second direction.