Computationally Enhanced Low-Performance Infrared Focal Plane Arrays

Abstract

A method uses inpainting, whereby the ability to optimize the reconstruction of images at high resolution and sensitivity with minimal pixels is hard wired into the IRFPA. By combining several of these systems, or by selecting different pixels in the array to form images of different colors, hyperspectral images and 3-D tomograms can also be obtained with a significantly smaller number of pixels.

Claims

1. A method of acquiring an image, comprising the steps of: illuminating an IRFPA with EM radiation of the desired infrared wavelength; identifying the best responding pixels; using the best responding pixels, forming a sub-sampled acquisition; and reconstructing the image from the sub-sampled acquisition using inpainting.

2. The method according to claim 1, wherein the step of illuminating is further defined by illuminating the IRFPA with multiple wavelengths to identify the best performing pixels for SWIR, LWIR and MWIR; forming masks for individual color images by inpainting; and combining the masks together to form an inpainted hyperspectral image.

3. A computational scheme in which cameras failing specifications for their rated application have pixels which are deliberately selected to reconstruct and form the full image during operation.

4. An infrared imaging system comprised of a focal plane array, readout electronics and a computing system in which the pixels are computationally enhanced during operation.

5. The system according to claim 4, wherein the pixels are automatically classified based on their performance levels.

6. The system according to claim 4, wherein the pixels are subsequently replaced by the computing system.

7. The system according to claim 5, wherein the pixels are subsequently replaced by the computing system.

8. The system according to claim 4, wherein the pixels are identified to cause a heavy bias and are computationally corrected.

9. The system according to claim 4, wherein the pixels over a series of frames are used to reconstruct an image with higher spatial resolution and/or lower temporal noise.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a schematic view of an exemplary system of the invention.

[0017] FIG. 2 is a demonstrative figure showing a method of inpainting using best pixels, some portions of the images have been redacted;

[0018] FIG. 3 is a demonstrative figure showing a method of inpainting using best pixels for three wavelengths of light, red, blue and green;

[0019] FIG. 4 is a demonstrative figure showing inpainted images using the masks shown in FIG. 3 and a combined image, some portions of the images have been redacted.

DETAILED DESCRIPTION

[0020] While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.

[0021] This application incorporates by reference U.S. Provisional Application Ser. No. 63/185,940 filed May 7, 2021; U.S. Provisional Application Ser. No. 63/185,934 filed May 7, 2021 and U.S. Pat. No. 10,256,072 in their entireties to the extent that they are not contrary to the teaching of the present disclosure. This application also incorporates U.S. Ser. No. 17/687,170 filed Mar. 4, 2022 in its entirety to the extent that it is not contrary to the teaching of the present disclosure.

[0022] An imaging system 10 according to the invention is shown in FIG. 1. The system 10 may include optical components 16 receiving infrared radiation 14, one or more IRFPAs 20, such as multi-color focal plane arrays, receiving infrared radiation from the optical components 16, readout electronics 22, such as a read-out integrated circuit (ROIC) generating signals 24 corresponding to the working pixels of the IRFPA 20, control electronics 26 receiving the signals 24, and a computing system 28 receiving signals from the control electronics. The computing system 28 chooses signals corresponding to a sub-sampled acquisition of the working pixels. IRFPA structures are described in U.S. Pat. Nos. 4,956,686; 5,479,032; 5,518,934; 6,657,194 and 9,883,178 herein incorporated by reference to the extent they are not contrary to the present disclosure. ROIC structures are described in U.S. Pat. Nos. 9410,850; 5,431,328; 7462,831; 5,196,703; 6,657,194 and 5,581,084, herein incorporated by reference to the extent they are not contrary to the present disclosure.

[0023] Using an inpainting method, the computing system 28 outputs a reconstructed image approximating the image otherwise generated by all of the working pixels, from a sub-sampled acquisition of the working pixels. Sub-sampling and inpainting algorithms are disclosed in U.S. Pat. Nos. 7,840,086; 10,224,175 and 10,256,072 herein incorporated by reference to the extent that they are not contrary to the present disclosure. The output from the computing system can be to a user interface, such as to a screen. Other inpainting techniques are known and examples are described in U.S. Pat. Nos. 9,467,628; 10,431,419; 11,056314; 10,740,881 and 11,080,833 herein incorporated by reference to the extent that they are not contrary to the present disclosure.

[0024] The IRFPA can be manufactured by any method to have a wide range of responses from the individual pixels in the detector. This range of performance could be caused by deliberate lower precision manufacturing methods, such as the creation of pixels from different sizes of CQDs or reduced quality control in high cost atomic/molecular deposition processes, or simply that one batch of active arrays did not meet the tolerances of the highest level detectors for any number of reasons.

[0025] As demonstrated in FIG. 2, by illuminating the array with EM radiation of the desired wavelength, MWIR, LWIR, SWIR etc., the top 1-5% best responding pixels can be identified. These are the only pixels used to form the sub-sampled acquisition, that is then reconstructed using inpainting. The inpainted image is comparable to a fully sampled image as shown.

[0026] As shown in FIG. 3, the same array IRFPA can be illuminated with multiple wavelengths to identify the best performing pixels for SWIR, LWIR and MWIR, for example. These pixels form the masks for the individual color images that can be combined together to form an inpainted hyperspectral image shown in FIG. 4.

[0027] The initial step is to determine which pixels in the camera are most sensitive to each selected wavelength—this is done by illuminating the camera with a single wavelength and mapping the response. This only needs to be done once per wavelength and can be done during the manufacture of the camera. Once the best pixels for each wavelength are identified, those pixels become the sub-sampled mask for that wavelength. The software can correlate that wavelength to a color, e.g., red, green or blue.

[0028] From the total image, a red image is inpainted from the best red pixels, a green image is inpainted from the best green pixels and a blue image is inpainted from the best blue pixels. The separation of the pixels into colors is performed by the software, as is the inpainting.

[0029] When the whole image is read out, it contains red, blue and green sub-sampled images that are reconstructed using inpainting methods. Accordingly, scanning over a large range of different images for the different energy range is not required, all the information is in a single image.

[0030] If the whole imaging array is used for the hyperspectral data cube then the detector will have the regular read-out performance, i.e., speed. If a smaller number of pixels is used for read-out, then the detector can balance read-out speed against the breadth of the hyperspectral datacube.

[0031] From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.