Complementary pixel reconstruction
AssigneeLockheed Martin Corporation
InventorsCalvin L Powell, Kevin F Williams, Michael C Snead
Life of this patent
Estimating the term…
Abstract
Systems and methods for reconstructing pixel values at bad (i.e. fully or partially defective, saturated, and/or non-responsive in one or more spectral bands) pixel locations in multi-spectral photo-detectors are provided herein. A detector having pixel locations responsive in two or more spectral bands may have pixel values at bad pixel locations reconstructed from adjacent pixel location band ratios so long as the bad pixel location is operational/responsive in at least one spectral band. Pixel locations may be two (or more) color pixels, stacked FPAs, “virtual” locations created by mapping pixels in a first detector to pixels in a second detector, or “super pixels” defined on a detector with a patterned band-pass filter.
Claims12
A method of restoring a pixel value associated with a bad pixel site in a first frequency band in a photo-detector that detects in at least a first and a second frequency band at each pixel site, the method comprising:
- locating the bad pixel site for the first frequency band;
- identifying, from among pixel sites adjacent to the bad pixel site, a pixel site having the highest value in the second frequency band;
- calculating a first band ratio between said first frequency band and said second frequency band for said identified pixel site;
- and
- restoring, as the pixel value of the bad pixel site in the first frequency band, a pixel value first obtained by multiplying the value of the bad pixel site in the second frequency band by the calculated band ratio or its inverse;
- wherein the point-spreads of said first frequency band and said second frequency band are similar and at least part of the point-spread of the bad pixel site falls onto surrounding pixel sites.
A non-transitory computer-readable medium having embodied thereon a program that, when executed by one or more processors, causes the processors to perform part or all of a method of restoring a pixel value associated with a bad pixel site in a first frequency band in a photo-detector that detects in at least a first and a second frequency band at each pixel site, the method comprising:
- locating the bad pixel site for the first frequency band;
- identifying, from among pixel sites adjacent to the bad pixel site, a pixel site having the highest value in the second frequency band;
- calculating a first band ratio between said first frequency band and said second frequency band for said identified pixel site;
- and
- restoring, as the pixel value of the bad pixel site in the first frequency band, a pixel value first obtained by multiplying the value of the bad pixel site in the second frequency band by the calculated band ratio or its inverse;
- wherein the point-spreads of said first frequency band and said second frequency band are similar and at least part of the point-spread of the bad pixel site falls onto surrounding pixel sites.
A photo-detector that detects in at least a first and a second frequency band and has defective pixel value restoration capability, the detector comprising:
- a plurality of pixels in the first spectral band;
- a plurality of pixels in the second spectral band;
- a pixel identification map that identifies at least one bad pixel site in the photodetector for the first frequency band;
- a local pixel intensity comparator that identifies, from among pixel sites adjacent to the bad pixel site, the pixel site having the highest value in the second frequency band;
- a band ratio calculator that calculates a band ratio between the first and second frequency band values for the identified pixel site;
- and
- a value restorer that restores, as the pixel value in the first frequency band at the bad pixel site, the pixel value in the second frequency band at the bad pixel site multiplied by the calculated band ratio or its inverse;
- wherein the point-spreads of said first frequency band and said second frequency band are similar and at least part of the point-spread of the bad pixel site falls onto surrounding pixel sites.
Dependencies are inferred from the claim text.