Patent ID: 6650273
Filing Date: 2003-11-18
Classification: G01S

Abstract:
A method effects coherent change subtraction of mission synthetic aperture radar (SAR) data and reference SAR data for suppression of combined noise and backscatter energy, said method comprising:a) forming a mission image from said mission SAR data; b) forming a reference image from said reference SAR data; c) registering said mission and reference images to form registered mission and reference images; d) forming said registered mission and reference images into a plurality of patches of said registered mission and reference images, wherein each of said patches contains mission data, being data from said registered mission image, and reference data, being data from said registered reference image, and wherein each of said patches is substantially equal to a separate portion of said registered mission and reference images; e) processing said mission and reference data in each patch of said plurality of patches to produce processed mission and reference data; f) producing a processed mission image and a processed reference image by concatenating said processed mission and reference data from each of said plurality of patches; g) subtracting a first one of said processed mission and reference images from a second one of said processed mission and reference images to form a delta image, wherein said mission image, said reference image, and said delta image each have substantially a like number of pixels; and h) postprocessing said delta image, said postprocessing activity h) comprising: determining, for each pixel of said delta image, if said each pixel has a clutter-to-noise ratio of less than one; and substituting, when said determining activity determines said each pixel has a clutter-to-noise ratio of less than one, a replacement pixel for said each pixel, wherein said replacement pixel is a coincident pixel from one of said processed mission image, said processed reference image, and said delta image having a lowest amplitude ratio.