Polarimetric synthetic aperture radar signature detector
First Claim
1. A system for processing an acquired polarimetric synthetic aperture radar (SAR) image of a region to identify a candidate pixel that correlates to a target representation, said polarimetric SAR image having a plurality of pixels, said candidate pixel corresponding to a position in said region that contains a candidate object, the system comprising:
- a sub-aperture processor configured to extract an N plurality of sub-apertures from the polarimetric SAR image;
a polarimetric decomposition processor configured to deconstruct a J plurality of parameter components from each sub-aperture of said N plurality of sub-apertures;
a log-likelihood processor configured to identify the candidate pixel by generating a log-likelihood value from said J plurality of parameter components by;
obtaining an acquired value for said sub-aperture from at least one parameter component of said J plurality of parameter components;
acquiring a reference value that characterizes said parameter component for the target representation;
determining a distance value between said reference value and said acquired value;
combining said distance value for said each sub-aperture of said N plurality of sub-apertures together to obtain said log-likelihood value; and
log-likelihood value against a classification criterion to determine whether the candidate pixel conforms to the target representative.
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Abstract
A method is provided for processing an acquired polarimetric synthetic aperture radar (SAR) image of a region to identify a candidate pixel that correlates to a target representation. The polarimetric SAR image is composed of a plurality of pixels, and the candidate pixel corresponds to a position in the region that contains a candidate object. The process includes deconstructing J parameter components each sample, obtaining acquired values for the image from select parameter components, acquiring reference values that characterize said parameter components for the target representation, determining distance values each reference value and each acquired value, comparing the distance values against a classification criterion to determine whether the candidate pixel conforms to the target representative. The process may further include extracting N sub-apertures from the polarimetric SAR image, and combining the distance values for the sub-apertures together to obtain distance summations for comparison. The process may additionally include multiplying the distance summations with their corresponding weighting factors to obtain weighted results and combining these to produce a weighted log-likelihood function that identifies whether the pixel conforms to the target. Determining a difference may further include subtracting reference values from their respective acquired values to respectively obtain set of differences, assigning normalized defaults to the differences in response to the difference having a specified relation to parameter thresholds, and otherwise normalizing the difference, and determining natural logs of unity minus said each difference to obtain their distance values.
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Citations
9 Claims
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1. A system for processing an acquired polarimetric synthetic aperture radar (SAR) image of a region to identify a candidate pixel that correlates to a target representation, said polarimetric SAR image having a plurality of pixels, said candidate pixel corresponding to a position in said region that contains a candidate object, the system comprising:
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a sub-aperture processor configured to extract an N plurality of sub-apertures from the polarimetric SAR image; a polarimetric decomposition processor configured to deconstruct a J plurality of parameter components from each sub-aperture of said N plurality of sub-apertures; a log-likelihood processor configured to identify the candidate pixel by generating a log-likelihood value from said J plurality of parameter components by; obtaining an acquired value for said sub-aperture from at least one parameter component of said J plurality of parameter components; acquiring a reference value that characterizes said parameter component for the target representation; determining a distance value between said reference value and said acquired value; combining said distance value for said each sub-aperture of said N plurality of sub-apertures together to obtain said log-likelihood value; and log-likelihood value against a classification criterion to determine whether the candidate pixel conforms to the target representative. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification