Method for providing a polarization filter for processing synthetic aperture radar image data
First Claim
1. In a polarimetric synthetic aperture radar imaging system, a method for polarization filtering in order to maximize the signal-to-noise ratio comprising the steps ofassuming a constant gain of said transmit and receive antennas and assuming uncorrelated noise as a first step,then maximizing SrT A St, as a second step where St and SrT are the Stokes vectors characterizing some arbitrary polarization configuration of said transmit and receive antennas, and A is the average Stokes 4×
- 4 real matrix ##EQU33## where u denotes the transpose of u,u and v are 3-element real vectors, andQ is a 3×
3 real matrix,by maximizing the expression ##EQU34## using the Lagrangian multiplier method to produce the equations ##EQU35## where λ
1 and λ
2 are the Lagrangian multipliers, and st and sr are Stokes vectors characterizing transmit and receive antennas, andhaving a known Stokes vector for the transmit antenna determining the receive antenna polarization which maximizes the signal-to-noise ratio as a third step from the equation ##EQU36## where | | denotes the norm, thereby effectively maximizing received power by matching the polarization of the scattered wave incident upon the receive antenna with polarization of the receive antenna such that power P is maximized under the constraints of assumptions set forth in the first step above in accordance with the equation ##EQU37##
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Abstract
A polarization filter can maximize the signal-to-noise ratio of a polarimetric SAR and help discriminate between targets or enhance image features, e.g., enhance contract between different types of target. The method disclosed is based on the Stokes matrix/Stokes vector representation, so the targets of interest can be extended targets, and the method can also be applied to the case of bistatic polarimetric radars.
19 Citations
7 Claims
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1. In a polarimetric synthetic aperture radar imaging system, a method for polarization filtering in order to maximize the signal-to-noise ratio comprising the steps of
assuming a constant gain of said transmit and receive antennas and assuming uncorrelated noise as a first step, then maximizing SrT A St, as a second step where St and SrT are the Stokes vectors characterizing some arbitrary polarization configuration of said transmit and receive antennas, and A is the average Stokes 4× - 4 real matrix ##EQU33## where u denotes the transpose of u,
u and v are 3-element real vectors, and Q is a 3×
3 real matrix,by maximizing the expression ##EQU34## using the Lagrangian multiplier method to produce the equations ##EQU35## where λ
1 and λ
2 are the Lagrangian multipliers, and st and sr are Stokes vectors characterizing transmit and receive antennas, andhaving a known Stokes vector for the transmit antenna determining the receive antenna polarization which maximizes the signal-to-noise ratio as a third step from the equation ##EQU36## where | | denotes the norm, thereby effectively maximizing received power by matching the polarization of the scattered wave incident upon the receive antenna with polarization of the receive antenna such that power P is maximized under the constraints of assumptions set forth in the first step above in accordance with the equation ##EQU37## - View Dependent Claims (2, 3, 4, 5, 6, 7)
- 4 real matrix ##EQU33## where u denotes the transpose of u,
Specification