Title :
Optimal Sharpness Function for SAR Autofocus
Author :
Schulz, Timothy J.
Author_Institution :
Dept. of Electr. & Comput. Eng., Michigan Technol. Univ., Houghton, MI
Abstract :
Phase-error correction through the optimization of an image-domain sharpness function provides one method for the auto-focus of synthetic aperture radar (SAR) imagery. Several ad-hoc sharpness functions have been proposed, implemented, and analyzed, but none of these has been motivated as the solution to a well-defined statistical estimation problem. In this letter, a SAR sharpness function is derived that induces the solution to maximum-likelihood and maximum-posterior estimation for idealized SAR data. Furthermore, a limiting form of the optimal sharpness function is shown to be the popular intensity-squared sharpness
Keywords :
error correction; error statistics; maximum likelihood estimation; radar imaging; synthetic aperture radar; SAR; autofocusing; image-domain sharpness function; intensity-squared sharpness; maximum-likelihood estimation; maximum-posterior estimation; optimization; phase-error correction; statistical estimation; synthetic aperture radar imagery; Computer errors; Discrete Fourier transforms; Error correction; Layout; Maximum likelihood estimation; Optimization methods; Phase estimation; Reflectivity; Signal processing; Synthetic aperture radar; MAP estimation; synthetic aperture radar (SAR);
Journal_Title :
Signal Processing Letters, IEEE
DOI :
10.1109/LSP.2006.881525
