  This paper describes a novel projection algorithm, the Projection Onto Span
Algorithm (POSA) for wavelet-based superresolution and removing speckle (in
wavelet domain) of unknown variance from Synthetic Aperture Radar (SAR) images.
Although the POSA is good as a new superresolution algorithm for image
enhancement, image metrology and biometric identification, here one will use it
like a tool of despeckling, being the first time that an algorithm of
super-resolution is used for despeckling of SAR images. Specifically, the
speckled SAR image is decomposed into wavelet subbands, POSA is applied to the
high subbands, and reconstruct a SAR image from the modified detail
coefficients. Experimental results demonstrate that the new method compares
favorably to several other despeckling methods on test SAR images.
