Translation invariant wavelets for speckle reduction of SAR images

Speckle reduction and enhancement of synthetic aperture radar (SAR) images with translation-invariant wavelets are proposed. The proposed transformations are useful for speckle reduction through its subband-images and the speckle reduction is obtained by thresholding the subband-image coefficients of the digitized SAR images. The thresholding are nonlinear functions which are adapted for each of selected subband-images and are based on sigmoid functions. The proposed method shows great promise for speckle removal and hence provides good detection performance for SAR based recognition