A modified version of the SAR speckle filter based on structure detection

A modified version of the structure detection filter (SDF), originally developed by Nezry et al. for speckle reduction in SAR images, is presented. The original SDF first detects edges and thin linear structures, then applies the maximum a posteriori (MAP) filter equation for gamma distributed scene (Gamma MAP) based on local statistics extracted from rectangular masks. The modified-SDF proposed in this paper exploits the edge detection step of the SDF to perform image segmentation. The new filter computes local statistics over areas that are subsets of image segments having any possible shape. The modified-SDF procedure is effective in speckle removal and its computation time is estimated to be of the same magnitude as the original SDF