Review and research of speckle reducing filters for SAR image

The article introduced several common filters used to reduce speckle in SAR image, including Lee filter, Frost filter, AD-homomorph filter, Speckle Reduction Anisotropic Diffusion (SRAD) and nonlocal means filter (NL means). The basic principles and characteristics of the above mentioned filters would be researched and compared in detailed. According to the filtering experimental results of synthetic image and real SAR image, it is obviously shown that SRAD is more suitable for image homogenous region filtering and speckle reduction, while NL means is more suitable to preserve the texture structures and weak characteristics in SAR image.