SAR Image Despeckling Based on Bivariate Threshold Function in NSCT Domain
Jia Jian①② Chen Li①
①(School of Information Science and Technology, Northwest University, Xi’an 710127, China) ②(Department of Mathematics, Northwest University, Xi’an 710127, China)
Abstract:Considering the dependencies between the coefficients of Contourlet transform and their parents’ coefficients, a non-Gaussian bivariate distribution is given, and corresponding nonlinear threshold function is derived from the model using Bayesian estimation theory. Combined nonlogarithmic additive model of SAR image with bivariate threshold function, a novel SAR image despeckling based on bivariate threshold function in Non-Subsampled Contourlet Transform domain (NSCT) is proposed. Experimental results for speckle reduction on amplitude and intensity of SAR images demonstrate that the method holds a good ability of radiometric preservation, the speckle is despeckled well in homogeneous regions, edges and textures of despeckled image are also clear.