Adaptive SAR image filtering based on wavelets and Bayesian estimation
Xia Liang-zheng · Journal of Astronautics · 2004
Coherent speckle noise of SAR images decreases the image quality seriously,and makes the image difficult to be understood.In this paper,a new filter algorithm using the advantages of both local statistical filter and wavelet threshold filter is introduced.The algorithm was an adaptive one,for the wavelet coefficients were adjusted according to various kinds of regions in a non-stationary SAR image.Being studied carefully,the distribution of noise in the wavelet domain was described by Gauss Mixture Model.The Expectation Method (EM) was used to calculate the distribution parameters of the wavelet coefficients.In the end,the wavelet coefficients of the noiseless SAR image were estimated with the Bayesian estimator.The filter result was compared with that of both the local statistical filters (such as Lee filter) and wavelet threshold filter.Results showed that the method introduced in this paper performed better to various regions,especially to non-stationary SAR images.