Refined Research on MAP Filtering for SAR Image

General form of the MAP filter was deduced and two decisive factors of it were defined. Some MAP equations were obtained in different speckle distribution and prior distribution, and they were analyzed according to the distributing status of real roots between the local averaging value and the observed value. Based on the statistical classification of SAR image, the threshold expressions of MAP filters were developed. In order to completely reflect the advantage and disadvantage of MAP filter, dynamic relation of their de-speckling capability to noise intensity was suggested. De-speckling experiments on SAR image and their quantitative measures demonstrate that MAP filtering performance is influenced directly by speckle intensity and prior distribution. When prior distribution is chosen unreasonable, MAP filtering performance is degraded seriously.