Study Of Iterative Filtering Algorithm For Speckle Noise Of SAR Image

Synthetic aperture radar plays a more and more important role in both civil and military areas for its all-weather and strong transmission characteristic. But the unavoidable coherent speckle noise in SAR image badly affects its display quality. Thus, to reduce the speckle noise becomes the first and indispensable step before making segmentation, classification, target detection and other information processing of SAR image.Several filtering algorithms in common use about speckle reduction of SAR image are introduced at first. Then several iterative filtering algorithms are expounded, whose filtering principle and character are analyzed. Considering respective character of these iterative filtering algorithms, a modified SAR image iterative filtering algorithm is presented. A sort of adaptive window is introduced to make up the shortage of fixed window, in which processing is done. By a correlated neighborhood model, a local image property is described availably. The estimate of the real intensity is obtained, and the optimal one to be the iterative result is selected by using Bayesian formulation. Real SAR image is processed by these iterative filtering algorithms, and the experimental results are also compared and analyzed. The experimental results show that, the modified algorithm improves the effect both structure preservation in heterogeneous areas, and speckle noise reduction in homogeneous areas. Moreover, it reduces iterative times and shortens compute time with satisfying results.