Study Of Speckle Reduction Algorithms For SAR Images

Speckle, appearing in synthetic aperture radar (SAR) images as granular noise, is generated by the coherent processing of radar signals. It severely affects the image qualities. To alleviate deleterious effects of speckle, various ways have been devised to suppress it. An ideal algorithm should smooth the speckle without blurring edges and fine detail. But most algorithms cannot satisfy these two demands very good.In the preface to this article, first, the basic purpose and significance of speckle smoothing algorithm for SAR images are introduced briefly. Secondly, we look back on the history of the speckle reduction algorithm. And finally, the principal contribution of this dissertation is summarized here.Chapter 2 described how the speckle formed ^ and discusses the noise model thus the fundamental properties of speckle in SAR images.In chapter 3, several well-known speckle filtering algorithms are discussed. The concept of each filtering algorithm is discussed in detail.To compare speckle smoothing algorithms quantitatively, a set of performance criteria is established in chapter 4. And tests are performed on real SAR images. Then comparisons are made for the effectiveness of these algorithms in speckle reduction and edge, point target contrast preservation.In the end, conclusions are made and the possible future work is explained.