Edge Detection in Speckled Sar Images Using Wavelet Decomposition

In this paper we propose an integration of speckle reduction and edge detection in synthetic aperture radar (SAR) images by using overcomplete wavelet decomposition. The input image is decomposed in multiple level without downsampling, as resolution needs to be preserved. For each subband, a threshold value is estimated according to the noise variance and used for soft-thresholding to reduce speckle. The points of sharp variation (edges) induce modulus maxima in highpass subbands, and the local maxima are detected to produce single-pixel edges. Depending on the requirement of details desired in the edges the level of decomposition can be selected. The method is successfully applied to JERS-1/SAR images, and some experiments are given.