Cascade filtering of high-resolution SAR images with L0 smoothing

In this paper, we present a method of cascade filtering of high-resolution SAR images with L0 gradient smoothing. First we pre-filter the image resorting to a simple Lee filtering method to suppress the speckle to a certain extent. Then we take the logarithm of the pre-filtered result, following with a wavelet multiscale decomposition, and process each level with L0 gradient smoothing. Finally, we obtain the filtered image by wavelet reconstruction. Experimental results on airborne and spaceborne high resolution SAR images show the efficiency of the proposed algorithm, which smoothes the speckle extremely in homogeneous areas and reserves the edges in target area. It shows that our method outperforms most classic and popular filtering method.