SAR image despeckling in directionlet domain based on edge detection

Presented is a novel directionally adaptive despeckling algorithm for a SAR image using a multi-direction anisotropic wavelet transform, called a directionlet. It efficiently extracts edge information along dominant directions from the spatially segmented SAR image. Then an optimal scale dependent subband adaptive threshold, based on the generalised cross-validation technique, is applied to the edge removed image. The despeckled image is finally synthesised using the extracted edge information to preserve the sharpness of edges and the texture. The proposed scheme outperforms many of the traditional despeckling schemes such as the Lee filter and the wavelet and bandlet based edge detection methods in terms of numeric and perceptual quality.