A new algorithm for SAR image despeckling using an enhanced Lee filter and median filter

Abstract

Speckle noise usually occurs in synthetic aperture radar (SAR) images , and SAR data is processed coherently. Speckle filters commonly are adaptive filters using local statistics such as mean and standard deviation, such as the Lee and its enhanced filters and median filter. They adapt the filter coefficients based on data within a fixed moving window, and this brings in contradiction between the quality of speckle noise suppression and the capability of preserving image details. The Lee filter decreases speckle noise well in homogeneous regions, and the enhanced filter performs well both in the homogeneous and heterogeneous areas. But it does not effectively maintain image edges and details, while depressing SAR image noise. The median filter does well in decreasing impulse noise. In this paper, we propose an improved algorithm fusing the enhanced Lee filter and median filter based on spatial filtering of SAR image speckle. The experiment proves it has a good performance in preserving edges and details while filtering images.