SAR image despeckling method based on improved Frost filtering

Abstract

In this paper, a novel despeckling algorithm for synthetic aperture radar (SAR) images based on improved Frost filtering is proposed. A reconstructed decay factor which can better characterize the homogeneous and edge regions of SAR image is added into the Frost filter model by using the Lee filter coefficient to implement adaptively controlling the degree of filtering in different regions. The three-stage filtering strategy is performed for effective despeckling and edge preservation. The SAR image is pre-filtered by using the Frost filtering of the small window to obtain local statistics, and then the original SAR image is refine filtered twice utilizing these local statistical parameters. The two values are, respectively, biased toward smoothing and edge preservation by adjusting the variable constant and the window scales. Finally, the final filtering result is obtained by weighting the two filtering results with the reconstructed decay factor we proposed. The experiments demonstrate that compared with advanced approaches, the proposed method improves both despeckling and edge preservation ability.