Spatial-domain filtering algorithm for speckle reduction of SAR images

In order to preserve edge characteristics and effectively reduce multiplicative speckle noise in SAR image, a new spatialdomain filtering algorithm is proposed. The new algorithm is based on the negative-exponential and weighted filtering model,and the weighting coefficients are produced by the decay factor obtained by combining several local statistics and are adaptive to the characteristics of regional distribution of SAR image. Meanwhile two-stage filtering strategy is used. The pre-filtering is executed for reducing speckle in SAR image and estimating fine local statistics, and the fine filtering for original SAR image is carried out based on the fine local statistics obtained by the pre-filtering. The experimental results show that compared with most existing despeckling algorithms, the proposed algorithm has better performance in the speckle suppression and edge preservation.