Abstract: In order to preserve edge characteristics and effectively reduce multiplicative speckle noise in SAR image, a new spatial-
domain 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.

摘要： 为在保护SAR图像边缘特征的同时有效抑制乘性相干斑噪声，提出了一种空域滤波新算法。该算法以负指数衰减型加权滤波模型为基础，通过将SAR图像多种局部统计参量巧妙结合作为联合衰减因子，形成与SAR图像区域分布特性相适应的负指数型加权系数；同时采取两次滤波策略，先由预滤波削弱SAR图像相干斑噪声并估计获得更精准的局部统计参量，然后借助精细局部统计参量再对原SAR图像实施精细滤波。实验结果表明，与多种抑斑算法相比，该算法在SAR图像抑斑与边缘保护方面均获得了更好的性能。

关键词: 合成孔径雷达图像, 相干斑抑制, 空域滤波, 边缘保护