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.

中文翻译：

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基于改进Frost滤波的SAR图像去斑方法

本文提出了一种基于改进Frost滤波的合成孔径雷达(SAR)图像去斑算法。在Frost滤波器模型中加入了能够更好表征SAR图像均匀区域和边缘区域的重构衰减因子，利用Lee滤波器系数实现对不同区域滤波程度的自适应控制。执行三阶段过滤策略以进行有效的去斑和边缘保留。利用小窗口的Frost滤波对SAR图像进行预滤波得到局部统计量，然后利用这些局部统计参数对原始SAR图像进行两次细化滤波。通过调整变量常量和窗口比例，这两个值分别偏向于平滑和边缘保留。最后，最终的滤波结果是通过我们提出的重构衰减因子对两个滤波结果进行加权得到的。实验表明，与先进方法相比，所提出的方法提高了去斑和边缘保留能力。