全方向自适应动态窗口SAR斑点噪声抑制算法

All Direction Auto-adaptive Dynamic Window filter for Noise Suppression in SLC SAR Image

有效地抑制或消除斑点噪声是SAR图像地学应用的前提。通过基于单视数SAR图像的Speckle统计特性和已发展的空间滤波算法分析,发展了一种改进的全方向动态窗口自适应SAR噪声滤波算法。该算法对处理的每一个像元可按图像边界细节划分为需要的全方向子窗口,利用相对标准差判断滤波窗口及子窗口内斑点噪声及边缘信息的存在情况,可实现滤波窗口大小动态调整和窗口内参加滤波像素的自适应选择。对ERS SAR SLC图像试验结果表明,该算法对单视数SAR图像具有较强的Speckle抑制能力,且可较好地保持图像的纹理边界细节信息,有一定的实用价值。

To smooth coherent speckle noise and preserve edge information in SLC SAR images as precise as possible, a new algorithm called all direction auto-adaptive dynamic window filtering method based on coherent speckle statistic characteristic and analysis of spatial filtering algorithms for SAR image, is developed in this paper. For every processing pixel the filtering window is divided into mutually exclusive all direct sub-windows according to the complexity of image texture and edge existence. Local relative standard deviation is used to determine whether local filtering window area is homogeneous. Kuan filter and a 3 x 3 directive operator are incorporated to process the SAR image. The proposed method can auto-adaptively modulate its filtering window size and selection of filtering pixels. The developed method is applied to a single-look ERS SAR image. Experimental result shows that the performance of the method is satisfactory in both speckle suppression and preservation of image details.