基于区域划分的合成孔径雷达图像相干斑各向异性扩散滤波算法

摘要

经典的细节保持各向异性扩散滤波算法(DPAD)在抑制合成孔径雷达(SAR)图像乘性相干斑噪声时,存在同质区块效应现象与边缘区噪声残留问题;为此提出了一种基于区域划分的各向异性扩散滤波算法.该算法通过在DPAD扩散方程中耦合方向扩散来抑制边缘区域相干斑与同质区块状起伏.通过阈值化的边缘强度映射对SAR图像实施同质区与边缘区的区域划分;并对不同区域采用不同尺度局域窗分别实施各向异性扩散滤波,从而在抑制同质区相干斑的同时有效保护边缘.实验结果表明:与多种各向异性扩散抑斑算法相比,算法在保护边缘的同时,能明显降低同质区块效应现象与边缘区噪声残留问题.%The classic detail-preserving anisotropic diffusion(DPAD)used for smoothing multiplicative speckle noise in SAR images suffers from blocking artefacts in homogeneous regions and poor despeckling performance near edges.In view of the above question,a new anisotropic diffusion filtering algorithm based on region division is pro-posed.The proposed algorithm is established to reduce speckle near edges and blocking artefacts in homogeneous regions by coupling directional diffusion equation into the DPAD's diffusion equation.The SAR image is divided in-to homogeneous regions and edge regions by the shreshold-processing edge strength maps.The anisotropic diffusion with different scale local windows in different regions is implemented,resulting in good speckle suppression in hom-ogeneous regions and well detail protection in edge regions.The experimental results and comparisons with several traditional anisotropic diffusion algorithms show that the proposed algorithm can significantly reduce blocking arte -facts in homogeneous regions and the residual noise in edge regions while protecting SAR images edges.