融合多方向Sobel算子的相干斑各向异性扩散抑制

Speckle Anisotropic Diffusion Suppression by Multidirectional Sobel

相干斑的存在严重干扰了SAR图像质量,亟需对其抑制处理。传统AD(Anisotropic Diffusion)滤波器边缘检测模型精准度仍有提升空间,且噪声抑制效果往往受限于扩散阈值较难准确估计的问题。针对上述问题,提出了一种融合多方向Sobel算子的相干斑各向异性扩散抑制方法。该方法是SRAD(Speckle Reducing Anisotropic Diffusion)的改进算法,其利用多方向Sobel算子在SAR影像各点处构建了全新的边缘检测模型,并基于此,融合高斯核函数建立了新的AD扩散函数,可有效解决传统AD扩散系数受参数估计限制,提升了相干斑各向异性抑制的准确性。实验选取了3景真实SAR影像进行滤波实验,结果表明:该方法可有效提高边缘检测能力,获取更优相干斑抑制效果。

Speckle is an inherent property of SAR image,but its existence seriously interferes with the quality of SAR image and affects the high-quality application based on SAR image,so it is urgent to suppress it.The accuracy of the edge detection model of the traditional AD(Anisotropic Diffusion)filter still has room for im‐provement,and the noise suppression effect is often limited by the problem that it is difficult to accurately estimate the diffusion threshold.To solve the above problems,a novel AD filter based on Multidirectional Sobel(MSAD)is proposed.MSAD filter is an improved algorithm of SRAD.It builds a new edge detection model based on Multidirectional Sobel templates.Based on this,a new AD diffusion coefficient is established by integrating Gaussian kernel function,which can effectively solve the limitation of traditional AD diffusion coefficient by parameter estimation and improve the accuracy of speckle anisotropy suppression.Three real SAR images are selected for filtering experiments.In experiments,SRAD,DPAD,EnLee,and PPB filters are selected as the comparison algorithms;ENL,SSI,ESI,and M-Index are selected to evaluate the performance of proposed algorithms.Experiments show that MSAD filter can effectively improve the edge detection ability and obtain better speckle suppression effect.