基于自适应Bilateral滤波的SAR图像相干斑抑制

SAR Image Despeckling Based on Adaptive Bilateral Filter

SAR图像的相干斑抑制一直是SAR图像预处理的关键步骤。Bilateral滤波器是一类可以同时利用像素间的空间相似性与灰度相似性进行图像去噪的算法。针对直接用Bilateral滤波器进行相干斑抑制时存在空间方差系数选择困难及灰度相似性模型不合理的问题,该文提出一种自适应Bilateral滤波算法,该算法根据图像的局域变差系数自动调整空间方差系数,利用SAR图像的似然概率函数代替高斯函数来进行灰度相似性度量。理论分析及实验表明,提出方法较相关算法有更强的噪声平滑能力和更好的细节保持能力。

SAR image despeckling is always a key and indispensable step in SAR image preprocessing.The Bilateral Filtering（BF）,which combines grey similarity and spatial closeness to reduce noise,is introduced to SAR image despeckling recently.However,when BF is directly used for SAR image despeckling,it is hard to select the optimal spatial closeness variance and imprecise to measure the grey similarity by Gaussian function,so an Adaptive Bilateral Filter（ABF） is proposed.The ABF adjusts spatial closeness variance to the local coefficient of variation and calculates the grey similarity of SAR image by the likelihood probability function instead of the Gaussian function.The tests on synthesized and real SAR images show that the ABF can notably smooth speckles with imperceptible details pollution,which achieves better performance than that of the other related methods.