基于典型散射差异指数的PolSAR图像Lee滤波

摘要

为提高滤波后极化合成孔径雷达图像的边缘清晰度和保持目标的极化特性,提出了基于典型散射差异指数(typical scattering difference index,TSDI)的PolSAR图像Lee滤波算法.算法根据滤波像素和邻域像素之间的TSDI,采用自适应阈值法筛选出滤波像素的同质像素,然后用同质像素进行Lee滤波.针对筛选阈值,首先利用Parzen窗估计同质区域TSDI概率分布,然后根据估计结果计算阈值.用美国AIRSAR系统和UAVSAR系统采集的极化数据进行实验.实验结果表明该算法相对于精致Lee滤波算法相干斑抑制更加彻底,同时图像边缘清晰度和目标极化特性保持更完好.%To improve the sharpness of polarimetric synthetic aperture radar (PolSAR) images and keep the polarimetric characteristics of targets after filtering,Lee filter of PolSAR image based on typical scattering difference index (TSDI) is proposed.According to the TSDI between pixel to be filtered and its neighboring pixels,an adaptive threshold method is used to select homogeneous pixels of the filtered pixel,which is used for Lee filter.For selecting threshold,the probability distribution of the TSDI is firstly estimated by Parzen window,based on which the threshold is calculated.The PolSAR data acquired by the AIRSAR and the UAVSAR system is used to illustrate the effectiveness of the proposed algorithm.Experimental results show that compared with the refined Lee filter,the proposed algorithm reduces the spackle noise more thoroughly,as well as keeps the edge sharpness of images and the polarimetric characteristics of targets better.