极化SAR图像自适应增强Lee滤波算法

精制极化Lee滤波算法以其简单、高效、健壮等优点在极化SAR图像处理解译中得到了广泛的应用。然而，此滤波算法存在明显的缺陷：扇贝效应和虚假细线。对此，本文提出增加一组均匀窗口及一组线性方向窗口，并采用大小自适应窗口机制，在同质度高的区域用大窗口滤波，在同质度低的区域用小窗口滤波，从而使得滤波窗口在形状和尺寸上都能自动适应实际场景。利用机载和星载全极化SAR数据进行的滤波实验结果表明，本文提出的自适应增强Lee滤波算法在同质区域的噪声抑制能力明显优于精制极化Lee滤波算法及改进的Sigma滤波算法，同时在保持点、线等细节信息方面也优于精制极化Lee滤波算法，并且能很好的保持图像中地物的极化散射信息。

An Adaptive Enhanced Lee Speckle Filter for Polarimetric SAR Image

The refined Lee filter, which is simple, efficient and robust, has been widely used in polarimetric SAR (PolSAR) processing. However, the filter has two severe defects: scallop effect and false-line effect. In this paper, we extend and improve the refined Lee filter by adding a square window and a group of linear windows. To better suppress the speckle noise as well as preserve the detail information, we adopt an adaptive window mechanism: big window is used in homogeneous areas and small window is used in heterogeneous areas. So the proposed filter can adapt actual scenes in both shape and size aspects. Both airborne and spaceborne PolSAR data are used to demonstrate its overall speckle filtering characteristics by comparing with other filters. The results show that the adaptive enhanced Lee filter has better performance in speckle suppressing and detail preserving than the refined Lee filter, and can preserve the polarimetric information very well.