Polarimetric SAR Speckle Filtering Using a Nonlocal Weighted LMMSE Filter

Sensors

Shengyuan Zhu¹  Yinbin Shen¹  Xiaoshuang Ma²  Jiangong Xu² 

[1] China JIKAN Research Institute of Engineering Investigations and Design, Co., Ltd., Xi’an 710000, China;School of Resources and Environmental Engineering/Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration, Anhui University, Hefei 230601, China;

关键词: polarimetric synthetic aperture radar;    speckle filtering;    complex Wishart distribution;    nonlocal means;   

DOI  :  10.3390/s21217393

来源: DOAJ

【 摘 要 】

Despeckling is a key preprocessing step for applications using PolSAR data in most cases. In this paper, a technique based on a nonlocal weighted linear minimum mean-squared error (NWLMMSE) filter is proposed for polarimetric synthetic aperture radar (PolSAR) speckle filtering. In the process of filtering a pixel by the LMMSE estimator, the idea of nonlocal means is employed to evaluate the weights of the samples in the estimator, based on the statistical equalities between the neighborhoods of the sample pixels and the processed pixel. The NWLMMSE estimator is then derived. In the preliminary processing, an effective step is taken to preclassify the pixels, aiming at preserving point targets and considering the similarity of the scattering mechanisms between pixels in the subsequent filter. A simulated image and two real-world PolSAR images are used for illustration, and the experiments show that this filter is effective in speckle reduction, while effectively preserving strong point targets, edges, and the polarimetric scattering mechanism.

【 授权许可】

Unknown