基于Envisat数据的地物后向散射特征研究

The research on polarization characteristics of type surface objects based on envisat data

本文采用ENVISAT ASAR的APMode(Alternating Polarisation Mode)数据,由雷达图像成像原理及物理机制入手分析广州市几种典型地物(水体、植被、建筑物)在不同极化方式下后向散射特征及其成因。在此基础上选取HH极化图像、VV极化图像及VH/VV比值图进行合成,并利用监督分类方法对该极化合成影像进行分类,与光学影像的分类结果图进行比较。结果表明:极化雷达具有探测水质的能力,建筑物的后向散射特征还与其排列方式有关,极化合成影像分类图能初步达到地物分类识别的效果。

The backscattering coefficients, which of different surface object in radar image and same surface object in radar image of different polarization, differ quietly from each other, which have relation with the structural characteristics of themselves. The backscattering characteristics and its causes is the theory foundation of monitoring objects by polarimetric radar. Using APMode data of ENVISAT ASAR, this article has analyzed the backscattering characteristics and their causes of type surface objects （buildings, vegetables, water） on different polarimetric images, based on the imaging theories of radar images. With the results, an image composed of Horizontal （HH） image,Vertical （VV） image and the ratio image of Cross （VH） and Horizontal （HH） has obtained. The resuhs show that： the information of waterbody can be monitored in images of VV polarimetic and VH polarimetic the backscattering of buildings （arranging along east-west orderly） in image of HH polarimetic is stronger than it in image of VV polarimetic; the classification has a good effect.