SAR影像多项式正射纠正方法与实验  

Algorithms and experiment on SAR image orthorectification based on polynomial rectification

作　　者：黄国满[1] 郭建坤[2] 赵争[1] 肖洲[1] 仇春平[1] 吕京国[1] 

机构地区：[1]中国测绘科学研究院,北京100039 [2]中国科学院地理科学与资源研究所,北京100101

出　　处：《测绘科学》2004年第6期27-30,共4页Science of Surveying and Mapping

基　　金：国家863项目(2001AA132010);国家测绘局项目(14601402024 01 03)

摘　　要：提出了一种针对SAR影像的多项式正射纠正法———引入投影差改正的多项式纠正法,并对ERS 2、RADARSAT和机载SAR影像进行了实验。引起SAR影像变形的因素很多,其中多数变形可以通过多项式纠正方法得到改正;但是,因高差引起的变形很难通过一般的多项式纠正方法进行改正。在本文中,先根据斜距和侧视角改正高差引起的投影差,然后用一般多项式纠正的方法改正其他因素引起的变形;重采样时则恰好相反,先根据多项式参数求得未受高差影响的像点坐标,然后加上投影差,从而获得真实的像点坐标。与其他正射纠正的方法相比,本文的方法非常易于实现,而且能够达到相当高的精度。根据以上原理,设计了相应的软件,并对云南大理一幅Radarsat的山区影像进行了纠正实验,控制点精度为2 2个像素;而采用一般多项式,使用同样的控制点,对这幅影像进行纠正,只能达到44 4个像素。另外,使用ERS 2影像和机载SAR影像进行了相应试验,结果类似于Radarsat影像的纠正。因此,本文提出的方法是有效、可行的,能适应地形起伏较大地区的SAR影像的几何校正。This paper introduces the algorithm on SAR image orthorectification based on polynomial rectification and height displacement correction, and experiments according to the algorithm on ERS2, RADARSAT, and airborne SAR image in mountain area. Many factors result in SAR image distortion, and most of them can be corrected by polynomial rectification. But the distortion of SAR image brought by elevation is very difficult to be corrected by polynomial rectification. In this paper, height displacement caused by elevation is corrected in advance according to the slant distance and elevation of each pixel, and the other distortion is corrected by polynomial rectification. Compared to other orthorectification algorithm on SAR image, it is very easy to implement. According to this method, programme has been designed. And then, experiment has been down on RADARSAT image in a mountain area in China (Dali, Yunnan), and polynomial rectification on the same image also has been down by the same ground control points. The accuracy of the former is about 2.2 pixels, and the latter 44.4 pixels. In this area, the most elevation difference of the ground control points is about 2972 meters. Some other experiments have been down on ERS2 image (Chengdu, Sichuan), and 3 meters resolution airborne SAR image (Dabieshan, Anhui), and the results are similar to that of the first experiment. So, the new algorithm on SAR image orthorectification introduced in this paper is efficient and practicable for SAR image orthorectification in mountain area.

关 键 词：SAR 影像 正射纠正 原理 实验 精度 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置]