顾及扫描侧视角变化的高分辨率卫星遥感影像严格几何模型

A Rigorous Geometric Model Considering the Variety of Side Watch Angle for High-resolution Satellite Imagery

根据遥感卫星传感器对地扫描成像过程中CCD线阵列侧视角匀速变化的机理,从理论上改进基于仿射变换的高分辨率卫星遥感影像严格几何处理模型,推导地物与影像间的正反算公式。经对一SPOT-5异轨立体像对的试验表明,利用改进的几何模型和视CCD线阵列侧视角为常数的仿射变换模型对立体影像进行几何处理,前者较后者的像点x坐标精度有一定的改善,物点的高程精度有所提高,平面精度两者基本一致。这说明成像过程中CCD线阵列侧视角的变化在高分辨率卫星遥感影像严格几何处理模型中是不可忽略的因素。

According to the mechanism of the side watch angle uniform variety during the imaging procedure using CCD line-scanner, the rigorous geometric model based on affine transformation for high-resolution satellite imagery is modified in this paper. Both the forward and backward formulas between object-space and image-space are presented. A stereo pair of SPOT-5 imagery acquired in across-track mode is selected and used. The empirical results have shown that the proposed geometric model, compared with the original model which considers the CCD line-scanner side watch angle as a constant, can improve the ;x-coordinate accuracy of image points, and can also raise the height accuracy of object space coordinates significantly while maintain the same level of the planimetric accuracy. This has shown that the side watch angle variety of CCD line-scanner during the process of imaging is a non-negligible factor in the rigorous geometric model for processing high-resolution satellite imagery.