针对已有地形纠正方法的不足, 在山区辐射传输模型简化的基础上, 提出了水平地面上接收到的漫射辐射与垂直于太阳方向表面接收的直射辐射比例因子的概念, 建立了仅需要太阳角度信息和大气模式作为输入参数, 主要针对地形效应本身进行纠正的简单纠正模型, 可以将复杂地形区光学遥感影像表观辐亮度纠正为无地形影响的水平地表辐亮度, 并以TM影像为例进行了实验验证。

In rugged areas, topographic effects severely influence the spectrum characters of remote sensing image. Topographic correction is a necessary step to estimate real land surface situation from remote sensing images. As a kind of topographic correction methods, empirical approaches can hardly achieve desirable results. Existing physical topographic correction methods which are based on radiant transfer models require a considerable number of input parameters. Furthermore, the topographic correction and atmospheric correction are mixed, which cause inconvenience and instability. A simplified physical algorithm is proposed in this paper to overcome the disadvantages of existing algorithms. A ratio factor of diffuse irradiance on horizontal surface to solar direct irradiance is introduced. The algorithm only need solar geometry information and atmosphere model parameters as its input data, and is mainly concentrated on the removal of topographic effects. It can correct the apparent radiance of optical remote sensing images over rugged terrain to the apparent radiance without topographic effects. The algorithm was illustrated using a Landsat TM image.