一种顾及空间相关性遥感影像辐射度的地形校正算法

地形校正的目的是消除太阳光照对不规则地面地物辐射值的影响。这种影响会使相似植被类型地物的辐射值发生很大的变化。因此,在地形复杂的地区,地形校正是影像预处理的一个重要步骤。传统的基于单像素的地形校正方法,虽然减小了辐射值的变化,但在太阳入射角低的地区常常出现校正过度的情况。针对这种误差进行分析,提出一种考虑了空间相关性的校正算法,并且利用鄂西地区的Landsat7卫星影像进行的试验证明,该算法优于传统的地形校正模型。

A Topographic Correction Approach for Radiation of RS Images by Using Spatial Context Information

The topographic correction refers to the compensation of the different solar illuminations due to the irregular shape of the terrain.The effect causes a high variation in the reflectance response for similar vegetation types.Therefore,the process of topographic normalization may be critical in areas of rough terrain,as a preliminary step to the multispectral image classification.The conventional pixel-based topographic correction methods usually overestimate the radiation in low sun incidence angle,although reducing the variation in averages.A spatial contextual approach is proposed after analyzing these errors.The experiments using a Landsat TM image and DEM in west of Hubei Province have proved that the results of the contextual method are better than that of the conventional correction methods.