An Improved Topographic Correction Approach for Satellite Image

The topographic correction refers to the compensation of the different solar illuminations due to the irregular shape of the terrain.This effect causes a high variation in the reflectance response for similar vegetation types.Therefore in remote sensing applications,precise topographic correction not only can improve the classification accuracy,but also is a prerequisite in any multitemporal approach.The C correction method based on the empirical linear correlation between observed radiance L and sun incident angle cosα is one of the most common correction methods.However,the C correction method requires building linear regression equation between radiance L and sun incident angle cosα in each band.It is a complex and arduous progress for multispectral image data.In this paper,an improved method was proposed without linear regression,based on the C correction method.It can yield very good results.The experiments using a Landsat TM image and DEM in Three Gorges proved that the results of the improved method are better than the cosine correction method and the C correction method.