A novel topographic correction for high and medium resolution images by using combined solar radiation

On mountain areas, one main important pre-processing step for optical satellite imagery is the topographic correction. The illumination condition strongly depends on the area topography, sun elevation and azimuth and acquisition geometry of the sensor. These elements generate unequal light distribution over the observed surface. This effect needs to be corrected to improve classification and parameters retrieval performances. In this paper, a novel empirical approach for topographic correction is presented using the combined (direct and diffuse) solar radiation. The combined solar radiation has the advantage to take into account the brightening effect of topography on scene radiance. The approach aims at defining correction coefficients depending on the different land cover. We tested our approach using both high and medium resolution images and terrain effects in both data sets were considerably reduced.