Topographic Correction Method for High Spatial Resolution Remote Sensing Data in Mountainous Area

With complex terrain and steep slopes, sharp orographic effect occurs in mountainous areas which obviously increases the difficulty of remote sensing geological mapping by the phenomenon of "different bodies with same spectrums" or "same body with different spectrums". Although several Topographic correction (TOC) methods have been proposed and applied to vegetationcovered area and snowfield successfully in the last decades, there is little discussion on topographic correction models for geological mapping under complex topographic conditions, which have totally different application environment since the uncovered geological bodies of mountainous areas have bigger spatial variability. Especially in the correction of high spatial resolution remote sensing images, the corresponding high-precision Digital Elevation Model (DEM) is often absent, and the correction results are vulnerable to topographic anomalies. This paper proposes a "Smoothed Mountains" correction method, which combines Richter "Mountains" correction model with terrain smoothing model. GF-1, GF-2 and SPOT6 mountain images obtained by this model have been compared with those by other 14 terrain correction models. The results show that the stability and correction effect of the "Smoothed Mountains" correction model are obviously better than other models. The correction images show that the terrain effect is weakened, and the image information is rich and undistorted. Moreover, the surface reflectance data can be obtained directly, which provides basic data for further remote sensing alteration extraction. Therefore, the "Smoothed Mountains" model could be a practical and feasible TOC model in remote sensing geological mapping over steep mountain terrain.