Topographic Radiation Correction Based On Landsat8 Remote Sensing Image

On the earth,the mountain area accounts for about 20% of the land area.Mountain ecosystems play an important role in the global environment and are sensitive areas for the rapid development of the earth.With the rapid development of remote sensing technology,it provides conditions for detecting changes in mountain areas.However,compared with the horizontal surface,the remote sensing image in rugged areas has obvious topographic effect,which will lead to the phenomenon of "same objects having different reflectance" or "different objects having same reflectance",which seriously reduces the precision of remote sensing applications such as biophysical parameter inversion and land cover change detection.Therefore,it is a necessary task to correct the terrain of satellite remote sensing images in mountainous or hilly areas However,few studies have focused on which terrain correction model is suitable for a particular terrain.In order to save data processing time and obtain more accurate surface information,it is necessary to find suitable terrain correction methods for different terrain..The main research contents and conclusions are as follows:(1)Focusing on the physical basis of the BRDF based physical correction model,describing the relationship between the received direct solar radiation,sky diffuse radiation and adjacent terrain reflected radiance in rugged terrain.The physical significance of BRDF and the basis of MODIS BRDF/Albedo model driven by linear semi-empirical kernel are explored and applied to the radiation transfer model.(2)Applying the BRDF correction model to Landsat8 remote sensing images to explore how to use 6S radiation transfer model to conduct atmospheric correction for Landsat8 data and obtain atmospheric parameters.(3)Topographic radiation correction is performed using empirical statistical correction model,C correction model,SCS correction model,SCS+C correction model and BRDF correction model for five representative terrain in the south,including plain terrain,hilly terrain,low mountain terrain,high mountain-hill terrain and high mountain-low mountain terrain and the corrected images were compared byvisual analysis,de-correlation analysis and mean and standard deviation analysis.The conclusions are as follows:Taking into account the results of the three analyses,for the five terrain,the best correction effect is the empirical statistical correction model and the C correction model,followed by the SCS+C correction model,while the worst effect is the SCS correction model and the BRDF based correction model.Although BRDF correction can effectively weaken the spatial stereo sense,for hilly terrain,low mountain terrain,high mountain-hill terrain and high mountain-low mountain terrain,the corrected image based on BRDF correction model has different degree of distortion.SCS correction model shows different degrees of over-correction in the smaller area of the local solar incidence angle cosine value of five kinds of terrain.