The Application Of Topographic Radiation Correction For TM Image

The remarkable characteristic of the remote sensing image of a mountain is that there is a lot of shadow areas.Mountain surface radiation seriously affected by the different slope,aspect of the direct solar radiation vary significantly,especially in low solar altitude,high hypsography region.In addition,sky scattering light and the nearby slope of the cross-radiation also affected by the topographical conditions. The existence of the shadow area brings difficulties for image recognition and classification and limits applications of the regional remote sensing image in mountain area.For example,lower the image classification accuracy often lead to image distortion,wrong attribute information and area error of forest cover in mountain regional image.Specially,for mountain region image,topographic radiation correction is an important part of image processing and it can improve classification accuracy of mountain remote sensing image,reduce remote sensing inversion error of the earth's surface information,improve the accuracy of mountain remote sensing survey.In this paper,ATCOR 2 model,which is widely used abroad,was to carry out the atmospheric correction.At the same time,the current common correction model, such as Cosine correction,C correction,SCS correction,SCS+C correction and Minnaert correction,are also used to do.After the topographic correction,the image brightness have been enhanced and spatial texture information have been greatly improved.Especially,the surface information of the shadow region is recovered greatly,and mistiness of the shadow information becomes clear.The visual effects, quantitative parameters,image brightness and light coefficient of plot,and histongam are used as evaluation factors.The result shows that Minnaert correction have the best processing effect,C correction followed and cosine correction and SCS correction induce over correction.Finally,using the maximum likelihood method and SVM classify to evaluate the correction effect,result shows that:classification accuracy can be effectively improved by C correction and Minnaert correction,and they are suitable algorithm to do topographic correction for the TM image.