Dem-based orthorectification method for high-resolution sar images and its influence on building detection

SAR observes only one side of the earth surface and tells different targets by slant range.As a result, in the SAR image some kinds of distortions appear which include compressing in the range direction,shadow,foreshortening and layover.Using the RD locating model,based on the DEM of the corresponding area,a simulated SAR image is produced.Then,get GCPS by registering the simulated SAR image and the original SAR image and transfrom the SAR image with the GCPS.In order to evaluate the effect of orthorectification in the related applications, the building areas are extracted followed by comparing the extraction results of the original image and the rectification image using the detection rate and false alarm rate.Finally it turns out that locating errors decrease and extraction of building areas is more precise.