Dual-aspect geometric and radiometric terrain correction method for high-resolution SAR data

Because of side looking illumination, terrain undulations affect the geometric and radiometric quality of synthetic aperture radar images. The correction of these effects becomes indispensable when quantitative image analysis is performed with respect to the derivation of geo- and biophysical parameters. In this paper a newly dual-aspect geometric and radiometric terrain correction method based on RD (Range Doppler) is put forward for geometric and radiometric correction of SAR images. This method is based on a pair of SAR images acquired from dual aspects. First either of the dual-aspect SAR image is ortho-rectified and radiometric slope corrected after the imaging geometry is reconstructed using a DEM (digital elevation model). This process could correct terrain caused geometric distortions and distorted backscatter coefficient caused by foreshortening. Then one image was used to compensate the lost information in shadow and layover areas in the other image. The resulting backscattering images are fully terrain corrected. At last an optimal SAR incidence angle pair selection plan based on SAR simulation was given and this method could help the users to order the SAR data which would achieve the best compensation result.