Research On Image Registration For InSAR System

Synthetic aperture radar interferometry (InSAR) is a vital remote sensing technique which combines Synthetic aperture radar (SAR) and interferometry, allowing for the estimation of three-dimensional terrain images with high spatial resolution and height accuracy. InSAR needs several observations over the same scene, together with the knowledge of the interferometer geometry and phase differences between each pair of the received signals that can be converted into a digital elevation model or topography- changing map. So image coregistration task is one of key processing procedures of InSAR. The accuracy of this step is crucial to the reliability of subsequent image processing and final results of the data processing chain, meeting subpixel precision request.Region correlation coregistration method is one of typical SAR complex images registration algorithms. By analyzing the effect of interferometric phase on the registration precision, a fast region correlation SAR image coregistration method is proposed based on the interferometric phase effect elimination. In the method, a fast region correlation technique is performed on the magnitude-spectrum of two complex images to obtain the spatial frequency of interferometric phase coarsely. While the master image is compensated by the estimated phase, the fast region correlation coregistration method can achieve a higher accuracy. The efficiency and precision of the proposed method has been demonstrated by comparing with the correlation matching algorithm and the spectral maximum matching algorithm.