Image registration in interferometric SAR processing

In interferometric synthetic aperture (IFSAR) applications image registration is needed to extract the correct phase difference between the two received signals. The authors present a new image registration procedure implemented at the raw data processing stage; the two complex SAR images are generated with respect to a common reference output system. The registration task is achieved via scaling and shifting compensation that can be efficiently and easily included in a standard SAR processing code. Examples on real as well as on simulated data validate the procedure. An algorithm to estimate the correct processing parameters, whenever the orbital information is inaccurate, is also presented and is based on the relation between spectral shift and linear stretch of the two images.