Complex Image Registration for Interferometric Synthetic Aperture Sonar based on Local Coherence Method

Complex image registration is a very important step during interferometric synthetic aperture sonar signal processing, and its performance is directly related to the accuracy of the final reconstructed digital elevation model. In order to improve the quality of the wrapped phase, a wrapped phase extraction method for interferometric synthetic aperture sonar based on local coherence method is proposed on the basis of fully analyzing the imaging characteristics of the interferometric synthetic aperture sonar. Firstly, the variation characteristics of range difference in local phase data block are analyzed. According to the analysis, the feasibility of using the central phase point range difference to replace the local adjacent phase point range difference is proposed. Further, the method of extracting wrapped phase by coherent method is derived. The experimental results performed on simulated data and real data show that the quality of the extracted wrapped phase by the proposed method is significantly better than that of the classical method, the number of residues is sharply reduced, and the error propagation in the global fitting can be effectively overcome, which helps to verify the effectiveness of the proposed method.