A Novel Residue Degenerate Phase Unwrapping Method Using the L¹-Norm

As we all know, phase unwrapping (PhU) is one of the key steps affecting interferometric synthetic aperture radar (InSAR) data processing. However, due to the residues, it is difficult to obtain ideal results in the areas with high noise and large-gradient changes. Therefore, how to effectively deal with residues becomes the top priority of the PhU. To address this issue, in this letter, a novel residue degenerate PhU (RDPhU) method is proposed. We use the fast iterative shrinkage thresholding algorithm (FISTA) to solve the residue degradation problem, which introduces a novel branch-cut strategy that can effectively prevent error propagation. To the best of our knowledge, FISTA is first applied to the PhU residues degradation problem. In addition, we introduce regularization theory into $L^{1}$ -norm PhU to further improve the robustness of PhU. More interestingly, the RDPhU method can effectively solve the problem of low accuracy of PhU in the areas with large-gradient changes, while the PhU efficiency of the RDPhU method is greatly improved. Through simulation and TanDEM-X InSAR datasets, it is proved that the proposed method is an efficient and high-accuracy PhU method.