A new method about placement of the branch cut in two-dimensional phase unwrapping

Phase unwrapping is one of the key problems in data processing of interferometric synthetic aperture radar (InSAR). One of the classic unwrapping algorithms is the path-following approach based on placement of branch cut. In this paper, we prove that existence of residues is a sufficient but unnecessary condition for the original phase discontinuity and the true placement of the branch cut is unique. Then a modified method of placing branch cuts which is guided by improved quality map is proposed. The simulation examples show that the modified method is more effective and practicable.