Improving phase unwrapping techniques by the use of nonlinear phase model

This paper presents a new efficient phase unwrapping algorithm for interferometric synthetic aperture radar (InSAR) phase images based on nonlinear phase model. Firstly, based on the analysis of statistical properties and signal characteristics of the interferometric phase, the concept of nonlinear phase model is proposed. It uses the nonlinear phase model of reflecting the topographic outline to approximate the interferometric phase change appeared in the local window. The lower amplitude bound of principal vector is defined and its value acquire method be given, which can effectively and adaptively extract the nonlinear components of the phase. Secondly, the nonlinear phase model is introduced to phase unwrapping, which increased the reliability of integration path and the accuracy of phase gradient, and improved effectively the performance of phase unwrapping. Real data processing results demonstrate the validity of the proposed nonlinear phase model and its corresponding processing method.