InSAR phase unwrapping algorithm using the branch-cut and finite element method

This paper develops a two-dimensional (2-D) phase unwrapping (PhU) algorithm based on a "patch" strategy: the largest one of the reliable regions is unwrapped via a branch-cut algorithm; the remaining regions, including the unreliable regions and some small reliable regions surrounded by the unreliable regions, are unwrapped by the finite element method (FEM) under Neumann and/or Dirichlet boundary conditions. Path crossing of unreliable regions generates a drastic error that propagates to all the subsequent integration points [3]. Therefore, it is necessary to first isolate unreliable regions. Then using the branch-cut method, we call retrieve the absolute phase in the largest reliable region. Finally, the unwrapped phases within all the remaining regions are computed via the FEW, which can easiily handle any irregular shape problem domain. Moreover, the total solution within these regions has less error norm.