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

Tlus 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 [R.M. Goldstein et al., July 1988]. Therefore, it is necessary to first isolate the unreliable regions. Then using the branch-cut method, we can retrieve the absolute phase in the largest reliable region. Finally, the unwrapped phases within all the remaining regions are computed via the FEM. which can easily handle any irregular shape problem domain. Moreover the total solution within these regions has less error norm.