I. Introduction
In interferometric synthetic aperture radar (InSAR) systems, the estimation of a phase is a crucial point since there exists a known relation between InSAR phase and height values of the ground [1]. It is known that the measured phase (wrapped phase) is given in the principal interval ; therefore, the phase unwrapping (PU) problem has to be solved, providing the absolute phase (unwrapped phase). This problem is known to be an ill-posed problem if the so-called Itoh condition (the absolute value of phase difference (PD) between neighboring pixels is less than ) is not satisfied [2]. Usually, in InSAR systems, the Itoh condition is violated due to the presence of discontinuities and/or interferometric noise.