Imagine two consecutive phase values are 0, and $\pi+0.1$. The phase difference is thus $\pi+0.1$. When the phases are wrapped to the interval $[-\pi,\pi]$, these consecutive phase values become $0$ and $-\pi + 0.1$. The phase difference is now $-\pi+0.1$, a negative value. This is why your unwrapped phase plots change direction.
Two-dimensional phase unwrapping is the process of recovering unambiguous phase data from a 2-D array of phase values known only modulo 2pi rad. SNAPHU is an implementation of the Statistical-cost, Network-flow Algorithm for Phase Unwrapping proposed by Chen and Zebker (see references...
def unwrap_phase_map_0(self): """Unwrap order 0 phase map. Phase is defined modulo pi/2. The Unwrapping is a reconstruction of the phase so that the distance between two neighboor pixels is always less than pi/4. Then the real phase pattern can be recovered and fitted easily.
Dec 28, 2018 · Direct link to this answer. https://www.mathworks.com/matlabcentral/answers/437528-phase-unwrapping-in-2d#answer_354793. Cancel. Copy to Clipboard. Depending on what your data looks like, you may be able to simply use "unwrap" on the two different dimensions. A = unwrap (A, ,1); A = unwrap (A, ,2);
Fast 2D phase unwrapping implementation in MATLAB. Fast unwrapping 2D phase image using the algorithm given in: M. A. Herraez, D. R. Burton, M. J. Lalor, and M. A. Gdeisat, "Fast two-dimensional phase-unwrapping algorithm based on sorting by reliability following a noncontinuous path", Applied Optics, Vol. 41, Issue 35, pp. 7437-7444 (2002).
Second, it presents a novel approach to the estimation of the FT-phase of the PSF, by solving a continuous Poisson equation over a predefined smooth subspace, in contrast to the discrete Poisson equation solver used for the classical least mean squares phase unwrapping algorithms...
Phase unwrapping is the key step in Digital Elevation Model extraction and the measurement of surface deformation of Interferometric Synthetic Aperture Radar (InSAR). When in steep terrain or larger slope, the unwrapping result is bad and causes error transmission using the existing Kalman Filter phase unwrapping algorithm.