Removal of monotonically increasing or decreasing phase ambiguity in retrieved phase by Riesz transform method in digital interferometric techniques

In this work, a method based on vortex operator, for removal of monotonically increasing or decreasing phase ambiguity in the retrieved phase by the Riesz transform method in digital interferometric techniques is presented. Since in digital interferometric techniques, the phase extraction methods and algorithms are essential because these techniques are being continuously employed in many scientific, industrial, and engineering applications to measure various physical parameters which are encoded as the phase of the fringe pattern. There exist many methods/algorithms for phase extraction from the fringe pattern such as temporal phase-shifting, spatial phase-shifting, fast Fourier transforms (FFT) method, wavelet transform, Hilbert transform etc. In recent years, phase extraction from a single fringe pattern by using the Riesz transform method is developed because of its several advantages. However, the retrieved phase by Riesz transform is affected by πshifts due to the lack of discrimination between positive and negative spatial frequencies. This problem could be resolved by using a vortex operator which filters the data in the frequency domain. We present here some simulated results demonstrating the removal of phase ambiguity in the retrieved phase by Riesz transform method.