A computational phase-shifting interferometric method using a single-shot microinterferogram and its application

Abstract

In this article, a fast computational phase-shifting interferometry (PSI) method for extracting the phase object from a single-shot two-beam microinterferogram has been proposed. This technique bases on utilizing the features of the two-beam microinterferometry to yield three daughter microinterferograms with accurately known phase shift between them from a recorded mother microinterferogram. The main idea of the proposed method relies on analyzing the recorded mother microinterferogram to compute the width of its bright and dark fringes which resulted equal in this study. Furthermore, we utilize the fact that the complete change from bright fringe to dark fringe or vice versa, in the two-beam microinterferogram, is identical to shift in phase by π radians. The proposed method is characterized by high ability to perform in-situ investigation for the objects on the contrary with the traditional PSI technique. The phase-shifting Pluta interference microscope is used for verifying this computational method for the polypropylene (PP) fiber. The calculated phase distribution values via this method show a good agreement with the obtained results by the phase-shifting Pluta interference microscope for the same fiber sample. Also, the proposed method is utilized to perform accurate in-situ investigation for the structural properties of the polypropylene fiber at different draw ratios. In addition, the proposed method is valid to investigate the fractures modes of fibers in short time comparing to the spatial carrier frequency algorithm and the spatial carrier-frequency phase-shifting (SCFPS) algorithm.