Phase measurement in temporal speckle pattern interferometry using the Fourier transform method with and without a temporal carrier

Abstract

The combination of speckle pattern interferometry and temporal phase unwrapping allows the measurement of large-object dynamic displacements without the propagation of spatial unwrapping errors. For retrieving phase data for whole-object displacement, the temporal Fourier transform method is a commonly used approach. As the temporal Fourier transform method can be applied with or without introducing a temporal carrier in one of the beams in an interferometer, this paper presents a comparison of both phase measurement techniques. The analysis is performed using computer-simulated speckle interferograms, an approach that allows to know precisely the original phase distribution and also to evaluate the spatial rms phase error as a function of the phase change introduced between two consecutive speckle interferograms. The performance of the temporal Fourier transform method to process experimental data modulated by a temporal carrier is also illustrated using results obtained from the study of a metal plate subjected to thermal loading.