In this paper, a spatiotemporal phase unwrapping method is proposed, which combines the dynamic optic fiber interferometric fringe projection method and the phase- shifting technique. A fringe projection fiber optic phase- shifting interferometer was set up, in which the fringe spacing and rotation can be easily adjusted. In the first step of the spatiotemporal phase unwrapping method, a large effective wavelength can be chosen so that the phase jump at the discontinuous profile is less than (pi) , then the spatial phase unwrapping method can be applied. Several intermediate phase maps can be obtained by changing fringe pitch and fringe orientation, reducing the effective wavelength step by step, and unwrapping each pixel along the time axis. In the final step, a high precision result can be obtained. A minimum number of steps may be chosen for obtaining the required accuracy according to the conclusion presented in this paper. An experimental result is presented for the measurement of a discontinuous object and shows the validity of the proposed method.

Date Published: 13 August 1999
PDF: 11 pages
Proc. SPIE 3744, Interferometry '99: Techniques and Technologies, (13 August 1999); doi: 10.1117/12.357715

Published in SPIE Proceedings Vol. 3744:
Interferometry '99: Techniques and Technologies
Malgorzata Kujawinska; Mitsuo Takeda, Editor(s)