[OPTICAL REVIEW Vol. 5, No. 6 (1998) 374-379]

Two-Dimensional Phase Unwrapping by Direct Elimination of Rotational Vector Fields from Phase Gradients Obtained by Heterodyne Techniques

Takahiro AOKI, Toshihiro SOTOMARU, Takeshi OZAWA, Takashi KOMIYAMA, Yoko MIYAMOTO and Mitsuo TAKEDA*

The University of Electro-Communications, Department of Communication and Systems Engineering, 1-5-1, Chofugaoka, Chofu, Tokyo, 182-8585 Japan

(Received May 11, 1998; Accepted August 13, 1998)

Noting the analogy between electro-magnetic fields and the vector fields of phase gradients obtained by heterodyne techniques, we propose a new algorithm for least-squares phase unwrapping. Instead of solving a Poisson equation for the unwrapped phase map or using Green's formulation, we directly remove singular points or residues from the measured phase map by superposing sign-reversed vortex fields which cancel out the rotational vector fields associated with the phase singular points.

Key words : phase unwrapping, interferometry, fringe analysis, optical metrology, heterodyne techniques

* takeda@cas.uec.ac.jp