For temporal phase unwrapping in phase measuring profilometry, it has recently been reported that two phases with co-prime frequencies can be absolutely unwrapped using a look-up table; however, frequency selection and table construction has been performed manually without optimization. In this paper, a universal phase unwrapping method is proposed to unwrap phase flexibly and automatically by using geometric analysis, and thus we can programmatically build a one-dimensional or two-dimensional look-up table for arbitrary two co-prime frequencies to correctly unwrap phases in real time. Moreover, a phase error model related to the defocus effect is derived to figure out an optimal reference frequency co-prime to the principal frequency. Experimental results verify the correctness and computational efficiency of the proposed method.

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Published in Optics Express, v. 27, no. 9, 13357-13371.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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National Natural Science Foundation of China (NSFC #61473198); Science and Technology Support Program of Sichuan Province, China (#2018GZ0198); Science and Technology Support Program of Chengdu City, China (#2018-YFYF-00029-GX); Intel Corporation and the National Science Foundation (1539157).