Automatic look-up table based real-time phase unwrapping for phase measuring profilometry and optimal reference frequency selection

Abstract

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.

Super-Resolution Phase Retrieval Network for Single-Pattern Structured Light 3D Imaging

“…This process is easily influenced by issues such as phase jump and noise. Temporal phase unwrapping methods are much more robust and accurate although they require an additional low-frequency phase as reference [64]. Alternatively, deep learning techniques can be used to train a network for phase unwrapping by using the same single pattern [26].…”