20 July 2023 Double-shot N-step phase measuring profilometry
Cai Xu, Yiping Cao, Haitao Wu, Hechen Zhang
Author Affiliations +
Abstract

Recently, a single-shot N-step phase measuring profilometry was proposed by our research group. It not only maintains the single-shot real-time measuring characteristics but also makes its measuring accuracy selectable as appropriate N. But when the spectral aliasing in the captured deformed pattern is severe, the alternative current (AC) component may be extracted imprecisely or even failed. So, a double-shot N-step phase measuring profilometry (double-shot N-PMP) is proposed. While two complementary sinusoidal gratings are projected onto the measured object, the AC component of the captured deformed patterns can be extracted precisely even if spectrum aliasing is very serious. If the AC component multiplies with N frames of the AC components of the N-step phase-shifting fringe patterns captured from the reference plane in advance, a new N-step phase-shifting algorithm for the phase difference between the measured object and the reference plane is accomplished to reconstruct the measured object. The experimental results show the possibility and effectiveness of the proposed method. It can either improve the measuring accuracy or expand application scope. Though the double-frame gratings are needed, the real-time measuring characteristics can still maintain with the time-division multiplexing method.

© 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)
Cai Xu, Yiping Cao, Haitao Wu, and Hechen Zhang "Double-shot N-step phase measuring profilometry," Optical Engineering 62(7), 074103 (20 July 2023). https://doi.org/10.1117/1.OE.62.7.074103
Received: 9 February 2023; Accepted: 5 July 2023; Published: 20 July 2023
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KEYWORDS
Deformation

Phase measurement

Phase shifts

Aliasing

Fringe analysis

Time division multiplexing

Optical engineering

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