3D profile measurement using heterodyne dual-frequency phase shift method

Fengxia Duan; Naiguang Lv; Xiaoping Lou; Peng Sun

doi:10.1117/12.885419

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31 December 2010 3D profile measurement using heterodyne dual-frequency phase shift method

Fengxia Duan, Naiguang Lv, Xiaoping Lou, Peng Sun

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Proceedings Volume 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation; 75444X (2010) https://doi.org/10.1117/12.885419
Event: Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 2010, Hangzhou, China

Abstract

In recent years, the reliable method to obtain absolute phase has been studied more and more widely in the field of structured light. A 3D profile measurement using heterodyne dual-frequency phase shift method is proposed in this paper. The method has three parts: phase shift, heterodyne dual-frequency and binocular stereo vision. The four-step phase shift technique is used to obtain wrapped phase map. The wrapped phase map is arctangent values between -π and π. To get the absolute phase map, wrapped phase map must be unwrapped. The traditional phase unwrapping methods, such as Gray code, produces wrong unwrapping results easily on image code boundary or break points. To solve this issue, firstly we project two spatial frequency fringes separately onto the object and obtain two wrapped phase maps by four-step phase shift technique. Secondly, by superimposing one wrapped phase map upon the other produces another phase map with a lower frequency according to heterodyne dual-frequency principle. This phase map is the absolute phase map. Finally, the binocular stereo vision accomplishes stereo matching according to the absolute phase map and 3D point reconstruction. Experimental results show that accurate and reliable phase result can be obtained on phase map boundaries and break points, which proves its feasibility in industry measurement.

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Fengxia Duan, Naiguang Lv, Xiaoping Lou, and Peng Sun "3D profile measurement using heterodyne dual-frequency phase shift method", Proc. SPIE 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 75444X (31 December 2010); https://doi.org/10.1117/12.885419

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