Acta Optica Sinica, Volume. 25, Issue 8, 1057(2005)

Digital Shadow Moiré Method with Phase-Shifting Based on Liquid Crystal Display Projector

[in Chinese]*, [in Chinese], and [in Chinese]
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    Shadow moiré is one of the simple optical techniques for topography and out-of-plane displacement measurement. The sensitivity of this procedure is in the range of 1~100 μm in best cases. Introduction of a phase-shifting procedure may further give a better resolution. A new digital shadow moiré method with digital phase-shifting based on liquid crystal display (LCD) projector is presented. One of four computer-generated phase-shifting fringe patterns, with using LCD projector, is projected on the surface of object to be tested while all fringe patterns are projected on a plate for generating phase-shifting moiré fringes. The projected fringe patterns are captured in real time by a charge coupled device (CCD) camera. This new method provides many advantages in performing topography and out-of-plane displacement measurement. First, the spatial line pitch and phase step are readily adjusted to suit the measurement precision. Second, the measuring speed is relatively fast and suit for dynamic testing because the digital phase shifting is no time-consuming comparing with other phase-shifting techniques. The experimental result on a cantilever beam well demonstrates the validity of the new method.

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    [in Chinese], [in Chinese], [in Chinese]. Digital Shadow Moiré Method with Phase-Shifting Based on Liquid Crystal Display Projector[J]. Acta Optica Sinica, 2005, 25(8): 1057

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    Paper Information

    Category: Instrumentation, Measurement and Metrology

    Received: Sep. 7, 2004

    Accepted: --

    Published Online: May. 22, 2006

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