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Title: Instantaneous velocity displacement and contour measurement by use of shadow moiré and temporal wavelet analysis
Authors: Tay, Cho Jui
Quan, Chenggen
Fu, Yu
Huang, Yuanhao
Keywords: DRNTU::Science::Physics::Optics and light
Issue Date: 2004
Source: Tay, C. J., Quan, C. G., Fu, Y., & Huang, Y. H. (2004). Instantaneous velocity displacement and contour measurement by use of shadow moiré and temporal wavelet analysis. Applied Optics, 43(21), 4164-4171.
Series/Report no.: Applied Optics
Abstract: A temporal wavelet analysis method is proposed for velocity, displacement, and three-dimensional surface-profile measurement of a continuously deforming object by use of the shadow moire´ technique. A grating is placed close to a deforming object, and its shadow is observed through the grating. The moire´ fringe patterns, generated by the interference of the grating lines and their shadows, are captured by a high-speed CCD camera with a telecentric gauging lens. Instantaneous frequency of gray-value variation is evaluated point by point with the continuous wavelet transform. From the instantaneous frequency of each point on the object, the velocity, displacement, and high-quality surface profile at different instants can be retrieved. In this application, two specimens are tested to demonstrate the validity of the proposed method: One is a small coin with a rigid body motion, and the other is a simply supported beam subjected to a central point load. The results are compared with those obtained from temporal Fourier-transform and mechanical stylus methods.
ISSN: 0003-6935
Rights: This paper was published in [Applied Optics] and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: []. Systematic or multiple reproduction or distribution to multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:TL Journal Articles

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