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Proceedings Paper

Defect measurement using structured light system
Author(s): Siew-Lok Toh; W. K. Low; Cho Jui Tay; Huai Min Shang; Anand Krishna Asundi
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Paper Abstract

Automated machine visual inspection, using non-contact optical means, is a fast and efficient approach for quality control and manufacturing process monitoring. One application is in shape measurement and defect detection which employs a structured light system based on the projection moire method. The fringe patterns of these specimens are obtained by pulsing a single strip of light from a diode laser on the rotating specimens. Defects on these surfaces can be observed when a single strip of light bends proportionally to their depths. The imaging of these fringes is done by a charge coupled device (CCD) camera operating at the time delay and integrating (TDI) mode. By synchronizing the camera scanning speed and the specimen's rotational speed, the 'unwrapped' surface fringe patterns can be obtained and viewed by a computer. The fast Fourier transformation (FFT) technique is used for quantitative measurement of the surface defect.

Paper Details

Date Published: 20 March 1997
PDF: 6 pages
Proc. SPIE 2921, International Conference on Experimental Mechanics: Advances and Applications, (20 March 1997); doi: 10.1117/12.269871
Show Author Affiliations
Siew-Lok Toh, National Univ. of Singapore (Singapore)
W. K. Low, Lam Research Singapore Pte Ltd. (Singapore)
Cho Jui Tay, National Univ. of Singapore (Singapore)
Huai Min Shang, National Univ. of Singapore (Singapore)
Anand Krishna Asundi, Nanyang Technological Univ. (Singapore)

Published in SPIE Proceedings Vol. 2921:
International Conference on Experimental Mechanics: Advances and Applications
Fook Siong Chau; C. T. Lim, Editor(s)

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