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Proceedings Paper

Triangular phase-shifting algorithms for surface measurement
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Paper Abstract

Two-step triangular phase-shifting has recently been developed for 3-D surface-shape measurement. Compared with previous phase-shifting methods, the method involves less processing and fewer images to reconstruct the 3-D object. This paper presents novel extensions of the two-step triangular phase-shifting method to multiple-step algorithms to increase measurement accuracy. The phase-shifting algorithms used to generate the intensity ratio, which is essential for determination of the 3-D coordinates of the measured object, are developed for different multiple-step approaches. The measurement accuracy is determined for different numbers of additional steps and values of pitch. Compared with the traditional sinusoidal phase-shifting-based method with same number of phase shifting steps, the processing is expected to be reduced with similar resolution. More phase steps generate higher accuracy in the 3-D shape reconstruction; however, the digital fringe projection generates phase shifting error if the pitch of the pattern cannot be evenly divided by the number of phase steps. The pitch in the projected pattern must therefore be selected appropriately according to the number of phase-shifting steps used.

Paper Details

Date Published: 20 October 2006
PDF: 12 pages
Proc. SPIE 6375, Optomechatronic Sensors, Instrumentation, and Computer-Vision Systems, 63750C (20 October 2006); doi: 10.1117/12.690734
Show Author Affiliations
Peirong Jia, Univ. of Ottawa (Canada)
Jonathan Kofman, Univ. of Ottawa (Canada)
Univ. of Waterloo (Canada)
Chad English, Neptec Design Group Ltd. (Canada)


Published in SPIE Proceedings Vol. 6375:
Optomechatronic Sensors, Instrumentation, and Computer-Vision Systems
Jonathan Kofman; Yasuhiro Takaya, Editor(s)

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