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Proceedings Paper

An illumination-invariant phase-shifting algorithm for three-dimensional profilometry
Author(s): Fuqin Deng; Chang Liu; Wuifung Sze; Jiangwen Deng; Kenneth S. M. Fung; W. H. Leung; Edmund Y. Lam
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Paper Abstract

Uneven illumination is a common problem in real optical systems for machine vision applications, and it contributes significant errors when using phase-shifting algorithms (PSA) to reconstruct the surface of a moving object. Here, we propose an illumination-reflectivity-focus (IRF) model to characterize this uneven illumination effect on phase-measuring profilometry. With this model, we separate the illumination factor effectively, and then formulate the phase reconstruction as an optimization problem. To simplify the optimization process, we calibrate the uneven illumination distribution beforehand, and then use the calibrated illumination information during surface profilometry. After calibration, the degrees of freedom are reduced. Accordingly, we develop a novel illumination-invariant phase-shifting algorithm (II-PSA) to reconstruct the surface of a moving object under an uneven illumination environment. Experimental results show that the proposed algorithm can improve the reconstruction quality both visually and numerically. Therefore, using this IRF model and the corresponding II-PSA, not only can we handle uneven illumination in a real optical system with a large field of view (FOV), but we also develop a robust and efficient method for reconstructing the surface of a moving object.

Paper Details

Date Published: 2 February 2012
PDF: 7 pages
Proc. SPIE 8300, Image Processing: Machine Vision Applications V, 830005 (2 February 2012); doi: 10.1117/12.911113
Show Author Affiliations
Fuqin Deng, The Univ. of Hong Kong (Hong Kong, China)
ASM Assembly Automation Ltd. (Hong Kong, China)
Chang Liu, ASM Assembly Automation Ltd. (Hong Kong, China)
Wuifung Sze, ASM Assembly Automation Ltd. (Hong Kong, China)
Jiangwen Deng, ASM Assembly Automation Ltd. (Hong Kong, China)
Kenneth S. M. Fung, ASM Assembly Automation Ltd. (Hong Kong, China)
W. H. Leung, ASM Assembly Automation Ltd. (Hong Kong, China)
Edmund Y. Lam, The Univ. of Hong Kong (Hong Kong, China)


Published in SPIE Proceedings Vol. 8300:
Image Processing: Machine Vision Applications V
Philip R. Bingham; Edmund Y. Lam, Editor(s)

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