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Optical Engineering

Photogrammetry-based two-dimensional digital image correlation with nonperpendicular camera alignment
Author(s): Zheng-Zong Tang; Jin Liang; Cheng Guo; Yong-Xin Wang
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Paper Abstract

2-D digital image correlation (DIC) is traditionally used with the camera's axis perpendicular to the object surface. The nonperpendicular camera alignment will inevitably introduce measurement error. An oblique-axis 2-D DIC method based on photogrammetry compensation is proposed in this paper. Not less than three reference points are pasted on the specimen surface. The photogrammetry technique is first used to get the 3-D coordinates of these reference points. A reference plane is obtained by fitting these reference points. Then the oblique-axis camera is oriented by using the space resection method. During deformation measurement, for each image points matched by DIC, its 3-D point can be acquired by simply intersecting the point ray with the reference plane. Using this method, not only is the measurement error caused by oblique-axis compensated, but also the displacement in millimeters rather than in pixels can be determined directly. Experiments results indicate that, for in-plane deformation in oblique-axis measurement situation, our method has comparable accuracy with 3-D DIC.

Paper Details

Date Published: 27 February 2012
PDF: 10 pages
Opt. Eng. 51(2) 023602 doi: 10.1117/1.OE.51.2.023602
Published in: Optical Engineering Volume 51, Issue 2
Show Author Affiliations
Zheng-Zong Tang, Xi'an Jiaotong Univ. (China)
Jin Liang, Xi'an Jiaotong Univ. (China)
Cheng Guo, Xi'an Jiaotong Univ. (China)
Yong-Xin Wang, Xi'an Jiaotong Univ. (China)

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