Application of stereo vision to three-dimensional deformation analyses in fracture experiments

Perng-Fei Luo; Yuh J. Chao; Michael A. Sutton

doi:10.1117/12.160877

1 March 1994 Application of stereo vision to three-dimensional deformation analyses in fracture experiments

Perng-Fei Luo, Yuh J. Chao, Michael A. Sutton

Author Affiliations +

Optical Engineering, Vol. 33, Issue 3, (March 1994). https://doi.org/10.1117/12.160877

Abstract

Based on a pinhole camera model, camera model equations that account for the radial lens distortion are used to map three-dimensional (3-D) world coordinates to two-dimensional (2-D) computer image coordinates. Using two cameras to form a stereo vision, the 3-D information can be obtained. It is demonstrated that such stereo imaging systems can be used to measure the 3-D displacement field around the crack tip of a fracture specimen. To compare with the available 2-D theory of fracture mechanics, the measured displacement fields expressed in the world coordinates are converted, through coordinate transformations, to the displacement fields expressed in specimen crack tip coordinates. By using a smoothing technique, the in-plane displacement components are smoothed and the total strains are obtained. Rigid body motion is eliminated from the smoothed in-plane displacement components and unsmoothed out-of-plane displacement. Compared with the theoretical elastic-plastic field at a crack tip, the results appear to be consistent with expected trends, which indicates that the stereo imaging system is a viable tool for the 3-D deformation analysis of fracture specimens.

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Perng-Fei Luo, Yuh J. Chao, and Michael A. Sutton "Application of stereo vision to three-dimensional deformation analyses in fracture experiments," Optical Engineering 33(3), (1 March 1994). https://doi.org/10.1117/12.160877

Published: 1 March 1994

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