APPLICATION OF STEREO VISION TO 3-DIMENSIONAL DEFORMATION ANALYSES IN FRACTURE EXPERIMENTS
APPLICATION OF STEREO VISION TO 3-DIMENSIONAL DEFORMATION ANALYSES IN FRACTURE EXPERIMENTS
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DOI：
10.1117/12.160877
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发表时间：
1994-03-01
影响因子：
1.3
通讯作者：
SUTTON, MA
中科院分区：
文献类型：
--
作者：
LUO, PF;CHAO, YJ;SUTTON, MA
基于针孔相机模型，考虑径向透镜失真的相机模型方程被用于将三维（3-D）世界坐标映射到二维（2-D）计算机图像坐标。利用两台摄像机构成立体视觉，可以获得物体的三维信息。它表明，这种立体成像系统可以用来测量周围的三维位移场的断裂试样的裂纹尖端。为了与现有的二维断裂力学理论进行比较，通过坐标变换，将在世界坐标中表示的测量位移场转换为在试样裂纹尖端坐标中表示的位移场。通过使用平滑技术，平滑面内位移分量，并获得总应变。从平滑的平面内位移分量和未平滑的平面外位移中消除刚体运动。通过与理论计算结果的比较，表明体视成像系统是一种可行的三维变形分析工具。
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.