摘要
提出一种针对单相机、斜光轴测量条件下,基于摄影测量校正的二维数字图像相关法(DIC)。变形前,在被测物表面粘贴不少于3个控制点(圆形标志点),通过摄影测量技术得到控制点的三维坐标,利用控制点的三维坐标及其在图像上对应的二维坐标,通过空间后方交会法得到斜光轴相机的三维空间方位,拟合控制点的三维坐标得到控制面。变形过程中,对于数字图像匹配得到的每一个相关图像点,通过其投影射线与控制面相交得到其对应的三维点坐标。该方法不仅可以校正由于相机光轴倾斜引入的测量误差,而且可以直接、准确得到三维空间位移而不是像素级位移。通过与已有的三维DIC对比,该方法的位移测量精度优于0.04mm,应变测量精度优于0.5%。
A novel single-camera two-dimensional digital image correlation method based on photogrammetry correction is developed for the situation that the camera axis is not perpendicular to the surface of the specimen. Before deformation, at least three control points （circle mark point） are placed on the specimen surface, and the three-dimensional （3D） coordinates of the control points are measured by the photogrammetry. Then the camera orientation is calculated by the space resection method, and a control plane is obtained by fitting the control points. During deformation process, for each point in the image matched by digital image correlation, its corresponding 3D point is acquired by intersecting between the point ray and the control plane, Using this method, not only the measurement error introduced by slant axis of the camera is corrected, but also the displacement in millimeters rather than in pixels can be gained directly. Experimental results comparing with the existing 3D digital image correlation method show that, the displacement measurement accuracy by the proposed method is better than 0.04 mm, and the strain measurement accuracy is better than 0.5 %.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2011年第11期157-165,共9页
Acta Optica Sinica
基金
国家自然科学基金(50975219)
苏州市应用基础研究计划(SYG201014)资助课题
关键词
光学测量
斜光轴
数字图像相关
摄影测量
空间后方交会
optical measurement
slant axis
digital image correlatiom photogrammetry
space resection
