Robust full-field measurement considering rotation using digital image correlation
Robust full-field measurement considering rotation using digital image correlation
复制标题
使用数字图像相关性考虑旋转的稳健全场测量
DOI：
10.1088/0957-0233/27/10/105002
复制
发表时间：
2016-10-01
影响因子：
2.4
通讯作者：
Zhang, Dongsheng
中科院分区：
文献类型：
--
作者：
Wu, Rong;Qian, Hao;Zhang, Dongsheng
数字图像相关法（DIC）作为一种位移和应变测量方法已被广泛接受，并应用于各种工程领域。大多数DIC算法在测量涉及旋转的条件下的变形时会遇到误差，因为它们的设计没有考虑变形对象的旋转。在本文中，一个强大的和自动化的DIC方法能够确定全场位移和应变分量的随机旋转。该算法首先确定种子点在整像素域中的初始位置。使用自动特征匹配技术估计参考和变形子集之间的近似旋转角度。一个两步牛顿-拉夫森算法已被开发用于优化一套变量，包括位移，应变和旋转角度，以实现亚像素精度。还提出了一种可靠的传播方案，它可以快速确定全场分析的初始猜测。数值模拟结果被用来验证所提出的DIC方法的可行性。通过对大挠度三点弯曲的测量表明，该算法可用于测量任意转角变形物体的位移或应变参数。
Digital image correlation (DIC) has been widely accepted as a method for displacement and strain measurement and is applied in a variety of engineering fields. Most DIC algorithms encounter errors in measuring the deformation in conditions that involve rotation since they are designed without considering rotation of the deformed object. In this paper, a robust and automated DIC method capable of determining full-field displacement and strain components with random rotations has been presented. The algorithm starts with the determination of the initial position of the seed point in the integer-pixel domain. An approximate rotational angle between the reference and the deformed subset is estimated using an automated feature matching technology. A two-step Newton–Raphson algorithm has been developed for optimizing a suite of variables including displacement, strain and the rotational angle to achieve subpixel accuracy. A reliable propagation scheme, which enables rapid determination of the initial guess for full-field analysis is also proposed. Results from numerical simulations are used to validate the feasibility of the proposed DIC method. An application to 3-point bending with large deflection shows that the algorithm can be employed to measure displacement or strain parameters of the deformed object with arbitrary angles of rotation.