激光与光电子学进展, 2018, 55 (9): 091001, 网络出版: 2018-09-08
数字图像相关法中一种动态应变子区选择算法 下载: 676次
An Dynamic Strain Subset Selection Algorithm in Digital Image Correlation Method
图像处理 数字图像相关 非均匀变形 动态子区 位移场 应变场 image processing digital image correlation heterogeneous deformation dynamic subset displacement fields strain fields
摘要
数字图像相关法测量具有非接触式、全场测量、结构简单等优点而得到广泛研究和应用。传统的应变场计算方法以位移场局部最小二乘拟合过程为核心, 使用全场统一的子区大小进行计算。在非均匀变形测量过程中, 这种计算方式存在较大的算法误差。较大的应变子区会使局部的变形梯度平滑, 而较小的应变子区不能对位移场误差进行有效地抑制。因此, 根据位移场局部梯度强度提出了一种位移场修正和动态选择应变计算子区大小的方法, 并且模拟生成散斑图像进行仿真。结果表明:所提方法有效降低了数字图像相关法在非均匀变形测量过程中的计算误差, 同时系统精度也得到提升。基于位移场局部梯度强度的动态子区选择算法原理简单, 计算准确度高。
Abstract
Digital image correlation method is widely studied and applied due to its advantages, such as non-contact, whole measurement, and simple structure. The traditional calculation method of strain fields takes the local least squares fitting process of the displacement field as the core, and uses the unified subset size of the whole field to be calculated. However, there is a biggish algorithm error in the process of heterogeneous deformation measurement. Larger strain subset size will smooth local deformation gradient, while smaller strain subset size cannot effectively reduce the displacement field error. Therefore, according to the local gradient intensity of the displacement field, a novel algorithm is proposed to correct displacement fields and dynamic select the strain for calculating the subset size, and simulate the results of the speckle images. The results show that the proposed method effectively reduces the calculation error of the digital image correlation method in heterogeneous deformation, and while the system precision is improved. The dynamic subset selection algorithm based on the local gradient intensity of the displacement fields has a simple principle and high calculation accuracy.
王莹, 沈峘, 夏瀚笙, 刘敦强. 数字图像相关法中一种动态应变子区选择算法[J]. 激光与光电子学进展, 2018, 55(9): 091001. Wang Ying, Shen Huan, Xia Hansheng, Liu Dunqiang. An Dynamic Strain Subset Selection Algorithm in Digital Image Correlation Method[J]. Laser & Optoelectronics Progress, 2018, 55(9): 091001.