三维数字图像相关法的匹配策略和应变场计算

Study on Stereo Matching Strategy and 3-D Strain Computation in Three-Dimensional Digital Image Correlation

针对在三维数字图像相关法的三维重建过程中存在着两种不同的匹配策略,利用三维仿真散斑图模拟变形,分析研究二者在不同场景下应用的品质。现有的三维应变场计算有直接对三维位移场计算和对位移场投影后再进行计算两种方法,这两种方法存在忽略局部特征、未去除噪声的缺陷。为了得到精度较高的应变场,采用基于最小二乘拟合的微单元体应变计算方法。仿真分析结果表明:利用该计算方法求得的应变场精度明显提高。

In three-dimensional Digital Image Correlation（DIC）,there are two different matching strategies in the process of three-dimensional reconstruction.This paper summarizes the application of these two matching strategies in different scenarios by using the three-dimensional simulation speckle maps to simulate the deformation.There are two methods to calculate the three-dimensional displacement field and to calculate the displacement field directly.The two methods have the disadvantages of ignoring the local feature and removing the noise.In order to obtain the strain field with high precision,the strain calculation method of the micro unit body based on the least squaresfitting is used in the calculation of three-dimensional strain fields.The Simulation analysis results show that the strain field precision obtained by using this strain calculation method is reliable.