Analysis of the Error Caused by Off-Plane Displacement in Two-Dimensional Digital Image Correlation Measurement
二维数字图像相关测量中离面位移引起的误差分析

Two-dimensional Digital Image Correlation (2D-DIC) method is a non-contact optical full-field deformation measurement method, and is widely applied in engineering. It assumes that the specimen has only in-plane displacement. However, the off-plane displacement often occurs in experiment. So the measurement error is inevitable. A pinhole model is applied, and the influence of off-plane displacement on measurement results is theoretically analyzed in this paper. Experimental results of aluminum block translation certify the theoretical analysis. The modified large deformation measurement results of rubber by normal lens are closer to the telecentric lens measurement results. At last, a reasonable way to decrease even eliminate the error caused by off-plane displacement is suggested in this paper.