Digital image correlation method for the analysis of 3-D internal displacement field in object

Abstract

In this paper, the digital image correlation method for the analysis of 3-D displacement field is firstly presented. The 3-D displacement field caused by internal microstructures evolution is obtained by correlative calculation of digital images taken before and after deformation of the object. The 3-D searching window, correlation function and the fitted function of correlation coefficient are obtained. The numerical simulation results confirmed this technique. The precision of displacement measuvement is 0.02 pixel.

Accurate and simple digital volume correlation using pre-interpolation

“…First, the location of the extreme point of the zeronormalized cross-correlation (ZNCC) is calculated by the integer search algorithm; the ZNCC function is established at the extreme point. The ZNCC function can be set as C(x,y,z) and the general curve-fitting equation is a ternary quadratic function [14]:…”

“…In some research, the least squares method is used to solve the equation parameters [12,15]; however, the least squares method involves complicated and time-consuming matrix operations. The explicit method is used for acceleration while the accuracy and stability of the existing explicit calculation method are insufficient [14]. Therefore, this method needs to be improved and solved using equation (13), which can be found in the appendix where detailed derivation processes are included.…”