Digital image correlation

Abstract

Digital Image Correlation (DIC) is an optical method that utilizes tracking and image registration techniques for accurate measurement of changes in digital images. Over the last two decades, developments in DIC have enabled it to become a practical and effective tool for in-plane deformation and strain measurements of a planar object surface.

By comparing images of a test object surface acquired before and after deformation, DIC provides the full-field displacement of the surface. Through various sub-pixel displacement registration algorithms such as the Newton-Raphson method, DIC can measure displacement up to sub-pixel accuracy.

This report investigates and gives comparison on the integer pixel and some of the sub-pixel displacement registration techniques commonly used in DIC.