Digital image correlation (DIC) is a classic pattern recognition technique that is widely used for experimental measurements, mainly for: (1) surface displacement analysis in solid mechanics, and (2) particle image velocimetry (PIV) in fluid mechanics. DIC is based on using a correlation function to locate the best matching position of two images thus predicting movements. An advanced form of DIC called adaptive cross correlation (ACC) has been adapted for this research. In this chapter, the basis of the technique and its application are explained. The anticipated errors of using DIC and ACC are also evaluated.