Digital image correlation is a whole field optical technique for displacement and strain measurement. The measurement is based on tracking a group of pixels (called subsets) in the deformed and reference images through temporal matching and correlation functions. Various parameters influence the accuracy of measurement in DIC. Further, there are various random sources of error in DIC. In order to suppress the experimental sources of error, the deformed speckle image is obtained numerically. The numerical approach is initially validated by comparing the numerically obtained deformed speckle image with that of the experimentally obtained deformed speckle image for the both cases of speckles obtained by spray painting and hand sketching. Further, the selection of parameters such as subset size for spray paint and hand sketch speckle pattern for displacement measurement is studied. The role of selection of correlation function is also investigated.

Keywords: DIC, Speckle image, Subset size, Correlation criteria, Numerical simulation.