We investigated a method to measure displacement distribution in the whole view field of a CCD camera using digital image correlation (DIC) technique. This method intends to measure displacement field on a surface by comparing two images before and after deformation taken with a CCD camera. In this method, accuracy of the search method of the corresponding points on the two images influences largely on the accuracy of the measured result. In this paper, we investigated an interpolation method to estimate gray level using neighboring pixel data and gray level correction method for template matching with accuracy less than one pixel.