Measurement of Displacement in the Whole View Field Using Digital Image Correlation (Template Matching and Interpolation Method of Gray Level Distribution)

摘要

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. Random pattern is painted on the object surface as gage marks. 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. We investigated a search method of corresponding points with accuracy less than one pixel. We considered methods to find position shift between two images within one pixel and interpolate gray level using neighboring pixel data for moving template image. Combining these methods, we found that it is possible to make template matching with sub-pixel accuracy.