Shape measurement using a new 3D-DIC algorithm that preserves sharp edges

Abstract

Digital Image Correlation is widely used for shape, motion and deformation measurements. Basically, the main steps of 3D-DIC for shape measurement applications are: off-line camera calibration, image matching and triangulation. The matching of each pixel of an image to a pixel in another image uses a so-called subset (correlation window). Subset size selection is a tricky issue and is a trade-off between a good spatial resolution, achieved with small subsets that preserve image details, and a low displacement uncertainty achieved with large subsets that can smooth image details. In this paper, we present a new multi-step DIC algorithm specially designed for measuring the 3D shape of objects with sharp edges. With this new algorithm an accurate 3D reconstruction of the whole object, including the sharp edges that are preserved, can be achieved. © The Society for Experimental Mechanics, Inc. 2014.