Shape and deformation measurement system by combining fringe projection and digital image correlation

An optical measurement system, which is capable of simultaneously measuring surface profile and three-dimensional (3-D) deformation of small objects, has been developed by the combination of fringe projection and a two-dimensional digital image correlation (DIC) technique. In the proposed approach, it requires only one camera and one projector. The surface profile and out-of-plane deformation are determined by fringe projection with the phase-shifting method. The in-plane deformation is determined by comparing the surface texture of specimen before and after deformation with the DIC technique. A simple procedure is described which enables determination of texture image from phase-shifting images. As an application, the developed system was used to investigate the mechanical behavior of molded pulp material in micro-zone during tension testing.

► We develop a system for simultaneously surface and 3-D deformation measurement of small objects.
► The system requires only one camera and one projector.
► Texture image used in digital image correlation is retrieved from four phase-shifting fringes.
► By use of two long-working distance microscopes, the system can measured small objects.