A combined temporal tracking and stereo-correlation technique for accurate measurement of 3D displacements: application to sheet metal forming

Optical methods that give displacement or strain fields are now emerging significantly in the mechanical sciences. Much work has been done on two-dimensional (2D) displacement/strain measurement from a single camera but the proposed methods give only in-plane strains. A binocular correlation-based stereovision technique has been developed: (a) to measure the three-dimensional (3D) shape of a static object or (b) to measure the strains of an object undergoing some 3D mechanical or thermal stress. In this paper, the application of the stereo-correlation technique to measure accurately the 3D shape of a stamped sheet metal part or the surface strain field undergone by the part during the stamping process is presented.