CAD-Based Calibration and Shape Measurement with StereoDIC Principle and Application on Test and Industrial Parts

Abstract : A new calibration procedure is proposed for a stereovision setup. It uses the object of interest as the calibration target, provided the observed surface has a known de nition (e.g., its CAD model). In a rst step, the transformation matrices needed for the calibration of the setup are determined assuming that the object conforms to its CAD model. Then the 3D shape of the surface of interest is evaluated by deforming the a priori given freeform surface. These two steps are performed via an integrated approach to stereoDIC. The measured 3D shape of a machined Bézier patch is validated against data obtained by a coordinate measuring machine. The feasibility of the calibration method's application to large surfaces is shown with the analysis of a 2-m2 automotive roof panel.