Analysis of the measurement capability of optical fringe projection systems

Quality control describes numerous methods for monitoring the quality of a production process. With respect to this it will be a growing requirement on optical 3D-measurement techniques to reach the demands of the measurement capability. Here the limitations to fulfill these demands under industrial conditions are discussed when using fringe-projection technique for 3D-measurement. The analysis is done while measuring an automotive stamping part and a 3D-gauge with a telecentric fringe projection system, as examples. In the analysis we determined some geometric features like diameter of hole and bending angles of parts of the object surface. The results demonstrate the possibility to achieve a standard deviation of lower than I pm within a measurement volume of 90 mm in diameter for the geometric features. Due to the low standard deviation a measurement capability has been reached like tactile measurement systems. To achieve this the influence of the locale choice of the geometric fitting procedure onto the point cloud has to be taken into account.