Flexible calibration and measurement strategy for a multi-sensor fringe projection unit

In this paper, a strategy for the calibration and the measurement process of a multi-sensor fringe projection unit is presented. The objective is the development of an easy to use calibration and measurement procedure. Only one simple geometrical calibration target is needed and the calibration of the projection unit is not mandatory. To make the system ready for measurement tasks, a common world coordinate system is established. The geometrical camera calibration is derived with respect to the world frame. Note, that the cameras of the system are under Scheimpflug condition which is considered using a modified camera model. Furthermore an additional optimization step of the extrinsic camera parameters is presented to compensate the uncertainties of the calibration target. For completeness, a suitable calibration strategy for the projection unit is given, too. Additionally, the quality of the presented strategy is demonstrated by experimental data.