Flexible Calibration for Digital Fringe Projection Profilometry

System calibration is essential for digital fringe projection 3D shape measurement. There are many calibration researches focusing on phase-to-height conversion, while the transverse calibration accuracy is less discussed, which is also very important. In this paper, we do reconstruction from object phase map to 3D coordinates through simple and global calibration and show improvements in transverse (X-Y coordinates) calibration, with camera lens distortion considered. algorithm only requires a 2D calibration board to be placed at several random positions. Projector calibration as an inverse camera is not needed. Since no specific parameters of the projector is needed to be calculated, our algorithm is flexible and easy to be applied on arbitrarily arranged digital fringe projection systems including those with a defocused projector.