Calibration of fringe projection profilometry using an inaccurate 2D reference target

Recently, the camera calibration techniques based on planar reference target have been widely used in 3D fringe projection profilometry (FPP). Commonly a reference target with high-accuracy is necessary for achieving the accurate calibration. However it is costly to fabricate such a reference target, especially for those with very large or small sizes. This paper focuses on a study of calibration with an inaccurate planar target. Two major contributions are made to the FPP system calibration: (1) using the bundle adjustment strategy to optimally locate the coordinates of feature points on the planar reference target, allowing compensation for the fabrication errors, and (2) introducing a standard sphere to determine the correct scale factor, resulting in an accurate calibration results. The experimental results are also presented to demonstrate the proposed approach.