Color crosstalk coefficient calibration technique with high precision for fringe projection profilometry

Nowadays, color-coded patterns are widely used to make real-time 3D shape measurement possible based on fringe projection profilometry (FPP). However, color crosstalk between the color camera remains a primary limitation of this method. In order to reduce the influence of color crosstalk on the phase retrieval accuracy, an accurate color crosstalk coefficient calibration method is proposed for color decoupling in this work. Firstly, based on the orthogonal fringe projection mode, the influence of color crosstalk coefficients on wrapped phase error is theoretically derived. Meanwhile, the truth phase values are generated based on smooth surface polynomial fitting to eliminate phase artifacts. Finally, by projecting the designed color orthogonal fringe patterns onto a standard plate, separate images from R, G and B channel could be obtained to extract the phase error, which can be further used for color channel crosstalk coefficients calibration. Multiple experiments with a standard white plate and sphere have verified that the method effectively improves phase quality, making it suitable for fast and accurate 3D shape measurement.