Simple correction method for projection fringe period based on parameter calibration

In the fringe projection profilometry system based on triangulation principle, the fringe projected on the reference plane always produces the period broaden phenomenon, which can cause phase distortion and even affect the measuring accuracy. The fringe position was taken as the control variable to derive the linear mathematical model of fringe period correction. The model parameters were obtained with a simple and convenient calibration process. Then the new projected fringe was calculated according to the correction model, and the periodic distribution fringe was obtained on the reference plane. The experimental results show that the varying range of the fringe period after correction is within ±0.1 pixel, and this method can obtain the more accurate 3D profile measurement results.