Fig. 1. PCFL system based on the global coordinate system (OXYZ). The measurement and reference fringes come from points W₁ and W₂, respectively. The global coordinate is defined as follows: the XOY plane is at the lowest position; the Z-axis is the optical axis of the high-speed camera; the X-axis is perpendicular to the fringes and the Y-axis is parallel to the fringes. A calibration plane (CP) perpendicular to the optical axis of the high speed camera (HCCD) was used to calibrate the system. PC, personal computer; FPP, fringe pattern projector.