Fig. 1. Optical path of FTP measurement system

Fig. 2. Schematic of common optical path interference

Fig. 3. Coordinate analysis of common optical path interference

Fig. 4. Interference patterns. (a) Simulated interference fringe when θ=3.55°; (b) simulated interference fringe when θ=3.57°; (c) simulated interference fringe when θ=3.58°; (d) actual interference fringe when θ=2°; (e) actual interference fringe when θ=3°

Fig. 5. Physical diagram of experimental equipment

Fig. 6. Object to be measured. (a) Physical object and deformed fringe pattern; (b) phase unwrapping pattern

Fig. 7. Phase distribution maps of the same row of each calibration plane at different positions. (a) Before unwrapping; (b) after unwrapping

Fig. 8. Calibration results of measurement system. (a) Parameter a; (b) parameter b

Fig. 9. Experiment results. (a) Three coordinate machine measurement chart; (b) three-dimensional topography of object; (c) error distribution map

Fig. 10. Calibration plane 9 error analysis. (a) Fringe pattern; (b) fringe pattern in line 300; (c) Fourier spectrum; (d) phase unwrapping pattern