Fig. 1. A typical optical setup for 3-D surface measurement using fringe-projection

Fig. 2. The measured height distribution of the spherical crown

Fig. 3. The fringe pattern in experiment captured

Fig. 4. The calculated height distribution of the spherical crown

Fig. 5. The comparison of the cross section data between the calculated and its true value at y=0 mm in x direction

Fig. 6. The comparison of the absolute error distribution of the measured crown height when the projector coordinates x_P and z_P are set as -25 mm and 0 mm respectively, the imaging distance z₀ is 1 805 mm with that of 1 800 mm

Fig. 7. The comparison of the absolute error distribution of the measured crown height when z₀ and z_P are set as -1 800 mm and 0 mm respectively, x_P is -30 mm with that of -25 mm

Fig. 8. The comparison of the absolute error distribution of the measured crown height when z₀ and x_P are set as 1 800 mm and -25 mm respectively, z_P is 5 mm with that of 0mm

Fig. 9. The fringe patterns in experiment captured

Fig. 10. The calculated height distribution of the mask surface