Fig. 1. Schematic of measurement principle of typical 3D shape measurement system

Fig. 2. Projected pattern number of different temporal phase unwrapping methods

Fig. 3. Generating process of different bit number fringe patterns. (a) Flow chart; (b) examples of generating 6 bit fringe patterns (i=6, N=3, n=1, T=912 pixel); (c) examples of bitwise extraction

Fig. 4. Projection and shooting process of 6 bit fringe patterns. (a)~(f) Projected 1 bit patterns from lowest to highest order; (g) captured integral fringe pattern by rapidly projecting six patterns on plane; (h) profile distribution of 230th row of Fig. 4(g)

Fig. 5. Operational parameter of fringe projection measurement system

Fig. 6. Accuracy analysis of measurement results of standard gauges. (a) Tested scene consisting of standard gauges; (b) one deformed fringe pattern; (c) reconstructed result with 8 bit projected fringe; (d) reconstructed result with 6 bit projected fringe

Fig. 7. Comparison of 3D reconstruction results of a plaster model using two projected fringe patterns with two different bit numbers. (a) Plaster model; (b) one deformed fringe pattern of 8 bit projected fringe; (c) one deformed fringe pattern of 6 bit projected fringe; (d) reconstruction result and partial enlarged view of 8 bit projected fringe; (e) reconstruction result and partial enlarged view of 6 bit projected fringe

Fig. 8. Comparative experiment of 3D reconstruction with different fringes in a statue with high noise. (a)-(c) 6 bit high, medium, and low frequency deformation fringe patterns; (d) 8 bit reconstruction phase of two-frequency (f_l=1, f_h=8); (e) overall phase error distribution diagram of Fig. 8(d); (f) profile distribution of 673rd row of Fig. 8(d); (g) 8 bit reconstruction phase of two-frequency(f_l=1, f_h=64); (h) overall phase error distribution diagram of Fig. 8(g); (i) profile distribution of 673rd row of Fig. 8(g); (j) 6 bit reconstruction phase of three-frequency (f_l=1, f_m=8, f_h=64); (k) overall phase error distribution diagram of Fig. 8(j); (l) profile distribution of 673rd row of Fig. 8(j)

Fig. 9. 3D reconstruction results and phase error rate using 8 bit and 6 bit projected fringes at different positions and rotation speeds

Fig. 10. 3D reconstruction results and error rate analysis of 8 bit and 6 bit projected fringes at different rotating speeds

Fig. 11. 3D reconstruction results using 6 bit in-focus projection and 1 bit binary defocusing projection at different depth positions

Fig. 12. 3D reconstruction results of projected fringe with different bits. (a) 8 bit; (b) 6 bit; (c) 4 bit

Fig. 13. Summary of performance and suitable application scenes for fringe projection with three kinds of bits