Fig. 1. Relationship between the defocus effect of the projector and the depth u

Fig. 2. Defocus kernel curve as a function of depthu (u₁<u₂<u₃<u_f<u₄<u₅<u₆)

Fig. 3. Under the different depth of dither fringes pattern and pattern cross section diagram (u₁<u₂): (a) T₁=24 pixel, moderate defocus; (b) T₁=24 pixel, excessive defocus; (c) T₂=48 pixel, slight defocus; (d) T₂=48 pixel, moderate defocus

Fig. 4. Flowchart of the optimal frequency mode determination

Fig. 5. Simulation results of the optimal frequency mode of Bayer-dithered pattern: (a) Under the different frequency fringe of phase error as a function of filter size; (b) The optimal frequency range and its defocusing smooth area; (c) The optimal frequency mode of Bayer-dithered pattern

Fig. 6. Simulation results of the optimal frequency mode of Floyd-Steinberg dithering pattern: (a) Under the different frequency fringe of phase error as a function of filter size; (b) The optimal frequency range and its defocusing smooth area; (c) The optimal frequency mode of Floyd-Steinberg-dithered pattern

Fig. 7. The hardware setup of the experimental system

Fig. 8. Measurement of objects with multi-frequency phase selection approach: (a) Object to be measured; (b) One of four-step phase-shifting fringe pattern; (c) Unwrapped phase of the measured object

Fig. 9. Three-dimensional reconstruction results for the object in a large depth range: (a) T=42 pixel, Floyd-Steinberg dithering pattern; (b) T=60 pixel, Bayer dithering pattern; (c) T=60 pixel, standard sinusoidal fringe