Fig. 1. Phase unwrapping of traditional two-frequency fringe

Fig. 2. Phase unwrapping using geometric constraint

Fig. 3. Phase unwrapping of modified two-frequency fringe

Fig. 4. Phase simulation of traditional two-frequency fringe

Fig. 5. Simulation of modified two-frequency fringe

Fig. 6. Relation curves between the ratio γ and the number of wrongly unwrapped pixels M under different levels (standard deviation σ) of Gaussian noises

Fig. 7. Experiment of traditional two-frequency fringe

Fig. 8. Experiment of modified two-frequency fringe

Fig. 9. 3D shape measurement of the Doraemon. (a) Traditional two-frequency fringe; (b) modified two-frequency fringe

Fig. 10. 3D shape measurement of the ball. (a) Traditional two-frequency fringe; (b) modified two-frequency fringe