Fig. 1. Schematic diagram of coaxial measurement system

Fig. 2. Schematic diagram of ray geometric model of projector at two projection positions

Fig. 3. Coaxial projection-imaging model

Fig. 4. Fringe patterns captured by virtual camera under different L_p. (a) L_p=690 mm; (b) L_p=710 mm; (c) L_p=730 mm; (d) L_p=750 mm; (e) L_p=770 mm

Fig. 5. Absolute phases corresponding to five projection positions. (a) Three-dimensional graph; (b) section of absolute phases passing through center of circle

Fig. 6. Planar reconstruction results. (a) Whole height information; (b) height section of row passing through center of circle; (c) height information of area away from center of circle; (d) height section of row away from center of circle

Fig. 7. Ladder round platform. (a) Three-dimensional view; (b) sectional view

Fig. 8. Simulation results of ladder round platform. (a) Reconstruction result; (b) height section at 360th line; (c) error distribution

Fig. 9. Object to be measured

Fig. 10. Simulation results of ellipsoid under different small angles. (a)-(c) 2°; (d)-(f) 4°; (g)-(i) 6°

Fig. 11. Experimental setup

Fig. 12. Reconstruction experiment of face model. (a) Measured object; (b) four phase shift fringe patterns; (c) reconstruction result; (d) section of reconstruction surface at 248th line

Fig. 13. Reconstruction experiment of steps. (a) Measured object; (b) one frame of fringe pattern; (c) reconstruction result of dashed line area