Fig. 1. Schematic of ray model of imaging system

Fig. 2. Schematic of ray's parameter representation

Fig. 3. Calibration of three-point ray model

Fig. 4. Biplane calibration method^[43]. (a) Target pose planning with biplane method; (b) binary encoded image; (c) index table

Fig. 5. Calibration of universal ray model^[44]. (a) Pinhole camera; (b) fish eye lens

Fig. 6. Ray calibration scheme for large field-of-view imaging system^[45]. (a) Pose planning of target for large field-of-view fish eye lens; (b) pose planning of target for spherical catadioptric system; (c) pose planning of target for ray calibration of non-central fish eye camera

Fig. 7. Calibration of multi-view imaging system^[46]. (a) Binocular stereo system; (b) catadioptric system composed of spherical mirror and perspective camera

Fig. 8. Ray implicit calibration method^[54]

Fig. 9. Residual vector maps after distortion correction^[58]. (a) Checkerboard method; (b) active target method

Fig. 10. Scheimpflug structure of fringe structured light microscopic three-dimensional measurement system^[61]

Fig. 11. Principle of fringe structured light three-dimensional measurement based on ray model^[61]

Fig. 12. Diagram of simplified target attitude^[61]

Fig. 13. Small field-of-view fringe projection measurement system based on Scheimpflug structure^[62]

Fig. 14. Local three-dimensional measurement results of a nickel coin^[61]

Fig. 15. Diagram of light field imaging device. (a) Thin-lens pinhole model to characterize light field imaging^[66]; (b) ray model to characterize light field imaging^[40]

Fig. 16. Schematic of camera-auxiliary structured light field ray calibration^[40]

Fig. 17. Schematic of 3D reconstruction of structured light field^[40]

Fig. 18. Ray calibration results of light field camera^[40]. (a) Calibration fitting accuracy of ray; (b) partial ray distribution under the same viewing angle

Fig. 19. 3D measurement of highly dynamic scene in structured light field^[73]

Fig. 20. Multi-view 3D measurement in structured light field^[40]

Fig. 21. Schematic of working principle of two-axis MEMS projection device based on laser scanning

Fig. 22. Schematic of projection ray calibration model^[64]

Fig. 23. Projection ray calibration results^[64]. (a) Calibration result of one ray; (b) calibration result of partial rays

Fig. 24. Fitting error distribution of MEMS projection three-dimensional measurement system based on ray model for standard sphere^[64]

Fig. 25. Fitting error distribution of standard plane point cloud reconstructed by two methods^[64]. (a) Projective model (3-step phase shifting); (b) ray model (3-step phase shifting)

Fig. 26. 3D reconstruction results of different models for plaster sculptures^[64]. (a) Projective model(3-step phase shifting); (b) ray model(3-step phase shifting); (c) projective model(12-step phase shifting); (d) ray model (12-step phase shifting)

Fig. 27. Schematic of working principle of uniaxial MEMS laser scanning projection device^[65]

Fig. 28. Schematic of three-dimensional phase mapping based on uniaxial MEMS^[65]

Fig. 29. Calibration diagram of 3D measurement system based on uniaxial MEMS projection of plane target^[65]

Fig. 30. Measurement result and error distribution for standard plane^[65]. (a) Standard plane; (b) laser MEMS projection fringe; (c) point cloud of reconstructed standard plane; (d) error distribution

Fig. 31. 3D measurement system and dynamic reconstruction scene^[65]

Fig. 32. Schematic of camera ray mapping coefficient calibration method

Fig. 33. Camera ray calibration results of fringe projection 3D measurement system based on different lenses. (a) Telecentric lens; (b) conventional lens; (c) wide angle lens

Fig. 34. Fitting error distribution of standard sphere obtained by fringe projection measurement system based on wide-angle lens. (a) Projective model; (b) ray model