Fig. 1. Schematic diagram of head-up binocular stereo imaging

Fig. 2. Schematic diagram of dual optical path design

Fig. 3. Negative-positive inverted telephoto system

Fig. 4. Initial optimization structure of objective lens

Fig. 5. Enhancement of rod lenses in the endoscopic relay system

Fig. 6. Initial optimization of the relay lens system in endoscopy

Fig. 7. Integrated optical structure of objective lens and relay system

Fig. 8. Comparison chart between the standard lens and the telecentric lens

Fig. 9. Bi-telecentric single-path optical posterior objective configuration

Fig. 10. Overall integrated design results

Fig. 11. MTF curves of the integrated objective lens and relay system

Fig. 12. MTF curves of the overall design

Fig. 13. Coordinate diagram after double light paths are connected to rear objective lens

Fig. 14. Full field spot diagrams for two optical paths. (a) Full field spot diagrams for the first optical path; (b) full field spot diagrams for the second optical path

Fig. 15. Distortion and field curvature maps of the first optical path. (a) +Y field curvature map; (b) +Y field distortion map; (c) -Y field curvature map; (d) +Y field distortion map; (e) X field curvature map; (f) X field distortion map

Fig. 16. MTF curves at different temperatures. (a) MTF curves at -20 ℃; (b) MTF curves at 20 ℃; (c) MTF curves at 80 ℃