Fig. 1. The principle of pulse accumulation single photon detection

Fig. 2. (a) Results of 3D imaging for a car at 330 m by Buller et al; (b) Results of 3D imaging for a human model at 325 m by Buller et al^[14]

Fig. 3. Coded modulation of random coding single photon detection technique^[16]

Fig. 4. Chaos single photon detection system^[21]

Fig. 5. Chirped modulation single-photon detection principle ^[16]

Fig. 6. (a) Working principle diagram of avalanche photodiode^[33]; (b) The typical PDE variation curve of Si SPAD with wavelength^[34]

Fig. 7. Point cloud before and after data processing for the SPL100

Fig. 8. Imaging algorithm effect diagrams of chirp modulated single-photon LiDAR^[61]. (a) Accurate depth map of the target scene “Art”; (b) Performance comparisons of different methods with various conditions; (c) Photon efficiency of different approaches

Fig. 9. Reconstruction results of the method proposed by Lindell et al^[64]

Fig. 10. Results of single photon for long-distance detection at 21 km^[70]. (a) Photograph of targets and its location in the map; (b) Histogram of return photons from the target

Fig. 11. Imaging system and results of single photon for long-distance detection at 201.5 km^[11]. (a) Imaging system for long-distance detection at 201.5 km; (b) Photograph of the target; (c) Results of the algorithm proposed by Lindell; (d) Reconstructed 3D profile

Fig. 12. A single photon system for underwater detection^[78]

Fig. 13. (a) Comparison of imaging results with smog^[81]; (b) The single photon imaging system with 64×64 InGaAs SPAD detectors^[84]

Fig. 14. The reconstruction results of the PCE-Net^[87]

Fig. 15. ATLAS system architecture and results for glacier height measurement by ATLAS^[89]. (a) ATLAS system architecture; (b) Results for glacier height measurement by ATLAS

Fig. 16. The Leica SPL100 system and terrain features acquired by the SPL100^[57]. (a) The Leica SPL100 system; (b) Results reconstructed by the SPL100

Fig. 17. (a) Performance metrics and imaging results of ZVISION EZ6; (b) The result of 3D imaging by iPhone 12 Pro