Fig. 1. (a) Correlation between Sync 8 and all the returning photons with (red) and without (black) LD8. (b) SBR as a function of the total photon counts.

Fig. 2. Schematic of the multi-beam frequency-multiplexing photon-counting LiDAR. LD1–LD16: laser diodes operating at different repetition rates around 1 MHz. Fiber Array, 16 multi-mode optical fibers in an array; BPF, interference bandpass filter at 850 nm with a bandwidth of 10 nm; SPD, single-pixel single-photon detector; TCSPC, 16-channel time-correlated single-photon counter module. Inset: zoom-in of the beam collimation part. CM, concave mirror.

Fig. 3. (a) Map of the hall where the experiment was carried out. (b) The rebuilt image of the hall from the top view acquired by the multi-beam frequency-multiplexing 3D photon-counting laser imaging system. (c) The reconstructed 3D image of the hall from the side angle. Dashed line box: the horse model with its shadow on the wall. (d) Detail of the horse model image in the black dashed line box in (c).