Fig. 1. Schematic diagram of the sampling point distribution and scanning trajectory for (a) mainstream linear scanning and (b) AOM supplementary scanning.

Fig. 2. Schematic diagram of the AOM supplementary scanning experimental setup. FC, fiber collimator; M, high reflectivity mirror; G1, G2, slow axis and fast axis galvanometers; F, optical filter with a central wavelength of 1550 nm; AFG, arbitrary function generator; TDC, time-digital converter; PD, photodetector; BE, beam expander; GHz-SPAD, GHz-gated InGaAs/InP single-photon avalanche photodiode; HWP, half-wave plate.

Fig. 3. (a) Timing diagram of galvanometer driving signals and AOM driving FM signals. TD, time domain; FD, frequency domain. (b) Schematic diagram of the numerical and spatial relationship among the beam divergence angle, receiving FOV, and AOM scanning angle.

Fig. 4. (a), (b) Photos of the targets 40 m away. (c) Schematic diagram of nine positions within the FOV.

Fig. 5. (a) Line graph of the recognition probability of small targets using two different scanning methods. The presence of no fewer than five points in the denoised point cloud is deemed a successful target recognition. (b) One frame of the imaging results.

Fig. 6. (a) Photo of the pedestrian. (b) One frame of the imaging results using AOM supplementary scanning. (c) One frame of the imaging results using traditional linear scanning.

Fig. 7. (a), (b) Physical photos of intersections (the black car was absent during the experiment). (c), (e) One frame of the imaging results using AOM supplementary scanning and traditional linear scanning, respectively. (d), (f) Partial enlarged image of the tricycle in the imaging results.