Small target reconstruction method for array GM-APD LiDAR under a low SBR condition

Extracting targets under high noise conditions, particularly for small and weak targets at long distances, presents a significant challenge. In this context, a noise suppression method grounded in variable mode extraction (VME) is proposed. This approach separates signal and noise in the echo based on differences in the center frequency of the mode. By combining the residual signals from Geiger-mode avalanche photodiode (GM-APD) laser imaging, detection, and ranging (LiDAR) systems, the method enhances the signal-to-noise ratio (SNR) of the response distribution, enabling accurate target position extraction. The processing performance of this method was validated through simulation analysis and real experimental data. When the average signal-to-background light ratio (SBR) of the echo reaches 0.006, the probability of successfully extracting a single-pixel target signal at a distance of 2.5 km in a sky background can exceed 90%.