Huang Mingwei, Zhang Zijing, Xie Jiaheng, Li Jiahuan, Zhao Yuan
School of Physics, Harbin Institute of Technology, Harbin 150001, China.
Entropy (Basel). 2021 Nov 12;23(11):1499. doi: 10.3390/e23111499.
Photon counting lidar for long-range detection faces the problem of declining ranging performance caused by background noise. Current anti-noise methods are not robust enough in the case of weak signal and strong background noise, resulting in poor ranging error. In this work, based on the characteristics of the uncertainty of echo signal and noise in photon counting lidar, an entropy-based anti-noise method is proposed to reduce the ranging error under high background noise. Firstly, the photon counting entropy, which is considered as the feature to distinguish signal from noise, is defined to quantify the uncertainty of fluctuation among photon events responding to the Geiger mode avalanche photodiode. Then, the photon counting entropy is combined with a windowing operation to enhance the difference between signal and noise, so as to mitigate the effect of background noise and estimate the time of flight of the laser pulses. Simulation and experimental analysis show that the proposed method improves the anti-noise performance well, and experimental results demonstrate that the proposed method effectively mitigates the effect of background noise to reduce ranging error despite high background noise.
用于远距离探测的光子计数激光雷达面临着由背景噪声导致测距性能下降的问题。当前的抗噪声方法在弱信号和强背景噪声情况下不够稳健，导致测距误差较大。在这项工作中，基于光子计数激光雷达中回波信号和噪声的不确定性特征，提出了一种基于熵的抗噪声方法，以减少高背景噪声下的测距误差。首先，定义了光子计数熵，将其作为区分信号与噪声的特征，用于量化响应盖革模式雪崩光电二极管的光子事件之间波动的不确定性。然后，将光子计数熵与加窗操作相结合，增强信号与噪声之间的差异，从而减轻背景噪声的影响并估计激光脉冲的飞行时间。仿真和实验分析表明，所提方法具有良好的抗噪声性能，实验结果证明，尽管存在高背景噪声，所提方法仍能有效减轻背景噪声的影响以降低测距误差。
