光子计数激光雷达的自适应时空关联深度估计  

Adaptive spatial-temporal correlation depth estimation of photon-counting lidar

作　　者：王瑞[1,2,3] 刘博 李志康[1,2,3] 陈臻[1,2] 易皓 Wang Rui;Liu Bo;Li Zhikang;Chen Zhen;Yi Hao(Key Laboratory of Science and Technology on Space Optoelectronic Precision Measurement,Chinese Academy of Sciences,Chengdu 610209,China;Institute of Optics and Electronics,Chinese Academy of Sciences,Chengdu 610209,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院空间光电精密测量技术重点实验室,四川成都610209 [2]中国科学院光电技术研究所,四川成都610209 [3]中国科学院大学,北京100049

出　　处：《红外与激光工程》2023年第5期197-205,共9页Infrared and Laser Engineering

摘　　要：光子计数激光雷达具有高灵敏度、高时间分辨率等优势,为了实现在大量回波数据及强噪声环境下目标信息的高效提取,提出一种自适应时空关联深度估计算法。首先,根据回波数据中信号光子和噪声光子与发射激光脉宽的关系,利用回波光子在时域上的统计差异,自适应重构具有不同时间分辨率的直方图,并结合邻域像素数据之间的空间关联性,自适应调整时间窗口的大小,寻找信号光子所在的时间区间并提取相应的数据,显著降低后续处理的数据量;其次,基于所提取的回波光子数据,设置滑动窗口初步估计各像素的时间值;最后,通过自适应均值滤波得到各像素的飞行时间,解算相应的距离信息。相较于峰值法和Chen算法,在起伏地形探测的仿真实验中,当信号光子数约为14、噪声强度小于6 MHz时,重建的均方误差至少降低了20%;在室内静态目标成像实验中,当噪声强度在5.08 MHz范围内,所提算法进行目标重建的最大均方误差为0.017。仿真及实验结果表明,所提算法对强噪声下起伏地形和室内静态目标探测的回波数据均具有较好的滤波效果。Objective Photon-counting lidar has the characteristics of high sensitivity and high time resolution.It can solve the application limitations and technical problems in traditional linear detection within a certain range,and the advantage is more obvious in long-distance detection.There are important applications in topographic mapping,autonomous driving,environmental monitoring,etc.However,when using single photon detection technology,the influence of background noise becomes non-negligible while the detection sensitivity is improved to single photon level.The arrival of noise photons in the active region of the Geiger mode avalanche photodiode detector may also trigger response.Therefore,in addition to the effective information for target imaging,the weak echo also carries a large amount of noise data.The noise photon count in the echo data is closely related to the size of the background noise.Although the narrowband filter module in the hardware system helps to reduce the interference of the background noise,the noise count generated in strong noise environment still restricts the improvement of image reconstruction quality.In order to realize the efficient extraction of target information in a large number of echo data and strong noise environment,an adaptive spatial-temporal correlation depth estimation algorithm is proposed.Methods The designed algorithm mainly completes filtering and depth estimation through three steps(Fig.2).Firstly,the algorithm analyses the photon statistical differences in the time domain based on the relationship between signal photons and noise photons in the echo data and laser pulse width,and reconstructs histogram with different time resolution adaptively.The size of the time window is adjusted adaptively to find the time interval where the signal photon is located based on the reconstructed histogram and the spatial correlation of neighboring pixels'photon counts data(Fig.2-3).This will significantly reduce the amount of subsequent processed data by only extracting the photon co

关 键 词：光子计数激光雷达 强噪声 时空关联 深度估计 

分 类 号：TN958[电子电信—信号与信息处理]