阵列光束棱镜扫描光束指向及点云精度分析  

Analysis of point cloud accuracy and beam pointing of array beam through prism scanning

作　　者：杨峰 石振东[2] 姜勇 冷杰[2] 王雅兰[2] 陈德章 徐林[2] 宋昭 徐诗月[2] 贾凯 高剑波[2] 白杨[2] 周寿桓[1] Yang Feng;Shi Zhendong;Jiang Yong;Leng Jie;Wang Yalan;Chen Dezhang;Xu Lin;Song Zhao;Xu Shiyue;Jia Kai;Gao Jianbo;Bai Yang;Zhou Shouhuan(College of Electronics and Information Engineering,Sichuan University,Chengdu 610065,China;Southwest Institute of Technical Physics,Chengdu 610041,China)

机构地区：[1]四川大学电子信息学院,四川成都610065 [2]西南技术物理研究所,四川成都610041

出　　处：《红外与激光工程》2023年第5期270-278,共9页Infrared and Laser Engineering

基　　金：国家高分专项;山东省重大科技创新工程专项(2018SDKJ0102-6)。

摘　　要：在面阵扫描成像激光雷达中,阵列光束照明与棱镜扫描相结合实现了高能量利用率、高分辨率和宽探测视场,但阵列子光束倾斜入射棱镜,破坏了光束传输的旋转对称性,棱镜对子光束偏转能力存在差异,规则光束阵列产生了形状畸变,导致光束指向误差,影响点云位置精度。首先,将阵列光束与棱镜结合的圆锥扫描方式分解为多角度入射多波束并行扫描,通过所有子光束的传输特征来综合表征阵列光束传输特征;然后,采用三维矢量光学方法推导了阵列光束在棱镜中的传输过程,建立了子光束指向变化与棱镜扫描角度的关系;最后,通过对机载激光雷达棱镜扫描成像过程的数值仿真,建立了光束指向变化与点云数据质量的联系。仿真结果表明:阵列光束(3×3)棱镜扫描系统在航高0.5 km时,光束阵列畸变导致平面误差RMS约为5 cm,并随航高呈线性变化;斜率约为0.1 m/km,并随着阵列光束规模和子光束角间距增加点云平面精度随之下降。通过对棱镜扫描过程中光束阵列畸变规律掌握,为后续机载飞行试验数据的校正、阵列光束结合多棱镜扫描系统的设计提供了基础。Objective The prism scanning system is used to achieve optical imaging with both large field of view and high resolution by adjusting the beam direction or optic axis.It is widely used in optical reconnaissance,laser communication,lidar,etc.In airborne laser imaging lidar,the prism scanning system,as a transmission scanning structure,has high optical utilization,effectively reduces the volume of the system,and has the advantages of low power consumption,high precision and good stability.In array imaging lidar,high energy efficiency,high resolution,and broad field detection are all achieved by means of array beam illumination and Risley-prism scanning.However,when sub-beams are obliquely incident on the prism,the rotational symmetry of the traces of ray propagation is broken,the beam deflection of the sub-beams through the prism is different,and the regular beam array produces shape distortion,resulting in beam pointing error and affecting the position accuracy of the point cloud.Therefore,it is necessary to analyze the rules of beam array distortion to improve the accuracy of the point cloud.Methods The conical scanning mode that combines the array beam and prism is broken down into multi-beam parallel scanning with numerous incident angles,and the propagation characteristics of the array beam are thoroughly described by the propagation characteristics of all sub-beams(Fig.2).The three-dimensional vector optical approach is used to establish the laser transmission process of the array beam through a Risley-prism(Fig.3),and the relationship between the pointing variation of the sub-beam and the scanning angle of the prism is obtained(Fig.4).The association between beam pointing variability and point cloud data quality is demonstrated by the numerical simulation of imaging process with prism scanning by flight experiment of airborne lidar(Fig.6-7).Results and Discussions When the array beam is orthographically and obliquely incident into the prisms with different angles,the beam steering of the prism to each sub-be

关 键 词：机载激光成像雷达 阵列光束 棱镜扫描 指向误差 点云精度 

分 类 号：O435[机械工程—光学工程]