基于球形标靶自动提取的大场景三维扫描仪地形测量方法  

Terrain measurement method of large scene 3D scanner based on automatic extraction of spherical target

作　　者：张旭 毛庆洲 徐浩轩 楼梁伟 王晓凯 ZHANG Xu;MAO Qingzhou;XU Haoxuan;LOU Liangwei;WANG Xiaokai(School of Remote Sensing and Information Engineering,Wuhan University,Wuhan 430079,China;Hubei Loujia Laboratory,Wuhan 430079,China;State Key Laboratory of High-speed Railway Track Technology,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;Railway Construction Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]武汉大学遥感信息工程学院,湖北武汉430079 [2]湖北珞珈实验室,湖北武汉430079 [3]中国铁道科学研究院集团有限公司高速铁路轨道系统全国重点实验室,北京100081 [4]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081

出　　处：《测绘通报》2024年第8期13-19,共7页Bulletin of Surveying and Mapping

基　　金：国家重点研发计划(2023YFC3009400);中央高校自主科研项目(2042023kf0221;2042022dx0001)。

摘　　要：针对地面三维扫描仪大点云地形测绘中缺乏可信特征点的问题,本文提出了一种高精度自动定位和提取球形标靶中心的方法。由三维点云获得点云强度图,并将强度图划分为多个子图,利用现有图像处理算法获取子图中候选标靶感兴趣区域(ROI);提出了一种基于一维最大熵改进的Zernike矩亚像素边缘检测算法,从而准确获取每个ROI中候选标靶的像素集合;利用标靶半径和圆球率相关阈值确定可信标靶,将可信标靶的点云交替完成圆球拟合和粗差剔除,得到准确的标靶中心。试验结果表明,直径14.5 cm的球形标靶布设测量范围在80 m内,该算法从点云中提取标靶的成功率达96.7%;基于自动提取球形标靶中心的方法完成扫描坐标系向指定坐标系的转换,其中三项中误差(高程中误差、平面中误差、三维空间误差)均小于1 cm。Aiming at the problem of lack of credible feature points in large point cloud terrain mapping of ground 3D scanner,a method flow of high-precision automatic positioning and extraction of spherical target center is proposed.The point cloud intensity map is obtained from the 3D point cloud,and the intensity map is divided into multiple subgraphs.The candidate target region of interest(ROI)in the subgraph is obtained by using the existing image processing algorithm.An improved Zernike moment sub-pixel edge detection algorithm based on one-dimensional maximum entropy is proposed to accurately obtain the pixel set of candidate targets in each ROI.The credible target is determined by the relevant threshold of the target radius and the sphere rate.The point cloud of the trusted target is alternately performed to fit the ball and eliminate gross errors,and the accurate target center is obtained.The experimental results show that when the measurement range of the target ball with a diameter of 14.5 cm is within 80 m,the success rate of the algorithm to extract the target from the point cloud is 96.7%.Based on the method of automatically extracting the center of the spherical target,the scanning coordinate system is converted to the specified coordinate system,and the mean square error of the three items(elevation mean square error/plane mean square error/3D space error)is less than 1 cm.

关 键 词：大点云 球形标靶 三维扫描仪 ZERNIKE 标靶提取 

分 类 号：P237[天文地球—摄影测量与遥感]