电缆隧道切片点云的自动提取及几何参数分析

针对基准面与隧道内壁点云法向量及地面的关系，提出了自动提取隧道内壁切片点云数据算法。该算法利用三维激光扫描的隧道内壁点云数据进行法向量的解算，根据正交整体最小二乘进行隧道地面的拟合，利用基准面与地平面垂直及基准面与内壁点云法向量平行的关系进行最佳基准面的搜索，通过搜索到的基准面进行切片点云的提取。通过该算法可以在无标靶情况下自动获取切片点云。通过切片可以计算隧道内部的重心、重心距及重心到顶面的距离等几何参数，利用计算的几何参数可以随时监视隧道内壁的变化状况。对不同时期的隧道切片进行对比分析便可实现不同地段隧道的变形情况。

Automatically extracted the slice point cloud of the cable tunnel and analysis of geometric parameters

This paper proposed the algorithm of automatically extracting slice point cloud data according to the relationship between the datum and the normal vector of tunnel wall. The algorithm uses the point cloud data of the tunnel wall obtained by the three-dimensional laser for solving normal vector, and fits the tunnel ground according to the Orthogonal total least squares. The relationship that the reference datum is perpendicular to the horizon and parallels to the normal vector of point cloud can be used to seek for the best datum. Through the use of the datum that has been found, the cross-section slice of the point cloud data can be extracted. This method makes it possible to automatically get the datum of cross-section slice of the point cloud data without target. The slice point cloud of the cross-section can quickly be extracted according to the acquired datum, and used to get the geometric parameters.