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。 According to the relationship between the datum plane and the normal vector of the point cloud in the inner wall of the tunnel and the ground, an algorithm of automatically extracting the point cloud data of the tunnel inner wall slice is proposed. The algorithm uses three-dimensional laser scanning of the tunnel wall point cloud data to calculate the normal vector, according to the orthogonal least square fitting of the tunnel ground, using the reference plane and the vertical plane and the reference point and the inner wall point cloud normal vector parallel The relationship between the best reference plane search, through the search to the reference plane slice cloud extraction. This algorithm can automatically get slice point cloud without target. The geometric parameters such as the center of gravity of the tunnel, the center of gravity and the distance from the center of gravity to the top of the tunnel can be calculated by slicing. The geometrical parameters of the tunnel can be used to monitor the change of the inner wall of the tunnel at any time. The comparison of the tunnel slices in different periods can realize the deformation of tunnels in different sections.