基于点云的弯曲地铁隧道断面提取

Extraction of curved metro tunnel section based on point cloud

三维激光扫描技术已广泛应用于运营期地铁隧道变形监测工作。针对常用地铁隧道中轴线获取方法存在的问题与不足,本文基于地铁隧道点云高程差异,提取隧道拱顶点云并拟合曲线,采用拱顶轴线代替中轴线对弯曲地铁隧道断面进行连续提取。针对传统断面去噪过程复杂、效率低下等问题,改进一种基于隧道断面几何特征的半径滤波去噪算法,且对去噪后的断面点进行椭圆拟合对比。利用武汉某弯曲地铁隧道点云数据进行试验,结果表明,以拱顶轴线代替中轴线提取弯曲地铁隧道断面的方法精度可靠,改进后的断面去噪算法简单高效,能够提高隧道变形监测工作效率。

3D laser scanning technology has been widely used in the deformation monitoring of metro tunnels during the operation period.In view of the problems and shortcomings of common methods for obtaining the central axis of metro tunnel,based on the elevation difference of metro tunnel point cloud,this paper extracts the tunnel crown point cloud and fits the curve,and uses the crown axis instead of the central axis to extract the curved metro tunnel section continuously.Aiming at the problems of complex process and low efficiency of traditional section denoising methods,a radius filtering denoising algorithm based on the geometric characteristics of tunnel section is improved,and the denoised section points are compared by ellipse fitting.The experiment is carried out with the point cloud data of a curved metro tunnel in Wuhan.The results show that the method of extracting the curved metro tunnel section by replacing the central axis with the crown axis is accurate and reliable,and the improved section denoising algorithm is simple and efficient,which can improve the efficiency of tunnel deformation monitoring.