Automatically extracting contours of cross-sections from 3D point clouds of tunnel

作者：Wang Zihao^*; Lan Qiuping; Wang Ermin

来源：International Conference on Advances in Mechanical Engineering and Industrial Informatics (AMEII), 2015-04-11 to 2015-04-12.

• 3-d laser scanning point clouds
• curving tunnel
• central axis
• section cutting
• Delaunay triangulation

For 3-d laser scanning point clouds of an expressway tunnel, a method of automatically extracting complete contours of cross-sections from them is proposed. By taking advantage of abundant normal vectors embedded in point clouds, this method can accurately compute the central axis of the tunnel and build a reference cylinder surface coaxial with the tunnel. To rebuild the surface model for tunnels, a cylindrical projection is used to map all point clouds into a 2-d space firstly, and an improved 2-d Delaunay algorithm which can deal with the border-less circumferential angles is subsequently employed to construct the triangulated mesh from projection points in this two-dimensional space. Following the one-to-one mapping from the original point cloud to the projection point set, a corresponding 3-d triangulated mesh of the original point cloud is finally constructed in accordance with the 2-d triangulation result. By intersecting 3-d triangular mesh of tunnel with cross sections perpendicular to the tangential direction of axis, a series of contours are generated at the specified locations. For the curved tunnel, this method can adjust the direction of sections finely to make them always suitable for the constant change of tunnel direction. At the end of this paper, the experimental result demonstrate the effectiveness and high efficiency of this method by the use of the point clouds acquired from a real highway tunnel.

• 出版日期2015
• 单位河海大学