Automated and Efficient Extraction of Highway Tunnel Lining Cross-Sections Using Terrestrial Laser Scanning (TLS)
D-L. Chen, Y-Y. Lu, Y-M. Chen, L. Ma, D-Z Jia, L. Cheng, M-C. Li, D. Hu and X-F. He
Over the past years three-dimensional (3-D) laser scanning technologies play an important role in civil engineering. In particular, man-made structures 3-D spatial information extraction methodology is one of the major fields of application of terrestrial laser scanning technology. In this paper, an automated and efficient method for extracting highway tunnel lining cross-sections using terrestrial 3-D laser scanning system is presented. First, the tunnel point cloud acquired from terrestrial laser scanner is registered based on the control network (CN) method and least-squares optimization, ensures minimization of the target-to-target registration errors. Then the 3-D tunnel point cloud is projected onto a horizon plane, converted to a two-dimensional (2-D) planar image, and skeletonized to estimate the tunnel 3-D centreline. The orientation of tunnel cross-section, which are orthogonal to the centreline, is defined to be in terms of the centreline. Finally, the cross-sectional planes are determined for every interval. The proposed method was implemented on concrete highway tunnel monitoring project on the G25 highway, in Jiangsu Province, China, and proved itself to offer advantages, including detailed description and improved surveying automations and data processing efficiencies.
Keywords: Terrestrial laser scanning (TLS), highway tunnel, tunnel cross-section, point cloud, monitoring, control network (CN), least-squares optimization, civil engineering