Three-dimensional tunnel reconstruction method based on laser scanning

Aiming at the high cost of tunnel surveying and mapping, the long time spent in the field, and the blind spots in the field of view when registering point clouds in the interior, this paper designed a measurement system based on lidar and camera data acquisition. First, the lidar is used to scan the cross section of the tunnel to obtain the geometric information of the inner wall of the tunnel. Secondly, the camera is used to observe the image information of the visual markers, and the EPNP algorithm is used to obtain the pose information of the camera. Then according to the external parameters calibrated by the camera and lidar and the pose information of the camera, the point cloud data measured by the lidar is normalized to complete the point cloud data splicing. Experimental results show that this method has the advantages of high degree of automation, comprehensive data, and high degree of visualization, and can meet the needs of three-dimensional reconstruction and quantitative analysis of long and narrow tunnels.