A Method for Detecting the Spacing of Steel Arch Frames in Construction Tunnels Based on Three-Dimensional Laser Technology
Chuanyi Ma, Hongzheng Luo, Chuan Xi Wang, Gaohang Lv · American Journal of Civil Engineering · 2023
The present invention provides a point cloud spacing extraction algorithm for tunnel steel arch frames. This method first calculates the angle between the point cloud of the tunnel steel arch construction section and the adjacent coordinate axis and rotates it so that its axial direction is parallel to the adjacent coordinate axis. Then, the point cloud axial normal vector is calculated, and a threshold is set based on the calculated normal vector to extract the steel arch point cloud. Then, a clustering algorithm is used to extract the single steel arch point cloud, Use the C2C-Distance method based on the kd tree to calculate the closest distance from each point in a single steel arch point cloud to another single steel arch. Take the average value to obtain the distance between the tunnel steel arches, fit the single arch point cloud, fit a spatial circular point cloud, calculate the difference between the single point cloud and the spatial circular point cloud, and extract the excessively distorted part in the single point cloud. This method has good robustness and is suitable for various working conditions of tunnels. It can effectively extract point clouds of steel arch frames and obtain point cloud spacing with millimeter level errors, making it suitable for monitoring tunnel construction quality.