We used the LiDAR sensor VLP-16 LiDAR Puck with an automatic lifting platform to capture surrounding scenes in 3D. The VLP-16 LiDAR Puck was mounted on a camera stand and placed on a portable automatic lifting platform to increase spatial resolution and complete a 3D cloud point model. Compared with traditional static and dynamic techniques, this method used equipment of considerably lower expense. The study areas included (1) indoor space of the Applied Geomatics Lab and the courtyard of the auditorium at National Chung Hsing University,and (2) the Henglingshan Tunnel. For the test area at the university, this study focused on spatial resolution, point cloud accuracy, and practicality; for the Henglingshan Tunnel, this study attempted to monitor the feasibility of monitoring tunnel leakage.
The results revealed the following. (1) The main reason for point cloud errors was artificial point cloud identification(human error). (2) Distance and error were not positively correlated. (3) The feature objects were difficult to identify from a long distance due to the lower point cloud density. Although high cloud density occurred at a short distance, the effect of human error was stronger. (4) Our method for monitoring tunnel leakage can be effective. We expect to continue improving this VLP-16 technology and hope this method can contribute to the monitoring of soil and water conservation structures.
Key Words: VLP-16, point cloud, tunnel