Tunnel Surface 3D Reconstruction from Unoriented Image Sequences
This provides a practical solution for tunneling personnel to quickly evaluate outbreak quality, though it appears incremental as it applies existing stereo-photogrammetry methods to a specific domain.
The paper tackles the problem of fast 3D documentation of tunnel surfaces during construction by using a single camera to capture images, which are automatically processed into a 3D model for quality assessment within minutes.
The 3D documentation of the tunnel surface during construction requires fast and robust measurement systems. In the solution proposed in this paper, during tunnel advance a single camera is taking pictures of the tunnel surface from several positions. The recorded images are automatically processed to gain a 3D tunnel surface model. Image acquisition is realized by the tunneling/advance/driving personnel close to the tunnel face (= the front end of the advance). Based on the following fully automatic analysis/evaluation, a decision on the quality of the outbreak can be made within a few minutes. This paper describes the image recording system and conditions as well as the stereo-photogrammetry based workflow for the continuously merged dense 3D reconstruction of the entire advance region. Geo-reference is realized by means of signalized targets that are automatically detected in the images. We report on the results of recent testing under real construction conditions, and conclude with prospects for further development in terms of on-site performance.