The climbing sensor: 3-D modeling of a narrow and vertically stalky space by using spatio-temporal range image

In this paper, we propose a novel type of 3D scanning system named 'climbing sensor'. This system has been designed for scanning narrow and vertically stalky spaces, which are hard or extremely inefficient to scan by commercial laser range scanners due to their dimensions and limitation of FOVs. The climbing sensor equips a platform with two line scanners on a lift, and they scan through the whole target while the lift moves downwards along a ladder. One scanner is for scanning the target, which scans horizontally as the lift moves vertically, and the other scanner is for localizing the platform, which scans vertically. By using spatio-temporal range image acquired from the vertical scanning, we can accurately calculate the speed of the moving platform, with which a correct 3D model can be constructed from horizontal scans. We applied this scanning system to the Bayon Temple in Cambodia as a part of our digital archiving project of cultural assets. The scanning results proved that the system gives a sufficiently accurate 3D model and the effectiveness of our proposed system and speed estimating process.