Fundamental study for real-time detection of sudden displacement by high-speed laser scanner

Abstract

Change detection is one of the most basic techniques using terrestrial laser scanner and many applications have been studied. High-speed laser scanner has some potential for real-time detection of sudden displacement. One of such new techniques is the detection of sudden displacement of tunnel face surface. In mountain tunnel excavation work, numerous accidents resulting from rock mass falls from a part of the face surface have been reported. It is known that the face surface suddenly displaces by a few millimetres or a few centimetres just before collapse. Detecting such small displacements in real-time enables urgent evacuation of construction workers to their safety. In this paper, we propose a new approach for the real-time detection of sudden small displacements using high-speed 3D laser scanner. Compared to previous works, our approach has several advantages such as the scanning area is large enough for capturing the entire face surface, and the installation of physical targets on the surface is not required. In addition, the scanning frequency of HDL-32e is high up to 20 Hz, and is thus suitable for real-time detection. Experimental results show a certain potential of the proposed system of the practical use in real tunnel construction site.