3D Digital Ohashi Junction: Fast Modeling of Large-Scale and Complex Road Structure under No GPS Coverage

Abstract

Ohashi Junction in Metropolitan Expressway is a road tunnel connecting underground and a skyway with quite complex structure, which started to be opened to traffic in March 2010. It is composed of elliptical double loops with four-layered storey, where the one-round distance of the loop is about 400 m. A precise 3-D geometric model of such a road structure can be a basic information for any purposes, such as verifying traffic safety measures, etc. We tried and succeeded to construct its dense 3-D model without using any external positioning devices such as GPS and gyro sensor. We equipped a laser range scanner on the roof of the scanning vehicle, and repeated by turns to make a scan with stationary state, and to move forward. The scanned data are optimally aligned by geometric processing so that they compose a whole structure. The time needed for the manual process was less than a day for one-way direction.