Simulation and calibration of infrastructure based laser scanner networks at intersections

Accident analysis shows that intersections are a focal point for accidents in urban areas. Due to that, traffic monitoring at intersections has attached much attention. A major part of the Ko-PER project, which is part of the research initiative Ko-FAS, promoted by the Federal Ministry of Economics and Technology of Germany, is the infrastructure based perception of all dynamic objects inside an intersection. In this project, a novel system of detecting and tracking objects inside intersections using multiple 4-layer laser scanners is proposed. To reduce occlusions and maximize the observed area the sensors are mounted high over ground-level to achieve a bird´s eye view of the scene. One difference between laser scanners and video cameras is the difficulty to identify the area of the street, which can be observed by laser sensors, especially when the monitored area is plain like roads. Therefore, a realistic 3D simulation of the urban intersection and the laser range scanners was implemented. Based on this simulation, a method to calibrate the sensors was developed. The technique is easy to use and due to the 3D model of the intersection we were able to verify the proposed calibration tool.