A probe car for parking-vehicle detection by using laser range sensor

This paper describes a novel method of parking-vehicle detection by using a laser range finder mounted on a probe car. One of the important issues to heavy traffic congestion in Japan is that many vehicles are parked on street and this situation usually decreases the capacity of the street, hence, traffic congestion occurs. Thus it is very important for Japanese road administrators to measure the actual capacity of their road network, including effect of parking vehicles. The method of counting parking vehicles is very simple. A line laser range sensor is vertically mounted on a probe car. As the car runs, we obtain two-dimensional depth image, from which we can reconstruct a set of points in 3D real world. We have developed two kinds of algorithm to count the number of parking vehicles. We have performed outdoor experiments to make sure that our algorithms work good. On the other hand, we have already developed a visualization system for enhanced navigation system: a probe car run in town to obtain various images (textures) of buildings and later we can create a 3-D map of the town with real world texture images. In order to apply this system, we now assume that we have 2-D map of the town. But combining with our new method, we can use 3D range images taken from a probe car instead of given 2-D map. We believe that our measuring method is the first step to town-activity detection.