Abstract: Aimed at the situation when the traffic flow is very big，and the distance between vehicles is so small that the vehicles extracted by background subtraction cannot segment in real-time at a crossing in intelligent transportation system，a novel method of moving vehicles monitoring based on road interspace is proposed.The background is estimated by the method of optical flow computation，using the district calculated realize the simplification of the road information，the behavior what vehicle transgress the line to overtake another car is judged out according to the state of the interspace transfer based on the finite state machine model.Experiment shows that this method is able to monitor the behavior of the vehicles in real-time when the situation is complicated at the crossing，at the same time it can be a very good solution of the monitoring the behavior of the vehicles with illumination variation and noise interference.

Key words: moving vehicles monitoring, road interspace, optical flow, finite state machine

摘要： 在智能交通系统中，针对交叉路口当车流量非常大、车辆之间间距太小，不能对背景差分提取的车辆实时地分割这种情况，提出了一种新的基于道路空隙检测的运动车辆监控方法。基于光流场计算估计出背景，利用分区计算实现了对路面信息的简化，基于有限状态机的模型根据道路空隙状态的迁移判断出车辆的越线超车行为。研究结果表明：此方法能实时监控交叉路口复杂情况时的车辆行为，同时能很好地解决光照变化、噪声干扰情况下的车辆行为监控。

关键词: 运动车辆监控, 道路空隙, 光流场, 有限状态机