Development of the methods for tracking and behavior understanding of vehicles and pedestrians in urban traffic scenes

上个财政年度，我们开发了一种算法，能够跟踪图像中的刚性物体（如车辆）和柔性物体（如行人）。本财政年度，我们改进了这种跟踪算法，能够获得这些各种类型的运动物体的详细轨迹，并实现了实时系统的原型。另一方面，我们开发了一个基于实验的事件检测系统，主要是在大都市高速公路上进行的。通过应用该算法中每个对象的时空轨迹，该系统采用基于规则的推理方法对交通事件进行分类，首先利用坐标类算子从跟踪结果中提取出每辆车的时空轨迹，然后，行为类算子从图像的时空轨迹中提取车辆的“失速”、“停车”等行为，事件类算子利用图像中车辆的行为信息检测交通事件，综上所述，本文的事件检测系统采用了由坐标类、行为类和事件类三种算子组成的语义层次结构，与人类认知过程有很高的亲和力，可以说同时跟踪车辆和行人的算法开发取得了一定的成功。当涉及到事件检测时，开发了基本算法来识别特别是车辆的行为。我们认为该算法也可以应用于包括车辆和行人的图像，并将继续验证系统的可扩展性。

Last fiscal year, we developed an algorithm which is able to track both rigid objects such as vehicles and flexible objects such as pedestrians in images.This fiscal year, improving this tracking algorithm, we enabled to get detail trajectory of these various types of moving objects, and implemented a prototype of Real-time System.On the other hand, we developed a system which detects events based on experiments mainly conducted on Metropolitan Expressway.By applying the Spatio-Temporal trajectory of each object from the algorithm, this system classifies traffic events by using a rule-based reasoning method.First Coordinate-class operator extracts Spatio-Temporal trajectory of each vehicle from tracking results.Secondly, Behavior-class operator extracts behavior of each vehicle such as "Stall" and "Stop" from the Spatio-Temporal trajectories.Lastly, using behaviors information of vehicles on the image, Event-class operator detects traffic events such as accidents, congestion, etc.As above, our event detection, system utilizes a semantic hierarchy consisting of three kinds of operators (Coordinate-class, Behavior-class and Event-class) and has high affinity with the human cognitive process.So, it can be said that development of algorithm which tracks vehicles and pedestrians simultaneously achieved some positive success. When it came to the event detection, fundamental algorithm was developed to recognize behaviors of vehicles in particular. We consider that this algorithm can also be applied to images including vehicles and pedestrians, and will continue the verification of the system extensibility.