Experimental Study Of Microscopic Character Of Moving Pedestrian Behavior Based On Image Processing

Recently, while the pedestrian evacuation modeling studies have made great progress, the pedestrian evacuation experimental studies are comparative less. One of most important reasons is that there is no effective tool can be used to extract the experiment data. In this study, a kind of pedestrian tracking technology which was based on Mean-Shift algorithm was introduced to the pedestrian evacuation experiment. With this technology, we can automatically extract the"trajectories"of moving pedestrian. The trajectories can be used to investigate the microscopic behavior characteristics of moving pedestrians such as velocity, density, flow, time gap and their relationships and their macroscopic behavior model. In order to investigate the microscopic behavior characteristics of moving pedestrians, a single-file movement and bottleneck evacuation experiments were conducted in this study.The single-movement experiment shows that the body size difference does not influence the shape of velocity-density relationship, but it may influence its value scope. And this difference does not change the linear relationship of velocity and the reverse of density. When the distance of sequential pedestrians decreases, the oriental people with a smaller body size and a more flexibility of changing their steps are more insensitive to the this decrease, while the western people are more sensitive. When the people's velocity is less than 1.2m/s, the amplitude of people's body oscillation shows a linear decrease as the velocity increase. And when people's velocity is more than 1.2m/s, the amplitude of people's body oscillation do not change. The maximum of amplitude is 13cm. The frequency of moving pedestrians with a free velocity is 2Hz.In the bottleneck evacuation experiment, the statistics about the time gap distribution of bottleneck evacuation have been collected, and the corresponding moving patterns have also been analyzed. What's more, the influence of bottleneck width on the evacuation efficiency has also been studied, and the flow-width relationship should show a"linear increasing, hold steady, linear increasing, hold steady……"trend as the density increases, where this study gives the microscopic mechanism explanation based on the experimental results. And it was pointed out that the weakening of lateral influence of pedestrians is the main factor results in the linear increase and the increase of the number of pedestrian layers will not result in the increase of flow. Finally, the main microscopic pedestrian movement behavior which influences the velocity-density relation during different density range has also been investigated. The results show that during the low and moderate density range, the main behavior is the interference between two consecutive pedestrians. A model depicts this force condition of consecutive pedestrians was also proposed in this study. During the high density, the main behavior is a special pedestrian body arrangement which is a kind of self-organized behavior. This behavior results in that the lateral interference plays a main role. And, during the extreme high density range, the main behavior is"synchronous steps", which is another kind of self-organized phenomena.The results from the pedestrian evacuation experiment in this study can provide important references to the design and analysis of pedestrian evacuation experiment, modeling establishment and validation, as well as evacuation facilities capacity evaluation.