Dynamic Structure in Pedestrian Evacuation: Image Processing Approach

Abstract

We show that there exists a typical dynamic arch-shape structure in pedestrian evacuation system governed by the social force model. It is well known that the simulation of pedestrian evacuation from a square room using the social force model shows arch-shape formation and clogging in front of the exit. It is also known experimentally and numerically that an obstacle near the exit could improve the flow rate, but detailed mechanism of this effect is not clear. In this paper, we show the existence of the “dynamic arch”, the typical structure in the long term, by using the social force model and the image processing. The time-averaged image of the system shows us the existence of the typical structure in the system and it can be interpreted as the probability distribution of the arch formation. With this method, we discuss the possible physical mechanism of the effect of an obstacle in the pedestrian system. From the observation of the morphological feature of the arch obtained by the simulation and image processing, we show that the obstacle affects the structure of the arch in three ways. These effects could lead the easy-to-break arch that enhances the flow rate of the system.