Urban Safety-orientated Tree-dimensional Crowd Visualization

The increasing urbanization of the world population presents new challenges for decision makers.How to visualize realistic crowd movement is the key point to addressing these challenges,including reducing the crowd evacuation time in complex building environment,preventing congestions in crowd,etc.The research of crowd visualization approaches and technology have been widely studied in the past few years,especially in the fields of computer games and visual effects.But for the research of urban safety-orientated 3D crowd visualization,the results of crowd visualization methods at present have some differences compared with real-world crowd movement,e.g.,the individual intelligence in crowd visualization and behavior diversity.It is of great significance in the field of urban safety to use the crowd visualization to study the movement characteristics and visualize realistic human crowds.Based on the research status of crowd simulation technology,this thesis analyzes the factors influencing crowd movement visualization and carries out a systematic research on urban safety-orientated 3D crowd visualization.The main contents of this thesis are as follows:(1)To solve the problems of low efficiency and poor authenticity of traditional crowd path planning algorithms,a navigation grid algorithm based on crowd density information is proposed.The static environment is first divided into a set of polygonal regions,and the crowd density information is mapped into navigation grid.Combined with density information and the shortest path,the optimal path cost is weighted to help individuals to find the fastest path to their goals.(2)For different ways of emotion contagion,a crowd visualization method using group-based emotion contagion is presented.The crowd is divided into different groups based on individuals’ location distribution and their movement information.The emotion contagion is combined by intra-group emotion contagion,inter-group emotion contagion and the thirdparty emotion contagion.The leader-follower model in group dynamics theory is employed to visualize the dynamics of group members.The third-party emotional transmission is used to suppress the spread of panic and improve the efficiency of crowd evacuation visualization.(3)Aiming at the problem of individual behavior diversity in crowd emergency evacuation visualization,a crowd visualization method based on layered-emotion contagion and dynamic guidance is developed.The emotion contagion process is subdivided into emotion recognition,emotion adjustment and emotion expression.Combined with the improved Torso model,the perception of individual is modeled,and the dynamic manager is introduced to visualize the diversity of individual behavior in emergencies by using the navigation map algorithm based on density information.