Crowd Simulation (eBook)

Daniel Thalmann, Soraia Raupp Musse (Autoren)

eBook Download: PDF

2012 | 2nd ed. 2013
XV, 296 Seiten
Springer London (Verlag)
978-1-4471-4450-2 (ISBN)

Infos

Research into the methods and techniques used in simulating crowds has developed extensively within the last few years, particularly in the areas of video games and film. Despite recent impressive results when simulating and rendering thousands of individuals, many challenges still exist in this area.

The comparison of simulation with reality, the realistic appearance of virtual humans and their behavior, group structure and their motion, and collision avoidance are just some examples of these challenges. For most of the applications of crowds, it is now a requirement to have real-time simulations - which is an additional challenge, particularly when crowds are very large.

Crowd Simulation analyses these challenges in depth and suggests many possible solutions. Daniel Thalmann and Soraia Musse share their experiences and expertise in the application of:

·         Population modeling

·         Virtual human animation

·         Behavioral models for crowds

·         The connection between virtual and real crowds

·         Path planning and navigation

·         Visual attention models

·         Geometric and populated semantic environments

·         Crowd rendering

The second edition presents techniques and methods developed since the authors first covered the simulation of crowds in 2007. Crowd Simulation includes in-depth discussions on the techniques of path planning, including a new hybrid approach between navigation graphs and potential-based methods. The importance of gaze attention - individuals appearing conscious of their environment and of others - is introduced, and a free-of-collision method for crowds is also discussed.

Inhalt

Crowd Simulation 3
Preface 6
Acknowledgements 8
Contents 9
Chapter 1: Introduction 14
1.1 Requirements and Constraints for Crowd Modeling 15
1.2 Crowd Simulation Areas 16
References 17
Chapter 2: State-of-the-Art 21
2.1 Crowd Dynamics 22
2.2 Sociological Models of Crowds 22
2.3 Crowd Simulation 23
2.4 Behavioral Animation of Groups and Crowds 24
2.5 Crowd Management Training Systems 27
2.6 Group Behavior in Robotics and Arti?cial Life 28
2.7 Environment Modeling for Crowds 28
2.7.1 Environment Models 28
2.7.2 Path Planning 29
2.7.3 Collision Avoidance 31
2.8 Crowd Rendering 32
2.9 Crowds in Non-real-time Productions 34
2.10 Crowds in Games 35
2.11 Crowd Scenario Authoring 36
References 37
Chapter 3: Modeling of Populations 43
3.1 Introduction 43
3.2 Creative Methods 44
3.3 Body Shape Capture 45
3.4 Interpolated Techniques 46
3.5 A Model for Generation of Population 48
3.5.1 De?nition of the Initial Data 50
3.5.2 Choice of a Template 50
3.5.3 De?nition of New Somatotypes 50
3.5.4 Calculation of In?uence of Sample Somatotypes 51
3.5.5 Calculation of Mesh Variation 52
3.5.6 Body Parts' Deformation 53
3.5.7 Results and Discussion 55
Microscopic Analysis 55
Macroscopic Analysis 58
3.6 Using Computer Vision to Generate Crowds 58
3.6.1 A Model for Generating Crowds Based on Pictures 59
Skeleton Initialization 60
Image Segmentation 61
Learning the Color Model 62
Finding the Silhouette 63
Silhouette Processing 65
3D Pose Identi?cation 66
Virtual Human Reconstruction 67
3.6.2 Results 68
3.7 Crowd Appearance Variety 69
3.7.1 Variety at Three Levels 70
3.7.2 Color Variety 71
Principles of the Method 72
HSB Color Spaces 73
The Need for Better Color Variety 74
Segmentation Maps 75
Principles of Segmentation 75
Color Variety Storage 77
3.7.3 Accessories 78
Simple Accessories 80
Complex Accessories 81
Loading and Initialization 82
Rendering 83
Empty Accessories 85
Color Variety Storage 87
Scalability 87
3.8 Final Remarks 90
References 90
Chapter 4: Virtual Human Animation 93
4.1 Introduction 93
4.2 Related Work in Locomotion Modeling 94
4.2.1 Kinematic Methods 94
4.2.2 Physically Based Methods 95
4.2.3 Motion Interpolation 96
4.2.4 Statistical Models 98
4.3 Principal Component Analysis 99
4.3.1 Motion Capture Data Process 99
4.3.2 Full-Cycle Model 100
Input Data 100
Main PCA 100
4.3.3 Motion Extrapolation 102
Second PCA Level (Sub-PCA Level 1) 103
Third PCA Level (Sub-PCA Level 2) 104
4.4 Walking Model 105
4.4.1 Motion Interpolation and Extrapolation 105
4.5 Motion Retargeting and Timewarping 107
4.6 Motion Generation 110
4.6.1 Speed Control 110
4.6.2 Type of Locomotion Control 111
4.6.3 Personi?cation Control 111
4.6.4 Motion Transition 112
4.6.5 Results 112
4.7 Animation Variety 114
4.7.1 Accessory Movements 115
4.8 Steering 116
4.8.1 The Need for a Fast Trajectory Control 116
4.8.2 The Seek and Funneling Controllers 117
4.9 Final Remarks 119
References 119
Chapter 5: Behavioral Animation of Crowds 123
5.1 Introduction 123
5.2 Related Work 123
5.3 Crowd Behavioral Models 126
5.3.1 PetroSim's Behavioral Model 126
Knowledge 127
Status 127
Intentions and Decision Process 128
Simplifying the FSMs 129
An Example of FSM 129
Results 131
5.3.2 A Physically Based Behavioral Model 132
Interaction with Environment 133
Agents' Perception 134
Agents' Decision and Action 135
Results 137
5.4 Crowds Navigation 138
5.4.1 Robot Motion Planning 139
Discrete Motion Planning 139
Exact Motion Planning 140
Sampling-Based Methods 140
Reactive Methods 141
Multiple Robots 141
5.4.2 Crowd Motion Planning 141
Models for Safety Applications 142
Models for Entertainment Applications 143
Models for Virtual Reality Applications 145
5.4.3 A Decomposition Approach for Crowd Navigation 146
Objectives 146
Navigation Graphs 148
Path Planning with Variety 150
Scalable Simulation 152
5.4.4 An Hybrid Architecture Based on Regions of Interest (ROI) 154
5.5 A Collision Avoidance Method Based on the Space Colonization Algorithm 157
5.5.1 The Crowd Model: Biocrowds 158
Input 159
Initialization 159
Computation of the Motion Direction 159
Computation of the Velocity Vector 161
Elimination of Collision Between Finite-Sized Agents 161
5.5.2 Experimental Results 162
Impact of the Density of Markers 162
The Shape of Trajectories 164
Collision Avoidance 164
The Stopping Effects 167
Interactive Crowd Control 168
5.6 Gaze Behaviors for Virtual Crowd Characters 169
5.6.1 Simulation of Attentional Behaviors 170
Attention Models 170
5.6.2 Gaze Behaviors for Crowds 171
Interest Points 171
5.6.3 Automatic Interest Point Detection 172
5.6.4 Motion Adaptation 173
Spatial Resolution 174
Temporal Resolution 175
5.7 Final Remarks 176
References 176
Chapter 6: Relating Real Crowds with Virtual Crowds 181
6.1 Introduction 181
6.2 Studying the Motion of Real Groups of People 181
6.2.1 Crowd Characteristics 181
6.2.2 Crowd Events 184
6.2.3 Parameters for Simulating Virtual Crowds Using Real Crowd Information 185
6.2.4 Simulating Real Scenes 185
First Sequence: People Passing Through a Door 186
Second Sequence: People Waiting and Entering the Train 188
6.3 Sociological Aspects 189
6.4 Computer Vision for Crowds 191
6.4.1 A Brief Overview on People Tracking 191
6.5 An Approach for Crowd Simulation Using Computer Vision 193
6.5.1 Using Computer Vision for People Tracking 194
6.5.2 Clustering of Coherent Trajectories 196
6.5.3 Generation of Extrapolated Velocity Fields 197
6.5.4 Simulation Based on Real Data 198
6.5.5 Some Examples 200
6.6 Final Remarks 202
References 203
Chapter 7: Crowd Rendering 206
7.1 Introduction 206
7.2 Virtual Human Representations 207
7.2.1 Human Template 207
7.2.2 Deformable Mesh 207
7.2.3 Rigid Mesh 209
7.2.4 Impostor 209
7.3 Architecture Pipeline 210
7.3.1 Human Data Structures 212
7.3.2 Pipeline Stages 214
7.4 Motion Kits 222
7.4.1 Data Structure 222
7.4.2 Architecture 224
7.5 Database Management 226
7.6 Shadows 227
7.7 Crowd Patches 229
7.7.1 Introduction 229
7.7.2 Patches and Patterns 230
Patches 230
Patterns 231
7.7.3 Creating Patches 231
Patterns Assembly 232
Static Objects and Endogenous Trajectories 232
Exogenous Trajectories: Case of Walking Humans 232
7.7.4 Creating Worlds 233
Assembly of Patches 233
Patch Templates 234
7.7.5 Applications and Results 235
Results 236
7.8 Final Remarks 237
References 237
Chapter 8: Populated Environments 239
8.1 Introduction 239
8.2 Terrain Modeling 240
8.2.1 Plants and Lakes 242
8.2.2 Sky and Clouds 243
8.3 Generation of Virtual Environments 243
8.4 A Model for Floor Plans Creation 245
8.4.1 Treemaps and Squari?ed Treemaps 246
8.4.2 The Proposed Model 248
Including Connections Among the Rooms 249
Including Corridors on the Floor Plans 250
3D House Generation 252
8.4.3 Results 253
8.5 Informed Environment 256
8.5.1 Data Model 259
8.5.2 Topo Mesh 261
8.6 Building Modeling 263
8.7 Landing Algorithms 263
8.8 Ontology-Based Simulation 264
8.8.1 Using Ontology for Crowd Simulation in Normal Life Situations 266
8.8.2 Applying Ontology to VR Environment 267
8.8.3 The Prototype of UEM 267
8.8.4 Simulation Results 270
8.9 Real-Time Rendering and Visualization 271
8.10 Implementation Aspects 273
8.11 Final Remarks 273
References 274
Chapter 9: Applications: Case Studies 277
9.1 Introduction 277
9.2 Crowd Simulation for Virtual Heritage 277
9.2.1 Virtual Population of Worshippers Performing Morning Namaz Prayer Inside a Virtual Mosque 278
System Design 278
Scenario Creation 279
9.2.2 Virtual Roman Audience in the Aphrodisias Odeon 281
Crowd Engine Resume 281
High-Fidelity Actors 282
Scenario Authoring 283
Audience Placement 283
9.2.3 Populating Ancient Pompeii with Crowds of Virtual Romans 284
Semantics to Behavior 286
Long Term vs Short Term Behaviors 287
Results 287
9.3 Immersion in a Crowd 288
9.4 Crowdbrush 289
9.4.1 Brushes 291
Scenario Management 293
Scripting 293
Results 295
9.5 Safety Systems 296
9.6 Olympic Stadium 297
9.7 Final Remarks 300
References 300
Book Contribution 302
Index 304

Produkt-Details

• Erscheint lt. Verlag: 3.10.2012
• Zusatzinfo: XV, 296 p. 175 illus., 147 illus. in color.
• Verlagsort: London
• Sprache: englisch
• Themenwelt: Mathematik / Informatik ► Informatik ► Grafik / Design
• Themenwelt: Mathematik / Informatik ► Informatik ► Software Entwicklung
• Themenwelt: Mathematik / Informatik ► Informatik ► Theorie / Studium
• Themenwelt: Sozialwissenschaften ► Soziologie
• Schlagworte: Animation • Modeling • Motion Capture • Rendering • Textures • virtual crowds • Virtual Population
• ISBN-10: 1-4471-4450-3 / 1447144503
• ISBN-13: 978-1-4471-4450-2 / 9781447144502