Foreword xv Preface xvii 1 Future Directions for XR 2021-2030: International Delphi Consensus Study 1 Jolanda G. Tromp, Gabriel Zachmann, Jerome Perret and Beatrice Palacco 1.1 Introduction 2 1.2 XR and the Delphi Study Forecast 4 1.3 Key Enabling R&D Prerequisites, Concerns and Targets 15 1.4 Future Research Agenda and Roadmap 21 1.5 Near-Term Challenges 26 Acknowledgments 31 References 31 2 Digital Narratives in Extended Realities 35 Luis Emilio Bruni, Nele Kadastik, Thomas Anthony Pedersen and Hossein Dini 2.1 Introduction 36 2.2 XR and Interactive Digital Narratives (IDN) 37 2.3 Domains of Applications 47 2.4 Future Perspectives 52 References 55 3 Haptic Interfaces 63 Jerome Perret 3.1 Introduction 63 3.2 State-of-the-Art 65 3.3 Scientific and Technological Challenges 66 3.4 Application-Specific Challenges 69 3.5 Future Research Agenda and Roadmap 71 References 73 4 Immersive Sound for XR 75 Arcadio Reyes-Lecuona, Tifanie Bouchara and Lorenzo Picinali 4.1 Introduction 75 4.2 Immersive Audio Rendering for XR 77 4.3 Technological Challenges 81 4.4 Envisioning Applications 88 4.5 Future Research Agenda and Roadmap 94 Acknowledgments 96 References 96 5 Visual Interfaces in XR 103 Rubén Mohedano and Julio Chaves 5.1 Introduction 103 5.2 Definitions 104 5.3 Visual Interfaces Building Blocks 105 5.4 Visual Interfaces in VR 108 5.5 Visual Interfaces in AR 119 5.6 Future Research Agenda and Roadmap 128 References 132 6 XR and Metaverse Software Platforms 135 Lorenzo Cappannari and Antony Vitillo 6.1 Introduction 136 6.2 Enabling Platforms 138 6.3 Content Platforms 143 6.4 Human-Centered Platforms 146 6.5 Utility Platforms 149 6.6 Application Platforms 152 6.7 Future Research Agenda and Roadmap 154 References 155 7 Human Perception Engineering 157 Evan G. Center, Katherine Mimnaugh, Jukka Häkkinen and Steven M. Lavalle 7.1 Introduction 157 7.2 XR and Human Perception 165 7.3 Future Research Agenda and Roadmap 167 Funding 177 References 177 8 Extended Reality and Artificial Intelligence: Synergic Approaches in Real World Applications 183 Maria di Summa, Vito Reno, Pierluigi Dibari, Gaetano Pernisco, Marco Sacco and Ettore Stella 8.1 Introduction 183 8.2 XR and Artificial Intelligence 186 8.3 Future Research Agenda and Roadmap 189 References 190 9 Extended Reality & The Backbone: Towards a 3D Mirrorworld 193 Jolanda G. Tromp 9.1 Introduction 194 9.2 Critical Uncertainties for the Future of XR 200 9.3 XR and Decentralization: Blockchain Infrastructure 208 9.4 XR and the Backbone: Enabling Critical Functionalities 211 9.5 XR Open Sharing and Interoperability 216 9.6 Future Research Agenda and Roadmap 220 Acknowledgments 223 References 223 10 Human Factors and Ergonomics 229 Marta Mondellini, Vera Colombo, Sara Arlati, Glyn Lawson and Sue Cobb 10.1 Introduction 230 10.2 XR and Human Factors 231 10.3 Future Research Agenda and Roadmap 244 Acknowledgments 248 References 249 11 XR and Neurorehabilitation 257 Sara Arlati and Davide Borghetti 11.1 Introduction 258 11.2 XR and Neurorehabilitation 259 11.3 Future Research Agenda and Roadmap 268 References 273 12 Use of XR’s Technologies for Consumer Behavior Analysis 283 Cristina Gil-Lopez, Jaime Guixeres, Javier Marín-Morales and Mariano Alcañiz 12.1 Introduction 283 12.2 The Concept of Virtual Consumer Experience 284 12.3 A Framework for the Use of XR in Consumer Behavior Research 288 12.4 Future Research Agenda and Roadmap 299 References 301 13 XR for Industrial Training & Maintenance 309 Luca Greci 13.1 Introduction 309 13.2 XR and Industrial Training and Maintenance 311 13.3 Future Research Agenda and Roadmap 316 References 318 14 Use of XR Technologies for the Assessment and Training of Leadership Skills 321 Elena Parra, Mariano Alcañiz, Cristina Giglio and Irene Alice Chicchi Giglioli 14.1 What is Leadership? 322 14.2 Leadership Assessment: Explicit Methods 322 14.3 Leadership Biomarkers: Organizational Neuroscience 323 14.4 Extended Reality Technologies and Leadership Assessment 327 14.5 Future Research Agenda and Roadmap 330 References 331 15 Surgery Applications: Expanding Surgeons’ Capabilities 337 Jose M Sabater-Navarro, Jose M Vicente-Samper, Sofia Aledo and Pedro L. Solarte 15.1 Introduction 337 15.2 XR and Surgery 338 15.3 Future Research Agenda and Roadmap 351 References 352 Index 357

This book offers a comprehensive overview of the technological aspects of Extended Realities (XR) and discusses the main challenges and future directions in the field. This book is important and timely – XR technologies have overcome the 3 main aspects that were holding it back from mainstream adoption: cost, cables, and size. However, there are many aspects of XR technologies that are now going to be explored and developed that still need urgent research in terms of security, privacy, health and safety, long-term effects, addiction risks, and age-related developmental concerns, and the aim of the book is to inform all readers of these open issues and challenges. There are currently a great number of interdisciplinary researchers and developers working in the XR R&D field. Recently, XR technologies moved from the Gartner Hype Cycle onto the Plateau of Productivity on the Gartner Hype Cycle signaling that the fundamental XR technologies are now deemed mature technologies and ready for deployment in a wide variety of application areas. Corroborated by the fact that XR technologies are part of the future Metaverse, a concept that went rapidly mainstream during the time of writing of this book. Roadmapping Extended Reality is divided into two parts: (1) fundamentals and (2) applications. The first part covers the main technological aspects of XR. The chapters in this section review and discuss relevant fundamental concepts of XR, the actual state-of-the-art, and future challenges. The second part of the book focuses on covering a wide range of applications of XR including a future roadmap. All in all, the book offers a snapshot of the state-of-the-art in XR and addresses the needs of a multidisciplinary audience working in both academia and the industry, as well as stakeholders at government agencies and non-profit organizations. Audience This book is aimed at academic and industrial developers, exploring and developing applications in the XR, VR, AR, AI, smart IoT, 4th Industrial Revolution space, including those that are solving technology requirements, human factors, evaluation methodology advances, and ROI investigations.