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  • 1. Virtual Reality Foundations Sven Loncaric, Ph.D. Faculty of Electrical Engineering and Computing University of Zagreb E-mail: sven.loncaric@fer.hr WWW: http://ipg.zesoi.fer.hr
  • 2. Overview of Presentation q Introduction to virtual reality q Overview of practical VR aspects q Overview of VR research projects in biomedicine
  • 3. Introduction to VR q Foundations of VR s human senses s perception q VR terminology q Technologies enabling VR q VR research areas
  • 4. Human Senses q Senses receive information from outside and inside the body q Senses: s external (receive information about outside environment) s internal (receive information about internal environment) q External senses: s sight, hearing, heat (distance receiving senses) s taste, touch, smell (contact external senses) q Internal senses: hunger, fatigue, pain, thirst
  • 5. Perception q Perception is the process by which we receive and interpret information from the world around us q Senses and brain form the basis for perception s senses receive information from the environment s brain interprets the received information q Perception is not determined only by sensory information but also by knowledge, emotion, and motivation
  • 6. Learning and Perception q The example shows how learning influences the result of perception: PARIS ONCE IN THE UPON A THE SPRING A TIME
  • 7. Deceiving Perception System q Idea: substitute real information received by human senses by artificially generated senses q Consequence: An impression of presence of a person in a virtual environment is created q In this manner we can replace real environment with a virtual environment q The person has impression of being immersed in a virtual environment
  • 8. Virtual Reality q The impression of being present in a virtual environment that does not exist in reality is called virtual reality q The user has impression of presence in that world and can navigate through it and manipulate objects in the world q Current practical restrictions of virtual reality comes from the fact that we are unable to artificially generate sensory stimulus with high fidelity s contact senses are very difficult to mimic (touch, smell, taste)
  • 9. Immersive vs. Non-immersive VR q When computer generated sensory information is accurate the operator has the impression of being immersed into the virtual environment q This is called immersive virtual reality q To create immersive VR a head-mounted display is required so when the user moves the head the view is adjusted accordingly q In non-immersive VR systems user views virtual world through the monitor or the projection screen
  • 10. Illustration of Virtual Reality real environment real but distant reality virtual environment virtual (artificial) environment
  • 11. Augmented Reality q Sometimes it is not necessary to completely replace the real environment with virtual environment q In some applications it is enough to augment the real environment with some elements of virtual environment q This is called augmented reality q Augmented reality = true + virtual reality q Example: wearable computers
  • 12. Illustration of Augmented Reality real environment augmented reality real virtual world world
  • 13. Wearable Computers q Idea: computer should be worn as a watch or a suit q Provide many new applications including virtual reality q US Army uses such systems for maintenance of complex systems q e.g. for service of aviation systems and other vehicles s service image and instructions are superimposed on the real image visible in the transparent display
  • 14. Telepresence q Also called virtual presence q The purpose of a telepresence system is to create a sense of physical presence at a remote location q Telepresence is achieved by generating sensory stimulus so that the operator has an illusion of being present at a location distant from the location of physical presence q Telepresence system extends operator’s sensory- motor facilities and problem solving abilities to a remote environment
  • 15. Illustration of Telepresence real environment remote environment virtual fast environment communication is a copy of network the remote environment
  • 16. Teleoperation q Teleoperation system enables operation at a distant remote site by providing local operator with necessary sensory information to simulate operator’s presence at the remote location q Teleoperation is a special case of telepresence where in addition to illusion of presence at a remote location operator also has the ability to perform certain actions or manipulations at the remote site
  • 17. Technologies Enabling VR q Virtual reality is a combination of several technologies that enable the realization of VR systems: 1. advanced (fast) computers 2. advance computer communication networks 3. human-computer interfaces
  • 18. Realization of VR Systems q Artificial sensory stimulus required for creation of virtual reality are generated by a computer q Input to the computer are parameters of the operator’s physical position and readouts of various human-computer interfaces q Based on the input computer generates required sensory data that is sent to human computer interfaces that create an illusion of immersion in a virtual environment q Fast computer networks enable exchange of information between remote locations
  • 19. Computers for VR q General purpose computers are used with the following requirements: s high processing power for real-time rendering of virtual environments to generate visual stimulus s powerful graphical subsystem for real-time stereo display of rendered virtual environment q Popular platforms include Silicon Graphics, SUN, …, and even PC q Permanent advances in computer technology enable development of more complex VR systems
  • 20. Distributed VR Systems q Distributed VR system consists of several networked computers and one virtual environment q Each computer tracks actions of one user and creates an illusion of user’s presence in the shared virtual environment q All users are present in the same virtual world although they may be physically at distant locations q In this manner it is possible to perform multi-user simulations with interactions between users
  • 21. VR Research q Modeling of material properties q Human-machine interfaces q Haptic interfaces q Visualization techniques
  • 22. Modeling of Material Properties q Force propagation models q Deformable models for tissue modeling q Real-time deformations for simulations q Volumetric elastic models
  • 23. Human-Computer Interfaces q Haptic interfaces are particularly difficult to realize q Force feedback q Tactile, smell, and taste sensors q Physiological and psychological effects of simulators (cyberpathology)
  • 24. Haptic Interfaces q Haptic interfaces are devices that allow human- machine interaction through force and touch q Areas of application include: s telemanipulation (for work in hazardous or challenging settings such as space and microsurgery) s virtual environments (for human operator training, design prototyping, and data visualization)
  • 25. Visualization Techniques q Visualization is important for creating of good visual sensory information q Surface rendering s advantage: hardware acceleration available on general purpose workstations, faster s disadvantage: cannot represent volume interior q Volume rendering s advantage: can represent volume interior s disadvantage: special hardware required for acceleration, slower
  • 26. VR Applications q VR systems enable user activities in the virtual world instead of the real world q VR systems are utilized for: s education s assessment of work skills s training s simulations s 3-D visualizations s computer-aided design s teleoperation and telemanipulation
  • 27. VR Application Areas q medicine q visualizations (in biochemistry, engineering, ...) q complex system design (e.g. fluid dynamics) q mechanical engineering q maintenance i service of complex systems q military applications (flight simulators) q art (visual, musical) q industrial design q games and entertainment
  • 28. Conclusion q Virtual reality is a subject of active research q Applications are in many areas of human activity

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