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  1. 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. 2. Overview of Presentation q Introduction to virtual reality q Overview of practical VR aspects q Overview of VR research projects in biomedicine
  3. 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. 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. 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. 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. 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. 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. 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. 10. Illustration of Virtual Reality real environment real but distant reality virtual environment virtual (artificial) environment
  11. 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. 12. Illustration of Augmented Reality real environment augmented reality real virtual world world
  13. 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. 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. 15. Illustration of Telepresence real environment remote environment virtual fast environment communication is a copy of network the remote environment
  16. 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. 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. 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. 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. 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. 21. VR Research q Modeling of material properties q Human-machine interfaces q Haptic interfaces q Visualization techniques
  22. 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. 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. 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. 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. 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. 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. 28. Conclusion q Virtual reality is a subject of active research q Applications are in many areas of human activity