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Multimedia Communications and Visualization Laboratory

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					 Visualization in Teleimmersive
          Environments

J. Leigh, A. Johnson, M. Brown, D. Sandin, T.
                      DeFanti
    Electronic Visualization Lab, University of
                 Illinois-Chicago


           Ref: IEEE Computer Dec 1999
            Presenter: K. Palaniappan
                        Presentation Overview


   Teleimmersion
   Display technologies
   Networking issues
   Cavernsoft software framework
   Sample applications




Multimedia
Communications and
Visualization
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                             Teleimmersion


   Collaborators at remote sites share the details of a virtual world that
    can autonomously control and evolve computation, query databases
    and gather results
   Collaborative VR - reproduce face-to-face meeting environment
   Teleimmersion - collaborative VR + audio- and video-conferencing,
    data mining, heavy computation




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                         Shared Virtual Enviornments

   Examples:
        part of car design - standing inside engine block
        visualization of severe storm weather simulation - standing inside storm,
        participate in non-physical 3D environments
   Avatars:
        Lifelike computer generated representations (of people, perhaps agents)
        Collaborators enter teleimmersive environment as avatars
   Environment transmits gestures as well as audio and video
   Steering:
        Change parameters of supercomputing simulation interactively and
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         collectively
Communications and      study the impact collaboratively
Visualization
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                                   CAVE


   Cave Automated Virtual Environment (1992)
   Cavern - CAVE Research Network
        A collection of participating industrial and research institutions with
         CAVE, ImmersaDesk VR systems, high performance computing and high
         speed networks
   Around 100 CAVE and ImmersaDesk installations worldwide
   Support for effective collaboration requires:
        New display devices for teleimmersion
      International networking infrastructure

      Software framework for teleimmersion applications
Multimedia
Communications andintegration of CAVEs, ImmersaDesks, other VR devices,
      Seamless
Visualization
         workstations
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                                     Synchronity


   Synchronous vs Asynchronous collaboration
        Nationally dispersed teleimmersive sites vs
        International collaboration with significant time differences
   Continuing virtual world
        One that persists even when the collaborators are not present
        May evolve autonomously
        Different groups of collaborators may share the virtual world at different
         times



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                         Display Technologies

    CAVE vs head mounted displays for VR
        Heavy helmets with liquid crystal displays or CRTs mounted in front of
         eyepieces
    CAVE VR -
          10 x 10 sq ft room with CRT projectors for projecting stereoscopic images
           on walls, floor, ceiling
        Up to 10 users

        Illusion that objects surround user

        Light weight liquid crystal shutter glasses

        Three button wand for 3D interaction

        Electromagnetic tracking system attached to glasses and wand to
           determine location and orientation of user’s head and hands
Multimedia
        SGI and
CommunicationsOnyx to render images from user’s point of view
Visualization
        Well suited for panoramic views
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                          Display Technologies


   ImmersaDesk, ImmersaDesk 2
        Drafting table like systems with stereoscopic projection
        Objects that fit on a desktop - CAD models, biomedical, network
         topologies, battlefield simulation, etc.
   Prototypes of 3 new devices being investigated
   ImmersaDesk3
        42” plasma screen mounted on a conventional office desk
        Vertical to horizontal positions
        Plasma screen generates too much EM noise for head tracking and stereo
         synchronization
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                          Display Technologies


   PARIS - Personal Augmented Reality Immersive System
       Desktop device around an office desk
       Prototyped in a VR environment before construction to study user
        preferences and application requirements for viewing angle geometry
       Semitransparent mirror enables user to see hands and computer rendering
        simultaneously
       Future: Place cameras under the mirrors to track hand location and gesture




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                          Display Technologies




   AccessBot
       Teleconference device that uses life-sized plasma display screen
       High fidelity video- and audio-conferencing
       Robotic camera: pan-tilt-zoom camera that lets remote user look around
        meeting room (zoom gives “augmented” vision capability)
       High speed (wireless) networking
       Equal telepresence with local participants in a meeting
       Prototype NCSA Access Center in Washington, DC
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                                     Networking

   Teleimmersive environments provide testbed for high performance
    networking
        Transmission of extremely large scientific and multimedia datasets
        Latency and bandwidth issues
        Complex distributed data handling - real-time audio and video streams,
         real-time tracker information on position and orientation of participants,
         updates to large multidimensional datasets, rendered geometry
   Multiple connections
       Realtime data & network performance instruments - low latency, low
        bandwidth
      Audio and video - multicast over high bandwidth, low latency

      Models - high bandwidth
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      Smooth interaction - guaranteed QoS
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                                   Networking

   Participants in
        MREN - Metropolitan Research and Education Network midwestern US
        NSF vBNS - Very high performance backbone network service
        Star Tap - Science, technology, and research transit access point for
         international infrastructure
   Teleimmersive applications are only beginning to use these networks




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                           Software Framework


   Current software framework for collaborative VR
        Low-bandwidth commodity Internet
        Massive connectivity involving thousands of simultaneous participants -
         gaming, military simulations
   VR for scientific, manufacturing, information visualization
        Smaller, focused groups
        More demanding realtime streaming data
        Higher volume of engineering, scientific datasets



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                        Software Framework


   Cavernsoft framework
       Many data classes
      Information Resource Broker (IRB) like CORBA’s Object Request
        Broker (OR B)
      Lower overhead than ORB

      Emulate distributed shared memory, message passing system but maintain
        them separately
      TCP, UDP, or multicast

      Persistence of shared memory segments so that client programs can cache
        frequently used data at local sites
      Client-server symmetry using IRB - collection of clients can easily form
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        arbitrary collaborative topologies
Communications and
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                          Software Framework


   Cavernsoft framework
       IRB-based libraries - avatars, audio-conferencing, collaborative interfaces,
        virtual email, model importing, data distribution, 3D manipulation
       Limbo and Tandem - higher level tool organization, source code available
       Example - Users import 3D models into teleimmersive env., Limbo
        distributes datasets to all participants for collective manipulation




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                                   Applications


   VisualEyes
       General Motors
       Import 3D CAD models from Alias into CAVE
       Quick visual inspection then do life-sized design review
       Changes in lighting and materials propagated automatically
       GM extension for transglobal design and manufacturing
       Synchronous and asynchronous access to design that persist, evolve


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Communications and
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                                  Applications


   Virtual Temporal Bone
       UIC Virtual Reality Medicine Lab
       Remote physician teaches medical students about 3D structure and
        function of inner ear
       3D interaction with model between students and instructor
       Remove organs and tissues to reveal inner anatomy




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Communications and
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                                   Applications


   ALIVE
       Architecture Linked Immersive Virtual Environment (Amsterdam Univ)
       Architects in Amsterdam and clients in Chicago use StarTap and
        teleimmersion for navigating 3D CAD models
       Network performance instruments - bandwidth usage, latency, jitter




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Communications and
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                                     Applications


   CAVE6D
       Center for Coastal and Physical Oceanography
       Uses CAVE5D and Cavernsoft
       Vis5D for visualization methods for multidimensional numerical data -
        isosurfaces, contour slices, volume visualization, wind/trajectory vectors,
        image projections
       Extensions - salinity, circulation vectors, temperature, etc.
       Distribute multiple observable dimensions to different users - coordinated
        vs independent displays
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Communications and
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                                  Applications


   TIDE
       Teleimmersive Data Explorer, UIC National Center for Data Mining
      Let collaborators query and access terascale datasets

      CAVE, Immersadesk, workstation users with avatars linked

      Streaming audio between geographically separated sites

      Data flow model on workstation used to construct visualization

      3D tools to manipulate visualizations online

      Offline generation of high resolution stereo animation sequence on remote
        rendering server in background while teleimmersion continues then users
        see animation stream
      Need 3D annotation and recording of discoveries during session
Multimedia
      US DoE and NOAA applications being investigated
Communications and
Visualization
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