ISVR

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ISVR

• Lecture 3
• Intro to VR concepts

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What is Virtual Reality

• emulating the real world
• making an electronic world seem real
• Being able to interact with the electronic
  representation
• moving within the world
• manipulating objects in the world

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types of VR

• desktop collaboration
• video image on screen
• computer tools - may be web-based
• video of room/work in progress
• see others work projected on your desk!
• immersive VR
• helmet/goggles, data glove
• Augmented VR
• Projected images
• physical world/VR mixes
• Interaction between VR and external device

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Augmentation
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Feedback mechanisms in VR
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VR headsets

• small TV screen for each eye
• slightly different angles
• 3D effect

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Head-Mounted Displays
Head set field-of-view varies Software
configured to map to tracked environment Stereo
enhances perception
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binocular/stereo vision
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Active Stereo
Images projected simultaneously for left and
right eye. Image is sent alternateley to match
left and right shuttering.
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Anaglyphic Stereo
Walls screen0 ColorMask screen0 left R ColorMask
screen0 right GB
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inside VR

• scenes projected on walls
• realistic environment
• hydraulic rams!
• real controls
• other people

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Curved-Screen Systems
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Curved-Screen Systems
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VR Cave
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Me in the Cave
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Crumbs

• General viewing tool for regularly gridded 3D
  scalar data in the CAVE. Developed to trace and
  measure 1D fibers

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Crumbs Environment
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Color Map Adjustment
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Opacity Adjustment
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Spline Plane
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Structure of Vorticella convallaria
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How does VR work

• we live in a 3D world
• We have developed many methods to make sense of
  the world around us
• VR techniques have to try to recreate these
  methods

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2D images can be confusing
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shadows and high lighting create the illusion of
3D
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but which is closer?
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occlusion
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Blue hazing with distance

• look at a distant hill or building
• fuzzy, less contrast, bluish tinge
• scattering effect of air
• brains get used to it
• blue objects seem further away
• red ones closer
• use in visualisation and VR (also used in garden
  design!)

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Perspective and Z-buffering

• Objects appear smaller further away
• Zero-point
• Uses Z co-ordinate to compute
• Relative position
• Occlusion

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Depth of field

• Further away objects become hazier
• Focus attention on nearer objects
• Occurs naturally but must be added to virtual
  environment

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Volume Rendering

• Texture Mapped

• Ray Traced

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Involves the senses

• sight
• visual realism, 3D effects shadows, etc.,
• sound
• surround sound, sub-seat woofers etc.
• touch
• feedback from(and to) touch-sensitive gloves

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Track the scene from one point...
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To another view
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Translation
Three degrees of Freedom in x, y, and z plane
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Six degrees of freedom
3 degrees of freedom correspond to the
rotational movement about each of the axes Pitch
Roll Yaw
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Scaling
Multiply one or more components of the line
vectors
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VRML file format

• filename (URL) ends ".wrl
• c.f. .html, .gif, .jpg etc.
• VRML 1.0 first line vrml 1.0 ascii
• VRML 2.0 first line vrml 2.0 utf8
• can have binary versions too

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contents of VRML file

• one or more nodes
• general format DEF object objecttype
  fieldname value . . .
  
• or simply objecttype
  fieldname value . . .

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sphere
VRML V1.0 ascii Sphere radius 1
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add colour
VRML V1.0 ascii Separator
groups things together Material
diffuseColor 1.0 0 0
red green blue Sphere radius
1
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a cone
VRML V1.0 ascii Separator Material
diffuseColor 0 0 1 bright blue
Cone height 3
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put them together ...
VRML V1.0 ascii Separator Separator
for sphere Texture2 filename
"big_man.jpg" Sphere radius 1
Separator for cone Material
diffuseColor 0 0 1 bright blue
Cone height 3
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applications

• Simulation
• Learning
• Modeling Behavior
• Games
• Art
• CAD

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Optical Tomography
David Brady Electrical and Computer
Engineering UIUC
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Argus
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Argus

• 64 cameras in 14 diameter, 8 tall cylinder
• 32 node dual processor Beowulf Linux cluster
• Cameras acquire 64 images in parallel at 60 Hz,
  synchronized and calibrated
• Computed data includes
• 3D computed tomography data volumes
• Stereo pairs computed for any viewpoint in volume
• Storing images on disk allows control over time
  dimension

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Argus in Action
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TWR