2 - Computer Hardware and Software
Video Display Devices
Storage Tube Display
made of three cells containing xenon and neon gas
vertical electrodes create unique grid to locate cell positions
each cell is ionized when a voltage difference is applied to intersecting
current creates a rapid flow of charged particles, which stimulates the gas
atoms to release photons of ultraviolet light
the phosphor coated on the inside wall of the cell.
(Pictures from: "How
Plasma Displays Work")
molecules that align themselves in crystalline structures in the absence of
external force rearranges them as if they were a liquid
crystals respond to heat or electromagnetic forces
LCDs used as
or crystalline state, LCDs rotate the polarization of light by 90 degrees.
presence of an electric field, LCDs behave like a liquid and align their
electrostatic charges with E field.
Augmented Display Systems
Definition - VR is a computer generated, interactive,
three-dimensional environment in which a person is immersed.
- Requires a high performance computer graphics
system to provide an adequate level of realism.
- The virtual world is interactive. A user requires real-time
response from the system to be able to interact with it in an effective
- The last point is that the user is immersed in this
virtual environment. This usually means that the user wears a head
Virtual Reality Interface Devices
HMD - head mounted
known approach to VR
with head tracking
binocular view of the virtual world often with stereo audio
virtue of tracking the viewing position (the head) and orientation in the physical
world, the view and perspective of the virtual are consistent with what
one would experience in the physical world from the same actions.
some means of input, such as a dataglove or some other high degree of
freedom input to support interaction with the displayed virtual
display, much like a pair of glasses that provides a view into the virtual
physical form of these “glasses” can range from something on the scale of
a motorcycle helmet to a pair of sunglasses
variety in display quality
is to provide the widest field of view at the highest quality and with the
least weight and at a reasonable cost.
- HMDs cover eyes
- Virtual world seen at the expense of the physical.
- Users cannot directly see:
- their hands or the devices that they are
- objects or other people who are in their immediate
- Some representation of physical world entities
must appear in the virtual
- Mount one or more video cameras onto the HMD and
feed the signals to the displays
Cave based VR
functions within a room on which one or more of the surfaces (walls, floor,
ceiling …) is the display
or all of the walls of a room are rear-projection stereo displays
wears glasses to enable viewing of stereo images
glasses are transparent, one can see the physical as well as the virtual
generated objects appear to enter into the physical space of the Cave
itself, where the user can interact with them directly
head position is tracked within the Cave so that what is displayed
preserves proper perspective, etc., in adapting to movements and change of
location of gaze
- Two people in cave - both are viewing the same
displays, preventing each from own “point of view.”
- Both viewers look at different things and
different directions, but do so as if from the perspective of the current
location of the head tracker.
mechanism for interacting with what is scene.
1992/93 - EVL's
Cruz-Neira, Sandin, DeFanti, Kenyon and Hart
Electronic Visualization Lab - University of Illinois at Chicago Circle
Immersive VR Environment
theater 10x10x9 feet, made up of three rear-projected screens for walls
and a reflective projection for the floor.
resolution, high bandwidth, short persistance CRT projectors throw
full-color workstation fields (1024x768 stereo) onto the screens, giving
approximately 3,000 linear pixel resolution to the surrounding composite
audio provides a sonification capability to multiple speakers.
head and hand orientation and position are aquired using an Ascension
tracking system with tethered electromagnetic sensors.
LCD stereo shutter glasses are used to separate the alternate fields going
to the eyes.
InfiniteReality Engine is used to create the imagery that is projected
onto the walls and floor.
Cabin - Fully enclosed cave
Image Construction : 5 - 6 Cameras
Domes and Walls
seats, zenith position.
projector orientations .
goal is to fill peripheral vision.
aspect ratio format
Elumens Visionstation (VS) - Hemispherical Display
Elumens Visionstation (VS3)
Elumens Visionstation (VS3)
Depth: 8'-10" (106")
Height: 7'-9" (93")
Width: 11'-4" (136")
Panoramic - Curved Walls
use RGB projectors (Varing focal depth)
blending (On computer or with video hardware)
Trimension (others - Barco)
- How to synchronise multiple devices (Computer, DVD)
- Multiple pipe graphics cards (Cost)
- Seams between walls (Aligned, edge blending)
- Front vs back projection (Space)
Three Wall - CAEV - Melbourne
Two Wall - PortaWedge - Melbourne
Tables, Desks, Single Screens
Immersadesk 2 - EVL
The Grip Project - UNC Chapel Hill - Molecular Visualization
The NanoManipulator - UNC Chapel
Responsive Workbench - 1993
interactive workspace originally developed by Wolfgang Krueger at GMD
stereoscopic images are projected onto a horizontal tabletop display
surface via a projector-and-mirrors system, and viewed through shutter
glasses to generate the 3D effect
6DOF tracking system tracks the user's head, so that the user sees the
virtual environment from the correct point of view.
pair of gloves and a stylus, also tracked by the system, can be used to
interact with objects in the tabletop environment.
Low Cost Stereo Table - Pace University (CAM)
Cubby - Delft
Mount Fuji Stereo Pairs
Cross Eyed Viewing
5DT HMD 800
Display Resolution: 800x600x3(rgb)
pixels - Full SVGA
Optics Field of View: 28 (H)
x 21 (V) degrees
Type: Sennheiser HD 25 closed
Frequency Responce: 16Hz -
Glasses (Active Stereo)
Crystal Eyes (Stereographics )
Glasses (Passive Stereo)
Dresden 3D (also Stereographics
and others) - 15" - 18"
MultiMo3D , Heinrich-Hertz-Institut für Nachrichtentechnik, Germany
Principles and prototype of a 50-inch projection-type dual lenticular screen
Volumetric Display -
and Display Type
10" diameter spherical image
- Swept-screen multiplanar volumetric display
- Autostereoscopic: no viewing goggles
- Volume-filling imagery
- Supports many simultaneous viewers – no
Tracker - Head
position and Orientation
- Determines viewpoint of
- tracking of orientation angles
- move up, down, side to side, and rotate
(yaw, pitch and roll)
Datagloves - Hand position and orientation
status of user's fingers
Data Glove 5 (www.5dt.com )
Measures each finger flexure and the
orientation (pitch and roll) of the user's hand
Haptics - Force Feedback
Other Input/Output Devices
Create a 3-D
model of object
model into thin layers -- typically five to 10 layers/millimeter
printer's laser "paints" one of the layers, exposing the liquid
plastic in the tank and hardening it
drops down into the tank a fraction of a millimeter and the laser paints the
repeats, layer by layer, until your model is complete
Mpeg Movie of part
Printing – (e.g. Z-Corp )
3D Printer spreads a thin layer of powder
- An ink-jet
print head prints a binder in the cross-section of the part being created
build piston drops down, making room for the next layer, and the process
part is finished, it is surrounded and supported by loose powder, which
is then shaken loose from the finished part.
Commands -> APIs
-> World -> Normalized -> Device
purpose graphics packages provide:
– I/O, attributes, transformations, viewing
primitives – building blocks of images
– properties of images
OpenGL – http://www.opengl.org/
Web3D – www.web3d.org