08VR

yardbellΤεχνίτη Νοημοσύνη και Ρομποτική

14 Νοε 2013 (πριν από 3 χρόνια και 7 μήνες)

64 εμφανίσεις

Virtual Reality

Advanced multimedia


B.Engg. (Hons) in Computing

Specialism in Multimedia

Advanced Multimedia

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Topic & Structure of the lesson


What is Virtual Reality?


Current limitation


VR Technologies


Immersive VR


Non
-
immersive VR


The Future

Advanced Multimedia

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Learning Outcomes


At the end of this lecture, you should be
able to:


Understand the concept of VR


Understand the technologies of VR


Comparing immersive and non
-
immersive
VR


Identify the limitation of VR



Advanced Multimedia

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Key Terms you must be able to use

If you have mastered this topic,
you should be able to
use the following terms correctly in your assignments
and exams
:


Virtual Reality


HMD


BOOM


CAVE


Shared Virtual Environments


VRML


QTVR




Advanced Multimedia

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What is Virtual Reality?


Virtual reality

(
VR
) is a technology which
allows a user to interact with a computer
-
simulated environment.


Most current virtual reality environments are
primarily visual experiences, displayed either
on a computer screen or through special
stereoscopic displays, but some simulations
include additional sensory information, such
as sound through speakers or headphones.



The simulated environment can be similar to
the real world, for example, simulations for
pilot or combat training, or it can differ
significantly from reality, as in VR games

Advanced Multimedia

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What is Virtual Reality?


To run the most basic VR system one must have
the following:


one or more powerful computers


sensors (or input devices)


display arrangements


virtual environment rendering software


The computer must be powerful enough to render
three
-
dimensional images in real
-
time or the
experience will not be a complete one

Advanced Multimedia

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Currently it is very difficult to create a high
-
fidelity virtual reality experience, due largely to
technical limitations on processing power,
image resolution and communication
bandwidth.


However, those limitations are expected to
eventually be overcome as processor, imaging
and data communication technologies become
more powerful and cost
-
effective over time.


Current limitation

Advanced Multimedia

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A typical HMD houses two
miniature display screens and an
optical system that channels the
images from the screens to the
eyes, thereby, presenting a
stereo view of a virtual world.


A motion tracker continuously
measures the position and
orientation of the user's head and
allows the image generating
computer to adjust the scene
representation to the current
view.


As a result, the viewer can look
around and walk through the
surrounding virtual environment

VR Technologies

Advanced Multimedia

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The BOOM (Binocular Omni
-
Orientation Monitor) is a head
-
coupled stereoscopic display device.


Screens and optical system are
housed in a box that is attached to a
multi
-
link arm.


The user looks into the box through
two holes, sees the virtual world, and
can guide the box to any position
within the operational volume of the
device.


Head tracking is accomplished via
sensors in the links of the arm that
holds the box.




VR Technologies

Advanced Multimedia

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The CAVE (Cave Automatic
Virtual Environment) provides
the illusion of immersion by
projecting stereo images on
the walls and floor of a room
-
sized cube.


Several persons wearing
lightweight stereo glasses can
enter and walk freely inside
the CAVE.


A head tracking system
continuously adjust the stereo
projection to the current
position of the leading viewer.









VR Technologies

Advanced Multimedia

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A variety of input devices like
data gloves, joysticks, and hand
-
held wands allow the user to
navigate through a virtual
environment and to interact with
virtual objects.


Directional sound, tactile and
force feedback devices, voice
recognition and other
technologies are being employed
to enrich the immersive
experience and to create more
"sensualised" interfaces.

VR Technologies

Advanced Multimedia

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Characteristics of Immersive VR


Head
-
referenced viewing provides a natural
interface for the navigation in three
-
dimensional
space and allows for look
-
around, walk
-
around,
and fly
-
through capabilities in virtual environments.


Stereoscopic viewing enhances the perception of
depth and the sense of space.


The virtual world is presented in full scale and
relates properly to the human size.


Immersive VR

Advanced Multimedia

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Realistic interactions with virtual objects via data
glove and similar devices allow for manipulation,
operation, and control of virtual worlds.


The convincing illusion of being fully immersed in
an artificial world can be enhanced by auditory,
haptic, and other non
-
visual technologies.


Immersive VR

Advanced Multimedia

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Shared Virtual Environments


Three networked users at different locations
(anywhere in the world) meet in the same
virtual world by using a BOOM device, a CAVE
system, and a Head
-
Mounted Display,
respectively.


All users see the same virtual environment
from their respective points of view.


Each user is presented as a virtual human
(avatar) to the other participants. The users
can see each other, communicated with each
other, and interact with the virtual world as a
team
.



Immersive VR

Advanced Multimedia

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Immersive VR

Advanced Multimedia

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The term 'Virtual Reality' is also used for
applications that are not fully immersive.


The boundaries are becoming blurred, but all
variations of VR will be important in the future.


This includes mouse
-
controlled navigation through a
three
-
dimensional environment on a graphics
monitor, stereo viewing from the monitor via stereo
glasses, stereo projection systems, and others.


Apple's QuickTime VR, for example, uses
photographs for the modeling of three
-
dimensional
worlds and provides pseudo look
-
around and walk
-
trough capabilities on a graphics monitor.

Non
-
immersive VR

Advanced Multimedia

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In addition to HTML (HyperText Markup Language),
that has become a standard authoring tool for the
creation of home pages, VRML provides three
-
dimensional worlds with integrated hyperlinks on the
Web.


Home pages become home spaces. The viewing of
VRML models via a VRML plug
-
in for Web browsers is
usually done on a graphics monitor under mouse
-
control and, therefore, not fully immersive.


The current version VRML 2.0 has become an
international ISO/IEC standard under the name
VRML97.


Non
-
immersive VR

Advanced Multimedia

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Non
-
immersive VR

VRML with Cortona Browser

Advanced Multimedia

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QTVR allows the creation and viewing of
photographically captured panoramas and the
exploration of objects through images taken at multiple
viewing angles.


It functions as a plugin for the standalone QuickTime
Player, as well as working as a plugin for the
QuickTime Web browser plugin


VR Panoramas are panoramic images which
surround

the viewer with an environment (inside, looking out),
yielding a sense of place.


They can be "stitched" together from several normal
photographs, or captured with specialised panoramic
cameras, or rendered from 3D
-
modeled scenes

Non
-
immersive VR

Advanced Multimedia

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The Future


On April 7, 2005 Sony went public with the
information that they had filed for and received
a patent for the idea of the non
-
invasive
beaming of different frequencies and patterns
of ultrasonic waves directly into the brain to
recreate all five senses.

Advanced Multimedia

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Q & A

Question and Answer Session