VIRTUAL REALITY (VR)
INTRODUCTION AND BASIC APPLICATIONS
Dr. Naji Shukri Alzaza
Assist. Prof. of Mobile technology
Dean of Community Service and Continuing Education
University of Palestine, Alzahra City, Gaza, Palestine
najishukri@hotmail.com, www.najishukri.wordpress.com
‫ مقدمة وتطبيقات‬:‫الواقع االفتراضي‬
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Objectives
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Students should be able to understand the:
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Classification of VR system
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Non-immersive (desktop)
Semi-immersive
Fully-immersive
Comparison between the various VR system
Dr. Naji Shukri Alzaza
VR Systems
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Model
or
Simulation
Virtual
Environment
Representation
Output
User(s)
Input
Peripheral Technologies
Virtual Reality System Architecture
Dr. Naji Shukri Alzaza
VR Systems
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VR systems are characterized by the following
features: Sense of presence (being there) in 3D computer
generated environment.
 Sense of immersion (deeply engaged or involved).
 High degree of interactivity (interacting with a
human user).
 Real-time (of or pertaining to applications in which
the computer must respond as rapidly as required
by the user or necessitated by the process being
controlled) response.
Dr. Naji Shukri Alzaza
VR Systems
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VR systems can be categorized into:
1. Non-Immersive (Desktop)
2. Semi-Immersive
3. Fully-Immersive
Dr. Naji Shukri Alzaza
1. Non-immersive (Desktop)
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Presents images on a monitor and user interacts with the
images using mouse, joystick and keyboard.
Although the user is not technically immersed, it is still
considered as a VR system as it could be compared to
viewing a real world through a window.
Other terms used: Desktop VR and Windows on World
System.
Advantage: the cost is significantly lower than other forms
of VR system.
Desktop VR system provides almost no sense of immersion.
For some applications this may be acceptable but where
perception of scale is important then this can be a serious
problem.
Dr. Naji Shukri Alzaza
1. Non-immersive (Desktop)
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Advanced Desktop VR System
Typical Desktop VR System
Dr. Naji Shukri Alzaza
2. Semi-immersive VR
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User is partially immersed in a VE.
Comprises of a relatively high performance
graphics computing system which include large
screen monitor, large screen projector system or
multiple television projection systems.
Projection system uses wide field of view FOV in
access of 60° which could increase the feeling of
immersion or presence experienced by the user.
Dr. Naji Shukri Alzaza
2. Semi-immersive VR
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The resolution of projection systems ranges from 1000 3000 lines but to achieve the highest levels it may be
necessary to use multiple projection systems which are
more expensive.
Stereographic imaging can be achieved, using some
type of shutter glasses in synchronisation with the
graphics system.
Provides a greater sense of presence than nonimmersive systems and also a greater appreciation of
scale.
Images provided are of a higher resolution than Head
Mounted Displays (HMDs).
Dr. Naji Shukri Alzaza
2. Semi-immersive VR
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Dr. Naji Shukri Alzaza
Workbench and wall
2. Semi-immersive VR
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3. Fully-immersive VR
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Based on the immersive VR technology, providing a
feeling of presence in the virtual world.
Allows users to step into the virtual world by means of
devices that will map them into the digital world.
Head Mounted Display (HMD) provides stereoscopic
(3D) images and audio signals to create binaural
(hearing with two ears) sound in order to influence the
user’s perception of the world around him/her.
Fully immersive VR systems tend to be the most
demanding in terms of the computing power and level
of technology.
Dr. Naji Shukri Alzaza
Head Mounted Display (HMD)
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Dr. Naji Shukri Alzaza
Cave System
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Cave System
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Cave System
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Dr. Naji Shukri Alzaza
Non-Immersive vs Fully- and Semi-Immersive Virtual Environments
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Non Immersive: delivered by a conventional desktop monitor
and standard interaction devices such as joystick, keyboards and
mouse.
Does not demand the highest graphics performance thus a normal
PC can be used.
The reduction of the computer’s price with increasing graphics
performance would make a desktop VR system extremely
attractive for many applications.
Non-immersive VE creates a comfortable interaction between user
and the system.
 Users are usually aware of the real world and only observe
the virtual world through a monitor.
 Unlike immersive devices like HMD, desktop VR does not
require any devices to be attached to the body.
 HMD causes simulator sickness.
Dr. Naji Shukri Alzaza
Non-Immersive vs Fully- and Semi-Immersive Virtual Environments
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An immersive VE user typically turns his/her head often, as one
would do in the real world, and the human neck is good at doing
fast and accurate rotation.
Unfortunately, this fast motion exacerbates (make worse) the effects
of the lag (fail to maintain a desired pace or to keep up), with the
result that some immersive VE systems can take up to a 0.5 second to
stop the world from spinning around the user.
In non-immersive systems, the movement of the input devices, such as
mouse or 6DOF (Degree of Freedom) input controllers are mapped
to the position and orientation of the user.
Current desktop technology is able to update the display in almost
real time, thus the problem of lag is greatly reduced in nonimmersive systems.
Dr. Naji Shukri Alzaza
Non-Immersive vs Fully- and Semi-Immersive Virtual Environments
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The cost of a non-immersive system is far lower than
that of an immersive system.
A non-immersive VE provides a practical solution for
Web-based VE.
Web-based VE provides visualisation via the Webbrowser and does not require sense of immersion.
This could not be achieved using immersive or semi
immersive VE as Web browser could not cater for
other peripheral devices than mouse and keyboard.
Dr. Naji Shukri Alzaza
Comparison between various VE implementations (Kalawsky, 1996)
Qualitative Performance
Non-immersive VR
(Desktop)
Semi-Immersive VR
(Projection)
Full Immersive VR
(Head- coupled)
High resolution
High 1000 - 3000
Low - medium
300 -1000
Scale (perception)
Low
Medium - high
High
Sense of situation awareness
(navigational skills)
Low
Medium
High
Low
50° typically
Medium
150°
High
360°
Low
Low
Medium - high
None - low
Medium - high
Medium - high
Main features
Resolution
Field of regard
Lag
Immersion
Dr. Naji Shukri Alzaza
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Dr. Naji Shukri Alzaza