virtual reality (vr) introduction and basic applications

VIRTUAL REALITY (VR) VIRTUAL REALITY (VR) INTRODUCTION AND BASIC INTRODUCTION AND BASIC APPLICATIONSAPPLICATIONS

: وتطبيقات مقدمة االفتراضي الواقع

Dr. Naji Shukri AlzazaDr. Naji Shukri AlzazaAssist. Prof. of Mobile technologyDean of Community Service and Continuing EducationUniversity of Palestine, Alzahra City, Gaza, [email protected], www.najishukri.wordpress.com

Objectives

Dr. Naji Shukri Alzaza

Students should be able to understand the:

Classification of VR system Non-immersive (desktop) Semi-immersive Fully-immersive

Comparison between the various VR system

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Modelor

Simulation

Modelor

Simulation

Virtual Environment

Representation

Virtual Environment

Representation User(s)User(s)

OutputOutput

InputInput

Peripheral Technologies

Virtual Reality System ArchitectureVirtual Reality System Architecture

VR Systems


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VR Systems


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.

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VR Systems


VR systems can be categorized into: 1. Non-Immersive (Desktop)2. Semi-Immersive 3. Fully-Immersive

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1. Non-immersive (Desktop)


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.

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1. Non-immersive (Desktop)


Typical Desktop VR System

Advanced Desktop VR System

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2. Semi-immersive VR


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.

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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 non-immersive systems and also a greater appreciation of scale.

Images provided are of a higher resolution than Head Mounted Displays (HMDs).

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Dr. Naji Shukri AlzazaWorkbench and wall

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2. Semi-immersive VR12

3. Fully-immersive VR


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.

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Head Mounted Display (HMD)


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Cave System


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Cave System


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Cave System


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Non-Immersive vs Fully- and Semi-Immersive Virtual Environments


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.

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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 non-immersive systems.

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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 Web-browser 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.

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Comparison between various VE implementations (Kalawsky, 1996)

Qualitative Performance

Main featuresNon-immersive VR

(Desktop)Semi-Immersive VR

(Projection)Full Immersive VR (Head- coupled)

Resolution High resolution High 1000 - 3000 Low - medium 300 -1000

Scale (perception) Low Medium - high High

Sense of situation awareness (navigational skills)

Low Medium High

Field of regard Low

50° typicallyMedium

150°High 360°

Lag Low Low Medium - high

Immersion None - low Medium - high Medium - highDr. Naji Shukri Alzaza


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virtual reality (vr) introduction and basic applications

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