VIRTUAL REALITY

By

STEFFI KERAN RANI JM.E.MULTIMEDIA TECHNOLOGY

Anna University

INTRODUCTIONWHAT IS VIRTUAL REALITY?

Virtual Reality(VR) also known as Computer–simulated life is a high-end user interface that involves real-time simulations and interactions through multiple sensorial channels.

Virtual Reality (VR) is the illusion of a three-dimensional, interactive, computer-generated reality where sight, sound, and sometimes even touch are simulated to create pictures, sounds, and objects that actually seem real.

MAJOR CONCEPTS –VIRTUAL REALITY

VR must allow the user to view the environment from any point and at any angle

VR must allow the user to interact with objects in the environment.

The environment consists of a complex library of VRML (Virtual Reality Modeling Language) objects. The library contains over 50 VRML objects that model primary 2D and 3D objects.

VIRTUAL REALITY TRIANGLE -

Immersion

ImaginationInteraction

Computer-graphics simulationBeing a part of the action on the screenCreate a realistic-looking worldInteractivity

Human ImaginationProblem-solving Application

Respond to user inputssynthesized world is not static

VIRTUAL REALITY TECHNOLOGY

2 Types Windows on World(WoW)

Also called Desktop VR. Using a conventional computer monitor to display the 3D virtual world.

Immersive VR Completely immerse the user's personal viewpoint inside the virtual 3D world. The user has no visual contact with the physical word.

STEREO PROJECTION SYSTEM OF VR

Stereo Viewing enables to see real 3D, meaning distances between objects.

Two images with an average distance of 6.5 cm, which is the average eye distance, are necessary to enable real 3D viewing.

The brain superimposes both images to a 3D image

Passive stereo: using glasses with color or polarization filter

Active stereo: using shutter glasses, LCD-displays

STANDARDS AND PROTOCOLS USED FOR VR

Standards and Protocols needed to support interoperability between virtual environments are :

HTTP (Hyper Text Transfer Protocol)RTP (Real-Time Protocol)VRTP (Virtual Reality Transfer Protocol) VSCP (Virtual Society Client Protocol) protocols Immersive Education Technology Group (IETG), Meta Grid (2008- Present)Virtual World Region Agent Protocol (VWRAP),(2009-2011)Open Source Metaverse Project (2004-2008)

VRML (Virtual Reality Modeling Language) which is standard of the Web 3D Consortium and in the same time it is the international standard ISO/IEC 14772-1:1997.

In the present, the Web 3D Consortium is working at a new standard, called X3D based on the current VRML 2.0 standards.

A VRML-based Virtual Office

ROLE OF NETWORKS IN VIRTUAL REALITY Each computer participating in the virtual reality simulation is called “HOST”.

Every host entity that corresponds to human participant’s virtual body is called their “AVATAR”.

Broadcast Mode: In a multi-player computer system, each host broadcasts the location of each entity that it maintains. These broadcasts are received by every host in the simulation and are used to update their local copy of the “ world database”.

The problem with the Broadcast Mode:

Even the idle machines (machines that don’t participate in the simulation) in the subnet must receive and process the update packet.

Broadcasting your current location requires a lot of bandwidth. Sometimes the system just hangs!!!

Three basic challenges are Compatibility, Limited Bandwidth and Latency

DISTRIBUTED INTERACTIVE SIMULATION PROTOCOL (DIS)

The largest, best-known and most successful standard for Virtual Reality is Distributed Interactive Simulation Protocol (DIS).

Mainly used for Military Simulations.

DIS addresses the Compatibility problem by defining a standard message format which is called Protocol Data Unit (PDU) or Entity State Protocol Data Unit (ESPDU).

DIS addresses the latency and bandwidth problems by a technique called “Dead Reckoning”.

Dead Reckoning: Instead of just sending an entity’s location, a host sends an ESPDU that contains the Entity’s location, TimeStamp, and a Velocity Vector. So each host can extrapolate the entity’s location without additional updates.

DIS uses UDP packets to send its PDUs to other hosts.

UPDATE FILTERING DIS and several other approaches to Virtual Reality make use of the technique called

“Update Filtering”.

The basic idea is that the Virtual World is divide into a large number of cells.

Each host participating in the simulation determines an Area of Interest (AOI).

As participant moves around, cells will enter and leave their Area of Interest; at any given time, they will receive updates for the cells that they see, resulting in small, manageable number of updates .

POWERFUL IDEAS OD DIS - A SUMMARY

Standard Message Formats

Fully –decentralized Model – no central server

Dead Reckoning

Areas of Interest

Possible Use of Multicasting for filtering of update messages

APPLICATIONS Entertainment

More vivid Move exciting More attractive

APPLICATIONS Medicine

- Practice performing surgery.- Perform surgery on a remote patient.- Teach new skills in a safe, controlled environment.

APPLICATIONS Manufacturing

Easy to modify Low cost High efficient

APPLICATIONS Education & Training

Driving simulators. Flight simulators. Ship simulators. Tank simulators.

Thank You for Listening