Virtual Reality is a computer generated world with which the user can interact. It is a 3D virtual world. It is an artificial environment created with computer hardware and software and presented to the user in such a way that it appears and feels like a real environment Virtual Reality can be defined as a computer simulation that models natural environments. It is a way of interacting with an artificial environment through extensions of senses and is controlled by the behavior of the user. Usually, many think that virtual reality is concerned with people wearing large helmets and gloves. But this is not the case always. Also, a simple projection on a large video screen is a form of Virtual Reality. This is often called Projected Reality. Yet another form of Virtual Reality is Augmented Reality. In Augmented Reality, the subject (i.e., user) is still able to look at the actual world around him but wears a helmet on which additional information can be projected.

To "enter" a virtual world, a user dons special gloves, earphones, and goggles, all of which receive their input from the computer system. In this way, at least three of the five senses are controlled by the computer. This section will give an overview of the equipment used in the Virtual Reality. First a broad overview of all the equipment and then a short description of how the different pieces work are given. A user wearing the complete Virtual Reality Equipment As shown in the figure above, here the subject (user) wears a Head Mounted Display (HMD) which is used to project the computer generated world in front of the subject. It is simply a helmet with two little TV screens. Head Mounted Display (HMD), A closer view Using optics, the picture on these miniature TV’s can be watched by the user. This optics is used to make sure that the picture can be watched from close-up. A data glove is a glove that is used for grasping and moving of things in a virtual world. This is also called as a Cyber glove which is fitted with sensors; the movements are then represented by the software that accompanies the glove, so any one movement can mean any number of things. Gestures can then be categorized into useful information, such as to recognize some symbolic functions. A data glove (fitted with sensors and metal pieces) Inside the glove there are small pieces of metal which are able to notice when they are bent. Using this information, it is possible to know the angle of each individual joint of the hand. Knowing this information about the different joints makes it possible to recognize gestures made with the hand. A tracker is a combination of a transmitter and a receiver. These are used to get information about the place the subject occupies in the real world. This information about the real world locations is then used in the virtual world. A receiver is often attached to the HMD. This way, whenever the subject moves his head in the real world the virtual world will change accordingly. A second receiver can be attached to the Cyber Glove or Data Glove. This way it is possible to find out where the hand is in the real world and again use this information in the virtual world. All these compraise the equipment for Virtual Reality.

SOME OF THE TECHNIQUES USED IN VIRTUAL REALITY:

The computer generated world consists of colored polygons. These polygons can also be colored using an image. The image is then put on the polygon and stretched until it fits the polygon. This technique is called texture mapping. Another technique by name shading i.e., changing of colors of objects in real world helps to make the virtual world look more real. Not only auditory and visual feedback is used in Virtual Reality. It is also possible to push the user whenever he hits an object. This is called force feedback. Using this technique the user can now feel the objects in the virtual world.

WORKING:

Virtual Reality works by measuring movement in the environment with magnetic tracking.In the future, tracking movements and activities in the environment will be done with the help of ultrasonic waves.

APPLICATIONS AND ADVANTAGES:

Virtual Reality has a lot of advantages that have improved main categories like medicine, architecture, design, entertainment and education.Some of the current applications are: Business: charts, graphs Industries: automotive--car testing, clothing--virtual shopping Military: training, simulations Medical: training, treatment of phobias Education: virtual museums, dissections, labs Some of the advantages are saving of money in many fields, increases productivity, decreases time-to-market, and increases chance of completed projects being fully functional, helps give companies comparative advantage.Virtual labs allow students to dissect animals without having to kill them and to perform experiments without requiring costly equipment. In the future, the Air Force, commercial airlines, and medical schools will use virtual reality more extensively for training purposes and the on-line clothing stores will use virtual reality to facilitate shopping and boost sales.

DISADVANTAGES:

Personal isolation, lack of interaction with real world and other people by living in virtual world, increase in unemployment as fewer people are needed to design projects are a few disadvantages of Virtual Reality. Despite these disadvantages, the benefits of using virtual reality far outweigh them. In order to fully utilize this technology people will have to become as familiar with it as they are with the Internet.

REFERENCES:

1. UM-VRL Virtual Reality A Short Introduction

2. Chapter 2 Virtual Reality

3. Virtual Reality

By Sree Lakshmi Peri

A Brief View Of Virtual Reality