yle="text-align: center;">Technical Report on Virtual Reality

Abstract

Virtual reality or virtual realities (VR), which can be referred to as immersive multimedia or computer- simulated reality, replicates an environment that simulates a physical presence in places in the real world or an imagined world, allowing the user to interact with that world. Virtual realities artificially create sensory experience, which can include sight, touch, hearing, and smell.

Most up-to-date virtual realities are displayed either on a computer screen or with an HD VR special stereoscopic displays, and some simulations include additional sensory information and focus on realsound through speakers or headphones targeted towards VR users. Some advanced haptic systems now include tactile information, generally known as force feedback in medical, gaming and military applications. The immersive environment canbe similar to the realworld in order to create a lifelike experience—forexample, in simulations for pilot or combat training—or it candiffer significantly from reality, such as in VR games.

The simplest form of virtual reality is a 3-D image that can be explored interactively at a personal computer, usually by manipulating keys or the mouse so that the content of the image moves in some direction or zooms in or out. More sophisticated efforts involve such approaches as wrap-around display screens,actual rooms augmented with wearable computers, and haptic devices that let you feel the display images.

Type of VR

Windows on World (WoW): With this kind of system, also known as "desktop VR" the user sees the 3-D world through the 'window' of the computer screen and navigates through the space with a control device such as a mouse. Like immersive virtual reality, this provides a first-person experience. One low-cost example of a 'Through the window' virtual reality system is the 3-D architectural design planning tool Virtus WalkThrough that makes it possible to explore virtual reality on a Macintosh or IBM computer. Developed as a computer visualization tool to help plan complex high-tech filmmaking for the movie The Abyss, Virtus WalkThrough is now used as a set design and planning tool for many Hollywood movies and advertisements as well as architectural planning and educational applications. A similar, less expensive and less sophisticated program that is starting to find use in elementary and secondary schools is Virtus VR (Law, 1994; Pantelidis, nd).

Immersive VR: Usually when we think of virtual reality, we think of immersive systems involving computer interface devices such as a head-mounted display (HMD), fiber-optic wired gloves, position tracking devices, and audio systems providing 3-D (binaural) sound. Immersive virtual reality provides an immediate, first-person experience. With some applications, there is a treadmill interface to simulate the experience of walking through virtual space. And in place of the head-mounted display, there is the BOOM viewer from Fake Space Labs which hangs suspended in front of the viewer's face, not on it, so it is not as heavy and tiring to wear as the head-mounted display. In immersive VR, the user is placed inside the image; the generated image is assigned properties which make it look and act real in terms of visual perception and in some cases aural and tactile perception (Brooks, 1988; Trubitt, 1990; Begault, 1991; Markoff, 1991; Minsky, 1991; Gehring, 1992). There is even research on creating virtual smells; an application to patent such a product has been submitted by researchers at the Southwest Research Institute (Varner, 1993).

Telepresence: The concept of cyberspace is linked to the notion of telepresence, the feeling of being in a location other than where you actually are. Related to this, teleoperation means that you can control a robot or another device at a distance. In the Jason Project, children at different sites across the U.S. have the opportunity to teleoperate the unmanned submarine Jason, the namesake for this innovative science education project directed by Robert Ballard, a scientist as the Woods Hole Oceanographic Institute (EDS, 1991; Ulman, 1993; McLellan, 1995).

Technologies of  VR

Head-Mounted Display (HMD): Head-mounted displays or HMDs are probably the most instantly recognizable objects associated with virtual reality. They are sometimes referred to as Virtual Reality headsets or VR glasses. As we might have guessed from the name, these are display devices that are attached to our head and present visuals directly to our eyes. At a minimum, if a device conforms to those two criteria we may consider it an HMD in the broadest sense. HMDs are not the sole purview of virtual reality, they have been used in military, medical and engineering contexts to name but a few. Some HMDs allow the user to see through them, allowing digital information to be projected onto the real world. Something which is commonly referred to as augmented reality. When we look at the diversity of HMDs that exist today within the context of virtual reality, it becomes apparent that there’s much more to these devices than strapping two screens to our eyes. In order to allow for an immersive experience either as a personal media device or as a full-on virtual reality interface, there are a number of technologies that can be incorporated in an HMD.

Data Glove: A data glove is an interactive device, resembling a glove worn on the hand, which facilitates tactile sensing and fine-motion control in robotics and virtual reality. Data gloves are one of several types of electromechanical devices used in haptics applications. Tactile sensing involves simulation of the sense of human touch and includes the ability to perceive pressure, linear force, torque, temperature, and surface texture. Fine-motion control involves the use of sensors to detect the movements of the user's hand and fingers, and the translation of these motions into signals that can be used by a virtual hand (for example, in gaming ) or a robotic hand (for example, in remote-control surgery).

VRML: VRML stands for virtual reality modeling language. It is a standard language for interactive simulation within the World Wide Web. This allows to create virtual worlds network via the internet and hyperlinked with the World Wide Web. Aspects of virtual world display, interaction and internetworking can be specified using VRML without being dependent on special gear like HMD.VR models can be viewed by Netscape or IE with a browser plug-in.

Architecture of VR System

Architecture of virtual system consists of input processor, simulation processor, rendering processor and world database.

Input Processor: Itcontrols the devices used to input information to the computer. The main objective of input processor is to get the coordinate data to the rest of the system with minimal lag time. The main components of input processor include keyboard, mouse, 3D position trackers, a voice recognition system, etc.

SimulationProcessor: The processof imitating real things virtually is called simulation. This is the core of the virtual reality system. It takes the user inputs along with any tasks programmed into the world and determine the actions that will take place in the virtual world.

Rendering Processor: Simulation processor imitates the real things but sensation are not produced to produce this sensation we use rendering processor .It creates the sensation that are output to the user. Separate rendering processes are used for visual, auditory, haptic and other sensory systems. Each renderer take a description of the world stat from the simulation process or derive it directly from the world database for each time step.

World Database: This is also known as World Description Files. It stores the object that inhabit the world, scripts that describes actions of those objects.This database contains all the objects which we are going to experience virtually. For instance if we want to experience the space virtually then the world database must have all the objects that are in space like the sun, the moon, stars, planets, etc.

Application of VR

Virtual reality parachuting simulation Virtual reality has been adopted by the military – this includes all three services (army, navy and air force) – where it is used for training purposes. This is particularly useful for training soldiers for combat situations or other dangerous settings where they have to learn how to react in an appropriate manner. A virtual reality simulation enables them to do so but without the risk of death or a serious injury. They can re-enact a particular scenario, for example engagement with an enemy in an environment in which they experience this but without the real world risks. This has proven to be safer and less costly than traditional training methods. Virtual Reality and Education: Education is another area which has adopted virtual reality for teaching and learning situations. The advantage of this is that it enables large groups of students to interact with each other as well as within a three dimensional environment. It is able to present complex data in an accessible way to students which is both fun and easy to learn. Plus these students can interact with the objects in that environment in order to discover more about them.

Virtual Reality in Healthcare:Healthcare is one of the biggest adopters of virtual reality which encompasses surgery simulation, phobia treatment, robotic surgery and skills training. One of the advantages of this technology is that it allows healthcare professionals to learn new skills as well as refreshing existing ones in a safe environment. Plus it allows this without causing any danger to the patients. A popular use of this technology is in robotic surgery. This is where surgery is performed by means of a robotic device – controlled by a human surgeon, which reduces time and risk of complications. Virtual reality has been also been used for training purposes and, in the field of remote telesurgery in which surgery is performed by the surgeon at a separate location to the patient.

Virtual Reality in Entertainment: Virtual reality games are becoming very popular with many teenagers who love the graphics, animations and best of all, being able to talk to others. After all, what could be better than the chance to interact with top end technology and without any adults to get in the way? These games are available for Xbox 360, PS2 and 3 as well as the Mac and PC so whatever console you use there is a VR game for that. This is pretty cool when you think about it.

Current Problems and Future Work

Problems:
Simulator Sickness Symptoms: Simulator sickness is by no means a new phenomenon. It is similar to motion sickness, which has existed for as long as humans have used additional modes of transportation, but can occur without any actual motion of the subject. The first documented case of simulator sickness occurred in 1957 and was reported by Havron and Butler in a US Navy helicopter trainer. The most common identifiable symptoms are general discomfort, nausea, drowsiness, headache and in some cases vomiting.
Expensive: Virtual reality technology is expensive. Common people can hardly manage to have such technologies. It requires additional hardwares which are also very expensive. A big problem with virtual reality is cost: a fully immersive set up such as a CAVE where someone is able to interact with objects in an enclosed space is expensive. In fact it’s that expensive that only university research departments and companies with a research and development (R & D) section are able to afford this type of set up.
Lack of Integration Between application packages: Integrating the virtual reality hardwares with the application package is a major issue. It requires very precise and expertise hands to integrate the application package with the hardwares.
Future works
High Fidelitysystems: Researches are being done to enhance the fidelity of virtual reality systems. To take a better experience and making vr systems more and more reliable scientists are trying hard and are developing new tools.
Cost-Saving: Virtual reality technology is not within the reach of common people because of its high cost and additional hardwares requirement. Developments are going on to make low cost vr technology. Scientists are trying to develop such tools that require less hardwares and can generate output with great reliability and accuracy.

Collaborative: Integrating application packages with the hardwares of the vr system was quite difficult in the early stage of vr technology but now with the efforts and development of new applications integration problem has been minimized to a great extent and the developers are trying hard to develop the applications which can be easily collaborated with the vr hardwares.

Summary

Everything we experience in life can be reduced to electrical activity stimulating our brains as our sensory organs deliver information about the external world. This interpretation is what we consider to be "reality." In this sense, the brain is reality. Everything you see, hear, feel, taste and smell is an interpretation of what's outside, and created entirely inside your head. We tend to believe that this interpretation matches very closely to the external world.Some people object to the term "Virtual Reality", saying it is an oxymoron. Other terms that have been used are Synthetic Environments, Cyberspace, Artificial Reality, Simulator Technology, etc. VR is the most common and sexiest. It has caught the attention of the media.