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Brief Introduction of Virtual Reality & its

Challenges

Sharmistha Mandal

Abstract— Virtual reality (VR) is a technology which allows a user to interact with a computer -simulated environment, whether that environment is a simulation of the real world or an imaginary world. It is the key to experiencing, feeling and touching the past, present and the future. It is the medium of creating our own world, our own customized reality. It could range from creating a video game to having a virtual stroll around the universe, from walking through our own dream house to experiencing a walk on an alien planet. W ith virtual reality, we can experience the most intimidating and gruelling situations by playing safe and with a learning perspective.

Very few people, however, really know what VR is, what its basic principles and its open problems are. In this paper a histor ical overview of virtual reality is presented, basic terminology and classes of VR systems are listed. An insightful study of typical VR systems is done and finds the challenges of Virtual Reality.

Index Terms— Evolution of VR, Sensorama, HMD, CAVE, Levels of immersion, Immersive Virtual Reality, Telepresence, Cyberspace

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INTRODUCTION

owadays it becomes possible even for an average user, to move into the world of computer graphics. This fascina- tion with a new (ir) reality often starts with computer
games and lasts forever. It allows to see the surrounding world in other dimension and to experience things that are not accessible in real life or even not yet created. Moreover, the world of three-dimensional graphics has neither borders nor constraints and can be created and manipulated by ourselves as we wish – we can enhance it by a fourth dimension: the dimension of our imagination But not enough: people always want more. They want to step into this world and interact with it – instead of just watching a picture on the monitor. This technology which becomes overwhelmingly popular and fashionable in current decade is called Virtual Reality (VR). Virtual reality is considered to have begun in the 1950’s but it came to the public’s attention in the late 1980’s and 1990’s. This can be attributed to pioneering computer scientist Jaron Lanier who introduced the world back in 1987 to the term ‘vir- tual reality’. Research into virtual reality continued into the
1990’s and that combined with the appearance of films such as
The Lawnmower Man helped to raise its profile.
Most virtual reality environments are primarily visual experi- ences, displayed either on a computer screen or through spe- cial stereoscopic displays. Virtual reality may also include au- ditory stimulation through speakers or headphones. Users can
interact with the virtual environment through the use of de- vices such as a keyboard, a mouse, or a wired glove.
The history of virtual reality has largely been a history of at- tempts to make an experience more real. The majority of his- torical examples are visual and to a lesser extent, auditory. This is because of all the human senses, vision provides by far the most information followed by hearing. Probably 90 per cent of our perception of the world is visual or auditory.
sound real, feel real, and respond realistically to the viewer’s actions” [Suth65]. It has been a long time since then; a lot of research has been done. Let us have a short glimpse at the last three decades of research in virtual reality and its highlights:
• Sensorama – The Sensorama Machine was invented in 1957 and patented in 1962 under patent # 3,050,870. Morton Heilig created a multi-sensory simulator. A prerecorded film in color and stereo, was augmented by binaural sound, scent, wind and vibration experiences. This was the first approach to cre- ate a virtual reality system and it had all the features of such an environment, but it was not interactive.

Fig 1. Sensorama

• The Ultimate Display – In 1965 Ivan Sutherland proposed the ultimate solution of virtual reality: an artificial world con- struction concept that included interactive graphics, force- feedback, sound, smell and taste.

EVOLUTION OF VIRTUAL REALITY

The very first idea of it was presented by Ivan Sutherland in
1965: “make that (virtual) world in the window look real,

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Fig 2. The Ultimate Display

• “The Sword of Damocles” – The first virtual reality sys- tem realized in hardware, not in concept. Ivan Sutherland con- structs a device considered as the first Head Mounted Display (HMD), with appropriate head tracking. It supported a stereo view that was updated correctly according to the user’s head position and orientation.

Fig 3. Head Mounted Display

• GROPE – The first prototype of a force-feedback system realized at the University of North Carolina (UNC) in 1971.
• VIDEOPLACE – Artificial Reality created in 1975 by My- ron Krueger – “a conceptual environment, with no existence”. VIDEOPLACE was created where the computer had control over the relationship between the participant's image and the objects in the graphic scene. It could coordinate the movement of a graphic object with the actions of the participant. In this system the silhouettes of the users grabbed by the cameras were projected on a large screen. The participants were able to interact one with the other thanks to the image processing techniques that determined their positions in 2D screen’s space.
• VCASS – Thomas Furness at the US Air Force’s Armstrong
Medical Research Laboratories developed in 1982 the Visually
Coupled Airborne Systems Simulator – an advanced flight
simulator. The fighter pilot wore a HMD that augmented the
out-the window view by the graphics describing targeting or
optimal flight path information.
• VIVED – VIrtual Visual Environment Display – constructed
at the NASA Ames in 1984 with off-the-shelf technology a ste-
reoscopic monochrome HMD.
• VPL – The VPL company manufactures the popular
DataGlove (1985) and the Eyephone HMD (1988) – the first
commercially available VR devices.
• BOOM – commercialized in 1989 by the Fake Space Labs.
BOOM is a small box containing two CRT monitors that can be
viewed through the eye holes. The user can grab the box, keep
it by the eyes and move through the virtual world, as the me-
chanical arm measures the position and orientation of the box.

Fig 4. The BOOM

• UNC Walkthrough project – in the second half of 1980s at the University of North Carolina an architectural walkthrough application was developed. Several VR devices were con- structed to improve the quality of this system like: HMDs, optical trackers and the Pixel-Plane graphics engine.
• Virtual Wind Tunnel – developed in early 1990s at the
NASA Ames application that allowed the observation and
investigation of flow-fields with the help of BOOM and
DataGlove.
• CAVE – presented in 1992. CAVE (CAVE Automatic Virtual
Environment) is a virtual reality and scientific visualization
system. Instead of using a HMD it projects stereoscopic imag-
es on the walls of room (user must wear LCD shutter glasses).
This approach assures superior quality and resolution of
viewed images, and wider field of view in comparison to

HMD based systems.

Fig 5. Cave

WHAT IS VR? WHAT IS VR NOT?

At the beginning of 1990s the development in the field of vir- tual reality became much stormier and the term Virtual Reali- ty itself became extremely popular. We can hear about Virtual Reality nearly in all sort of media, people use this term very often and they misuse it in many cases too.
Virtual Reality (VR) is popular name for an absorbing, interac- tive, Computer-mediated experience in which person per- ceives a synthetic (simulated) environment by means of spe- cial human-computer interface Equipment. It interacts with simulated objects in that environment as If they were real. Several persons can see one another and interact in shared Synthetic environment such as battlefield.
Virtual Reality is a term used to describe a computer generat- ed virtual Environment that may be moved through and ma- nipulated by a user in real time. A virtual environment may be displayed on a head-mounted display, a computer monitor, or a large projection screen. Head and hand tracking systems are employed to enable the user to observe, move around, and manipulate the virtual environment.
The main difference between VR systems and traditional me-
dia (such as radio, television) lies in three dimensionality of
Virtual Reality structure. Immersion, presence and interactivi-
ty are peculiar features of Virtual reality that draw it away
from other representational technologies. Virtual reality does
not imitate real reality, nor does it have a representational

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function. Human being’s have inability to distinguish between
perception, hallucination, and illusions.
VR has grown into a new phase and becomes a distinct field in
world of computing. The utility of VR has already been re-
searched in car design, robot design, medicine, chemistry, bi-
ology, education, as well as in building design and construc- tion (Whyte, j. et al., 1999).

SOME BASIC DEFINITIONS AND TERMINOLOGY

Virtual Reality (VR) and Virtual Environments (VE) are used in computer community interchangeably. These terms are the most popular and most often used, but there are many other. Just to mention a few most important ones: Synthetic Experi- ence, Virtual Worlds, Artificial Worlds or Artificial Reality. All these names mean the same:
• “Real-time interactive graphics with three-dimensional models, combined with a display technology that gives the user the immersion in the model world and direct manipula- tion, we call virtual environments.” [Fuch92]
• Merriam-Webster's New Collegiate Dictionary, Ninth Edi- tion, defines virtual as "being in effect but not in actual fact", and environment as "the conditions, circumstances, and influ- ences surrounding and affecting an organism".
• “The illusion of participation in a synthetic environment rather than external observation of such an environment. VR relies on a three-dimensional, stereoscopic head-tracker dis- plays, hand/body tracking and binaural sound. VR is an im- mersive, multi-sensory experience.” [Giga93a]
• “Computer simulations that use 3D graphics and devices such as the DataGlove to allow the user to interact with the simulation.” [Jarg95]
• “Virtual reality refers to immersive, interactive, multi- sensory, viewer-centered, three dimensional computer gener- ated environments and the combination of technologies re- quired to build these environments.” [Cruz93a]
• “Virtual reality lets you navigate and view a world of three dimensions in real time, with six degrees of freedom. (...) In essence, virtual reality is clone of physical reality.” [Schw95]
• According to Jerry Prothero, a research associate at the Uni-
versity of Washington, who works in the Human Interface
Technology Laboratory, definition of virtual reality saying: "It
can be defined in technological terms as a set of input devices
which stimulate a high percentage of our sensory input chan-
nels, for instance, by providing a wide visual field-of-view and
stereo sound. It can be defined in psychological terms a pat-
tern of sensory stimuli which gives one an impression of being
in a computer-generated space.”
Although there are some differences between these defini-
tions, they are essentially equivalent. They all mean that VR is
an interactive and immersive (with the feeling of presence)
experience in a simulated (autonomous) world [Zelt92].
Many people, mainly the researchers use the term Virtual En-
vironments instead of Virtual Reality “because of the hype
and the associated unrealistic expectations” [Giga93a]. Moreo-
ver, there are two important terms that must be mentioned
when talking about VR: Telepresence and Cyberspace. They
are both tightly coupled with VR, but have a slightly different
context:
• Telepresence – The term was coined by Marvin Minsky (1980) in reference to teleoperation systems for remote manip- ulation of physical objects. It is a specific kind of virtual reality that simulates a real but remote (in terms of distance or scale) environment. Another more precise definition says that telepresence occurs when “at the work site, the manipulators have the dexterity to allow the operator to perform normal human functions; at the control station, the operator receives sufficient quantity and quality of sensory feedback to provide a feeling of actual presence at the worksite” [Held92].
• Cyberspace – was invented and defined by William Gibson
as “a consensual hallucination experienced daily by billions of
legitimate operators (...) a graphics representation of data ab-
stracted from the banks of every computer in human system”
[Gibs83]. Today the term Cyberspace is rather associated with
entertainment systems and World Wide Web (Internet).
• Telexistence – This concept was first proposed by Susumu Tachi in Japan in 1980 and 1981 as patents and the first report was published in Japanese in 1982 and in English in 1984. It enables a human being to have a real-time sensation of being at a place other than where he or she actually exists, and being able to interact with the remote environment, which may be real, virtual, or a combination of both. It also refers to an ad- vanced type of teleoperation system that enables an operator at the control to perform remote tasks dexterously with the feeling of existing in a surrogate robot working in a remote environment.
• HCI (Human-Computer Interaction) – refers to the study
and process by which humans interact with computers. Very
basic HCI is something as simple as a keyboard and mouse
while advanced HCI could be thought-controlled interactions
between a person and a computer.
• Haptics – The word “haptics” refers to the capability to
sense a natural or synthetic mechanical environment through
touch. Haptics also includes kinesthesia, the ability to perceive
one’s body position, movement and weight.
• Haptics technologies – provide force feedback to users
about the physical properties and movements of virtual ob- jects represented by a computer. A haptic joystick, for exam- ple, offers dynamic resistance to the user based on the actions
of a video game. Haptics incorporates both touch (tactile) and motion (kinesthetic) elements. For applications that simulate real physical properties—such as weight, momentum, friction, texture, or resistance—haptics communicates those properties through interfaces that let users “feel” what is happening on the screen.

LEVELS OF IMMERSION IN VR SYSTEMS

In a virtual environment system a computer generates sensory impressions that are delivered to the human senses. The type and the quality of these impressions determine the level of immersion and the feeling of presence in VR. Ideally the high- resolution, high-quality and consistent over all the displays, information should be presented to all of the user’s senses [Slat94]. Moreover, the environment itself should react realis- tically to the user’s actions. The practice, however, is very dif-

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ferent from this ideal case. Many applications stimulate only one or a few of the senses, very often with low-quality and unsynchronized information. We can group the VR systems accordingly to the level of immersion they offer to the user (compare with [Isda93, Schw95]):

• Non-Immersive (Desktop VR) systems –

Desktop Virtual Reality is a lower level of immersive VR that can be easily employed in many applications without the need for special devices. Sometimes called Window on World (WoW) systems. This is the simplest type of virtual reality applica- tions.

Desktop VR is when a computer user views a virtual envi- ronment through one or more computer screens. A user can then interact with that environment, but is not immersed in it. It uses a conventional monitor to display the image (generally monoscopic) of the world. No other sensory output is sup- ported.
Desktop Virtual Reality has begun to make its way and popu- larity in modern education because of its ability to provide real time visualization and interaction within a virtual world that closely resembles a real world.
• Semi-Immersive (Fish Tank VR) systems – improved
version of Desktop VR. These systems support head tracking
and therefore improve the feeling of “of being there” thanks to
the motion parallax effect.They still use a conventional moni-
tor (very often with LCD shutter glasses for stereoscopic view-
ing) but generally do not support sensory output.
• Immersive systems – the ultimate version of VR systems.
They let the user totally immerse in computer generated world
with the help of HMD that supports a stereoscopic view of the
scene accordingly to the user’s position and orientation. These
systems may be enhanced by audio, haptic and sensory inter-
faces.

CHARACTERISTICS OF IMMERSIVE VR

The unique characteristics of immersive virtual reality can be summarized as follows:
• Head-referenced viewing provides a natural interface for the navigation in three-dimensional space and allows for look- around, walk-around, and fly-through capabilities in virtual environments.
• Stereoscopic viewing enhances the perception of depth and
the sense of space.
• The virtual world is presented in full scale and relates
properly to the human size.
• Realistic interactions with virtual objects via data glove and
similar devices allow for manipulation, operation, and control
of virtual worlds.
• The convincing illusion of being fully immersed in an artifi-
cial world can be enhanced by auditory, haptic, and other non-
visual technologies.
• Networked applications allow for shared virtual environ-
ments.

TYPES OF IMMERSION

Immersion means the extent to which high fidelity physical
inputs (e.g., light patterns, sound waves) are provided to the different sensory modalities (vision, audition, touch) in order to create strong illusions of reality in each.
According to Ernest Adams, immersion can be separated into three main categories:
• Tactical immersion – Tactical immersion is experienced when performing tactile operations that involve skill. Players feel “in the zone” while perfecting actions that result in suc- cess.
• Strategic immersion – Strategic immersion is more cere-
bral, and is associated with mental challenge. Chess players
experience strategic immersion when choosing a correct solu-
tion among a broad array of possibilities.
• Narrative immersion – Narrative immersion occurs when
players become invested in a story, and is similar to what is
experienced while reading a book or watching a movie. Staf-
fan Björk and Jussi Holopainen, in Patterns In Game Design,
divide immersion into similar categories. They call them sen- sory-motoric immersion, cognitive immersion and emotional immersion, respectively. In addition to these, they add three
new categories:
• Spatial immersion – Spatial immersion occurs when a
player feels the simulated world is perceptually convincing.
The player feels that he or she is really “there” and that a sim-
ulated world looks and feels “real”.
• Psychological immersion – Psychological immersion oc-
curs when a player confuses the game with real life.
• Sensory immersion – The player experiences a unity of
time and space as the player fuses with the image medium,
which affects impression and awareness.

USES OF VIRTUAL REALITY

It is not easy to define all the uses of VR because now it’s enough develop in many fields. Here, some uses of VR are explained.
EDS Jack is an example of a commercially available virtual reality software package. It is mainly used for visibility and ergonomics study. These are two of the areas that using Virtu- al Reality really benefits. For example when designing a large mechanical device such as a bulldozer or even a car, visibility and ergonomics are very important to the operators. Would you buy a car that was uncomfortable to drive or had poor visibility, probably not? Many companies spend a large amount of money making their products interface better with the operators. The cost of building prototypes is very expen- sive, upwards of a few million dollars for one machine using the bulldozer example. By using virtual reality the company could check out the viability and ergonomics of their machine quickly and make changes to it without ever spending money on building hardware.
Another area that Virtual Reality is heavily used in is driving
or flying simulations. These provide the users a chance to
gain expertise operating a vehicle without the real world con-
sequences of making a mistake.
MPI Vega Prime is an example of a software package that
supports any type of driving simulation. The user builds the
virtual environment within the software package. It biggest

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advantage is its realistic physics engine which supports colli- sion detection.
Flight simulators are the most common type of machine simu- lation. Some other examples would be the US Army’s use of simulators to train tank solders with virtual tank wars. NASA also trains its astronauts on how to land the space shuttle with a virtual reality simulator.

ADVANTAGES

Virtual reality has also been used extensively to treat phobias (such as a fear of heights, flying and spiders) and post trau- matic stress disorder. This type of therapy has been shown to be effective in the academic setting, and several commercial entities now offer it to patients.
Although it was found that using standardized patients for
such training was more realistic, the computer-based simula-
tions afforded a number of advantages over the live training.
Their objective was to increase exposure to life-like emergency
situations to improve decision-making and performance and
reduce psychological distress in a real health emergency.

DISADVANTAGES

Some psychologists are concerned that immersion in virtual environments could psychologically affect a user. They sug- gest that VE systems that place a user in violent situations, particularly as the perpetuator of violence, could result in the user becoming desensitized. In effect, there’s a fear that VE entertainment systems could breed a generation of sociopaths. Engaging virtual environments could potentially be more ad- dictive.
Another emerging concern involves criminal acts. In the virtu- al world, defining acts such as murder or sex crimes has been problematic. At what point can authorities charge a person with a real crime for actions within a virtual environment? Studies indicate that people can have real physical and emo- tional reactions to stimuli within a virtual environment, and so it’s quite possible that a victim of a virtual attack could feel real emotional trauma.

CHALLENGES

The big challenges in the field of virtual reality are developing better tracking systems, finding more natural ways to allow users to interact within a virtual environment and decreasing the time it takes to build virtual spaces. While there are a few tracking system companies that have been around since the earliest days of virtual reality. Likewise, there aren’t many companies that are working on input devices specifically for VR applications. Most VR developers have to rely on and adapt technology originally meant for another discipline, and they have to hope that the company producing the technology stays in business. As for creating virtual worlds, it can take a long time to create a convincing virtual environment - the more realistic the environment, the longer it takes to make it. It could take a team of programmers more than a year to du- plicate a real room accurately in virtual space.
Another challenge for VE system developers is creating a sys- tem that avoids bad ergonomics. Many systems rely on hard- ware that encumbers a user or limits his options through physical tethers. Without well-designed hardware, a user could have trouble with his sense of balance or inertia with a decrease in the sense of telepresence, or he could experience cybersickness, with symptoms that can include disorientation and nausea.

FUTURE WORK

The future of Virtual Reality depends on the existence of sys- tems that address issues of ‘large scale’ virtual environments. In the coming years, as more research is done we are bound to see VR become as mainstay in our homes and at work. As the computers become faster, they will be able to create more real- istic graphic images to simulate reality better. It will be inter- esting to see how it enhances artificial reality in the years to come.
It is very possible that in the future we will be communicating with virtual phones. Nippon Telephone and Telegraph (NTT) in Japan is developing a system which will allow one person to see a 3D image of the other using VR techniques.
The future is virtual reality, and its benefits will remain im- measurable.

CONCLUSION

Virtual Reality is now involved everywhere. You can’t imag- ine your life without the use of VR Technology. In this paper we define the Virtual Reality and its history. We also define some important development which gives the birth of this new technology.
Now we use mail or conference for communication while the
person is not sitting with you, but due to technology distance is not matter.This technology give enormous scope to explore the world of 3D and your own imagination.
It has many applications from product development to enter- tainment. It is still very much in the development stage with many users creating their own customized applications and setups to suit their needs.

ACKNOWLEDGMENT

I thank International Journal of Scientific & Engineering Re- search (IJSER), who motivates me to write my own first paper. Also thanks to website http://www.vrs.org.uk/virtual- reality/index.html for its resources to guide and give enor- mous help to processed my research.

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