Overview of Virtual Reality Technologies
Yuri Antonio Gonçalves Vilas Boas
School of Electronics and Computer Science
University of Southampton
Southampton, United Kingdom

yavb1g12@soton.ac.uk
ABSTRACTThe promise of being able to be inside anotherworld might be resolved by Virtual Reality. It
wouldn’t be naïve to assume that we will be able toenter and completely feel another world at somepoint in the future; be able to interact withknowledge and entertainment in a totally immersive
state.
Advancements are becoming more frequent, andwith the recent popularity of technology in thisgeneration, a lot of investment is being made.
Prototypes of head displays that completely cover
the user’s view and movement recognition which
doesn’t need an intermediate device for input ofdata are already Virtual Reality devices available todevelopers and even to the public. From time totime, the way we interact with computers change,
and virtual reality promises to make this interaction
as real as possible. Although scenes like flying a jetor tank, are already tangible, another scenes, suchas being able to feel the dry air of the Sahara ingeography classes or feel the hard, cold scales of a
dragon in a computer game seem to be in a longw a y f r o m n o w. H o w e v e r , t e c h n o l o g i cadvancements and increase in the popularity ofthese technologies point to the possibility of suchamazing scenes coming true.

Keywords
Virtual Reality, Simulation, Immersion, HumanComputer Interaction, Head-Mounted Display,
Wired Gloves, Computer Vision, Motion Control.

1. INTRODUCTION
Virtual Reality has been pursued for some time
now, as it is known by many to be, perhaps, theultimate computational experience. One would feelcomplete immersion through it, unable to differ thecomputer generated data from reality [1]. That goal,
however, is still far away, but advancements are

made everyday. Virtual Reality embraces a diverseamount of field applications, such as the military,educational, medical, entertainment fields, among
others.
This paper will focus on giving the reader an
overview about virtual reality devices, briefly
passing through the history and evolution of the
field and giving special attention to technicalinformation regarding currently available
technology. In this section, definitions some terms
commonly used are given. Section 2 includes
information about the history of Virtual Reality.
Section 3 shows the common technologies related
to it. Section 4 contains applications and conclusion
comes in Section 5.

1.1 Definitions
Virtual Reality stands for the field of computing
which has the objective of creating a virtual world,having one immerse into it and giving one thecapability of interacting with this world, while
using specific devices to simulate an environmentand stimulate one by feedback in order to make theexperience as real as possible.

1.1.1 Immersion

When someone reads a book and get so captivatedby it, the person feels completely absorbed by thewords. Immersion is the suspension of disbelief
possibly being given by any media.
There are three types[2] of systems in Virtual
Reality:. Non Immersive Systems, such as Desktops, which
are not very sophisticated devices for Virtual
Reality applications, as they are cheap and don’t
require great performance,. Fully Immersive Systems, which give the user theclosest experience to reality through high quality
graphics and performance as well as complete or
major absence of unrelated stimuli.

. Semi-Immersive Systems are between the above
two. Flight simulators are a good example. Thesesystems combine high performance software withstereoscopic vision, increased field of view, haptic
feedback, among other Virtual Reality inducing
technologies, to deliver a more immersive
experience.

1.1.2 Perception

Perception is the awareness of the surroundings
through physical senses. So, in order to give one theperception of something, sensorial stimuli must be
used. Two approaches [3] are usually seen:. The data-oriented approach, which aims
immersion through quality of data, meaning themore the data seems like reality, more immersive
the experience will be. That can be seen as
experiences with higher definition medias provoke
more immersion to the user.
. And the constructivist approach, which, on theother hand, uses the human capability of building areality, thus being capable of immersing one withnot so high quality technologies. Evidence for thiscan also be found, as there’s not one human being
which haven’t being amazed by a book.

Designed in the 50s and with a mechanicalprototype in 1962 which used 3D visual, audio,
haptic, olfactory stimuli and even wind to provide
an immersive experience [1]. It is regarded as oneof the first examples of virtual reality. The
Sensorama displayed a movie of a motorcycle
running through Brooklyn, giving a high amount offeedback to make the user feel like he is actually
there. However, there was no interaction with themovies. Heilig was not able to find financial
support of production, so the project wasabandoned.
On 1961, Philco developed the first Head-mounted
Display (HMD): the Headsight. It was a helmet
with cathode ray tube display and a tracking systemthat made possible to identify the position of thehead.
One of the most famous HMD, or better: BOOM
(Binocular Omni Orientation Monitor), is the“Sword of Damocles”, invented by Ivan Sutherland
in 1968 [5]. It had to be hanged to the ceilingbecause is was too bulky to head-mount(characteristic of BOOMs) as seen in Figure 2.
Hence, it received the name from the Greek story of
Damocles, which a sword was suspended over the
king’s throne by a hair.

1.1.3 Telepresence

Virtual Reality also uses the concept of
Telepresence, which is the characteristic of being
able to feel present somewhere different of yourreal location, a remote presence. It was created by
Marvin Minsky in 1980 [4] and is a term widelyused by the virtual reality community for it ishighly connected with the concept of immersion.

2. HISTORY
A classic virtual reality novelty is Morton Heilig’s
Sensorama.

Figure 1: The Sensorama.

Figure 2: Ivan Sutherland and the Sword of
Damocles.
The Sword of Damocles was capable of tracking
both the position of the user and his eyes and update
the image of its stereoscopic view according touser’s position.
Another common Virtual Reality related device is
the Wired Gloves. The first one created were the
Sayre glove in 1977, by Tom DeFanti and Daniel J.
Sandin, and worked by fiber-optics [6]. Thomas G.
Zimmerman worked in the early 80s to develop the
Dataglove, which heavily influenced other devices,such as the Power Glove. It was manufactured by
Mattel for the Nintendo Entertainment System,
available at a reasonable price[6], although is
considered a commercial failure.

Figure 3: The Power Glove.
There were attempts to launch other Virtual Reality
related products to the public after the Power
Glove, but the reception of them were never morethan lukewarm. Virtual Reality development were
manly found in the military and academic research
until technologies became more cost-effective.

3. TECHNOLOGY
There are many different specific devices
throughout Virtual Reality (VR). In this section arefound descriptions about the most common
technologies, some of them being closely related towell-known commercial devices.

The Oculus Rift is a headset focused on gaming. It
provides an extended field of view of 110 degrees,
stereoscopic vision, and fast head tracking. It doesthat by processing data that comes through 3-axis
gyroscope, accelerometer and magnetometer, giving
the user a fast image update, meaning no delay
should happen. It is still in development but adeveloper’s kit is available, which include theOculus Rift, access to the Oculus SDK and a copyof the game Doom 3, ready to be played. A
consumer version is said to be in the market by
2013.

3.2 CAVE
Cave Automatic Virtual Environment is a virtual
reality room. Projectors cover the walls of a roomwith stereoscopic image and the user need to use
glasses which are synchronized with the alternating
images the projectors (much like current 3Dmovies) and speakers are placed around the room tosurround it with sounds [8].

3.1 Head-Mounted Display
One of the classical images that comes to mind
when thinking about VR is of someone with adevice on the head, covering the eyes.
There are currently many Head-Mounted Displays(HMDs) in the market. Most of them havestereoscopic displays and tracking systems,
enabling the user to see 3D images through a big
field of vision and have the virtual camera moveaccordingly to the user’s head position. As there are
one display of each eye, stereoscopic images are
made simply by including two virtual cameras ont h e s o f t w a r e . U s u a l l y, G y r o s c o p e s a n d
accelerometers make position recognition
possible[7].

Figure 5: a CAVE environment.
Also, the ImmersaDesk is a device influenced by
the CAVE. The ImmersaDesk is a screen whichcorrespond as one wall of the CAVE. Equippedwith the same stereoscopic vision and head tracking
devices of the CAVE, but only use one screen, thus
becoming semi-immersive.

3.3 Input Devices

Figure 4: the Oculus Rift prototype.

The usual approach to data input in VR systems
includes movement recognition. Having a device
that reads and processes natural movements wouldchange human-computer interaction to a moreintuitive way. Here we see the most common typesof data input related to VR.

3.3.1 Wired gloves

Wired gloves are capable of measuring joints
angles, pressure, tracking and haptic feedback.
There are three main technologies used in wired
gloves: using light through fiber optics; using
conductive ink to measure electrical resistance; andusing mechanical sensors.
Gloves that used fiber optics measure finger flexion
with the use of light and photo sensors. That means
the amount of light received by each photocell isused to determine the angle of bending of the joints,
the more the user bend his fingers, the less light is
captured by the sensors, and vice-versa [6].

Figure 6: a fiber-optics wired glove.
Other gloves use a electric conductive ink and as
the user makes movements, the electrical resistancechanges and makes possible for a processor to
identify movements[6]. This technology does nothave a performance as good as the fiber-optics
gloves, but are cheaper. This led a lot of VR
enthusiasts to get a Power Glove, which uses thistechnology, to make their own software.
Another approach is the use of an Dexterous Hand
Machine, which is more similar to an exoskeleton
than to a glove, as mechanical sensors need to be
fixated at the hand’s joints [6], as seen in Figure 7.

Figure 7: a Dexterous Hand Machine.
These are more precise than the other two
technologies, at the price of being rather bulky towear.

3.3.2 Wands

The Nintendo Wii was the first console to bringmotion-sensor controllers in popularity. The Wii
remote controller possess a infrared sensor to
identify the IR light emitted by a sensor bar placedat the top or bottom of the television, provided withfive IR emitters in each side. The console, then,calculates the position of the controller bytriangulation, based on the distance of a fixed point
and the point the wii controller reads the infrared[9].

Figure 8: the Wii remote controller.
The controller is also equipped with aaccelerometer which detect three axis movements
and are sent to the console through bluetooth. A
gyroscope determine the inclination by thecalculation of the angle of such axis formed withthe force of gravity. It also have speakers and asimple rumble pack to give the user feedback.
Sony’s response to the Wii was the combination of
the Playstation Eye, which is an usual digital
camera, and the Playstation Move, the propermotion controller.

Figure 9: the Playstation Eye and twoPlaystation Move controllers, respectively.

The first thing one see about the PS Move is theball on the top of it. It is actually important to the
motion detection, as the PS Eye identify the ball torecognize movements. It possess three LEDs (Red,blue and green), which make the orb change to adifferent color, thus easing the detection made by
the PS Eye. Similar to the Wii controller, PS moveis equipped with a three axis accelerometer and agyroscope to determine its position. In addition, amagnetometer, which measure the Earth’s magnetic
field and is used to calibrate inertia sensors on thecontroller.
Its performance is better than the Wii remote,however it has not much software support to makeit a huge commercial success yet.

3.3.3 Computer vision

Another way to enable movement interaction isusing cameras to recognize models and identify
motion.
The PS Eye was briefly mentioned previously, but
the most famous device using such technology is
the Microsoft Kinect. It has being greatly exploredby the industry, universities and hobbyists since its
launch through reverse engineering or later
available SDK. Its main capabilities are using a
RGB camera that allows face recognition; a depth
sensor that enables it to scan the surroundings;
built-in microphone to capture sound; and a
microchip to track and recognize movements [10].

joints, to recognize movements and positions [10].
Plus, microphones enables it to capture soundcommands.

4. APPLICATIONSBasically, Virtual Reality may be applied to any
area computers are involved.
Here are the most common fields that use VR:

4.1 MilitaryThis field is one of the most important ones when it
comes to VR investment and development. The
most common use of VR in the military is that oftraining by simulation [11]. The use of vehicle
simulators is well-known in the field, as it proves tobe safer and, although expensive to install, morecost-effective than real training. Flight simulation isdone by either providing the user sets of computer
monitors to resemble a airplane view, or actuallyinserting the user in an simulation cockpit as shownin Figure 11.

Figure 11: a pilot in a military flight simulator.

Figure 10: the kinect motion sensing device
Its depth sensor captures 3D videos with a infraredprojector and a CMOS image sensor, whichmeasures the distance between its pixels and theobjects. These two sensors work together to identify
the room and the user in 3D. The depth sensor
perceives the nearer objects as more bright and thefurther ones in a darker tone. The generated image,by machine learning, is used to identify a human
body, 48 joints per user. Then, the image isprocessed along with a library of pre-recorded
positions in case the Kinect doesn’t capture all theBoth of these approaches use high performance
software, along with haptic feedback that greatly
improves user’s experience.
Ground and water vehicles simulation are also usedby the military, although they are not as famous astheir air counterpart. Heavy armored or tactical
vehicles navigation, as well as tactical andcommunicational scenarios are simulated.
Submarines simulation is an interesting area, as it
don’t need to use of visuals, but rather precise
methods to simulate readings and underwater
movement.
Military also uses VR in soldier training with theuse of head-mounted displays and joysticks that
resemble real firearms. The experience is muchsimilar to computer games and partnerships
between the military and computer games studios

are made to deliver a more immersive experience,from weapon simulation to strategy rehearsal.

4.2 Entertainment
The entertainment field has also being following
VR evolution for some time[12]. Crudely speaking,any modern computer game has the basic aspects ofvirtual reality: simulation, immersion andinteraction. The addition of VR devices are
becoming more common throughout the years. The
major video-gaming companies of today havealready entered in the motion control market. Movie
theaters and televisions have stereoscopic
technologies as well. And smartphones are capableof giving haptic feedback to users. Evidently,
technology is becoming more popular each day.

4.3 Educational
ScienceSpace is a well-known application focusedon education [13], which contains three different
applications: NewtonWorld, MaxwellWorld andPaulingWorld. It uses mainly a HMD whichdisplays stereoscopic images and a magnetic
position tracking system for heads and hands.
NewtonWorld focus on teaching students physics,
specially the Laws of Motion, by interacting with avirtual hand with balls that rebound from eachothers and walls, while experiencing different
states, such as no gravity or no friction sections.
In MaxwellWorld, users can explore electrostaticforces and fields, understand concepts and learn
about Gauss’s Law. The user is capable of placing
charges into the virtual space, creating electricfields of different intensities and polarities at will,
while being able to test the behavior of othercharges affected by the created electric fields.
And PaulingWorld enables the user do visualize
molecules, through different representations, andseeing details about its structure and its atoms.
Interaction is a future plan from PaulingWorld, inwhich the user would be able to remove or
substitute atoms and observe the consequences.

5. CONCLUSION
Virtual reality may affect every field in which
computers are involved. It can change the way
interaction with computers are made and it has thepotential of being the most powerful experiencedelivering media, as it is connected with theconcept of reality.
Also, the current generation Z cannot remember atime where computers were not involved in theirlife, therefore it is important to notice that virtual

reality popularity is increasing as a result, as it canbe seen through the recent success of emerging
technologies and products throughout the decades.
Perhaps it will take long before humans can fully
experience another “reality”, not being able to telldifference between real and virtual. But everythingis leading to the conclusion: it is possible.

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