'Virtual Reality' and
'Augmented Reality' buzzwords that can mean a lot of different things
depending on who you talk to, and the line between them can be blurred.
There have been
various ways of of trying to create scales or continuums from fully real
worlds to fully virtual worlds - https://en.wikipedia.org/wiki/Reality%E2%80%93virtuality_continuum
in general looking
something like this:
environment - you are completely immersed in the natural world
with minimal access to any synthetic worlds (e.g. your smartphone)
- augmented reality - you out in the real world with some gadgets (phone, headset) that allow you to experience the real world and a synthetic world simultaneously where the tech could range from a watch to a smart phone to a see through head mounted display.
- virtual reality - you are completely immersed in a synthetic world with minimal access to the real world
There is a large grey
area of 'mixed reality' that covers most of the space from purely real
to purely virtual where we spend most of our lives. I may be walking
down the street looking at a set of directions on my smartphone, or I
may be sitting on my couch with some chips and a drink playing a video
game on a big TV.
Lets take a look at
the different elements of Virtual Reality, and how technology, in
particular video games, have been moving us closer and closer to
We are all pretty
familiar with the 'pure reality' side of the spectrum so lets start with
The key element to virtual reality is immersion ... the sense of being surrounded.
A good novel is immersive without any fancy graphics or audio hardware. You 'see' and 'hear' and 'touch' and 'taste' and 'smell'
A good play or a film
or an opera can be immersive using only sight and sound.
But they aren't interactive
which is another key element.
'Choose Your Own Adventure' books in the late 70s added limited
interaction to books giving the reader a handful of choices every few
pages that would lead to 40 endings in the case of the first book 'The
Cave of Time', but it was computers that would run with this concept.
There is a sample
page here: http://www.sundancepub.com/c/@.IXKWkq4ugJuY/Pages/cyoa_studentbook_zoom.html
(and if you wish more
'serious' literary context on the topic, please see https://en.wikipedia.org/wiki/Hypertext_fiction
for several very serious pieces of literature with similar methods)
computer games from the late 70s and early 80s such as Adventure,
Zork, and the Scott Adams (not the Dilbert guy) adventures are immersive
and interactive and place the user within a computer generated
world, though that world was created only through text. You can
play adventure online at http://www.astrodragon.com/zplet/advent.html.
You can play the personal computer version of Zork online at
Scott Adams adventures are playable at
Games in the early
80s started to incorporate primitive computer graphics visuals
to go along with the text, such as Mystery House (1980) below.
and even simple 1st
person graphics in games such as Akalabeth (1980) and Wizardry (1981),
though the screen refresh rate was something less than real-time.
The screen took a long time (up to several seconds) to re-draw so these
games tended to be more strategy-based on a turn-taking model.
Myst in 1993 took the
visuals to a whole new level using CD-ROM storage for all of its (for
the time) very realistic imagery, though you could only move between a
set of fixed locations and viewpoints and use the mouse to click on
objects to interact with them - https://www.youtube.com/watch_popup?v=4xEhJbeho7Q
Moving on towards more modern computer games, they are immersive and interactive. These also have the advantage of being real-time running at 30+ frames per second, another key element.
Another key element
of VR is a viewer centered perspective where you 'see'
through your own eyes as you move through a computer generated space.
Akalabeth, Wizardry, and Myst were first person view games, though you
could only look where the game allowed you to look. Modern first person
shooters and other games use this view as you move through a virtual
world and interact with objects there, and more often than not kill
everyone you meet. The way you see the environment is limited to a
screen with a narrow angle of view and you use a keyboard / joystick /
gamepad to change your view of that scene, and interact.
One of the most
successful early ones was Wolfenstein 3D from 1992 - https://www.youtube.com/watch_popup?v=NdcnQISuF_Y
(image from Wikipedia)
Of course as time went on the visuals became better and some would stick with a first person perspective and others using a third person perspective to better show what was going on around the player.
First person or viewer centered perspective on the left vs third person perspective on the right from the Jedi Knight series from the 1990s.
VR adds the concepts of head tracking, wide field of view and stereo vision
Head tracking allows the user to look around the computer generated world by naturally moving his/her head. A wide field of view allows the computer generated world to fill the user's vision. Stereo vision gives extra cues to depth when objects in the computer generated world are within a few feet.
As Dan Sandin,
original co-director of evl likes to say, VR gives us the first
re-definition of perspective since the Renaissance in the 16th century.
Instead of having a fixed point for the viewer as denoted by the
obelisk, the user is free to move around with perspective changing as
he/she does so.
Draughsman Drawing a Recumbent Woman (1525) Woodcut illusion from 'The
Teaching of Measurements.'
interaction is also important in VR. If you want to
reach out and touch a virtual object then tracking the users hands lets
the user do that, rather than using a keyboard or gamepad to 'tell' your
virtual representation to interact.
One of the best
examples of this from the current crop of VR games is Job Simulator,
giving you a small environment to walk around in such as a cubicle with
a lot of different things to interact with using both hands.
also plays a very important role in immersion (try listening to a modern
Hollywood film without its musical score) and haptic (touch)
feedback can provide important cues while in smaller immersive spaces.
And there is some work in trying to deal with smell (the HITLab in the late 90s, and Yasuyuki Yanagi, Advanced Telecommunications Research Institute, Kyoto more recently) and taste (Hiroo Iwata, University of Tsukuba.)
So here is a picture
(from a video) that puts a lot of this together in a more serious use of
VR ... Randy Smith of General Motors in their CAVE in the mid 1990s
looking at different instrument cluster layouts for cars GM is
designing. Randy is real. The car seat Randy is sitting in is real. The
rest is computer generated, including the remote passenger joining Randy
from another location. If you have been in an automobile, truck, or
airplane built since the mid 1990s, VR was used as part of its design
In this case the
camera taking the photo is tracked so perspective is correct for us, the
viewer. Note that the crew of 'The Mandalorean' would rediscover this
technique 25 years later to integrate actors into their virtual sets.
Augmented Reality has a very similar feature set but whereas Virtual Reality usually is set up in controlled settings - typically indoors within a fixed space where you can set up and calibrate tracking systems, and you have access to power for the computers to drive the graphics), augmented reality usually takes place out in the real world where tracking is less accurate, electrical power needs to be portable, and computational power needs to be portable.
Augmented reality has the additional constraint that the synthetic world
it is creating must match up with the real world in real-time.
batteries help with making power more available, and access to local
phones that have access to cloud computing resources can help offload
the weight and the computation, but accurate tracking is still
difficult. In some minimal levels of AR where I want to know the
weather, I probably only need accuracy down to the city level, if I want
to know where is the closest coffee shop then I need accuracy down to
the block level, if I want to see what power lines are running under the
street or the names of the people who are walking past me then I need
much more accuracy and access to data at a much faster rate.
of creating virtual or augmented realities isn't new, and the desire to
experience these immersive worlds isn't new.
1580s - Giambattista della Porta develops the 'Pepper's Ghost' illusion - it is rediscovered in 1862 by Henry Dirks and John Pepper. It has recently been rediscovered yet again to produce 'holographic' concert performances link and a short video with some history and explanations here
1793 - Fixed 360 degree Panoramas
painted on the walls - Robert Barker in Leicester Square, London - link
(Image from the British Library)
1840s - Moving Panoramas painted on large rolled cotton sheets - John Banvard's Mississippi Panoramas - 3.6m (12 feet) high and 800m (2600 ft) long - link
A smaller one by John Egan was 7.5'
high and 348' long survives (think of a 185" diagonal TV back in the
with a video recreation at https://www.youtube.com/watch_popup?time_continue=25&v=uoqVfDEm5Rk
There was a 50
m) tall and 400 foot (122 m) long 'cyclorama' of the 1871
Chicago fire installed downtown from 1892 to 1893.
1800ds - Stereoscope - https://en.wikipedia.org/wiki/Stereoscope
The US Library of Congress has a nice
collection of stereographs including quite a number of them taken in
Chicago - https://www.loc.gov/photos/?fa=online-format:image%7Cpartof:stereograph+cards&q=stereograph
The stereoscope viewed single pairs
of images mounted on cards (sometimes glass) that could be swapped in
and out. The View-Master used discs containing 7 sets of paired slid
images where the viewer could use a lever on the side to cycle between
the images without needing to take their eyes out of the viewer.
(Stereoscope image from the US library of Congress. View-Master Reel from https://en.wikipedia.org/wiki/View-Master)
version (my3D) that used an iPhone as the display device allowing
content to be delivered through an app from over the web, including 3D
video, and audio. The device included finger holes to interact, and a
hole for the iPhone's camera. Google would use a similar idea in 2014 to
make google Cardboard.
would quickly start to see the possibilities ...
1901 - The Master Key: An Electrical Fairy Tale, Founded Upon the Mysteries of Electricity and the Optimism of Its Devotees by L Frank Baum (who had published the Wonderful Wizard of Oz the year before) proposed a set of 'character marker' eyeglasses that, when you looked at a person, showed the character of that person overlaid on their forehead (G for good, K for kind, etc.)
1935 - Pygmalion's Spectacles by Stanley Weinbaum describe a pair of spectacles which give a virtual reality experience: "But listen�a movie that gives one sight and sound. Suppose now I add taste, smell, even touch, if your interest is taken by the story. Suppose I make it so that you are in the story, you speak to the shadows, and the shadows reply, and instead of being on a screen, the story is all about you, and you are in it." and also VR's common critique ""Fools! I bring it here to sell to Westman, the camera people, and what do they say? 'It isn't clear. Only one person can use it at a time. It's too expensive.' Fools! Fools!"http://www.gutenberg.org/files/22893/22893-h/22893-h.htm
1950 - The Veldt short story by Ray Bradbury contains an educational nursery able to recreate any place
Circarama as part of Tommorowland at Disneyland with 11 projectors
showing a 360 degree film captured from 11 cameras, which were sometimes
mounted on a car - basically what google does for streetview today, but
back in the 1950s with film cameras.
1960 - Morton Helig
Sensorama - https://www.youtube.com/watch_popup?v=vSINEBZNCks
(image from http://www.mortonheilig.com/InventorVR.html)
patent for first HMD - the Telesphere
Mask - for 3D video
(image from http://accad.osu.edu/~waynec/history/lesson17.html)
1965 - Ivan Sutherland - University of Utah
1966 - Ivan Sutherland
(image from http://accad.osu.edu/~waynec/history/tree/images/hmd.JPG)
1967 - Fred Brooks - University of North Carolina
1973 - The Recreation Room (later
called the Holodeck) in Star Trek: the Animated Series
mid 70s - mid 80s Myron Krueger
(image from http://resumbrae.com/ub/dms424/05/01.html)
1977 - Richard Sayre, Dan Sandin, Tom DeFanti - UIC
1979 - Eric Howlett
1982 - Thomas Furness III
1984 - Michael McGreevy and friends
1985 - Jaron Lanier - VPL research
1986 - Kazuo Yoshinaka - NEC
1989 - Autodesk
1989 - Fake Space Labs
(image from: http://www.fakespacelabs.com/tools.html)
1990 a nice short BBC segment from 1990 on the state of the art at the time - https://www.youtube.com/watch?v=T2CYLlSn1gA
1991 - Virtuality -
1992 - Electronic Visualization Laboratory, UIC
1992 Tom Caudell - Boeing
1992 Steve Feiner and friends -
1993 - GMD - German National Research Center for Information Technology
1993 - SensAble Technology
1992 Steve Feiner and friends -
Mid 90s - Steve Mann - MIT
1998 - TAN / Royal Institute of Technology in Stockholm
1998 - Electronic Visualization Laboratory, UIC
1999 - Mark Billinghurst - HITLab at University of Washington
2000 - Hong Hua - University of Arizona
2013 - Google Glass
2014 - Oculus / Vive / Gear
- Google Cardboard
2016 - Microsoft
2017 - Dell, Asus and others release their Microsoft mixed reality based headsets ($300) with 'inside out' tracking where the hand-held controllers are tracked from the HMD with mixed success
2018 - Magic Leap AR display Dev Kits
released ($2,300 with no PC or tether)
2019 - Oculus releases Oculus Quest
as a $400 stand-alone device using smart phone level technology with
'inside out' tracking and two controllers, that is somewhat
under-powered but works really well.
2019 HoloLens 2
VR has gone through several hype phases with the biggest being in the mid 80s and mid 90s. With the release of low cost headsets we are now in the midst of another VR hype phase while AR is in its first hype phase.
As of 2019 both VR
and AR have made it past the Trough of Disillusionment and can be
considered 'mature' technologies.
As of 2018 Virtual
Reality made it onto the plateau of productivity, but AR was still deep
in the trough.
while in 2017 VR was still on the
slope of enlightenment and AR was headed into the depths of the through.
(image from https://www.gartner.com/smarterwithgartner/5-trends-emerge-in-gartner-hype-cycle-for-emerging-technologies-2018/)
back in 1995, when the first of these
charts came out, VR was just sliding down into the trough of
(image from https://www.gartner.com/doc/484424/gartners-hype-cycle-special-report#1169528434)
For large format based systems, some companies that sell these things are:
For Head Mounted Displays, the previous generation of $10,000 - $20,000 displays by companies like NVIS have mostly been supplanted by a new generation of low cost sub $1000 gaming-related displays:
Instead of totally isolating the user
from the real world, Augmented Reality displays overlay computer
graphics onto the real world with devices like Google
Glass and the Microsoft
HoloLens and the Magic Leap
and there are other interesting
solutions that have been in development for a couple decades such as the
and to some extent your smartphone or
tablet with GPS, camera, and a Gyroscope already acts as an AR display.
There is quite a
bit of work going on in various research labs in VR. New devices are
being created, new application areas being worked on, new interaction
techniques being explored, and user studies being performed to see if
any of these are valuable. What is much harder is getting the technology
and the applications out of the research lab and into real use at other
sites - getting beyond the 'demo' stage to the 'practical use' stage is
still very difficult.
I'm going to give a brief overview here and then we will go into each of these areas in more detail in the coming weeks
For virtual reality it is important to note that the goal is not always to recreate reality.
Computers are capable of creating very realistic images, but it can take a lot of time to do that. In VR we want at bare minimum 20 frames per second and preferably 60+ in stereo.
The trade off is
image quality (especially in the areas of smoothness of polygons,
anti-aliasing, lighting effects, transparency) vs speed of rendering. In
some cases, like General Motors, they sacrifice frame rate (frames per
second) for better visual quality.
Gamers tend to want
much higher frame rates than people watching TV / Movies / YouTube
In AR we are
typically not covering the entire field of view of the user so the
rendering requirements are lower, but there is a greater need to do a
better compositing between the real and the synthetic (i.e. based on
lighting conditions) and faster graphics updating.
If we want stereo visuals then we need a way to show a slightly different image to each eye simultaneously. The person's brain then fuses these two images into a stereo image.
One way is to isolate
the users eyes (as in a HMD or BOOM) and feed a separate signal to each
eye using 2 display devices where each eye watches its own independent
display (as in older HMDs), or take a single wide display and render the
left and right eye views onto the same screen and then make sure each
eye can only see its appropriate half of the display (as in current less
Another way is to show the imagery on a larger surface and then filter which part of the image the user sees. There are several different ways to do this.
We can use
polarization (linear or circular) - polarization was used in 3D
theatrical films in the 1950s and 1980s and the current generation. One
projector is polarized in one direction to show images for the left eye,
and the other projector is polarized in the other direction to show
images for the right eye. Both images are shown on the same screen and
the user wears lightweight glasses to disambiguate them.
This same technology
can be used on televisions by adding a polarized film in front of the
display where even lines are polarized in one direction and odd lines
are polarized in the other direction. The user only sees half of the
resolution of the display with each eye. This is the technology we use
We can use colour -
this has been done for cheaper presentation of 3D theatrical films since
the 50s with red and blue (cyan) glasses as you only need a single
projector, or a standard TV. It doesn't work well with colour and is
somewhat headache inducing after an hour.
We can use time - this was common in VR in the 90s and the 00s as in the original CAVE. Here we show the left eye image for a given frame then the right eye image for the same frame, then move on to the next frame. The user wears LCD shutter glasses which ensure that only the correct eye sees the correct image by going opaque on the eye that should be seeing nothing. These glasses used to cost over $1000 each in the early 90s. They were the basis for the early 3D televisions and cost around $100 per pair. Now they are down to $30 per pair.
In all these cases both of the eyes are focusing at a specific distance - wherever the screen is located. There is no way for the user to change focus and bring parts of the scene into focus and let others go out of focus as in the real world .
"people hate helmets, but people like sunglasses"
ergonomics and health issues of various displays
Typically museums and
other places with many visitors it is necessary to either give the
glasses away to the user (with the paper ones) or wash them (with the
polarizing ones) to keep things sanitary. This is more difficult with
HMDs and AR headware where people have tried using alcohol wipes.
don't spend all day in VR but people may spend all day in AR. VR also
tend to be done in private where AR is more done outside. AR headware
has to be light and unobtrusive, but still be able to operate. The
entire computation system may be in the headgear as well, or some may be
offloaded to a smart phone or to the cloud. Google Glass was one light
solution. Headware for bikers like the Solos
http://www.solos-wearables.com/ are another, as is the Microsoft
Need a computer capable of driving the display device at a fast enough rate to maintain the illusion.
In the past (i.e. the
90s) that usually means either simple scenes, very specialized graphics
hardware, or a lot of work in optimizing the software. But this is less
true today where scenes are getting more complex, the hardware more
commonplace, and the software more capable, mostly thanks to the
Benchmarks on CPUs and graphics cards aren't really very meaningful. They can give ballpark figures but there are a lot of factors that combine to give the overall speed/quality of the virtual environment.
Multiple processors are usually required, since there tend to be multiple simultaneous jobs to be performed - i.e. generating the graphics, handling the audio, synchronizing with network events.
Multiple graphics engines are pretty much required if you have multiple display surfaces
Ability to 'pipeline'
the graphics is pretty much required
With a very fast
network it is possible to render the graphics remotely on a more
powerful computer and just use the local display as a receiver.
At minimum you want to track the position (x, y, z) and orientation (roll, pitch, yaw) of the user's head - 6 degrees of freedom.
You often want to
track more than that - 1 or 2 hands, legs?, full body?
How accurate is the
How far the user can move - what size area must the tracker track?
Can line of sight be
guaranteed between the tracker and the sensors, which is necessary in
many tracking systems?
What kinds of latencies are acceptable?
Input devices are perhaps the most interesting area in VR research. While the user can move their head 'naturally' to look around, how does the user navigate through the environment or interact with the things found there?
Ambient sounds are useful to increase the believably of a space
Sounds are useful as a feedback mechanism
Important in collaborative applications to relay voice between the various participants
Spatialized 3D sound can be very useful
Often useful to network a VR world to other computers.
We need high bandwidth networking for moving large amounts of data around, but even more important that that we need Quality of Service guarantees, especially in regards to latency and even more especially related to jitter.
Photo of the classic evl CAVE from the early 90s with 4 1-megapixel screens with active (shutter glasses) stereo giving typically 2 megapixels to each eye depending where you stand) , a 10' by 10' area to move, magnetic tracking for the head and one controller. Total cost was around $1,000,000 in 1991 dollars (about $2,000,000 in 2020 dollars) with about $500,000 of that 1991 price for the refrigerator sized computers to drive it.
to put this hardware into context, in
1991 we had
In 2017 the VIVE could send roughly
1-megapixel to each eye, gives the user a similar space to walk around
in, IR camera tracking for the head and two controllers for about $2,500
including the computer.
If you don't mind lower quality
visuals in 2019 the Oculus Quest gives the user a similar experience for
$500 with no additional hardware needed.
Vision / Visuals and Audio