AUGMENTED REALITY

By

Rick Oller

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This report examines the technology and uses of augmented reality. The history,

technology and a wide variety of applications across diverse disciplines are discussed in

depth. The report concludes with some observations about the future directions possible

with this technology.

TABLE OF CONTENTS

LIST OF FIGURES…………………………………………………………… iv

ABSTRACT…………………………………………………………………… v

I. INTRODUCTION……………………………………..……… 1

II. HISTORY…………………………………………………..…. 2

III. TECHNOLOGY…………………………………………….… 4

Registration…………………………………………….……… 4

Fiducial registration…………………………………… 5

Image-based registration………………………….….... 5

Tracking……………………………………………………..… 5

Displays………………………………………………….…….. 5

Optical displays……………………………….……..… 6

Video displays……..………………………….……..… 6

Hand-held displays………...………………………..… 6

Projected displays……………………………………… 6

Retinal displays………………………………………… 7

Screen-based displays………………………………..… 7

Software……………………………………………………….. 7

ARVIKA………………………………………………. 7

ARTag…………………………………………………. 7

ARToolkit……………………………………………… 8

Wearable Computing…………………………………………... 8

CPUs…………………………………………………… 8

Display devices………………………………………… 8

Location tracking devices……………………………… 8

Pointing devices……………………………………….. 9

Network Infrastructure………………………………………… 9

3rd-generation wireless networks and IPv4…………… 9

4th-generation wireless networks and IPv6…………… 10

IV. APPLICATIONS……………………………………………… 11

Medical Applications………….………………………………. 11

Augmented ultrasound………………………………… 11

Pre-surgical planning………………………………….. 12

A birth simulator………………………………………. 12

Military Applications………………………………………….. 12

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Land Warrior………………………………………….. 12

Battlefield Augmented Reality System……………….. 13

Industrial and Manufacturing Applications………………………. 14

Boeing’s wire bundle assembly project……………….. 14

DaimlerChrysler’s augmented reality initiatives……… 15

Truck wiring harness design…………………………… 15

Visualization of data in airplane cabins…………..…… 15

Motor maintenance and repair…………………………. 15

BMW’s intelligent welding gun……………..……… 16

Mobile Applications………………………………………… 16

LifeClipper………………………………………….. 16

LifeClipper2………………………………………… 17

LifeClipper3………………………………………… 17

Wikitude World Browser…………………………… 18

Seer…………………………………………………. 18

TAT Augmented ID………………………………… 18

TwittARound……………………………………….. 18

Yelp…………………………………………………. 18

The Touring Machine……………………………….. 19

Entertainment Applications…………………………………. 19

ARQuake……………………………………………. 19

Virtual sets…………………………………………… 19

First down…………………………………………… 20

Concert augmentation……………………………….. 20

Education Applications……………………………………… 20

BBC Jam storybooks for kids……………………….. 20

The Invisible Train………………………………….. 20

AR Polygonal Modeling…………………………….. 20

Architecture and Urban Planning Applications……………... 21

The ARTHUR project……………………………….. 21

V. THE FUTURE OF AUGMENTED REALITY…………….. 22

VI. CONCLUSION……………………………………………… 24

INFORMATION SOURCES…………………….………………………….. 25

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LIST OF FIGURES

Figure Page

1. Sword of Damocles………………………………………………….. 2

2. A Modern Head-Mounted Display…………………………………... 3

3. Land Warrior Individual Soldier Combat System…………………… 13

4. ARTHUR…………………………………………………………….. 21

5. Contact Lenses with Electronic Circuits…………………………….. 22

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ABSTRACT

Augmented reality is a technology that merges visual perception of real world

environments and objects with virtual, computer-generated content. Augmented reality

systems achieve this combination of the real and virtual using computers, displays,

specialized devices for geospatial and graphic alignment, wired and wireless networks

and software.

Research in augmented reality draws on development from a number of other fields

including virtual reality, wearable and ubiquitous computing, and human-computer

interaction. Whereas virtual reality and virtual worlds immerse the subject in a computer-

simulated environment, augmented reality augments and annotates the natural

environment with virtual components. Augmented reality brings virtual reality into the

real world and in the process enhances what we can do in real-world scenarios.

This history of augmented reality can be traced to work done at MIT in the late 1960s. In

the ensuing decades, a growing cadre of researchers in university, medical, industrial and

military settings built upon the early breakthroughs. Diverse applications of augmented

reality followed, and today we are witnessing a dazzling array of innovations across a

wide spectrum of industries and disciplines.

The technology behind augmented reality is a blend of custom-made and off-the-shelf

hardware and software. Display solutions include: (1) head-mounted displays; (2) hand-

held displays; (3) projected imagery; (4) screen-based displays; and (5) retinal projection

devices. Users can be tethered to wired networks or free-ranging, using broadband

wireless networks. Advances in wearable computing technology have spawned

applications of augmented reality in military operations, tourism, gaming, architecture

and urban planning. The software for building augmented reality systems has advanced

measurably since the early days. Full-featured, powerful software libraries and

frameworks are now routinely used, sparing developers the need to program their

applications from scratch.

Despite the challenges and difficulties of bringing this sophisticated technology to society

in a form that is user friendly, inexpensive and vitally useful, advances in augmented

reality are occurring every day. From mobile applications for cell phones to

breakthroughs in computerized contact lenses, the pace of innovation has quickened

noticeably in recent years. What was once the province of university laboratories and

science fiction is rapidly becoming accessible for everyday use.

Report

on

Augmented Reality

I. INTRODUCTION

Augmented reality is a technology that merges visual perception of real world

environments and objects with virtual, computer-generated content. The research

literature defines augmented reality as systems that have the following three

characteristics: (1) combine real and virtual content; (2) are interactive in real time and

(3) are registered in 3-D [1:356].

Augmented reality systems achieve this combination of the real and virtual using

computers, displays (head-mounted, hand-held, projected, screen and retinal), specialized

devices for geospatial and graphic alignment, wired and wireless networks and software.

Research in augmented reality draws on development from a number of other fields

including virtual reality, wearable and ubiquitous computing, and human computer

interaction [2: 167]. Augmented reality is related to virtual reality and virtual worlds

(such as Second Life) in its use of virtual content however it does not fully immerse the

user in a virtual environment. Whereas virtual reality and virtual worlds immerse the

subject in a computer-simulated environment, augmented reality augments and annotates

the natural environment with virtual components. Augmented reality brings virtual reality

into the real world and, in the process, enhances what we can do in real-world scenarios.

There are many challenges to the widespread, everyday acceptance and use of augmented

reality applications. Alignment of virtual content with real-world environments is a

complex and vexing challenge. Wireless networks for mobile augmented reality

applications are inconsistent and often lack sufficient bandwidth for sophisticated

applications. Head-mounted displays, although improving constantly with advances in

miniaturization of optical and display technology, can be uncomfortable and socially

awkward.

All of these challenges are being addressed. Augmented reality technology and

applications are advancing rapidly. The purpose of this report is to provide a background

on this exciting field: it will cover the history, technology, applications and future

directions.

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II. HISTORY

Augmented reality, which is rapidly becoming the “next big thing” in technology, is

actually over 40 years old. Because it is a hybrid of a number of technologies, augmented

reality had to wait for its components to mature before it was ready for mass acceptance.

Early pioneers had to create much of the equipment and software from scratch, which

made for a slow development cycle. Researchers persevered and the fruit of their labor is

the burgeoning marketplace for devices and applications that is today’s augmented

reality.

Early Academic Research

The beginnings of augmented reality can be traced to the work of computer scientist Ivan

Sutherland at MIT in 1968. Sutherland’s invention, dubbed the “Sword of Damocles”

(after a Greek legend told by Cicero) was the first augmented reality head-mounted

display. The user wore a helmet tethered to the ceiling. Three-dimensional vector

graphics (wire frame or line drawings) generated by software created by Sutherland’s

team were displayed on video screens mounted on the helmet. The images from the

screens were conveyed to the user’s eyes by means of lenses and half-silvered mirrors, a

technique that is still in use in many of today’s head-mounted displays. The user saw the

graphic images superimposed on the real world scene, visible through the partially

reflective display.

The user’s gaze was tracked by sensors that detected head movements via the helmet and

changed the generated graphic visual overlay accordingly [3:107-108].

Figure 1. Sword of Damocles [30:757]

Both flight simulator technology and medical imaging augmented reality research grew

out of Sutherland’s work at MIT and the University of Utah.

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Military and Commercial Development

In the 1970s and 1980s a small number of researchers studied augmented reality at

institutions such as the U.S. Air Force’s Armstrong Laboratory, the NASA Ames

Research Center and the University of North Carolina at Chapel Hill [4:50].

Military use of head-mounted display technology began with the Honeywell Integrated

Helmet and Display Sighting System (IHADDSS), first used in 1985 [5:44].

The first commercial head-mounted display, called the EyePhone, was marketed in 1989.

It was created by VPL Research, a company founded by Jaron Lanier, a computer

scientist who first popularized the term “virtual reality”. The EyePhone was a boon to

researchers in the nascent virtual and augmented reality fields, and many institutions and

laboratories began experimenting with the new technology. Many head-mounted displays

have been developed and commercialized since the EyePhone [5:45]. Contemporary

commercial head-mounted displays have been reduced to the size of a pair of sunglasses,

and are quite stylish and futuristic in appearance.

Figure 2. A Modern Head Mounted Display [31]

The term augmented reality was first coined by researcher Tom Caudell in 1992 in the

context of a pilot project in which the technology was used to simplify industrial

manufacturing processes in a Boeing airplane factory.

Computer Graphics Advances

Along with the invention and evolution of head-mounted displays, 3D computer graphics

technology that provides the virtual component of augmented reality has seen dramatic

growth and promise. Beginning with the primitive vector graphics used in Sutherland’s

Sword of Damocles, graphics innovations such as solid modeling, texture mapping and

physics engines have enabled spectacular advances in such areas as filmmaking, gaming,

virtual worlds and, of course, augmented reality.

Augmented Reality Today

The past decade has seen a flowering of augmented reality research as hardware costs

have fallen enough to make the necessary lab equipment affordable. Scientists have

gathered at yearly augmented reality conferences (ISWAR and ISMAR) since 1998.

Despite the tremendous changes in information technology since Sutherland’s

groundbreaking work, the key components needed to build an augmented reality system

have remained the same: displays, trackers, graphics computers and software.

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III. TECHNOLOGY

The technology behind augmented reality draws from a number of disciplines and

exhibits a wide array of approaches to the problem of combining virtual and real-world

objects and scenes. Display technology solutions range from head-mounted, hand-held,

projected, and screen-based to what many consider the future of augmented reality –

retinal displays. Augmented reality applications can be stationary and tethered (wired to

local networks), mobile and wireless (using broadband wireless networks) or some

mixture of the two. Few technologies have explored as many different approaches to their

problem space as augmented reality.

Human vision is the most reliable and complicated sense, providing more than 70% of

total sensory information [5:45]. With so much emphasis placed on the visual, it is of

utmost importance that augmented reality provide a seamless merging of the virtual and

real, and this is also its biggest challenge.

Alignment Strategies

Aligning computer-generated imagery with real-world scenes is achieved through two

basic approaches:

Registration: Augmented reality applications need to be able to consistently

identify location and depth cues within the user’s view for accurate placement of

virtual content. Registration strategies are employed to this end.

Tracking: Applications must know the position and alignment of the user’s point

of view to consistently render properly aligned and situated content.

Registration. Registration is the real-time alignment of computer-generated graphics

with the user’s view of the real world. Registration requires the computer to have

accurate knowledge of the structure of the physical world and the spatial relationships

between the world, the display, and the viewer [5:24].

For a medical application where computer-generated images are overlaid on a patient,

accurate registration with the patient’s anatomy can be a matter of life or death. For a

manufacturing application, incorrect registration can result in errors or accidents.

Several strategies for registration in augmented reality applications have been developed.

Some applications use a combination of these strategies in an effort to gain the best

possible registration however this has caused another problem due to the processing

power required – latency, or lag in synchronization of virtual and real scene elements.

There are two distinct approaches to registration in augmented reality applications:

Fiducials

image-based (markerless)

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Fiducial registration. Fiducials are markers placed in the real-world scene to facilitate

alignment between computer-generated content and the world. These markers employ an

easily recognizable symbol or shape, preferably one that can be computationally

recognized in a maximum of different conditions and from any angle or alignment. The

augmented reality software deduces not only lateral alignments, but also depth and

distance information from the fiducials. Many popular augmented reality applications use

fiducial registration as it is the easiest to handle computationally.

Image-based registration. Markerless or image-based registration relies on a number of

environmental cues for alignment of computer-generated content with real-world scenes.

There are edge-based methods that use computer vision algorithms to detect object

boundaries. There are also texture-based methods that isolate and uniquely identify points

on a surface and then correlate the points in real-time to incorporate motion (both of the

real-world objects and of the user) while maintaining registration. A problem with image-

based registration is that for edge- or texture-based methods, a baseline scene must be

established. This is not always possible with real-world augmented reality applications

however faster processors and new approaches have enabled applications to establish

baselines on the fly.

Tracking. Tracking allows augmented reality applications to properly render the virtual

components of a scene as the user’s point of view shifts. Virtual objects should not follow

the user’s gaze around a scene, unless that is the intent of the designers. Likewise, virtual

objects should not tilt if the user tilts his or her head. Tracking data is used by the virtual

reality application to make sure that the virtual and real components of a scene align

properly regardless of the position of the user’s head and the direction of gaze.

Tracking can be achieved with a wide variety of different technologies that are based on

different physical principles. Mechanical, magnetic, acoustic and optical tracking

approaches are commonly used [5:213].

Not all augmented reality applications require precise tracking. Popular modern

applications, such as those that employ cell phones, need only be concerned with aligning

virtual content with the camera’s view of the scene.

Displays

A wide variety of display technologies are employed for augmented reality applications.

The main categories of display are:

Optical

Video

Hand-held

Projected

Retinal

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Screen-based

Display technologies vary according to requirements. Optical and video displays are

considered head-mounted displays and afford the user maximum freedom of motion. For

head-mounted displays, weight and balance of equipment is an important consideration

for comfort and freedom of movement. If stereoscopic vision is required, the distance

between the user’s eyes must be calibrated for accurate depth imaging.

Optical displays. Also known as see-through displays, optical displays allow the user to

view the real world directly with the addition of computer-generated graphics or text

superimposed on the scene. Optical displays are worn like glasses with image-generating

and blending components placed in a location that does not interfere with vision. An

optical combiner, typically a half-silvered mirror, is placed in the optical path of the

viewer. Image-generation devices, typically tiny LCD (liquid crystal display) screens, are

situated at the side of the user’s head, and their content conveyed via relay optics to the

optical combiner.

Video displays. Video displays combine live video of real-world scenes with computer-

generated graphics or text. With video displays, the user does not view the real-world

directly, but from the point of view of two small video cameras mounted on the headset.

Chroma-key (green screen) techniques, like those employed to combine meteorologists

with weather maps on the television news, are used to fuse video and generated imagery.

Although resolution is lower with video displays than optical, the combination of

generated and real-world imagery is much more seamless, as the entire visual field can be

rendered together for display to the user.

Hand-held displays. Cell phones, PDAs and tablet PCs are all examples of hand-held

augmented reality displays. Hand-held displays incorporate all aspects of augmented

reality equipment in one device: processor, memory, camera, display and interactive

components. Imagery from the device’s camera is combined with generated imagery to

produce the augmented scene on the screen.

While they do not afford the immersive experience of optical and video displays, hand-

held displays have a unique advantage: they employ widely accepted, inexpensive

equipment that most people already own or have access to. These devices have the

greatest potential for bringing augmented reality applications to a mass audience.

Projected displays. Projected displays are employed by location-specific augmented

reality applications. Museums, art galleries and scientific simulations are all candidates

for projected augmented reality. A camera captures the real-world scene, processors

combine real and virtual elements, and a projector projects the scene onto a screen or

wall. Projected displays are limited by their physical immobility as well as the resolution

and sharpness of the projected imagery.

Retinal displays. Retinal displays project light directly onto the retina. This eliminates

the need for screens and imaging optics, theoretically allowing for very high resolutions

and wide field of view [5:48]. Low-powered lasers have been used to project images

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directly onto the retina, but current technology limits the display to monochromatic red

light. The US military has pioneered the use of this technology: the Stryker armored

vehicle augmented reality system has a component that projects battlefield computer

imagery onto the commander’s retina.

Screen-based displays. Screen-based displays mix real and virtual imagery for display

on a regular computer or video monitor. This technology is usually combined with

webcams to produce personal computer-based augmented reality applications. Like hand-

held displays, this technology has a high potential for mass acceptance and has already

seen a proliferation of internet-based advertising applications that highlight a specific

product.

Software

Early augmented reality researchers had to write all of their software from scratch. This

made research and development highly time consuming and required extensive

programming resources for each project. In recent years, frameworks for augmented

reality software development have emerged, making the creation of robust applications

possible in a fraction of the time and with far fewer bugs and errors than the early

adapters faced. The most popular frameworks in augmented reality software development

are:

ARVIKA

ARTag

ARToolkit

ARVIKA. ARVIKA is a consortium funded by the German government to research and

create augmented reality applications, and it is also the name of their framework for

application development. ARVIKA supports stationary applications using high-end

graphics systems, as well as mobile systems with lower resolution graphics. The principal

mobile front-end used by ARVIKA is a standard web browser with a plug-in. Particularly

suited to industrial applications, ARVIKA applications specialize in incorporating CAD

(computer-aided design) drawings and supporting text and graphics into augmented

reality applications. ARVIKA’s collaboration tools foster interaction between mobile

users and lab- or factory-based experts to facilitate remote support for highly technical

repair and maintenance applications [6:244].

ARTag. ARTag, developed by the National Research Council of Canada, is a fiducial

marker system for augmented reality. ARTag markers are digitally generated and

scientifically verified as a trusted reference for augmented reality applications. ARTag

employs special black-and-white square markers to register virtual content accurately

relative to the real world. Markers are printed and placed where users would like the

virtual elements to appear [7:5-6].

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ARToolkit. ARToolkit is an open source software library for building augmented reality

applications. Registration is accomplished with fiducial markers, and tracking is done

using computer vision algorithms. ARToolkit supports both optical and video devices and

can also run on a PC or Mac with a USB webcam. A version of the toolkit uses Flash (a

popular graphics animation program for the web) to display virtual and real content in a

YouTube-like viewer.

Wearable Computing

An essential ingredient for many augmented reality applications is complete portability of

hardware. For augmented reality to exist in the world while not being tethered to a bundle

of wires, an independent but related technology, wearable computing, is available.

Wearable computers are not solely used for augmented reality applications: virtual

reality, multiplayer gaming environments, and ubiquitous computing hobbyists and

researchers all employ aspects of wearable computing.

Wearable computing is defined as a fully functional, self-powered, self-contained

computer that allows the user to access information anywhere and at any time [8:471].

Professor Steve Mann, an early proponent of wearable computing described in the press

as the “world’s first cyborg” [9] (due to his personal commitment to full-time wearable

computing) defines wearable computers as “a computer that is subsumed into the

personal space of the user, and has both operational and inter-actional constance, i.e., is

always on and always accessible.” [2:159].

CPUs. Curiously, the CPU (central processing unit or computer box) component of

wearable computing has not caught on commercially while other components have a

robust roster of commercial products. Augmented reality researchers that require

wearable computing typically have to use notebook computers, adapt existing CPUs or

build special, one-off lightweight CPUs for users to wear. This will likely change as more

applications are built to take advantage of advances in wireless networks and augmented

reality software.

Display devices. In addition to the computer, wearable computing applications for

augmented reality require a display device. Head-mounted displays are the generally

accepted choice for wearable applications. Head-mounted displays have evolved from

large, heavy, unwieldy contraptions to light, stylish glasses. Several manufacturers have

entered the head-mounted display market with futuristic designs favored by mobile

gamers and augmented reality pioneers alike.

Location tracking devices. Location tracking devices, such as GPS receivers and digital

compasses, are also key components of wearable computing for augmented reality

applications. While commercial GPS receivers are intentionally lacking in precision (for

reasons of military security), clever augmented reality programmers are able to refine and

enhance location sensing via other means. This is true mainly in mobile phone-based

applications, where designers can use cell tower location tracking to supplement the GPS

data. However, there is no reason why this technology cannot be incorporated into

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wearable computers and used for augmented reality applications that use head-mounted

displays and other wearable computing equipment.

Pointing devices. Pointing devices are a design challenge for wearable computing.

Obviously, traditional command line or even 2D graphics interfaces with mice are not

practical. Joysticks and trackballs are the preferred pointing devices, and twiddler or

chording keyboards (keyboards with alternate layouts from the QWERTY standard) are

employed when full text entry is required by the application. Frequently, augmented

reality applications with wearable computers use innovations that are unique to the

augmented realm: icons and symbols appear as virtual objects projected over the real

world scene, and can be activated by hand gestures, wearable pointing devices or even

eye movements. Another methodology, particularly suited for hands-free application

requirements, is voice-activated command. When voice commands are employed, the

wearable computing system must include headphones or earbuds as well as a head-

mounted microphone. Voice command sub-systems can also supplement other interaction

technologies.

Network Infrastructure

Network infrastructure is important to the widespread acceptance of augmented reality.

While some applications can function perfectly well in a static, tethered (wired) network

environment, the latest directions in application functionality indicate a mobile approach

will dominate this field. The key components of wireless network infrastructure that will

need to be addressed are: (1) the next-generation capabilities available in 4th-generation

wireless technology; and (2) the virtually limitless addressing capability of IPv6.

3rd-generation wireless networks and IPv4. Today’s untethered (mobile) augmented

reality applications are severely limited by the current state of wireless network

technology. Wireless phone and broadband internet access today is largely of the third-

generation (3G) variety. Third-generation wireless is a bundle of standards for mobile

telecommunications defined by the International Telecommunication Union (ITU).

Services include wide-area wireless voice telephone, video calls and wireless data, all in

a mobile environment. 3G allows simultaneous use of speech and data services at rates up

to 14.4 megabits per second on the downlink and 5.8 megabits per second on the uplink

[10].

The current network addressing scheme used over the Internet is referred to as Internet

Protocol version 4 (IPv4). This scheme is limited to approximately 4 billion addresses

and is about to run out of addresses as the world continues to go online.

In order for mobile applications to be able to offer comparable full-blown augmentation

to the wired-network or closed-circuit applications in existence today, rather than the

text-only augmentations typical of mobile augmented reality, wireless network

infrastructure will need to advance to the next standard, 4G. Additionally, addressing

standards for devices and computers will need to advance from the current IPv4 to IPv6.

IPv5 was a streaming network protocol that never caught on, hence the jump from

version 4 to version 6.

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4th-generation wireless networks and IPv6. The wireless networking standard known

as fourth-generation (4G) has been in the planning stages for several years. It promises

100 megabit per second wireless connectivity between any two devices on the planet

while one or more is in motion, and 1 gigabit per second connectivity while stationary

[11]. This will easily accommodate mobile augmented reality applications with full-

motion, photorealistic 3D virtual objects and environments.

Additionally, the next generation of internet addressing schemes, Internet Protocol

version 6 (IPv6), will accommodate 2128

network addresses, bringing literally trillions of

devices online. It will be possible to directly address millions of wireless sensors per

square kilometer over the internet [2:8]. Although implementation of IPv6 is still a long

way from happening, its arrival will signal the advent of the era of global ubiquitous

computing.

The onset of 4G is much closer than that of IPv6. Rollouts of large carriers’ 4G networks

are scheduled to begin in late 2009 into 2010. We will undoubtedly start to see the

development of serious mobile augmented reality applications soon after the arrival of

4G, as the technology for full-blown 3D augmentation has been a capability of tethered

augmented reality applications for a number of years already.

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IV. APPLICATIONS

With little fanfare, augmented reality systems have been used in a wide variety of fields

over the past two decades. While many of the applications described here are purely

research prototypes, quite a few are beginning to see widespread acceptance, particularly

the mobile applications. This survey of augmented reality applications explores

technological innovation in a full spectrum of fields:

Medical

Military

Industrial / Manufacturing

Mobile

Entertainment

Education

Architecture and Urban Planning

Medical Applications

Augmented reality applications are appearing in both training and real-world medical

scenarios. The capability to look within a body without cutting it open has long been a

goal of medical technology research. Augmented reality systems are realizing this goal

with displays that mix real-world views of patients with virtual internal views facilitated

by real-time ultrasound, magnetic resonance imaging (MRI), computed tomography (CT)

scan, and laparoscopic data.

Augmented ultrasound. Researchers at the Department of Computer Science at the

University of North Carolina, Chapel Hill, have pioneered the development of medical

applications of augmented reality. Physicians were outfitted with head-mounted displays

that enabled viewing of a pregnant woman with an ultrasound scan of the fetus

overlaying the woman’s abdomen. Walking around the patient allowed the physicians to

observe the fetus from different angles and to diagnose its position in relation to the

woman’s internal organs [8:20].

UNC researchers also developed an application allowing physicians to see directly inside

a patient using ultrasound echographic imaging and laparoscopic range imaging

combined with a video head-mounted display. A high performance graphic computer was

used to generate imagery from the imaging systems and render it for integration with the

live video feed of the patient [12].

Another application of medical augmented reality at UNC involved ultrasound-guided

biopsies of breast lesions. Early results from experimenting with computer models and

with one human subject have been encouraging.

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Pre-surgical planning. Harvard Medical School researchers used 3D images in pre-

operative surgical planning and simulation for neurosurgical and craniofacial surgical

applications. They built an augmented reality display that allowed surgeons to

superimpose 3D images on patients with accurate, realistic interior viewpoints of the

target anatomy. They also mixed computer models of a patient’s brain and tumor with a

live video image of the patient to plan the removal of diseased tissue [8:20].

A birth simulator. Siemens Corporate Research has developed an augmented reality

system for real-time augmentation in medical procedures (RAMP). It is optimized for

accurate registration, high resolution and fast refresh rate. Using RAMP, the Orthopedic

Clinic of Munich, Germany has developed a birth simulator for medical training.

The birth simulator provides a 3D visualization of the birth process on a head-mounted

display that supports stereo vision. Head movements are tracked and the display altered

accordingly, providing depth cues as if the user were viewing a live baby inside the

mother. The imagery is overlaid onto an anatomically correct partial dummy representing

the mother. The skin and hip bones of the virtual mother can be display or removed for

different depth-level visualization.

The user also sees real-time vital statistics for the mother and the baby projected on the

head-mounted display field of view. Blood pressure, heart rate, pain and oxygen supply

data are provided. Biomechanical data are provided as well, including position of the

baby’s head, friction in the birth canal and tissue forces. Sensors and force-feedback

allow trainees to apply forceps to the proper location on the articulated dummy and feel

(and see) dynamic simulation of a birth procedure.

The birth simulator system uses a high resolution video head-mounted display. Visual

tracking data is used for accurate rendering of virtual objects. The all-video nature of the

system facilitates third-party monitoring of the training process via traditional video

monitors. Initial results of the simulator in training were positive. Further development of

the RAMP system with other medical applications is in progress [13].

Military Applications

The US military, in conjunction with major defense contractors and aerospace

companies, has been researching and experimenting with augmented reality systems for

the better part of two decades. Their stated goal is to improve situational awareness for

pilots and soldiers and to facilitate enhanced communication with their peers and the

chain of command. Heads-up displays (transparent displays of data mounted in the pilot’s

line of sight) have long been a reality for fighter jet pilots, and recent developments make

use of advanced eye-tracking to allow pilots to acquire targets and fire upon them simply

by looking at them.

Land Warrior. Land Warrior is a US Army wearable computing and augmented reality

application that is part of the Future Combat Systems initiative. It combines commercial,

off-the-shelf technology and standard military equipment, integrating weapon systems

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(M16 rifle or M4 carbine) with video, thermal and laser sighting in a head-mounted

display that overlays situational awareness data with real world views in real time [14].

The head-mounted display shows digital maps, intelligence information and troop

locations together with imagery from the weapon sighting systems. Thermal imaging

enables the soldier to see through obstacles as well as offering greatly enhanced night

vision [15]. A GPS receiver provides location information and an integrated radio

facilitates communication among troops. Integration with Stryker class military vehicles

provides enhanced voice and data communication between soldiers and vehicles across

the battlefield.

The Land Warrior system was used by the 2nd Infantry Division’s 4th Battalion, 9th

Infantry Regiment in Iraq in 2007 during the much publicized surge [16].

Figure 3. Land Warrior Individual Soldier Combat System [32]

Battlefield Augmented Reality System. The Naval Research Laboratory is developing a

prototype augmented reality system called the Battlefield Augmented Reality System

(BARS). Consisting of an optical head-mounted display, computer and tracking system, it

will network multiple outdoor mobile users together with a command center [18].

The system contains detailed 3D models of real-world objects in the environment which

are used to generate the registered graphic overlays. The models are stored in a shared

database which also stores metadata such as descriptions, threat classifications and object

relevance (to each other and to the mission). Intelligent filters display or hide information

based on physical location and contextual information gleaned from the shared database.

User interaction with the system is facilitated by a handheld wireless mouse which

superimposes a cursor on the scene. Speech and gesture-based interaction is also being

developed.

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The prototype BARS consists of:

GPS receiver

Orientation tracker

Sony Glasstron optical display

Laser retinal scanning head-mounted display

Dell Inspiron 7000 Notebook computer

Wireless hand-held gyroscope-equipped mouse

Like the Land Warrior project, BARS is a situational awareness tool. It has also been

targeted for training scenarios under the auspices of the US Army Simulation, Training

and Instrumentation Command (STRICOM). The goal of the BARS project participants

is to interactively improve the current prototype to be field-deployable in the coming

years.

Industrial and Manufacturing Applications

Many modern manufacturing systems have largely abandoned the “one size fits all”

approach in favor of methodologies that allow highly customized, one-off versions of a

product line as customer demands become increasing specialized. Workers must consult

multiple versions of assembly guides, templates, parts lists and other related documents

in order to fulfill customer orders.

Augmented reality can provide hands-free visual overlays of dynamic manufacturing

information targeted to specific, highly controllable automated and semi-automated

assembly environments. Problems of registration and tracking within busy, noisy factory

environments remain however these stumbling blocks are sure to be overcome in the

pursuit of the competitive advantages afforded by augmented reality and related

technologies.

Boeing’s wire bundle assembly project. The first application of augmented reality

technology to manufacturing was Boeing’s wire bundle assembly project, started in 1990.

The term “augmented reality” was coined by Tom Caudell, a researcher on the project.

Boeing’s Everett, Washington engineering and manufacturing facility, the world’s largest

factory building, was a logical choice of sites to introduce this ground-breaking

technology.

At Boeing, wiring bundles are assembled prior to installation in aircraft. The traditional

method is to prefabricate one or more 3’ by 8’ easel-like boards called formboards. Plotter

paper glued to the surface of the boards contains full-scale schematic diagrams of the

wire bundles to be assembled. Workers refer to the diagrams and also to stacks of printed

material in assembling the bundles on pegs mounted to the boards.

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Boeing researchers developed an augmented reality system using a stereo optical head-

mounted display. Registration and tracking were limited to the highly controllable

environment of the formboard. When a worked looked through the headset at the

formboard, the 3D path of the next wire to mount in the bundle was indicated by a

colored line superimposed on the view. The wire gauge and type were indicated in a

graphic shown to the side. As the worker changed his or her perspective on the

formboard, the graphical indicators appeared to stay in the same location, as if painted on

the board. With this new approach, workers were able to better concentrate on the

accuracy of the bundle assembly without having to look away from the work to consult

documents or changed formboards for every different assembly required [8:17-19].

DaimlerChrysler’s augmented reality initiatives. DaimlerChrysler has used virtual

reality systems for design and modeling of automotive parts and assemblies. Recently it

has enhanced and extended its virtual reality initiatives to include augmented reality

applications. Its in-house virtual reality system, known as DBView, was used as the

virtual image generation platform for its augmented reality initiatives.

Truck wiring harness design. Purchasers of DaimlerChrysler trucks have a high degree

of freedom in configuring their vehicles. Because of this, wiring must be individually

planned for virtually every truck produced. DaimlerChrysler developed an augmented

reality system for designing customized wiring configurations for truck assembly.

The system uses head-mounted displays to project a virtual geometric line known as a

spline curve representing the wiring within the structure of the truck chassis. The workers

can interact with the system, changing the path of the line using a 3D pointing device.

Once they have configured the optimum wiring path, the design is exported in the form of

manufacturing orders for subcontractors or for their own factories [6:217].

Visualization of data in airplane cabins. DaimlerChrysler developed an application for

interpreting computational fluid dynamics data within an airline cabin. The user wears an

optical head-mounted display and data such as air temperature, velocity and pressure are

overlaid in colored-coded volumetric graphics, like transparent smoke or vapor clouds.

After an initial calibration step, the application can be run in any airplane cabin [6:218-

219].

Motor maintenance and repair. Site-specific repair of car engines was the target of an

augmented reality initiative by DaimlerChrysler. Rather than having to look away from

the work area to reference a paper manual or CD-ROM, the workers wear head-mounted

displays connected to an augmented reality service and maintenance system that overlays

repair information on real-world car engines. The information is conveyed as both static

text overlays and as video and 3D animated graphics. DaimlerChrysler also developed a

user-friendly authoring system to build the sequence-based instructions called

PowerSpace, using the slide metaphor of Microsoft’s popular PowerPoint software

[6:220-222].

BMW’s intelligent welding gun. Constructing prototypes of experimental vehicles

presents a challenge to automobile manufacturers. Since only a few cars of an

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experimental design are ever built, the process is largely based on manual work.

Automated factories cannot be customized quickly enough to accommodate prototype

construction. BMW turned to augmented reality technology in order to streamline the

prototype construction process.

Stud welding is a time-consuming process for prototype construction. Typically, it is a

two-person process: the first person reads the coordinates of a stud from a computer

printout and positions the locater arm; the second person marks the position of the stud

with an etching device. Typically around 300 studs need to be welded to every car frame.

Once all of the stud positions have been marked, the welders place the studs at the

specific locations using a welding gun.

BMW’s augmented reality application skips the two-person stud marking process. The

system guides welders directly to the exact stud locations using visual overlays on a

video screen attached to the welding gun. They found this to be a safer solution than the

usual head-mounted display which would restrict the welder’s field of view and

compromise safety. This approach added a layer of complexity to the tracking and

registration of the system: it not only had to track the position of the welder’s head and

viewpoint, but also the position of the welding gun.

In testing the intelligent welding gun, BMW found that workers using this technology

were able to quadruple their speed without any loss of precision compared to unaided

workers [6:334].

Mobile Applications

Mobile augmented reality combines augmented reality technology with mobile devices,

including wearable computers, PDAs and mobile phones. Geospatial positioning and

registration is accomplished with built-in digital compasses, GPS units, and, in the case

of the iPhone, a technology known as location service. Location service uses a

combination of wifi, cellular tower location, and GPS to determine the geospatial location

of the iPhone user.

While mobile augmented reality generally does not provide the precision or resolution of

tethered, indoor augmented reality, it has one dominant factor in its favor: near ubiquity

of mobile phones, GPS devices, and their supporting infrastructure. Mobile augmented

reality applications may seem like toys today, but they are the leading edge of mass

acceptance of this up and coming technology.

LifeClipper. LifeClipper is a mobile augmented reality application that has evolved

significantly across three major release cycles: LifeClipper, LifeClipper2, and

LifeClipper3.

The original LifeClipper, designed by Swiss artist Jan Torpus, incorporates a walking

tour of the medieval quarter of Basil, Switzerland. The user’s location is tracked via GPS,

and audiovisual augmentations relevant to the location are presented on the head-

mounted display.

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The equipment consists of:

Wearable Mac computer

Optical head-mounted display

Video camera

Microphone

GPS receiver

Compass

Pressure sensors in the user’s shoes

When the LifeClipper user visits the town square, a fairy-like figure appears in the

augmented scene and leads the visitor to a fountain. When the user enters the center of

the square, there appears “an abstract divine appearance” [18].

A reporter from the BBC News described the experience: “When I walked past a paper

mill I could see the inner workings, and hear the sound of the mechanics thumping in my

ears” [19].

LifeClipper2. LifeClipper2, a research project supported by the University of Applied

Sciences Northwestern Switzerland, uses the technology and design of LifeClipper in a

research environment. It has been designed to be less site-specific and allows plug-in

modules for different environments and scenarios. Augmented scenarios created by the

LifeClipper2 team include:

Archaeology (visualization of archaeological knowledge)

Archiviz (projects of urban planning)

Playground (experiments with perception) [20]

LifeClipper3. LifeClipper3, still in the design stage, is a proposed “massively augmented

reality” project in which two-dimensional barcodes will be placed in real environments to

provide registration and reference points for text augmentation. The text can be anything

from tour guide-style information to users’ comments and social media tags. The goal is

to foster collaborative, wiki-style augmentation of the world [21].

Wikitude World Browser. Wikitude World Browser is a mobile augmented reality

application developed by Mobilizy for Android-based phones. Android is an open source

operating system created by Google for use in mobile phones, PDAs and netbooks.

Wikitude was originally developed to overlay Wikipedia information onto real-world

scenes using camera-equipped mobile phones. The user points the cell phone camera at a

scene, and, using the phone’s built-in location technology, the World Browser overlays

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the scene with relevant information from Wikipedia. The software accomplishes this by

determining the longitude and latitude of objects in the camera’s field of view using the

GPS receiver and digital compass of the phone and matching this data with coordinate-

enhanced entries in Wikipedia, of which there are approximately 600,000 [23].

With the development of Wikitude.me, users can add content to Wikitude by creating

unique points of interest and location-specific hyperlinked media content and saving

them to the Wikitude database. Then, any World Browser-equipped mobile device will

overlay the user’s content on the scene [22]. This application, in use today, goes a long

way toward realizing the concept of massively augmented reality as envisioned by the

LifeClipper3 designers.

Seer. A special version of Wikitude called Seer was introduced at this year’s Wimbledon

tennis tournament. Developed for the Android G1 handset by IBM and the advertising

agency Oglivy, it overlaid information on the phone’s camera view about tennis courts,

restaurants and bars and provided live updates from the tennis matches [23].

TAT Augmented ID. Swedish software and design company TAT has developed a

mobile augmented reality application that matches cell phone camera images of people’s

faces with information from social networking sites to present text overlays such as

Facebook messages. The subject’s image must be in TAT’s database in order to match up

the information, and users have the ability to register facial images with TAT for this

purpose. Augmented ID uses technology from Polar Rose to match facial characteristics

with the TAT database, enabling the application to consistently identify faces in different

viewing angles and lighting situations [24].

TwittARound. Developed by WebIt, TwittARound is a mobile augmented reality

application for the iPhone 3GS which overlays graphics on the real world indicating

Twitter tweets that are occurring nearby in real time. The application uses the iPhone’s

location service to pinpoint the user’s location, and the built-in compass to determine the

user’s viewing direction. Location-stamped tweets appear on the phone’s screen, showing

the content of the tweet and how far away the tweet-creator is located [25].

Yelp. Yelp is a social networking company that specializes in local search and user

reviews of businesses. Yelp has a popular iPhone app that has a hidden feature called

Monocle. To launch Monocle, iPhone users with the Yelp app installed must shake their

phone three times. This will activate an augmented reality overlay onto the live camera

view showing icons for nearby Yelp-reviewed businesses, including restaurants. The

icons include distance and location information so that users can easily find the nearby

businesses [26].

The Touring Machine. Researchers at Columbia University have developed a mobile

augmented reality application called The Touring Machine. The system uses both hand-

held and head-mounted displays. Interaction with the display is accomplished with a

trackball or touch pad worn by the user. GPS receivers track the user’s location and

orientation tracking sensors monitor the user’s point of view.

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The Touring Machine displays virtual flags which appear to be planted in various

locations across the Columbia University campus. The flags represent locations that have

stories associated with them. If the user selects a flag, the application displays a series of

still photos and video snippets with a narrator’s voice-over playing over headphones.

One story recounts the student anti-war protests at Columbia in 1968. Another story

describes the Bloomingdale Asylum, which previously occupied the current site of the

Columbia campus. The asylum’s buildings, rendered in 3D models, are overlaid at their

original locations on the optical head-mounted display. Meanwhile, the hand-held display

presents an interactive annotated timeline of the asylum’s history. The user can choose

different dates on the timeline and the application synchronizes the overlay of relevant

buildings on the head-mounted display [4:55].

Entertainment Applications

The entertainment industry is a fertile ground for augmented reality applications. The

promise of combining virtual imagery with real-world scenes, particularly for live-action

entertainment categories such as sporting events and concerts, opens up a world of new

possibilities.

ARQuake. ID Software’s classic first-person shooter game Quake was massively

popular soon after its release in 1996. This was due, in part, to its innovative capability to

be played by groups over the internet.

ARQuake uses the Quake game engine and moves the game action into the real world.

Developed at the University of South Australia, ARQuake uses a head-mounted display,

notebook computer, head tracker and a GPS system to overlay virtual monsters onto the

player’s point of view. As the player’s head moves, the game calculates which virtual

monsters should appear [7:8].

Since the development of ARQuake, other commercially available augmented reality

game systems have come on the market, including board games by Beyond Reality and

the thrilling Zombie Attack, which overlays miniature animated 3D zombies on a game

board with integrated registration and graphics, viewable on a smartphone.

Virtual sets. Several AR applications have been developed with virtual sets, a

compositing system that merges real actors with virtual backgrounds, in real time and 3D.

This is frequently utilized in television sports news and other scenarios featuring live

commentators superimposed on graphically generated sets. With this technology the

entertainment industry has been able to reduce costs, as creating and storing virtual sets is

frequently more cost effective than building new physical sets from scratch [1:8].

First down. Anyone who has watched a US football game in the past several years

cannot help but notice the colored first down line superimposed on the playing field.

Hockey viewers may have seen a colored trail indicating the location and direction of

travel of the puck. These are augmented reality elements that have made their way into

the mainstream with little fanfare. In Great Britain, rugby fields and cricket pitches are

20

branded by their sponsors via augmentation of the live video feed: giant logos are

inserted onto the fields for the benefit of the television viewing audience [27:32].

Concert Augmentation. British new wave band Duran Duran was the first performing

group to use augmented reality in a live show. Working with Charmed Technologies, the

group deployed projection screens which enabled virtual animated characters to appear

onstage during their 2000 Pop Trash tour [27:32].

Education Applications

Augmented reality has been associated with educational institutions since its beginnings.

Much of the research and many of the breakthroughs have been accomplished by teams

in colleges and universities. Augmented reality applications are beginning to find their

way into elementary and secondary schools, made possible by inexpensive yet powerful

hand-held devices and personal computers and widely available authoring systems like

ARToolkit.

BBC Jam storybooks for kids. The BBC has been a leader in funding augmented reality

application development in education. The first trial application, BBC Jam, is an online

learning service available in the UK. The application consists of a series of story packs

available for download. Using a standard personal computer equipped with a USB

webcam, the story packs include booklets with registration markers which become

animated 3D pop-up books when viewed on the pc screen via the webcam. Narration and

other educational materials accompany the story packs [7:8].

The Invisible Train. The Vienna University of Technology has developed an augmented

reality application for children called The Invisible Train. The application is written for

PDAs and can accommodate multiple players. The players set up a real wooden track and

then can control virtual trains superimposed on the track via the PDA screen. Players use

the stylus to steer the trains, switch tracks and control train speed [7:9].

AR Polygonal Modeling. Purdue University has developed an augmented reality

application for 3D modeling. Extending the capabilities of the popular 3DS Max

modeling and animation suite, AR Polygonal Modeling uses a head-mounted display

augmented reality component to create and manipulate 3D models that appear on a

physical desktop marked with registration points. 3DS Max’s tools are represented with

3D overlays and can be manipulated via a 3D mouse which is a wireless mouse attached

to a rigid array of markers which the head-mounted cameras synchronize with the

application for precise user interaction with the models [7:11-12].

Architecture and Urban Planning Applications

Augmented reality applications for architectural visualization with walk-through

capabilities are currently in development. Likewise, collaborative design applications are

being developed which facilitate shared virtual models and data projected onto a shared

platform, such as a table or desktop.

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As with many other industries and practices, the ability to superimpose imagery on the

real world is a boon to architects and designers as they can plan their creations in situ and

collaborate with colleagues using shared models.

The ARTHUR project. German and British architecture and design firms, in

collaboration with Aalborg University in Denmark and University College in London,

have developed the Augmented Round Table for Architecture and Urban Planning

(ARTHUR). The application uses optical augmented reality glasses developed by Saab

Avionics to view virtual models of urban design schemes. Using printed registration

markers, the ARTHUR environment can be implemented on a table or desktop, around

which collaborators sit. Models are projected over placeholder objects, and the

collaborators can move model components by physically moving the placeholders.

Designers can model different pedestrian and vehicular traffic flows through urban

models and even add animations of people and cars for increased realism [28].

Figure 4. ARTHUR [28]

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V. THE FUTURE OF AUGMENTED REALITY

The future of augmented reality holds tremendous promise. With display technology

getting better, smaller, lighter and requiring less power every year, it is only a matter of

time before augmented reality displays can be fitted to an ordinary pair of glasses, or

even contact lenses. In fact, researchers at the University of Washington have created

contact lenses with embedded LED and supporting circuitry. This technology will one

day be able to augment the wearer’s view with computer-generated text and imagery, just

as head-mounted displays do today.

Figure 5. Contact Lenses with Electronic Circuits [33]

For augmented reality applications that are stationary, holography will become the

preferred display technology. In the movie Star Wars, Princess Leah recorded a message

and inserted it in a droid for later playback. The message was projected holographically

by the droid. With holographic augmented reality, this future fantasy will become a

reality with the added benefit of greatly enhanced resolution and picture quality.

With the arrival of advances in wireless broadband networking and device addressing

(4G and IPv6) the environment will be filled with microscopic tagging and sensing

devices. Tag-based environments will provide real-time feedback to augmented reality

systems for accurate registration of mobile applications [29:321].

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As for augmented reality applications, the imagination runs wild with possibilities.

Computing tasks will be freed from the desktop and laptop and will accompany us

wherever we want them. Virtual animals, humans, and objects will proliferate, filling the

landscape and cityscape with helpers, game characters, tour guides, and much more.

Virtual meetings with participants located anywhere on earth can happen anywhere, free

of the cumbersome and expensive equipment required for today’s teleconferencing

systems. Work, play, health care, manufacturing, education, advertising and more will be

transformed by the fully realized potential of augmented reality.

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VI. CONCLUSION

Despite the challenges and difficulties of bringing this sophisticated technology to society

in a form that is user friendly, inexpensive, and vitally useful, advances in augmented

reality are occurring every day. From mobile applications for cell phones to

breakthroughs in computerized contact lenses, the pace of innovation has quickened

noticeably in recent years. What was once the province of university laboratories and

science fiction is rapidly becoming accessible for everyday use. Those with the

imagination and determination to create breakthrough augmented reality applications will

stand to benefit and lead this wave of innovation, and in the process, expand the scope of

human communications and capabilities immeasurably.

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INFORMATION SOURCES

1. Azuma, Ronald T. “A Survey of Augmented Reality” Presence: Teleoperators

and Virtual Environments. (August 1997), 355-385.

2. Lightman, Alex. Brave New Unwired World. New York: John Wiley & Sons,

2002.

3. Rheingold, Howard. Virtual Reality. New York: Touchstone, 1991.

4. Feiner, Steven K. “Augmented Reality: A New Way of Seeing” Scientific

American. (April 2002), 48-55.

5. Haller, Michael; Billinghurst, Mark; Thomas, Bruce H. Emerging Technologies of

Augmented Reality: Interfaces and Design. Hershey: Idea Group, 2007

6. Ong, S.K and Nee, A.Y.C. Virtual and Augmented Reality Applications in

Manufacturing. London: Springer-Verlang, 2004.

7. Cawood, Stephen and Fiala, Mark. Augmented Reality: A Practical Guide.

Raleigh: The Pragmatic Bookshelf, 2007.

8. Barfield, Woodrow and Caudell, Thomas. Fundamentals of Wearable Computers

and Augmented Reality. Mahwah: Lawrence Erlbaum, 2001.

9. Wikipedia. Steve Mann http://en.wikipedia.org/wiki/Steve_Mann

10. Wikipedia. 3G http://en.wikipedia.org/wiki/3G

11. Wikipedia. 4G http://en.wikipedia.org/wiki/4G

12. UNC Ultrasound/Medical Augmented Reality Research

http://www.cs.unc.edu/Research/us/

13. Sielhorst, Tobias; Obst, Tobias; Burgkart, Rainer; Riener, Robert and Navab,

Nassir. “An Augmented Reality Delivery Simulator for Medical Training”.

Proceedings of the AMI-ARCS 2004 Workshop. http://ami2004.loria.fr/

14. Wikipedia. Land Warrior http://en.wikipedia.org/wiki/Land_Warrior

15. FAS Military Analysis Network. Land Warrior http://www.fas.org/man/dod-

101/sys/land/land-warrior.htm

16. General Dynamics C4 Systems Land Warrior Lifting the ‘Fog of War’ in Iraq

http://www.gdc4s.com/content/detail.cfm?item=aa0d1b86-ac8d-47ed-b59d-

f8c2157beb7e&page=2

17. Livingston, Mark A.; Rosenblum, Lawrence J.; Julier, Simon J.; Brown, Dennis;

Baillot, Yohan; Swan, J. Edward II; Gabbard, Joseph L. and Hix, Deborah. “An

26

Augmented Reality System For Military Operations In Urban Terrain”

Proceedings of the Interservice / Industry Training, Simulation, & Education

Conference, Orlando: (December 2-5, 2002), p. 3, 8

18. LifeClipper…The Walking Experience http://www.torpus.com/lifeclipper/

19. Reid, David. BBC Click Online Beyond virtual reality.

http://news.bbc.co.uk/2/hi/programmes/click_online/4472491.stm

20. LifeClipper2 Staging public space – immersive outdoor augmented reality for

tourism and visualization. http://www.lifeclipper.net/EN/index.html

21. Muller, Florian. University of Basel LifeClipper3: Massively Augmented Reality

and its Realization Using Community Processes.

http://www.lifeclipper.net/download/PaperFlorianMueller.pdf

22. Wikitude World Browser Add Content http://www.wikitude.org/add-content

23. “Reality Improved” The Economist Technology Quarterly (Sep. 3, 2009)

http://www.economist.com/sciencetechnology/tq/displaystory.cfm?story_id=1429

9602

24. TAT – The Astonishing Tribe TAT Augmented ID http://www.tat.se/

25. Sorrel, Charlie “Twitters Enters Meatspace: The End is Nigh” (July 8, 2009)

wired.com http://www.wired.com/gadgetlab/2009/07/twitters-enters-meatspace-

the-end-is-nigh/

26. Herrman, John “Augmented Reality:Yelp Will Murder All Other iPhone

Restaurant Apps, My Health” gizmodo.com

http://gizmodo.com/5347194/augmented-reality-yelp-will-murder-all-other-

iphone-restaurant-apps-my-health

27. Wikipedians Mixed Reality. Pedia Press, 2008

28. Penn, A.R. UCL Bartlett School of Graduate Studies Augmented Round Table for

Architecture and Urban Planning http://www.vr.ucl.ac.uk/projects/arthur/

29. Bimber, Oliver and Raskar, Ramesh. Spatial Augmented Reality: Merging Real

and Virtual Worlds. Wellesley: A.K. Peters, 2005

30. Sutherland, Ivan E. “A Head-Mounted Three-Dimensional Display”. Proceedings

of the AFIPS Fall Joint Computer Conference Washington: Thompson Books,

1968 http://design.osu.edu/carlson/history/timeline.html

31. Vuzix VR 920 vuzix.com http://www.vuzix.com/iwear/products_vr920.html

27

32. Photo by Gerry J. Gilmore June 07, 2007

http://en.wikipedia.org/wiki/File:Land_Warrior_060707.jpg

33. IEEE Spectrum Augmented Reality in a Contact Lens Photos: University of

Washington http://spectrum.ieee.org/biomedical/bionics/augmented-reality-in-a-

contact-lens/0