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We are on the verge of ubiquitously adopting Augmented Reality (AR) technologies to enhance our perception and help us see, hear, and feel our environments in new and enriched ways. AR will support us in fields such as education, maintenance, design and reconnaissance, to name but a few. It describes the medical, manufacturing, visualization, path planning, entertainment and military applications that have been explored.A subset of computer graphics, augmented reality is becoming more useful outside of research, inspiring new methods of human-computer interaction and interface design.
This report describes the field of AR, including a brief definition and development history of augmented reality, the enabling technologies , its origins in virtual reality, the various technologies required with its use, and its current and future applications and their characteristics. It surveys the state of the art by reviewing some recent applications of AR technology ,its ease of use implementations as well as some known limitations regarding human factors in the use of AR systems that developers will need to overcome.
Imagine a technology with which you could see more than others see, hear more than others hear, and perhaps even touch, smell and taste things that others can not. What if we had technology to perceive completely computational elements and objects within our real world experience, entire creatures and structures even that help us in our daily activities, while interacting almost unconsciously through mere gestures and speech?
With such technology, mechanics could see instructions what to do next when repairing an unknown piece of equipment, surgeons could see ultrasound scans of organs while performing surgery on them, fire fighters could see building layouts to avoid otherwise invisible hazards, soldiers could see positions of enemy snipers spotted by unmanned reconnaissance aircraft, and we could read reviews for each restaurant in the street we‟re walking in, or battle 10-foot tall aliens on the way to work .
Augmented reality (AR) is this technology to create a “next generation, reality-based interface” and is moving from laboratories around the world into various industries and consumer markets. AR supplements the real world with virtual (computer-generated) objects that appear to coexist in the same space as the real world. AR as recognised as an emerging technology of 2007, and with today‟s smart phones and AR browsers we are starting to embrace this very new and exciting kind of human-computer interaction.
At least six classes of potential AR applications have been explored: medical visualization, maintenance and repair, annotation, robot path planning, entertainment, and military aircraft navigation and targeting. The next section describes work that has been done in each area. While these do not cover every potential application area of this technology, they do cover the areas explored so far.
To many people, augmented reality is about annotating what you can see. Names of landmarks, reviews of restaurants, the sale price of houses, and so on. However with a little imagination, augmented reality can allow us to see what is around us but invisible, or what our environment will be like at another time.
The field is highly interdisciplinary, combining work in disciplines such as signal processing, computer vision, computer graphics, user interfaces, human factors, wearable computing, mobile computing, computer networks, displays, and sensors. The growing interest in AR applications is creating new challenges for research in all of these areas.
The first AR prototypes (Fig. 3), created by computer graphics pioneer Ivan Sutherland and his students at Harvard University and the University of Utah, appeared in the 1960s and used a see-through to present 3D graphics . A small group of researchers at U.S. Air Force‟s Armstrong Laboratory, the NASA Ames Research Center, the Massachusetts Institute of Technology, and the University of North Carolina at Chapel Hill continued research during the 1970s and 1980s. During this time mobile devices like the Sony Walkman (1979), digital watches and personal digital organisers were introduced. This paved the way for wearable computing [103, 147] in the 1990s as personal computers became small enough to be worn at all times. Early palmtop computers include the Psion I (1984), the Apple Newton MessagePad (1993), and the Palm Pilot (1996). Today, many mobile platforms exist that may support AR, such as personal digital assistants (PDAs), tablet PCs, and mobile phones. It took until the early 1990s before the term „augmented reality‟ was coined by Caudell and Mizell , scientists at Boeing Corporation who were developing an experimental AR system to help workers put together wiring harnesses.
Why is Augmented Reality an interesting topic? Why is combining real and virtual objects in 3-D useful? Augmented Reality enhances a user's perception of and interaction with the real world. The virtual objects display information that the user cannot directly detect with his own senses. The information conveyed by the virtual objects helps a user perform real-world tasks. AR is a specific example of what Fred Brooks calls Intelligence Amplification (IA): using the computer as a tool to make a task easier for a human to perform. Augmented Reality combines Real and Virtual as well as interactive in real-time.
Recently with the emergence of Virtual Reality (VR) and related technologies it became possible to immerse users in artificial worlds that are impossible or difficult to reproduce in reality. A number of training studies have shown the usefulness of Virtual Reality (VR) in training spatial ability . However, little to no work has been done towards systematic development of VR applications for practical education purposes in this field. This thesis aims to introduce Augmented Reality (AR), a technology closely related to VR, to mathematics and geometry education.
A Head Mounted Display (HMD) places images of both the physical world and registered virtual graphical objects over the user's view of the world. The HMD's are either optical see–through or video see–through. Optical see-through employs half-silver mirrors to pass images through the lens and overlay information to be reflected into the user's eyes. The HMD must be tracked with sensor that provides six degrees of freedom. This tracking allows the system to align virtual information to the physical world. The main advantage of HMD AR is the user's immersive experience. The graphical information is slaved to the view of the user.
Instead of the user wearing or carrying the display such as with head mounted displays or handheld devices, Spatial Augmented Reality (SAR) makes use of digital projectors to display graphical information onto physical objects. The key difference in SAR is that the display is separated from the users of the system. Because the displays are not associated with each user, SAR scales naturally up to groups of users, thus allowing for collocated collaboration between users. SAR has several advantages over traditional head mounted displays and handheld devices. The user is not required to carry equipment or wear the display over their eyes. This makes spatial AR a good candidate for collaborative work, as the users can see each other’s faces. A system can be used by multiple people at the same time without each having to wear a head mounted display. Spatial AR does not suffer from the limited display resolution of current head mounted displays and portable devices. A projector based display system can simply incorporate more projectors to expand the display area. Where portable devices have a small window into the world for drawing, a SAR system can display on any number of surfaces of an indoor setting at once. The drawbacks, however, are that SAR systems of projectors do not work so well in sunlight and also require a surface on which to project the computer-generated graphics. Augmentations cannot simply hang in the air as they do with handheld and HMD-based AR. The tangible nature of SAR, though, makes this an ideal technology to support design, as SAR supports both a graphical visualisation and passive haptic sensation for the end users. People are able to touch physical objects, and it is this process that provides the passive haptic sensation.
Modern mobile augmented reality systems use one or more of the following tracking technologies: digital cameras and/or other optical sensors, accelerometers, GPS, gyroscopes, solid state compasses, RFID and wireless sensors. These technologies offer varying levels of accuracy and precision. Most important is the position and orientation of the user's head. Tracking the user's hand(s) or a handheld input device can provide a 6DOF interaction technique.When creating an AR application, two of the most important requirements of such a system are where the camera is in relation to the virtual objects being displayed and where to display the virtual objects. Without this knowledge, virtual objects can appear misshapen, on the wrong plane, or simply fail to appear. This problem is called location tracking or simply tracking, because the computer needs to keep track of where the camera is, where the virtual objects, and how they relate to one another. There are numerous ways of solving these requirements, and each has its advantages and disadvantages.