Working
AR system tracks the position and orientation of the user’s head so that the overlaid material can be aligned with the user’s view of the world. Through this process, known as registration, graphics software can place a three dimensional image of a tea cup, for example on top of a real saucer and keep the virtual cup fixed in that position as the user moves about the room. AR systems employ some of the same hardware technologies used in virtual reality research, but there’s a crucial differences: whereas virtual reality brashly aims to replace the real world, augmented reality respectfully supplement it. Augmented Reality is still in an early stage of research and development at various universities and high-tech companies. Eventually, possible by the end of this decade, we will see first mass-marketed augmented reality system, which one researcher calls “The Walkman of the 21st century”. What augmented reality attempts to do is not only super impose graphics over a real environment in real-time, but also change those graphics to accommodate a user’s head- and eye- movements, so that the graphics always fit and perspective.
About
Augmented reality (AR) refers to computer displays that add virtual information to a user’s sensory perception. Most AR research focuses on see-through devices, usually worn on the head that overlay graphics and text on the user’s view of his or her surroundings. In general it superimposes graphics over a real world environment in real time. Getting the right information at the right time and the right place is key in all these applications. Personal digital assistants such as the Palm and the Pocket PC can provide timely information using wireless networking and Global Positioning System (GPS) receivers that constantly track the handheld devices. But what make Augmented Reality different is how the information is presented: not on a separate display but integrated with the user’s perceptions. This kind of interface minimizes the extra mental effort that a user has to expend when switching his or her attention back and forth between real-world tasks and a computer screen.
Engineering Design
Imagine that a group of designers are working on the model of a complex device for their clients. The designers and clients want to do a joint design reviews even though they are physically separated. If each of them had a conference room that was equipped with an augmented re4ality display this could be accomplished. The physical prototype that the designers have mocked up is imaged and displayed in the client’s conference room in 3D. The clients can walk around display looking at different aspects of it. To hold the discussion the client can point at the prototype to highlight sections and this will be reflected on the real model in the augmented display that the designers are using.
Out door Tracking
Head orientation is determined with a commercially available hybrid tracker that combines gyroscopes and accelerometers with magnetometers that measure the earth’s magnetic field. For position tracking we take advantage OF a high-precision version of the increasingly popular Global Positioning system receiver. A GPS receiver can determine its position by monitoring radio signals from navigation satellites. GPS receivers have an accuracy of about 10 to 30 meters. An augmented reality system would be worthless if the graphics projected were of something 10 to 30 meters away from what you were actually looking at.
Consumer Design
Virtual reality systems are already used for consumer design. Using perhaps more of a graphics system than virtual reality, when you go to the typical home store wanting to add a new deck to your house, they will show you a graphical picture of what the deck will look like. It is conceivable that a future system would allow you to bring a video tape of your house shot from various viewpoints in your backyard and in real time it would augment that view to show the new deck in its finished form attached to your house. Or bring in a tape of your current kitchen and the augmented reality processor would replace your current kitchen cabinetry with virtual images of the new kitchen that you are designing.
Conclusion
Augmented reality is far behind Virtual Environments in maturity. Several commercial vendors sell complete, turnkey Virtual Environment systems. However, no commercial vendor currently sells an HMD-based Augmented Reality system. A few monitor-based “virtual set” systems are available, but today AR systems are primarily found in academic and industrial research laboratories. The next generation of combat aircraft will have Helmet Mounted Sights with graphics registered to targets in the environment. These displays, combined with short-range steer able missiles that can shoot at targets off-bore sight, give a tremendous combat advantage to pilots in dogfights. Instead of having to be directly behind his target in order to shoot at it, a pilot can now shoot at anything within a 60-90 degree cone of his aircraft’s forward centerline.
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