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Joined: Dec 2008
07-02-2009, 10:50 PM
Augmented Reality (AR) is a growing area in virtual reality research. The world environment around us provides a wealth of information that is difficult to duplicate in a computer. This is evidenced by the worlds used in virtual environments. Either these worlds are very simplistic such as the environments created for immersive entertainment and games, or the system that can create a more realistic environment has a million dollar price tag such as flight simulators. An augmented reality system generates a composite view for the user. It is a combination of the real scene viewed by the user and a virtual scene generated by the computer that augments the scene with additional information. Augmented reality presented to the user enhances that person's performance in and perception of the world. The ultimate goal is to create a system such that the user cannot tell the difference between the real world and the virtual augmentation of it. To the user of this ultimate system it would appear that he is looking at a single real scene.
Augmented Reality vs. Virtual Reality
Virtual reality is a technology that encompasses a broad spectrum of ideas. The term is defined as "a computer generated, interactive, three-dimensional environment in which a person is immersed. There are three key points in this definition. First, this virtual environment is a computer generated three-dimensional scene, which requires high performance computer graphics to provide an adequate level of realism. The second point is that the virtual world is interactive. A user requires real-time response from the system to be able to interact with it in an effective manner. The last point is that the user is immersed in this virtual environment. One of the identifying marks of a virtual reality system is the head mounted display worn by users. These displays block out all the external world and present to the wearer a view that is under the complete control of the computer. The user is completely immersed in an artificial world and becomes divorced from the real environment. For this immersion to appear realistic the virtual reality system must accurately sense how the user is moving and determine what effect that will have on the scene being rendered in the head mounted display.
The discussion above highlights the similarities and differences between virtual reality and augmented reality systems. A very visible difference between these two types of systems is the immersiveness of the system. Virtual reality strives for a totally immersive environment. In contrast, an augmented reality system is augmenting the real world scene necessitating that the user maintains a sense of presence in that world. The virtual images are merged with the real view to create the augmented display. There must be a mechanism to combine the real and virtual that is not present in other virtual reality work. The computer generated virtual objects must be accurately registered with the real world in all dimensions. Errors in this registration will prevent the user from seeing the real and virtual images as fused. The correct registration must also be maintained while the user moves about within the real environment. Discrepancies or changes in the apparent registration will range from distracting which makes working with the augmented view more difficult, to physically disturbing for the user making the system completely unusable. An immersive virtual reality system must maintain registration so that changes in the rendered scene match with the perceptions of the user.
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computer science crazy|
Joined: Dec 2008
07-02-2009, 10:52 PM
AUGMENTED REALITY (AR)
Augmented reality (AR) refers to computer displays that add virtual information to a user's sensory perceptions. 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. AR systems track 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.
Consider what AR could make routinely possible. A repairperson viewing a broken piece of equipment could see instructions highlighting the parts that need to be inspected. A surgeon could get the equivalent of x-ray vision by observing live ultrasound scans of internal organs that are overlaid on the patient's body. Soldiers could see the positions of enemy snipers who had been spotted by unmanned reconnaissance planes. 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 makes augmented reality different is how the information is presented: not on a separate display but integrated with the user's perceptions. In augmented reality, the user's view of the world and the computer interface literally become one.
Video games have been entertaining us for nearly 30 years, ever since Pong was introduced to arcades in the early II 970?s.Computer graphics have become much more sophisticated since then, and soon, game graphics will seem all too real. In the next decade, researchers plan to pull graphics out of your television screen or computer display and integrate them into real- world environments. This new technology called augmented reality, will further blur the line between what is real and what is computer-generated by enhancing what we see, hear, feel and smell.
Augmented reality will truly change the way we view the world. Picture yourself walking or driving down the street. With augmented-reality displays, which will eventually look much like a normal pair of glasses, informative graphics will appear in your field of view, and audio will coincide with what ever you see. These enhancements will be refreshed continually to reflect the moments of your head.
Augmented reality is still in the early stage of research and development at various universities and high-tech companies. Eventually, possibly by the end of this decade we will see the first mass-marketed augmented-reality system, which can be described as ?the Walkman of the 21st Century?.
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01-04-2010, 12:22 AM
to get seminar and presentation report and presentation of Augmented Reality please read topicideashow-to-augmented-reality--5394
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23-03-2011, 09:53 AM
AR final.ppt (Size: 3.64 MB / Downloads: 79)
What Is Augmented Reality?
Augmented reality is…
● a technology
● a field of research
● a vision of future computing
● an emerging commercial industry
● a new medium for creative expression
Augmented reality is the display of computer graphics and media, overlaid and registered on real-world environments, interactively in real time.
Real vs. Virtual
● VR was first introduced by Jaron Lanier
● The term is defined as a computer generated , interactive , three dimensional environment in which a person is immersed.
● Eg: Virtual Keyboard
● Augmented reality will further blur the line between what's real and what's computer-generated.
● Real scene viewed by the user & virtual scene by computer augments
● Virtual reality + Reality =AR
● The idea of mixture of virtual with real objects is not new. Hollywood and photography people have used it since very long before…
Let’s Give a More Strict Definition
● Augmented Reality (AR) -supplements the real world with virtual (computer-generated) objects that appear to coexist in the same space as the real world.
● AR systems have the following three characteristics:
−Combines real and virtual objects in a real environment
−Runs interactively, and in real time
−Registers real and virtual objects with each other ( Registered in 3-D )
● AR platforms exist at the intersection of several technical disciplines, including computer graphics, machine vision, sensing and sensor fusion, geographic information systems, mobile systems, ubiquitous computing and the web.
● The goal of AR is to create the sensation that virtual objects are present in the real world.
● Ivan Sutherland’s vision of AR -User is “inside” the computer
● AR enhances a user’s perception of 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 is known as Intelligence Amplification (IA): using the computer as a tool to make a task easier for a human to perform.
AR System Components
The three basic components of an augmented reality system are:
● The Head-Mounted Display
The head-mounted display used in augmented reality systems will enable the user to view superimposed graphics and text created by the system. −Optical see-through based
− Video see-through based
● Tracking and Orientation
This system pinpoints the user's location in reference to his surroundings
and additionally tracks the user's eye and head movements.
● Portable Computer
Augmented reality systems will need highly mobile computers.
Optical See-through Based AR
Optical see-through systems make use of technology that "paints" the images directly onto the user's retina through rapid movement of the light source.
Video See-through Based AR
The video see-through systems block out the user's view of the outside environment and play the image real time through a camera mounted on the head gear.
Discussion on the characteristics of AR systems and design issues encountered when building an AR system.
● Besides adding objects to a real environment, AR also has the potential to remove them.
● AR might apply to all senses, not just sight.
● AR could be extended to include sound.
Another example is haptics
2. Optical vs. Video
● When virtual objects are added to a scene , it is known as visual AR.Visual AR relies up on some sort of display.
● Head Mounted Displays(HMD) will enable us to view graphics and text created by AR system.
● A basic design decision in building an AR system is how to accomplish the combining of real and virtual. Two basic choices are available:
-Optical see through based
-video see through based
3. Focus & Contrast
● Focus can be a problem for both optical and video components. Ideally the virtual should match the real.
-Depending on video camera’s depth-of-field (DOF) and focus settings, parts of the real world may not be in focus.
-In computer graphics, everything is rendered with a pinhole model, so regardless of distance, everything is in focus.
-To overcome this, graphics can be rendered to simulate a limited DOF, and the video camera can have auto focus lens
● Contrast is a big issue owing to its large dynamic range in real environments.
-If the real environment is too dark, the virtual image will wash out the real world. If the real world is too bright it will wash out the virtual image.
-Human eye can detect a wide range of dynamic environment. Optical devices are usually made dark-tinted to reduce this range. For video, everything must be clipped or compressed into the monitor’s dynamic range.
● In most VR systems, the user is not encouraged to walk around much.
-Instead, the user navigates by "flying" through the environment, walking on a treadmill, or driving some mock-up of a vehicle, etc.
-Whatever the technology, the result is that the user stays in one place in the real world.
● Some AR applications, however, need support for a user who will walk around a large environment (usually move to the place where the task is to take place).