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?.
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).