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Describes the augmented reality and its features
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(Approved by AICTE, Affiliated to JNTUH) Narayanaguda, Hyderabad, Telangana- 2020-
This is to certified that seminar work entitled “Artificial Neural Networks” is a bonafide work carried out in the seventh semester by “NAME ROLL NO” in partial fulfilment for the award of Bachelor of Technology in “COMPUTER SCIENCE & ENGINEERING ” from JNTU Hyderabad during the academic year 2020 - 2021 and no part of this work has been submitted earlier for the award of any degree. SEMINAR CO-ORDINATOR HEAD OF THE DEPARTMENT
Video games have been entertaining us for nearly 30 years, ever since Pong was introduced to arcades in the early In 1970'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 wa lking 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 very 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". So how about reality served with a sugar coating of information? Augmented Reality can help in multiple ways – provide critical information about your surroundings, give you your personal babel fish, help soldiers survive wars better, help law enforcement officials catch criminals, avoid car accidents, train surgeons, and much more. But AR is not just about this, it can be fun too! Yep it has limitless possibilities in gaming Should you be interested in not just experiencing AR but also creating that same magic, the last chapter will help you take your first steps into AR programming. We tell you about the domain knowledge required for starting off with each type of AR implementation and we end with an introduction to some of the most useful frameworks / toolkits available to begin your journey.
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 makes 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. In augmented reality, the user's view of the world and the computer interface literally become one. Real Environment Augmented Reality Augmented Virtuality Virtual Environment
Between the extremes of real life and Virtual Reality lies the spectrum of Mixed Reality, in which views of the real world are combined in some proportion with views of a virtual environment. Combining direct view, stereoscopic videos, and stereoscopic graphics, Augmented Reality describes that class of displays that consists primarily of a real world environment, with graphic enhancement or augmentations. In Augmented Virtuality, real objects are added to a virtual environment. In Augmented Reality, virtual objects are added to real world. An AR system supplements the real world with virtual (computer generated) objects that appear to co-exist in the same space as the real world. Virtual Reality is a synthetic environment. 1.1 Comparison between AR and virtual environments The overall requirements of AR can be summarized by comparing them against the requirements for Virtual Environments, for the three basic subsystems that they require. 13 Scene generator : Rendering is not currently one of the major problems in AR. VE systems have much higher requirements for realistic images because they completely replace the real world with the virtual environment. In AR, the virtual images only supplement the real world. Therefore, fewer virtual objects need to be drawn, and they do not necessarily have to be realistically rendered in order to serve the purposes of the application. 14 Display devices: The display devices used in AR may have less stringent requirements than VE systems demand, again because AR does not replace the real world. For example, monochrome displays may be adequate for some AR applications, while virtually all VE systems today use full color. Optical see-through HMD's with a small field-of-view may be satisfactory
Although augmented reality may seem like the stuff of science fiction, researchers have been building prototype system for more than three decades. The first was developed in the 1960s by computer graphics pioneer Ivan Surtherland and his students at Harvard University. In the 1970s and 1980s a small number of researchers studied augmented reality at institution such as the U.S. Air Force's Armstrong Laboratory, the NASA Ames Research Center and the university of North Carolina at Chapel Hill It wasn't until the early 1990s that the term "Augmented Reality”was coined by scientists at Boeing who were developing an experimental AR system to help workers assemble wiring harnesses. In 1996 developers at Columbia University develop 'The Touring Machine' In 2001 MIT came up with a very compact AR system known as "MIThriir. Presently research is being done in developing BARS (Battlefield Augmented Reality Systems) by engineers at Naval Research Laboratory, Washington D.C.
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 2 Is1^ 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. Here are the three components needed to make an augmented-reality system work: a.i Head-mounted display
more recently, for drivers of luxury- cars). Lenses can be placed between the beam splitter and the computer display to focus the image so that it appears at a comfortable viewing distance. If a display and optics are provided for each eye, the view can be in stereo. Sony makes a see-through display that some researchers use, called the "Glasstron". Fig-2 Video see-through displays Combined Video In contrast, a video see through display uses video mixing technology, originally developed for television special effects, to combine the image from a head worn camera with synthesized graphics. The merged image is typically presented on an opaque head wo rn display. With careful design the camera can be positioned so that its optical path is closed to that of the user's eye; the video image thus approximates what the userwould normally see. As with optical see through displays, a separate system can be provided for each eye to support stereo vision. Video composition can be done in more than one way. A simple
way is to use chroma-keying: a technique used in many video special effects. The background of the computer graphics images is set to a specific color, say green, which none of the virtual objects use. Then the combining step replaces all green areas with the corresponding parts from the video of the real world. This has the effect of superimposing the virtual objects over the real world. A more sophisticated composition would use depth information at each pixel for the real world images; it could combine the real and virtual images by a pixel- by-pixel depth comparison. This would allow real objects to cover virtual objects and vice-versa.
Each of approaches to sec through display design has its pluses and minuses. Optical see through systems allows the user to see the real world with resolution and field of view. But the overlaid graphics in current optical see through systems are not opaque and therefore cannot completely obscure the physical objects behind them. As result, the superimposed text may be hard to read against some backgrounds, and three-dimensional graphics may not produce a convincing illusion. Furthermore, although focus physical objects depending on their distance, virtual objects are alt focused in the plane of the display. This means that a virtual object that is intended to be at the same position as a physical object may have a geometrically correct projection, yet the user may not be able to view both objects in focus at the same time. In video see-through systems, virtual objects can fully obscure physical ones and can be combined with them using a rich variety of graphical effects. There is also discrepancy between how the eye focuses virtual and physical objects, because both are viewed on same plane, the limitations of current video technology, however, mean that the quality of the visual experience of the rea l world is significantly decreased, essentially to the level of the synthesized
through HMD, the user still has a direct view of the real world. The HMD then becomes a pair of heavy sunglasses, but the user can still see.
through is that the virtual objects do not completely obscure the real world objects, because the optical combiners allow light from both virtual and real sources. Building an optical see-through HMD that can selectively shut out the light from the real world is difficult. Any filter that would selectively block out light must be placed in the optical path at a point where the image is in focus, which obviously cannot be the user's eye. Therefore, the optical system must have two places where the image is in focus: at the user's eye and the point of the hypothetical filter. This makes the optical design much more difficult and complex. No existing optical see-through HMD blocks incoming light in this fashion. Thus, the virtual objects appear Ghost- like and semi- transparent. This damages the illusion of reality because occlusion is one of the strongest depth cues. In contrast, video see-through is far more flexible about how it merges the real and virtual images. Since both the real and virtual are available in digital form, video see-through compositors can, on a pixel-by-pixel basis, take the real, or the virtual, or some blend between the two to simulate transparency.
Infrared-light-emitting diodes (LED's) embedded in special ceiling panels. The system uses the known location of LED's the known geometry of the user- mounted optical sensors and a special algorithm to compute and report the user's position and orientation. The system resolves linear motion of less than 0.2 millimeters, and angular motions less than 0.03 degrees. It has an update rate of more than 1500Hz, and latency is kept at about one millisecond. In everyday life, people rely on several senses- including what they see, cues from their inner earsand gravity's pull on their bodies- to maintain their bearings. In a similar fashion. "Hybrid Trackers" draw on several sources of sensory information. For example, the wearer of an AR display can be equipped with inertial sensors (gyroscope and accelerometers) to record changes in head orientation. Combining this information with data from optical, video or ultrasonic devices greatly improve the accuracy of 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.
User can get better result with a technique known as differential GPS. In this method, the mobile GPS receiver also monitors signals from another GPS receiver and a radio transmitter at a fixed location on the earth. This transmitter broadcasts the correction based on the difference between the stationary GPS antenna's known and computed positions. By using these signals to correct the satellite signals, the differential GPS can reduce the margin of error to less than one meter. The system is able to achieve the centimeter-level accuracy by employing the real-time kinematics GPS, a more sophisticated form of differential GPS that also compares the phases of the signals at the fixed and mobile receivers. Trimble Navigation reports that they have increased the precision of their global positioning system (GPS) by replacing local reference stations with what they term a Virtual Reference Station (VRS), This new VRS will enable users to obtain a centimeter- level positioning without local reference stations; it can achieve long-range, real- time kinematics (RTK) precision over greater distances via wireless communications wherever they are located. Real-time kinematics technique is a way to use GPS measurements to generate positioning within one to two centimeters (0,39 to 0. inches). RTK is often used as the key component in navigational system or automatic machine guidance. Unfortunately, GPS is not the ultimate answer to position tracking. The satellite signals are relatively weak and easily blocked by buildings or even foliage. This rule out useful tracking indoors or in places likes midtown Manhattan, where rows of tall building block most of the sky. GPS tracking works well in wide open spaces and relatively low buildings.
For a wearable augmented realty system, there is still not enough computing power to create stereo 3-D graphics. So researchers are using whatever they can get out of laptops and persona! Computers, for now. Laptops
