Virtual Reality

Virtual reality, is a computer-generated, multi-sensory human interface to computers. Virtual reality extends beyond the capability of typical workstation graphics in two ways. First, through the use of tracking sensors, the computer knows precisely the location and angle of the user’s head, which enables the graphics scene to be generated in the correct perspective for each eye. Second, because a very wide-angle image is provided, which is updated 10 to 60 times a second and is often augmented with synthesized surround sound, motion, and even scent, a level of immersion in the simulated scene is achieved.

Immersion, combined with correct perspective, allows the development of facile methods for navigation in three dimensions. (Gump) Scene complexity is determined by the computer system’s capability to display a great number of shaded, lighted, textured, and occluded polygons necessary to visually describe the many objects in the scene. Change to the scene is governed by the computer simulation program or database driving the creation of the scene. Thus the visual quality of a VR experience is dependent on the speed of both the graphics-rendering hardware/software and the computer system itself. (Gump)

There are four major types of virtual reality devices currently in use: the head-mounted display (HMD), the binocular omni-oriented monitor (BOOM), the workstation “desktop” model (DEERING), and the projection model (CAVE). The HMD is a tracked helmet worn by the user that provides small television screens properly placed in front of the eyes. Although modest in comparison with other VR devices, it is not lightweight enough to prevent fatigue, and the screen resolution is typically medium at best. The BOOM also uses small television screens, but the angle of view is improved by wide-angle optics.

The screens are suspended from a mechanical arm articulated in five dimensions that eliminates the weight of the HMD and provides accurate tracking over its range of operation. The desktop model uses a standard workstation screen outfitted with stereo liquid crystal display (LCD) shutter glasses synchronized with the screen so that each eye’s view, drawn in correct perspective, is presented to that eye only. The disadvantage is a limited field of view, but this can be partially overcome by using a much larger projection screen in front of the user, the goal being to get the edges of the screen out of view. Warrick) The CAVE is a room 3 by 3 by 3 meters (10 by 10 by 10 feet) constructed of at least two walls and a floor made of projection screens.

It has a very wide field of view and high resolution and provides a rather complete feeling of immersion. Since the CAVE is large and two to four times as expensive as the other models, it is not an office device. However, since it allows multiple participants at once (only one is tracked), the CAVE can be used in sales, teaching, and presentation contexts. (Benedickt) The field of virtual reality is in its infancy.

Improvements in tracker accuracy and range, display resolution and cost, rendering hardware, real-time simulation software and networking, human interfacing techniques (for example, voice and gesture recognition), audio synthesis, and high-performance computing are needed to assure its use in manufacturing, education, science, and art. Virtual reality is the new frontier of the computer-human interface. Researchers in computer-imaging technology are developing systems by which users can experience a simulated three-dimensional reality.

This simulated reality is known as virtual reality The termcyberspace has sometimes been used synonomously with VR but has by now gained its own meaning. (Gump) Since the 1970s, technologists have learned how to produce animated computer images of objects that exhibit the colors, textures, and changing spatial orientations that their counterparts exhibit in the real world. The images can also be subjected to changing light conditions and to simulated effects of gravity and other forces (see computer graphics; computer modeling).

The results can look as real as actual motion pictures. The further aim of technologists is to make it possible for persons to “enter” and actually manipulate VR. (Gump) Thus far this is being achieved to a limited degree only by having an observer wear complex headgear through which computer images are fed to small screens in front of the eyes. At the same time, gloves or full suits that are equipped with networks of sensors are transmitting apparent changes of body orientation in VR.

A simpler form of these VR techniques is seen in the flight simulators used for training military pilots. (Warrick) Besides its application in training systems, many other potentially practical uses of VR can be suggested. They range from the long-distance manipulation of robot devices to the retraining of stroke victims in the use of their limbs. Computer graphics is the use of computers to produce pictorial representations of information, from a graph of a company’s earnings to a video-game maze.

Almost any pictorial image may be stored in a computer and rendered and manipulated according to the user’s wishes. To generate such graphics, the user needs a computer, a graphics software program and input-output devices adapted to the nature of the images. Even a typical personal computer system, with a keyboard and color monitor, can execute fairly complicated graphics programs. Other input-output devices, such as electronic sketchpads, video digitizers, video cameras, printers, and color plotters, can enhance the computer’s graphics capabilities. (Warrick)

Pictorial images generally contain an enormous amount of information, each piece of which must be translated by the computer into a digital code and stored in computer memory. For example, a study of thermal convection in the Earth’s mantle, in which huge amounts of raw data are converted by the computer into colorful three-dimensional images, is possible only by using a supercomputer, an extensive network of linked desktop computers, or some combination of supercomputers and specialized smaller computers. (Warrick) Computer graphics often employs specialized hardware and software technologies.

On the hardware side, a great deal of effort has been devoted to perfecting video displays. Most computer graphics are shown on a monitor, or Video Display Terminal, in the form of a cathode-ray tube (CRT). Two display methods are typically used: raster-scan CRTs and vector CRTs. In the more common raster-scan CRT, an electron beam sweeps the screen horizontally many times per second, creating an image that consists of a two-dimensional grid of dots. Each of these dots, or pixels (for picture elements), may be manipulated in color and intensity.

The greater the number of pixels that can be generated, the finer is the resolution of the image; but the higher the resolution, the greater is the amount of memory needed for image storage. In vector CRTs, the electron beam sweeps back and forth between two or more points on the screen, creating an image composed of lines. Because vector CRTs are commonly employed in drafting, this image is adequate. (Gump) On the software side, graphics programs employ a wide variety of special display algorithms, or internal data-processing procedures, to create realistic images (see image processing).

For example, fractal algorithms produce computer-generated geometric images. They are ideal for creating and analyzing representations of irregular patterns in nature, such as clouds, mountains, and coastlines. Fuzzy sets, or algorithms based on statistical probabilities, are useful for generating images of natural phenomena. An iterative algorithm can reproduce the same image countless times, making tiny changes in each one. Hidden-surface removal algorithms can erase lines and surfaces from unseen portions of an image. Colorizing” can endow a colorless image with a wide range of hues. (Leonard) With computer-aided design (CAD) systems, images can be intricately detailed and easily modified and manipulated, allowing them to be viewed from any angle. Researchers use computer graphics for such purposes as producing three-dimensional (3D) views of the human brain or studying how pollutants interact with various meteorological phenomena. In addition to the exploration of 3D possibilities in themselves , there are also growing educational applications.

For example, flight simulators have become indispensable tools for training pilots and astronauts, visualizations of complex equations increase understanding for mathematics students, and “virtual” bodies enable physicians to practice delicate procedures before operating on patients. Few industries have taken as thorough advantage of the computer’s ability to generate and manipulate images as the video game business. The computer’s imaging ability has also found a home in Hollywood and in advertising. (Gump) Improved capabilities of personal computers and their programs have also put powerful graphics tools into the hands of many consumers.

Paint programs enable users to create a drawing and then color it. With draw programs they can create two- and three-dimensional images that can be manipulated in many ways. Animation tools allow users to create action sequences automatically. Photographs, drawings, and video clips can also be digitized and imported into many graphics programs. Such programs typically include collections of stored images called “clip art,” which users can electronically “clip out,” “paste into” the working file, and then manipulate.

The output of graphics programs can also be exported to desktop publishing programs and used in creating multimedia productions. (Gump) Virtual Reality is an interesting topic. Virtual Reality is one of the many new innovations emerging today. Virtual reality is a part of the future. Researchers are working daily to solve the problems that produce cyber sickness. Researchers are using innovations for virtual reality. These innovations may change the business and personal life. Managers will be using virtual reality, as well as groups and employees. (Haag, Cummings, Dawkins)


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