Virtual Reality
Virtual Reality
Applications of virtual reality
On the horizon of virtual reality
Virtual reality (VR) is a technology that provides users with an interaction with computer-simulated environments. It is a product of the evolution of the computer from an instrument that merely received input from a user to a machine that can adapt to the user’s cues to create an almost life like experience.
The term virtual reality was coined in 1989 by American virtual reality developer Jaron Lanier (1960–). Others have described the concept as artificial reality, cyberspace, and virtual worlds.
Virtual reality combines state-of-the-art imaging with computer technology to allow users to experience a three-dimensional simulated environment. It is this environment that was called cyberspace in a novel by American-Canadian science-fiction writer William Gibson (1948–).
Cyberspace is interactive. In other words, the user can alter the appearance of the image or the nature of the scene. This interactive medium incorporates powerful computers with video displays, sensors, electronic headsets, and gloves. With these tools, users can both see and manipulate a phantom environment that appears real. Virtual reality tools under development include a whole body suit, which, like diving into water, would totally immerse the user in a virtual world. Although virtual reality has been popularized as a new form of entertainment, it has applications in business, industry, and medicine.
The origin of virtual reality
The concept of virtual reality dates back to World War II (1939–1945). Then, piloting training for combat missions had need of realistic flight simulators. The technology of the day was insufficient to produce much beyond a rudimentary simulation.
By the 1960s, technology advanced to a point where virtual reality became possible. In 1966, American computer programmer and Internet pioneer Ivan Sutherland (1938–) conducted experiments with the first head-mounted three-dimensional displays at the Massachusetts Institute of Technology’s Lincoln Laboratory. Although the headset was extremely cumbersome, users were able to view a computer-generated three-dimensional cube floating in space. By moving the head, users could then inspect various aspects of the cube and determine its dimensions. Sutherland built the first fully functional head-mounted display unit in 1970.
American computer artist Myron Krueger (1942–) also worked on the infant science of virtual reality, first at the University of Utah and later at the University of Connecticut. His artificial realities used both computers and video systems. VIDEOPLACE, a virtual reality laboratory, was first exhibited in 1975 at the Milwaukee Art Center. Using video displays, computer graphics, and position-sensing technologies, Kreuger was able to create a virtual environment in darkened rooms containing large video screens. People in the room could see their own computer-generated silhouettes and follow their movements in the virtual world projected onto the screen. In addition, people in two different rooms could see each others’ silhouettes and interact in the same virtual world.
As is the case with other technological advance, much of the initial development of virtual reality was funded by the military. By 1972, the General Electric Corporation had built one of the first computerized flight simulators, using three screens surrounding the training cockpit to provide a 180-degree field of view that simulated flying conditions. In 1979, virtual reality technology was incorporated into a head-mounted display developed by the McDonnell-Douglas Corporation. Three years later, American engineer and research scientist Thomas Furness III, who had created visual displays for the military since 1966, developed the prototype Visually Coupled Airborne Systems Simulator. Donning a specialized oversized helmet, pilots were presented for the first time with an abstract view of flying conditions instead of a reality-based image. Since they were unable to see anything but the computerized cockpit’s field of view, pilots became totally immersed in the graphic representation.
While scientists like Sutherland and Furness concentrated on the visual components of virtual reality, American software engineer and computer scientist Frederick Phillips Brooks, Jr. (1931–) began experimenting with tactile feedback, or the sense of touch, in the early 1970s at the University of North Carolina. However, it was not until 1986 that the computer industry developed the tools to simulate tactile experience (i.e., sensing by touch). Brooks was able to develop his GROPE-III system, which used a specialized remote manipulator based on a device that mimicked arm motions to handle radioactive substances. Specifically, the GROPE-III system generated stereoscopic images of molecules and protein structures that could be felt and manipulated as though they existed in the physical world.
Components of virtual reality
Essentially, virtual reality systems consist of the computer and software—known as the reality engine—input sensors, and output sensors. The input sensors are the equipment to computer enthusiasts, and include the keyboard, mouse, knobs, and joysticks. Output devices include the printer and the video display monitor. In addition, virtual reality input and output devices include the head- and ear-mounted equipment mentioned above, and gloves for controlling the virtual world. Finally, the fourth sensory component is the user, who both directs and reacts to the chosen environment.
The reality engine
The reality engine employs both computer hardware and software to create the virtual world. Reality engines are based largely on the same components that make up a personal computer (PC), although much more computing power is required for the reality engine than what is available in a standard PC.
One reason for the increased computing power is the complexity of the hardware and software necessary to create a world that appears real. The images created by the computer and software are extremely complex, compared to the relatively simple line-based graphics associated with computer games. Virtual reality images are made with thousands of dots called pixels (or picture elements). The more pixels per given amount of area, the higher the quality of the image. Hence, an image will be more realistic. Creating realistic images that can be manipulated is known as realization. These images can be either opaque, in which all the viewer sees is the virtual world, or see-through, in which the virtual image is projected or superimposed onto the outer world.
The reality engine is also involved in bringing sound to the virtual world. Sound enriches the virtual world. For example, in a flight simulator, the experience of soaring through the air in a simulated cockpit is more realistic if the user hears the roar of the engines. Sound also enhances participation in the virtual world by providing the user with audio cues. For example, the user may be directed to look for another virtual airplane flying overhead.
To incorporate the total experience provided by the sight and sound cues, the reality engine can use what is known as haptic enhancement. Haptic enhancement utilizes the participant’s other senses of touch and pressure in the virtual world. Haptic enhancement is a complex process, and the hardware and software that are required increase the cost of the system tremendously. To date haptic enhancement is used mainly military and research applications.
Headsets
Head-mounted display (HMD) units use a small screen or a pair of screens (one for each eye) that are worn in a helmet or a pair of glasses. The HMD allows viewers to look at an image from various angles or change their field of view by simply moving their heads. In contrast, a movie is a passive experience, where the view of the audience is controlled by the position of the camera that recorded the scene.
HMD units usually employ cathode ray tube (CRT) or liquid crystal display (LCD) technology. The optical systems in CRTs reflect an image onto the viewer’s eye, creating an image of very clear and realistic image. CRT images can be semi-reflective. This means that the user can experience the virtual world while still being able to see the outside world. This permits the user to operate another machine or device while viewing the virtual world.
LCD technology has lagged behind CRT in picture quality. LCD monitors display two slightly different images to each eye. The brain processes and merges the images into a single three-dimensional view. However, LCD systems have the advantages of being slimmer, lighter, and less expensive than CRT systems. Thus, LCD is better suited to home entertainment. As the image quality improves, LCDs will find a lucrative niche in the home entertainment market.
Audio units
Sound effects in virtual reality rely on a prerecorded sound set. This aspect of the virtual reality experience is less prone to alteration.
The audio portion of virtual reality is transmitted through small speakers placed over each ear. Audio cues may include voices, singing, the sound of bubbling water, thud-like noises of colliding objects—in short, any sound that can be recorded.
While the sounds themselves cannot be changed from a recording, the presentation of the sounds to the user can be changed. Three-dimensional (omnidirectional) sound further enhances the virtual reality experience. Sound that seems to come from above, below, or either side provides audio cues that mimic how sounds are heard in the real world (e.g., footsteps approaching or a plane flying overhead). Three-dimensional sound is achieved through the use of complex filtering devices. This technology must take into account the delay in the detection of sound by the ear that is furthest away from the source of the sound (interaural time difference) and the tendency of one ear to hear a sound more loudly than the other ear (interaural amplitude difference).
The most complex human hearing dynamic is called head-related transfer functions (HRTF). HRTF accounts for how the eardrum and inner ear process sound waves. Factors that are influential in HRTF include the various frequencies at which the sound waves travel, and how waves are absorbed and reflected by other objects. HRTF audio processing enables the listener to locate a sound source and to focus in on a specific sound out of a multitude of sounds. (i.e., the sound of their name called out in the midst of a noisy party).
Gloves
A popular image of a virtual reality experience shows the user wearing gloves. The gloves allow the user to interact with the virtual world. For example, the user may pick up a virtual block, and, by turning their gloved hands, turn the block over and set it on a virtual table.
Virtual reality gloves are wired with thin fiberoptic cables, or have light-emitting diodes positioned at critical points over the gloves’ surface. The optics detects the amount of light passing through the cable in relation to the movement of the hand or joint. The computer then analyzes the corresponding information and projects this moving hand into the virtual reality. Magnetic tracking systems are also used to determine where the hand is in space in relation to the virtual scene.
Some gloves use haptic enhancement to provide a sense of touch and feel. In haptic enhancement, the reality engine relays the various sensations of force, heat, and texture that are experienced by the user to the computer software. The software can use the information to determine an outcome of the user’s actions, and relay the outcomes back to the user. For example, if the user closes a hand on a virtual squeeze toy, the software will alter the virtual image to show the toy becoming compressed. To achieve this two-way communication, virtual reality gloves may use either air pressure (such as strategically placed, inflated air pockets in the glove) or vibrating transducers placed next to the skin (such as a voice coil from a stereo speaker or alloys, which change shape through the conduction of electrical currents) to simulate tactile experience.
Tools under development
Many other virtual reality tools are in the phases of research and development. Remote control robotic or manipulation devices are being tested for industry and medicine. Already, surgery has been done by a physician located hundreds of miles away from the patient, by means of robotics and virtual imaging.
Special wands with sensors, joysticks, and finger sensors such as picks and rings will eventually be as common to virtual reality technology as microwaves are to cooking. The technology to control the virtual world through voice commands is also rapidly advancing.
Perhaps the most impressive technology under development is the whole body suit. These suits would function similarly to the gloves, creating a virtual body that could take a stroll through a virtual world and feel a virtual windstorm.
Applications of virtual reality
The potential for virtual reality as an entertainment medium is apparent. Instead of manipulating computerized images of two boxers or a car race, the virtual playground allows the user to experience the event. Disney World’s Epcot Center houses a virtual reality system.
Most entertainment applications of the present day are visually based. Virtual reality will allow players of the future to experience a variety of tactile events. For example, in a simulated boxing match, virtual reality users would bob and weave, and throw, land, and receive punches in return.
Virtual reality also has practical applications in business, manufacturing, and medicine. Already, the National Aeronautics and Space Administration (NASA) has developed a virtual wind tunnel to test aerodynamics shape. Virtual reality holds promise for discovering the most efficient manufacturing conditions by allowing planners to evaluate the actual physical motions and strength needed to complete a job. For example, the McDonnell-Douglas Corporation is using virtual reality to explore the use of different materials and tools in building the F-18 E/F aircraft. The study of people in relation to their environments (ergonomics) may also be revolutionized by trials in cyberspace. Engineers at the Volvo car company use virtual reality to test various designs for the dashboard configuration from the perspective of the user.
In medicine, virtual reality systems are being developed to help surgeons plan and practice delicate surgical procedures. Philip Green, a researcher at SRI International, has developed a telemanipulator, a special remote-controlled robot, to be used in surgery. A physician in Halifax, Nova Scotia, on a patient located hundreds of miles away, performed such surgery in 2002. Using instruments connected to a computer, the operation was performed cyberspace, while the computer sent signals to direct the telemanipulator. Because of the time delay factor for distances exceeding a few hundred miles (communications can travel only at the speed of light, which is still a crucial amount of time for surgeries), such remote surgery was not possible until about 2004–2005 when robotic surgery was able to be tested between the United States and Europe. The tests involved a dedicated broadband fiber optic cable connection that minimized the time delay to only 155 milliseconds. As bandwidth and next-generation Internet capabilities improves, such remote surgeries will become a reality around the world.
Virtual reality may even have applications in psychiatry. For example, someone with acrophobia (a fear of heights) may be treated by having the patient stand atop virtual skyscrapers or soar through the air like a bird.
On the horizon of virtual reality
Virtual reality will no doubt mirror the breath taking pace of development that is the norm for
KEY TERMS
Pixel —A word used for picture elements, or dots, that make up a computerized image.
Three-dimensional —A visual representation in terms of height, width, and depth as opposed to a “flat” image that represents only height and width.
other computerized applications. Thus, what is state of the art now will be commonplace in decades.
Aspects of virtual technology that are just ideas now will become reality soon. For example, technology is being developed to use the retina of the eye as a screen for images that could be transmitted directly to the brain through the optic nerve. Virtual sight would become a replacement for natural sight in those blind people whose optical hardware was intact.
Also under development is technology to allow the remote operation of aircraft and other machines as though the user were actually in the machine. Traveling to France or Greece, including the experience of climbing the Eiffel Tower or basking on a sundrenched beach, may be as easy as donning a headset and body suit and plugging in.
Like most technological advances, virtual reality has social and psychological ramifications. Critics argue that virtual reality could cause some people to forego emotions and interpersonal relationships for the safe, controllable virtual world. But proponents say advances from the proper applications of this technology—both as a means of interacting with the real world and as an end of facilitating training and entertainment—far outweigh the potential for antisocial abuse.
Resources
BOOKS
Bartle, Richard A. The Designing Virtual Worlds. Indianapolis, IN: New Riders, 2004.
Dix, Alan J., Janet E. Finlay, Gregory D. Abowd, et al. Human-Computer Interaction. 3rd ed. Harlow, UK, and New York: Pearson/Prentice Hall, 2004.
Hsu, Feng-Hsiung. Behind Deep Blue: Building the Computer That Defeated the World Chess Champion. Princeton: Princeton University Press, 2002.
Sherman, William, R., and Alan B. Craig. Understanding Virtual Reality: Interface, Application, and Design. San Francisco: Morgan Kaufmann Publishers, 2002.
Vince, John A. Introduction to Virtual Reality. London, UK, and New York: Springer, 2004.
OTHER
University of Michigan Virtual Reality Laboratory. “Virtual Reality: A Short Introduction.” College of Engineering. February 10, 2004. <http://www-vrl.umich.edu/intro/index.html> (accessed November 6, 2006).
David Petechuk