2. 1 Definition of Virtual Reality (VR)

2.1 Definition of Virtual Reality (VR)

The term Virtual Reality (VR) is used by many different people with as many different meanings. There are some to whom VR is a specific collection of technologies (i.e. Head Mounted Display, Glove Input Device and Audio Device). Others stretch the term to include movies, games, entertainment and imagination. Virtual Reality is a way for humans to visualize, manipulate and interact with extremely complex data in a variety of immersive environments. A computer is used to generate visual, auditory or other sensual outputs to the user. This data may encompass a CAD model, a scientific simulation, or a view into a database. The user can interact with the virtual world and directly manipulate objects within it. Some worlds are animated by other processes such as physical simulations or simple animation scripts. Interaction in an immersive environment is perhaps the most intriguing part of virtual reality. In conventional human-computer interaction, humans remain "separated" from the computer environment. In VR, humans are totally immersed in the visualization-based world. They have the ability to manipulate and interact with the objects analyzed just as they do in the real world. Virtual Reality is often referred to by other terms, such as Augmented Reality, Synthetic Environments, Cyberspace, Artificial Reality, Simulator Technology and Immersive Environments. All of these terms actually refer to the same thing - Virtual Reality (VR). VR remains the most used term by the media.

2.2 History of VR

In order to gain an understanding of where today’s technology is in the field of high-end visualization, it is helpful to look at the history of Virtual Reality in both fiction and reality. Surprisingly, VR is closely linked to the development of calculating machines as well as the development of mechanical devices (such as automata). The concept of VR can be traced back to the automata of the ancient Greeks [¹]. Archytas of Terentim (circa 400-350 BC) was reported to have developed a pigeon whose movements he controlled remotely using a jet of steam or compressed air. In China, at about the same time, inventors had created an entire mechanical orchestra that could be controlled by operators sitting yards from the instruments [²]. Calculating machines such as Charles Babbage’s Analytical Engine were attempts to simulate reality in numeric form and then manipulate that reality to learn the results of different forces [2]. During World War II, the first computer was developed to decipher intelligence as well as to assist in missile research. Rocket trajectory, airflow patterns, and other characteristics of rocket engines were simulated on computers before prototypes were actually developed.

As with most technologies, fiction preceded fact in VR. In the 1932 novel, Brave New World [³], Aldous Huxley described “feelies”, movies which allowed the viewers to feel the action taking place. Isaac Asimov [⁴] explored the subject of virtual environments in his Robot series. The books in that series featured positron brains that operated in virtual worlds. Arthur C. Clarke [⁵], in many of his books, talked about a “cyberspace” created by orbiting satellites. The first fictional description of a true VR concept may have come from William Gibson, an American who moved to Canada during the late 1960s. VR, (or "the matrix" or "cyberspace") plays an important role in Gibson's trio of 1980s novels, Neuromancer [⁶], Count Zero [⁷], and Mona Lisa Overdrive [⁸].
Possibly the most well-known fictional VR system today is the Holodeck from the TV series Star Trek: The Next Generation [⁹]. In this show, the Holodeck is controlled by a computer that translates voiced commands into various scenarios. These scenarios can be peopled with lifelike characters that seem to have volition. In fact, a computer bug occasionally causes the characters to go awry, threatening the Holodeck user. The Holodeck requires no special gear such as goggles, earphones, or tracking devices connected to the user's body. Rather, all the mechanisms are hidden within the room, providing what may be called "unencumbered VR" - a system not yet available in reality.

The roots of non-fictional VR in a form that might be recognized as VR today may be traced back to early 1940s. An entrepreneur by the name of Edwin Link [¹⁰] joined forces with Admiral Luis DeFlorez to develop flight simulators in order to reduce pilot training time and costs. The early simulators were complex mechanical contraptions and illusion of the flight was relatively poor in the early models. However, the increasing power of computers and image technology have now made these simulators very realistic. Today, the mocked-up cockpit turns and rolls on a moving platform almost exactly simulating what would occur in an actual plane. The original simulators required that the user sit in front of a computer or TV screen, which normally represents either a window or a set of gauges [¹¹]. The room was built to look like the equipment or vehicle the user is being trained on - a cockpit, bridge or power plant control room.

When a VR system requires that the user view the virtual environment through a screen, it is called Desktop VR or a Window on a World (WoW). Its origin can be traced back to 1965, when Ivan Sutherland published a paper called The Ultimate Display [¹²,¹³] in which he described the computer display screen as "…a window through which one beholds a virtual world". He challenged scientists to create images that would justify the computer screen as the window analogy. While WoW systems may represent an earlier form of VR, they are still considered an important part of the VR family.
In newer VR systems, more of the environment exists as a function of software. This environment is displayed via goggles and represented as force feedback joysticks or other sensing devices. An advantage of these systems is that without the requirement to build large rooms or mock cockpits, they are less expensive to build and maintain.
Another level of representation is the video mapping approach. This merges an image of the user's silhouette with an on-screen two-dimensional computer graphic called parallax. In order to accomplish this, the user has to wear stereographic shutter glasses that provide input to the computer as to his or her physical orientation. Artificial reality and Artificial Reality II, both published in the 1960s by Myron Kruger [¹⁴], described such systems. A few TV game shows have used variations of image mapping techniques. For example, Nick Arcade (on cable channel Nickelodeon) places young contestants into video games.
Immersive VR systems, when and if they can be perfected, represent the final step as of the VR technology ladder as we know it today. In theory, these systems should, from the users perspective, replicate reality exactly. In other words, the user should not be able to discern whether the world he or she is interacting with is real or virtual.