Virtual reality (VR) refers to a set of techniques for creating synthetic, computer-generated environments in which human operators can become immersed. In VR systems, human operators are connected to computers that can simulate a wide variety of worlds, both real and imaginary, and can interact with those worlds through a variety of sensory channels and manipulators (National Research Council, 1995, pp. 247-303). Simple VR systems include home video games that produce three-dimensional (3D) graphical displays and stereo sound and are controlled by an operator using a joystick or computer keyboard. More sophisticated systems—such as those used for pilot training and immersive entertainment experiences—can include head-mounted displays or large projection screens for displaying images, 3D sound, and treadmills that allow operators to walk through the virtual environment.

Such systems are increasingly being used in a variety of applications, from telecommunications and information visualization to health care, education and training, product design, manufacturing, marketing, and entertainment. Among other things, they enable operators to explore foreign cities from the comfort of their own homes, train for hazardous missions, develop new surgical procedures, and test new product designs.

VR is the outcome of a complex alignment of research fields that include computer graphics, image processing, computer vision, computer-aided design, geometric modeling, user-interface design, and physiological psychology. It also incorporates robotics; haptics and force feedback; computer architectures and systems development; entire new generations of processors, graphics boards, and accelerators; and a host of software applications converted to firmware in computers for rendering data visually. Finally, VR also involves work on high-speed data transmission and networks.