Virtual reality (VR): Virtual reality is a term that applies to computer-simulated environments that can simulate physical presence in places in the real world, as well as in imaginary worlds. These are visual experiences displayed either on a computer screen or through special stereoscopic displays etc.
It mainly deals with making the user feel to be in another space and work in environments different from his existing surroundings while he physically is present in his surroundings.
It provides virtual presence of users with the concepts of telepresence and telexistence or a virtual artifact (VA) either through the use of standard input devices such as a keyboard and mouse, or through multimodal devices such as a wired glove, the Polhemus, and omnidirectional treadmills. Using these devices the user can touch, feel and sense the virtual world and its objects – it provides a life-like experience. Virtual Reality is being used in simulations for pilot or combat training, VR games etc.
Users normally view the VR’s using a head mounted displays and data suits.
Augmented reality (AR): Augmented reality is conventionally a binding of the real and virtual objects, in this the user will be in his original time space and surrounding while, integrated with his normal view he will be able to see virtual objects as well. Instead of considering AR and VR as opposites, AR can be considered as an extension of VR. It is a live, direct or indirect, view of a physical, real-world environment whose elements are augmented by computer-generated sensory input such as sound, video, graphics or GPS data.
It provides a view of reality which is modified (possibly even diminished rather than augmented) by a computer. As a result, the technology functions by enhancing one’s current perception of reality. By contrast, virtual reality replaces the real world with a simulated one. You may have seen the sports scores on the tv screen during a match, which is an example.
Head-up displays in AR cars such as some BMW 7 Series models or on airplanes are typically integrated into the windshield are other examples of VR.
Both these technologies are of immense use in many fields such as medical, navigation, industries, military, space programs, pilot training etc