AR (Augmented Reality) & Virtual Reality (VR) applications (apps) are both based on computer simulation of real-life scenarios and environments. The simulation will bear a high degree of resemblance with whatever is being depicted from real-life, either graphically or sensorially. The term ‘sensorially’ is broader than ‘graphically’ because it means all things perceptible to our senses I.e. graphics, touch, sound, voice, smell and so on. Usually, the degree of resemblance with the original has to be many times higher and more accurate in the case of VR than in AR apps.
Consider the video recording of a 100-metre dash from the recent Olympic Games. The original commentary may be in English and if so, as it is, that video will not be very welcome to the French. Either changing the commentary to French or adding suitable French sub-titles will make it more enjoyable to a French audience. This, in essence, is where AR finds its opportunity – augmenting the original with more useful info – in our example, substituting French for English and consequently, making the content more valuable to the French-speaking. As another example, consider the video capture of a road accident. Two cars collide on a highway and one is badly damaged. The police might not be able to pin-point which of the two drivers was responsible for the accident by merely viewing the video. If, however, the video was pre-processed by an AR application that added mass, speed and direction info. of the cars to the video, then, the one responsible could be established with close to, maybe, hundred-percent certainty.
VR (Virtual Reality), on the other hand, is quite different from AR. In fact, the two only share one thing in common – computer based simulation. As mentioned above, the simulation provided by VR needs to be of such good quality that it is indistinguishable from reality. Theoretically, this is impossible. Therefore, for practical purposes, VR only means a degree of approximation, sufficient for a user to get a ‘live’ experience of the simulated environment. Moreover, VR is interactive and responds sensorially, in ‘real-time’, and just as in real-life e.g. in a VR application, imagine you are in a forest, getting ready to burn a pile of cut-down bushes and dry leaves. You douse the pile with gasoline. A fox is keenly watching you from a nearby place. Then you throw a lighted match-stick on to the pile… the system will respond immediately showing a strong, quickly spreading fire burning on the pile, its shape occasionally altered by the blowing wind… and as in real-life… the fox (scared by the fire), must run away? – and it does! The system may allow you to change the direction, speed and alteration in the speed of the blowing wind, angle of throw of the match-stick etc. and the system will respond with the new results immediately! Thus, VR enables one to experiment with real-life scenarios and get sufficiently accurate results just as though he/she were in the desired environment/ place, in person, but saving time, travel & resource costs etc.
VR applications consume awesome amounts of computing power. In comparison, AR applications are not at all demanding on resources – AR applications run comfortably on mobile phones, tablets, other hand-helds, laptops and desktops. Very probably, you are using a couple of AR apps on your Android/ iOS device, right now, without knowing it! (e.g. Wordlens, Wikitude World Browser etc.).
The reason for the difference is that VR apps first need to correctly interpret whatever action the user performed and then ‘make out’ the appropriate response that the real environment would return, complete with animated graphics, movements in the right directions, sounds and so on and also, as per correct physics, math and any other sciences involved. Most importantly, ‘latency’, or the response time from the application, has to be sufficiently high. If not, the user, who has come with understandably high expectations, is sure to get so completely put-off that he/she might burst out with a string of unprintable words to the effect “to hell with this dumb thing!’. To avoid such failures, a computer (or network of computers) equipped with unusually powerful mobile processors, high-fidelity graphics software, precision motion trackers and advanced optics, is required. And that explains, why.