





Augmented Reality















Augmented reality is the integration of digital information with the user's environment in real time. Unlike virtual reality, which creates a totally artificial environment, augmented reality uses the existing environment and overlays new information on top of it.





How does AR work?

If you're out and about in the real world with your laptop, netbook, or cellphone, it's easy enough to get information: just bring up Google and type in some words. In the brave new world of augmented reality, it's even easier: you get the extra information automatically. That means your portable computing device needs some automatic way of finding out where you are or what you're looking at—a problem known as tracking .

The simplest form of tracking is for the device to use GPS (or some other satellite navigation system) to figure out your position automatically, which is fine if you want broad, background information about a place you're visiting (a local street map, a list of nearby coffee bars, directions to the nearest hotel, or whatever). It's relatively easy to use tracking information from Wi-Fi hotspots as well. But what if you're somewhere like an art gallery or museum and what you actually want is information about each picture or exhibit automatically coming up on your cellphone as you walk through the building? GPS isn't (yet) precise enough for an application like that, so what could we do instead? Broadly speaking, there are two different solutions known as marker-based and markerless tracking.

Markerless tracking : You could point your phone at each picture or exhibit and have some kind of pattern recognition or feature-detection system try to identify it. That's how our own perceptual systems work, after all: our eyes see things and our brains figure out what we're looking at, then "call up" background information. Our brains are amazingly good at this and make it seem very easy, but it's a much harder problem for a computer to tackle, not least because the best computer vision systems are only a fraction as good as our own.

Marker-based tracking : A simpler option would be for the gallery or museum to print small, two-dimensional barcodes (also called data-matrix codes) next to each item on display. Then you'd simply point your phone's camera at one of them, your phone would turn the barcode into a web address, and its browser would call up an appropriate web page with further information. AR systems can be designed to read all kinds of other markers (or fiducial markers) as these "added reference points" are called.

Marker-based tracking is currently proving to be the more popular option, largely because it's so simple to implement. But in the longer term fully automatic, markerless tracking seems certain to win out because that's how our own visual systems work—and it's what most users prefer. After all, we recognize our friends automatically without them having to walk around with barcodes printed on their foreheads.





The 5 Types of Augmented Reality