The "Terminator" had it, US fighter pilots use it and it's the next hot feature on Japanese smartphones -- "augmented reality" which peppers the world around you with useful bits of information.
Imagine wearing high-tech glasses and having small, cartoon speech balloon-style tags pop up within your field of vision, overlaying real-world objects and buildings to describe what you're looking at.
That is essentially what Japan's two largest cellphone operators are about to offer their millions of customers, except they will use the cameras and screens of smartphones plus vast online databases.
By harnessing the power of the Internet and bringing it more deeply into people's everyday lives, they plan to change the way we perceive reality and move a step closer to digitising our world view -- literally.
Japan's NTT DoCoMo is set to launch "chokkan nabi", or "intuitive navigation", in September to help people find their way around megacities such as Tokyo and Osaka and other places in Japan.
"You just need to focus on a street, a building or a particular spot with your camera-equipped cellphone to see if there is a bank, a restaurant, a supermarket or other location," said a DoCoMo official.
"Labels or signs indicate, for example, the distance to a chosen restaurant, schedules, menus, etc ... With a simple gesture, you can switch back to a conventional map in two dimensions."
The service has so far registered some 600,000 points of interest throughout Japan, including restaurants, shops and train stations, which can be searched through user-defined criteria.
The technology, developed with map maker Zenrin, uses a global positioning system (GPS) and sophisticated software to place virtual tags on real-world objects and also provide directions to places outside the user's direct view.
It also links with micro-blogging site Twitter, which has been wildly successful in Japan, so that its users can spot each other in real time and real space, and tweet comments about where they are.
Japan's number two mobile operator KDDI, meanwhile, has developed a platform that allows users to scan for example a CD advertising poster with their camera phone to gain additional material, such as an extract from a song.
The service will then offer the user the option to buy a download of the song with just two clicks, or can guide them to the nearest real-world CD shop.
The application, which also features virtual characters, is an advanced version of an already popular Japanese application for Apple's iPhone, called "Sekai Camera" or "World Camera".
That programme identifies visual landmarks and then displays live and past tweets from others as "air tags" in the same location.
Internationally, several operators are harnessing similar technology.
Finnish cellphone giant Nokia is offering a free application called Point & Find, which involves pointing your camera phone at real-world objects to access information and functions.
The service also allows users to scan barcodes to compare prices, read reviews, or save a product to a wish-list.
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