Already, you can point your phone's camera at a building to identify it, and someday soon you may be able to aim your device at a person to see their name and personal information displayed on the live camera view. Think of it as "pop-up video" for your life, or having your own Terminator-like vision to learn more about your surroundings.

These mind-bending examples are being made possible through a technology known as "augmented reality" that's already being used by some applications for the Apple iPhone and Google Android phones. Although still in its infancy, it's poised to be one of the next big trends in mobile.

At its most basic form, it means taking a live view of the real world and displaying useful information on top of that view, such as photos, titles or graphics. On a mobile phone, augmented reality apps use the phone's camera to display the live image, the GPS to pinpoint your location and the compass to figure out which direction you are facing. The app then uses that data to overlay information on the live image about restaurants, gas stations, buildings or other locations in the direction you are facing.

Because a compass is required, the iPhone 3GS is the only iPhone capable of augmented reality.

For now, the majority of augmented-reality apps allow you to view listings of nearby places on a live picture of what's in front of you, instead of as points on a map. That's a big help for people who aren't spatially oriented and have trouble following directions to go north or south. Be aware that these apps quickly drain your battery.

The most well-known augmented-reality iPhone app is the newest version of Yelp, a popular restaurant- and local-review site. Tapping the "Monocle" button will bring up the phone's camera, and as you move it around, you will see little black floating bubbles with information about nearby restaurants, such as the rating, category and distance. But it's not perfect: My test of Yelp found that it often displays restaurants in the wrong direction, even after recalibrating the compass as suggested.

Other uses of augmented reality on the iPhone include finding the nearest subway stop ("Nearest Tube," several city-specific apps), and finding the cheapest gas ("Cheap Gas!," which was made by Winter Park developer David J. Hinson).

Two useful iPhone apps are "NearestWiki" ($1.99), which displays entries from Wikipedia on the live-camera view and "NearestPlaces" ($1.99), which lets you choose categories of places to be displayed, such as banks, parks, museums, restaurants and hotels.

When I opened up NearestWiki and pointed my phone at the Lake Eola fountain in Orlando, information from the Lake Eola Wikipedia page popped up, which would be helpful for a tourist. But it was not current, as it contained details that had been removed from Wikipedia.

There's also "Bionic Eye" (99 cents), which lets you choose specific restaurant chains to display.

The best Google Android app is "Layar," which can display info on a live-camera view from dozens of "layars," including Wikipedia entries, hotel listings, skateboard spots and even social-networking sites.

So if you see people nearby who look as if they are posting to Twitter, you could use Layar to find out what they wrote (assuming their Twitter message had geographic information). "Wikitude" offers similar functions to "NearestWiki."

Though the technology may seem like a novelty right now, it has a lot of potential. For instance, Disney could develop apps for visitors that would display icons showing the name of attractions, restaurant menus and how long the wait is at that moment, providing an easier way to navigate than relying on signs and maps.

There are privacy concerns that will have to be addressed as this new software progresses, and if the thought of being able to identify someone by pointing your phone's camera at them freaks you out, don't worry, for that to happen, you'd likely have to choose to broadcast that information about yourself.
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