That glitzy mall TV may be profiling you

If you have recently walked into a shopping mall or large grocery store and gazed at the TV screens showing ads for the products on offer, it is quite possible that the screens were gazing right back at you - registering your age, sex, and whatever other details they can gather.

In shades reminscent of George Orwell's 1984 or the Tom Cruise blockbuster Minority Report, small cameras can now be embedded in the screen or hidden around it, tracking whoever looks at the screen and for how long. The makers of the tracking systems say the software can determine the viewer's gender, approximate age range and, in some cases, ethnicity - and can change the ads accordingly.

This could mean razor ads for men, cosmetics ads for women and video-game ads for teens. But even if the ads don't shift based on what people are watching, the technology's ability to determine the viewers' demographics is a boon for advertisers who want to know how effectively they're reaching their target audience.

While the technology remains in limited use for now, advertising industry analysts say it is finally beginning to live up to its promise. The manufacturers say their systems can accurately determine gender 85 to 90 per cent of the time, while accuracy for the other measures continues to be refined.

Of course, the technology is nowhere near being capable of identifying individuals personally - it simply categorises them by outward appearances. So a video screen might show a motorcycle ad for a group of men, but switch to a minivan ad when women and children join them.

Because the tracking industry is still in its infancy, there isn't yet consensus on how to refer to the technology. Some call it face reading, face counting, gaze tracking or, more generally, face-based audience measurement. Whatever it is called, advertisers seem finally ready to try it.

Because face tracking might feel like 'Big Brother is watching you', manufacturers are racing to offer reassurances. When the systems capture an image of who's watching the screen, a computer instantly analyses it. The systems' manufacturers insist, however, that nothing is ever stored and no identifying information is ever associated with the pictures. That makes the system less intrusive than a surveillance camera that records what it sees, the developers say.

In general, the tracking systems work like this: a sensor or camera in or near the screen identifies viewers' faces by picking up shapes, colors and the relative speed of movement. The concept is similar to the way modern digital cameras can automatically make sure faces are in focus.

When the ad system pinpoints a face, it compares shapes and patterns to faces that are already identified in a database as male or female. That lets the system predict the person's gender almost immediately.

"The most important features seem to be cheekbones, fullness of lips and the gap between the eyebrows," said Paolo Prandoni, chief scientific officer of Quividi, a French company that is another player in face-tracking technology. Others include Studio IMC Inc in New York.

The companies say their systems have become adept at determining a viewer's gender, but age is trickier: The software can categorise age only in broad ranges - teens, younger to middle-aged folks and seniors. There's moderate demand for ads based on ethnic information, but the companies acknowledge that determining ethnicity is more challenging than figuring out gender and age range.

However, the system's ability to detect gender correctly 80-90 per cent of the time is still remarkable, considering that even the human brain cannot always determine gender, age or ethnicity.

Adspace Networks Inc of New York, a company that sells video advertising on 1400 video screens at 105 malls around the US, is testing six TruMedia systems at malls in Winston-Salem, NC, Pittsburgh and St Louis. The kiosks display a daily list of top 10 sales at the mall, as well as paid advertising that comes largely from movie studios and TV networks.

A 15-second video ad that replays across Adspace's national network can cost as much as $765,000 per month. So advertisers expect rigorous information about who sees the spots - information that face tracking can now provide, says Bill Ketcham, the chief marketing officer of Adspace.

For now, at least, Adspace isn't changing the ads based on who's watching - Ketcham said the kiosks' audiences are so large that it wouldn't be practical to personalise ads to individuals.

But privacy advocates continue to question the system as being too intrusive. Harley Geiger, staff counsel for the Center for Democracy & Technology in Washington, DC, said advertisers should be telling consumers what details about them are being collected and for what purpose.

"With the technology proliferating, now or the short-term is the time to consider privacy protections," he said. "If you don't build it in at an early stage it becomes very difficult to build it into an already established system."