British advertisers are using eyetracking technology more commonly used on the internet to monitor who views outdoor billboards.
The eyeBox2, developed at Queen's University in Ontario, includes a camera that can monitor viewers' eye movements at up to 35 feet away.
Eyetracking has become commonly used by web developers monitoring the effectiveness of their design and information architecture.
One notable eyetracking study has been carried out by the Poynter Institute to research the use of news websites.
But developer Roel Vertegaal said the eyeBox2 can accurately measure how much attention is being given to billboards, supermarket posters and other real-world displays
"It can track interest for your advertisers so you can actually have a business model where you sell the ad by the eyeball," he told Associated Press, adding companies in the UK are already using the device to monitor ad effectiveness. He did not name participants.
The technology opens up the possibility of revisions to advertising business models, where advertisers might only pay according to the number of people who view their displays.
Such a move would see the outdoor display advertising market borrow many norms already in use in web marketing.