DIT research into gaze-tracking technology could allow people with limited mobility to control a computer cursor or a wheelchair with their eyes, writes Claire O'Connell
Imagine a pair of glasses that could let you talk, use a computer or even move a wheelchair with just a glance or a nod. That's the goal of researchers at Dublin Institute of Technology (DIT), who are unlocking new channels of communication for people with severe paralysis.
By building gaze-tracking technology into a pair of glasses, they hope to create a portable device that could even let you dial your mobile phone with your eyes.
After a stroke or high spinal injury, a person may not be able to talk, write or operate a conventional computer, and, in severe cases, may literally be imprisoned in their own body.
But if they can still voluntarily move their head or eyes, even a little, there's a chink for communicating with the aid of assistive technology, according to Dr Ted Burke, who lectures at DIT's school of control systems and electrical engineering.
His group's research aims to sense and record a person's eye movements so they can, for example, direct a screen cursor to spell out a message. To measure the movement, they place small electrodes on the skin around the eyes to measure the "electro-oculogram", or changes in the electrical field as the eyeball moves up and down or from side to side, explains Burke. "In terms of the various signals that you can measure from the body, the electro-oculogram is one of the biggest and easiest signals to read," he says.
The skin voltage changes because the eye is polarised, like a battery, explains Burke. "The front of the eye becomes electrically positive compared to the back," he says. "As a result of that standing potential difference on the eyeball, when the eye moves within the eye socket it causes voltage changes on the skin surface near the eyes, and that's what we measure."
Gaze-tracking technology is nothing new, and designers and advertisers often use the approach to work out how people naturally read page layouts or computer screens. But using the electro-oculogram to physically direct a cursor around a computer screen is less straightforward, because the eye's electrical potential changes over time and the system needs to correct for that, explains Burke.
That's why master's student Oscar Pueyo is modifying the approach to allow users to fix their gaze and instead move their heads to change the electro-oculogram and direct the cursor, which is easier to manage in practice. And for those who can move only their eyes - the system can pick up glances of even a few degrees - the researchers are also designing the measurement software to absorb some of the necessary recalibration. "It's quite tricky but so far the results are encouraging," says Pueyo.
Another novel aspect is to build the system into a pair of glasses, he adds. "The electrodes are attached to the pair of glasses and that would make the device quite portable," he says.
The project, which is internally funded through DIT, uses cheaply available technology, which Burke hopes will help it to become widely adopted. "At the moment we are thinking about using the system primarily for things on a computer screen, like drawing or spelling out text. But one we would also like to investigate is using it for wheelchair control through eye movement," he says.
And to encourage wider use, the ultimate design could be geared for everyday wear. "If the electro-oculogram is built into the glasses, it's unobtrusive - you could be wearing it on the bus," says Burke.
In theory, the eye-control technology could even be applied to procedures such as dialling a mobile phone, he notes. "It might have other advantages for everyday interfaces, too, but that's to be determined."