26 March 2010

Innovation: Gaze trackers eye computer gamers

Eye tracking technology can be seamlessly integrated into computer displays, like this one from Swedish firm Tobii, making a jump to machines for gamers plausible


Gamers in search of a more thrilling experience look set to get it thanks to interfaces that let them use what are probably the body’s fastest and most fatigue-resistant muscles: the ones that move our eyes.

Gaze-tracking technology has been honed over the years for psychology experiments and to help disabled people. Now it’ s proving capable of providing faster interaction than conventional games controllers, touchscreens or mice – and can lead to trickier gaming challenges to boot. At least one leading manufacturer of eye-tracking systems says it’s likely that the technology will be a part of the computer gaming future.

Eye spy

The trackers uses a small camera to track the movement of the pupil of one eye. Typically the user first calibrates the system by focussing on a series of onscreen targets, after which they can use a glance to control cursor movement.


The potential speed gains over having to find a target and then move a mouse to it are obvious. “With eye tracking, once you’ve discovered the target you are already aiming at it,” says John Paulin Hansen at the IT University of Copenhagen, Denmark.

He recently vindicated this bit of common sense by giving a number of people either a mouse, a touchscreen, a joystick or a gaze interface to use and then racing them against each other to find and select a small target. Those using a gaze tracker simply had to frown to select the target once they were looking at it, thanks to a headband that monitored muscle activity.

Target selection time using gaze took, on average, 350 milliseconds – over 50 milliseconds faster than the nearest competitor, the mouse.

Other systems have used blinking to trigger a click, something that can be detected by the eye-tracking camera without the user having to don special headgear.

Blink to shoot

Perhaps ideally, gaze would augment existing interfaces. But games can also be controlled by eye alone.

Howell Istance at De Montfort University in Leicester, UK, and colleagues are trialling a gaze-controlled version of the online role-playing game World of Warcraft (WoW). A translucent control panel floats over the game area and the user navigates, launches spells and attacks monsters by gazing at its virtual buttons in the correct sequence.

This week the team reported that trials with 12 experienced WoW players showed that experienced gamers can quickly adapt to an eyes-only control scheme.

Hidden in plain sight

Past research has shown that an eye tracker can also allow games to respond to a player more intelligently, or even deviously. A shoot-’em-up game developed at the Centre for Intelligent Machines at McGill University in Montreal, Canada, changes the places where enemies appear in response to where a player is looking: players have an easy time when new enemies pop up near their focus of attention, but struggle when they are spawned far from where they are looking.

Given the evidence of eye-controlled gaming’s potential, it’s not surprising that the gaze-tracking systems company Tobii, based in Stockholm, Sweden, would like to develop its technology into a new, gamer-centric direction.

“We do a lot of research and development projects, and gaming is an obvious field to explore,” says a Tobii spokesperson. The technology is still relatively expensive, though, so the company would need a partner from the games industry to bring the idea to market, she says. “The most likely first step would be some eye controller in arcade games rather than home computers.”

Journal references: PsychNology Journal, vol 7, p 213; ACM Transactions on Multimedia Computing, Communications, and Applications, vol 4, issue 3; the DeMontford team reported their WoW trials at the Eye Tracking Research and Applications conference in Austin, Texas, this week

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