The ability to determine the location of a person's gaze is opening up an enormous range of new applications...
ELIMINATING "zombies" on product packaging is good for sales--but first they must be discovered. In French marketing lingo, "zombies" are logos, images or phrases on packaging that shoppers dislike, without even realising it, says Eric Singler of In Vivo BVA, a marketing consultancy based in Paris. His firm does brisk business determining exactly which elements on packaging attract or repel shoppers using a small device called an eye tracker. Resembling a chunky pair of glasses, it records the wearer's eye movements. Mapping them out reveals the places where the wearer's gaze lingers with pleasure, jerks back and forth in confusion, or fails to look at all.
In Vivo BVA runs 19 mock supermarkets, known as "shopper labs", in America, Britain, China, France, Germany and Italy. As test shoppers wander between the shelves, their eye movements are recorded to see which products catch the eye. A decade ago test shoppers were tethered to bulky computer equipment pushed along behind them in a trolley. Today, wireless goggles do the job. As the cost of eye-tracking gear has fallen in recent years and its accuracy has risen, the technology has found a range of new uses.
Eye tracking can do more than just help designers by revealing visual shortcomings in websites, advertisements and product prototypes. More than 9,000 paralysed people operate computers and wheelchairs using eye trackers (most survivors of spinal injuries and neuromuscular diseases retain control of their eyes). The technology is also being used to alert drowsy drivers, diagnose brain trauma, train machine operators and provide surgeons with "a third hand" to control robotic equipment. Costs are falling so quickly that mainstream consumer use of the technology may not be far off. Haier, a Chinese maker of household appliances, recently unveiled a prototype TV controlled by a viewer's gaze. Eye tracking may also find use in desktop computers, video-games consoles and e-readers.
Eye trackers combine a camera with an infra-red light source that illuminates the eye with bursts of invisible infra-red light. Some of this infra-red light disappears into the pupil (the dark opening in the centre of the iris), and some of it bounces back off the iris (the coloured part of the eye), the cornea (the back of the eye), the eyelid or the surrounding skin. All these different areas reflect different amounts of infra-red light, which is picked up by the camera. By analysing the reflections using "a lot of very fancy matrix math" it is then possible to work out where the eye is pointing, says Bryan Reimer of the Massachusetts Institute of Technology. Because eyes move in tandem, this only needs to be done for one eye. The technique is able to cope with blinking, head movements, dim light, glasses and contact lenses.
There are two main types of eye tracker. Charting someone's gaze as they use a computer screen or watch television can be done using an eye tracker aimed at the user from as far as two metres away. Tracking someone's gaze as they move around is more difficult. A special headset is needed, with an eye tracker pointing towards the wearer's eyes, and an extra video camera facing forward to record what he is seeing. The output from the eye tracker is then used to superimpose crosshairs or a coloured dot on the video from this camera, to show what the wearer was looking at.
The cost of headset eye trackers has fallen from around $30,000 a decade ago to a bit less than $15,000 today. Fixed eye trackers used in conjunction with computer screens cost less than $5,000. Tobii Technology, a Swedish company that manufactures eye-tracking gear, reckons that the price of these high-end devices will soon fall to below $3,000.
For the time being, the main use of eye tracking is in design and marketing. Trials involving just a few dozen viewers of an advertisement, website or product design can reveal exactly what looks good and what does not. Software sold by iMotions, a Danish firm, creates colour-coded maps that show where gazes glide, linger, or twitch back and forth in frustration. Such "heat maps" can reveal more about how well an advertisement will work than asking people to express themselves in words, says Peter Hartzbech, the firm's boss.
Wandering eyes
But as eye-tracking gear gets cheaper, new applications are emerging. Lenovo, a Chinese PC-maker, has made 20 prototype laptops with Tobii eye trackers built into a bulge in the top of the lid. The Eye Tribe, a start-up based in Copenhagen, has modified a tablet computer so that it can be controlled using eye movements. (Its demo video shows the game "Fruit Ninja" being played using eyes alone.)
The Gaze Group, a research centre at the IT University of Copenhagen from which The Eye Tribe is a spin-off, is developing eye-tracking software for Android, the leading smartphone operating system. More than 30,000 people have downloaded the Gaze Group's software, which supports eye-tracking using relatively inexpensive night-vision cameras. The group's leader, John Paulin Hansen, says the software has been used by "nerds who like to play with stuff" to create eye-tracking controls for home appliances and a modified version of "World of Warcraft" that quadriplegics can play.
The ability to use eye tracking to control a computer has obvious advantages for disabled people, but fans of the technology believe it could become a widely used input technology for the able-bodied, too. Moving an on-screen cursor with a glance is much faster than using a mouse, for example. Tobii is also working with console-makers and video-game publishers to develop new markets for its technology.
Another use is in e-readers. Researchers at the German Research Centre for Artificial Intelligence and the University of Kaiserslautern have created a program called Text 2.0 that uses eye tracking to analyse how a displayed text is being read. If the reader lingers on a foreign word, Text 2.0 can display its translation. Lingering on a word and then sweeping one's gaze to the right margin calls up a definition. If the reader starts to skim, the software dims common words. The program could be used by authors to see which passages caused readers to stumble or skip ahead.
Eye tracking can also keep an eye on drivers. In America each year more than 750 people are killed in road accidents involving drivers who fall sleep, notes Tim Johnson, head of crash-avoidance technologies at the National Highway Traffic Safety Administration. One way to detect and alert a dozing driver is to use an ear clip that beeps when it detects the driver's head nodding forward. But an "attention monitoring" system based on eye tracking is more effective. Pioneered by Toyota, the world's largest carmaker, it sounds a warning if an eyelid sags, blinking speed slows, the shifting of the driver's gaze becomes sluggish or his head tips forward.
In early 2013 a Canadian firm called Six Safety Systems will begin installing similar drowsiness-detection technology in vehicles operated by three big mining and drilling companies. The system, called LUCI, calculates the driver's alertness score and sounds an alarm if it slips to a dangerous level. At more than $15,000 per vehicle, LUCI is not cheap. But Richard Robillard of Six Safety Systems notes that for one of his customers, driver fatigue causes about half of all vehicle accidents--and an hour of downtime for a single mining vehicle costs about $57,000 in lost production.
Eye-Com Corporation, based in Reno, Nevada, has designed an eye-tracking scuba mask for Navy SEALs that detects fatigue, levels of blood oxygen and nitrogen narcosis, a form of inebriation often experienced on deep dives. "Eyes can tell you so much--it's pretty amazing," says the firm's founder, William Torch. EyeTracking, based in San Diego, has developed software that determines whether circular or radial muscles in the iris are opening or closing the pupil. Radial muscles take over as stress and brain effort increase. Because a novice's brain has to work harder than an expert's to perform a given task, this offers a way to measure a person's level of expertise. EyeTracking's technology is being used by two American university hospitals to determine when urology surgeons are ready to leave training programmes.
The death stare
Inevitably, eye tracking has military applications too. American flight instructors are using eye-tracking gear provided by Polhemus, a firm based in Vermont, to monitor the eye movements of pilots in flight simulators. The equipment can reveal whether trainees are scanning gauges in the right sequence, or skipping one altogether. Pilots dislike the technology because it exposes their mistakes, says John Farr of Polhemus.
Eye tracking may also have uses in real aircraft. In particular, it could be used to aim weapons just by looking at a target. At the moment a pilot aims by turning and tilting his head, the orientation of which is determined using helmet-mounted sensors. But pilots cannot always control their head movements during high-G manoeuvres, during which a helmet can feel "like a tonne of bricks", says Jonathan Waldern of SBG Labs, a Silicon Valley defence contractor. It is developing a gaze-controlled targeting system for the US Air Force.
ISCAN, a firm based in Woburn, Massachusetts, has built a weapon system in which a small drone is wirelessly controlled by an eye-tracking headset. Fitted with explosives, the "eye-slaved" drone can then act as a smart missile that can be sent to blow up whatever the wearer is looking at. It gives a whole new meaning to the idea that looks can kill.
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