Monday, 24 September 2012

Eye Tracking, a brief history and potential future...

Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head. An eye tracker is a device for measuring eye positions and eye movement. Eye trackers are used in research on the visual system, in psychology, in cognitive linguistics and in product design. There are a number of methods for measuring eye movement. The most popular variant uses video images from which the eye position is extracted. Other methods use search coils or are based on the electrooculogram.
In the 1950s, Alfred L. Yarbus did important eye tracking research and his 1967 book is often quoted. He showed the task given to a subject has a very large influence on the subject's eye movement. He also wrote about the relation between fixations and interest: "All the records ... show conclusively that the character of the eye movement is either completely independent of or only very slightly dependent on the material of the picture and how it was made, provided that it is flat or nearly flat." The cyclical pattern in the examination of pictures "is dependent not only on what is shown on the picture, but also on the problem facing the observer and the information that he hopes to gain from the picture." "Records of eye movements show that the observer's attention is usually held only by certain elements of the picture.... Eye movement reflects the human thought processes; so the observer's thought may be followed to some extent from records of eye movement (the thought accompanying the examination of the particular object).
It is easy to determine from these records which elements attract the observer's eye (and, consequently, his thought), in what order, and how often." In the 1970s, eye tracking research expanded rapidly, particularly reading research. A good overview of the research in this period is given by Rayner. In 1980, Just and Carpenter formulated the influential Strong eye-mind Hypothesis, the hypothesis that "there is no appreciable lag between what is fixated and what is processed". If this hypothesis is correct, then when a subject looks at a word or object, he or she also thinks about (process cognitively), and for exactly as long as the recorded fixation. The hypothesis is often taken for granted by beginning eye tracker researchers.
However, gaze-contingent techniques offer an interesting option in order to disentangle overt and covert attentions, to differentiate what is fixated and what is processed. The 1980s also saw the birth of using eye tracking to answer questions related to human-computer interaction. Specifically, researchers investigated how users search for commands in computer menus. Additionally, computers allowed researchers to use eye-tracking results in real time, primarily to help disabled users.
In the late 1990s, organizations including one of the world’s largest advertising and marketing agency networks EURO RSCG began using eye-tracking technology to measure and study reactions to information on the World Wide Web. For a large number of web designers up until this point, it was assumed that web design should be fashioned off of print and newspaper design. In 2006, British behavioral consultancy research firm Bunnyfoot researched in-game advertising using eye-tracking and physiological data. The study examined how effective advertising was in video games in virtual worlds with digital billboards.
From 2001 till present day, Tobii Technology has been developing eye-tracking technology that both allows disabled users to control devices using only their eyes, as well as helps designers understand how users view websites. Today, eye-tracking is widely used in the scientific community, marketing, and in usability studies. This technology has seemingly become far more popular in the past decade than any other time in history, and is heavily used in developing effective advertising campaigns and usable websites.
Eye-tracking equipment it would normally have cost you upwards of $8,000 would of been beyond the reach for most people. Now, scientists in London have pioneered a device, like the existing technology Tobii PCEye and the EyeTech TM3 , using components anyone of us can buy from the shopping mall. The breakthrough could help millions of people suffering from Multiple Sclerosis, Parkinson's, muscular dystrophy and, potentially, opens the door to a new era of hands-free computers, allowing us to use them without a mouse, keyboard or touch screen.
For the lead researcher Dr Aldo Faisal, a neuroscientist at Imperial College in London, the new device only came about because of his obsession with disassembling gadgets. "I like to play with gadgets and was playing with a popular video-game console," he said. "I hacked it and discovered it was very fast and better than any webcam for movement. Actually, it was so fast that I found we could record eye movement with it." Tracking eye movement is no mean feat. Our eyes moves 10 to 20 times a second, so a standard webcam or even film camera will miss most eye movements and where we are looking. As such, it is perhaps no surprise commercial eye-tracking devices are so expensive.
Luckily for Faisal and his team of researchers, video game console makers have been willing to bulk buy the technology needed to make good enough cameras. They make a loss on the console cameras in the expectation of making it back on accompanying video game sales. "We originally created the device for £39.80 ($64) but recent falls in the price of video game console cameras mean we could now actually make the same device for about £20 ($32)," says Faisal. The eye-tracking device works by first establishing where the eyes are looking, through a relatively straight-forward calibration process. The user puts on the glasses, with the two attached cameras, and stares at a computer screen full of dots. They are then told to look at different dots, with software developed by the researchers working out how the eye looks at each dot.
With simple software and basic mountable cameras a kinetic like hack could bring down prices, already there is a open sourced project for people to try eye tracking for themselves. Eventually market prices might reflect the reachable budget of what an open sourced project would cost. The future of this technology would probably be incorporated in more then just applications in research and computer interfacing. My suspicions is that mobile phone companies and the games industries would want better interfacing and such device would be the next game changer...

Construct your own low cost EYE tracker

Open source software for your Eye tracker 


  1. Great stuff ! ... Looks like the predictions in the 1981 book by Joel Garreau "Nine Nations of North America" came true. You should read it (If you haven't) it's a great book.

  2. Try
    WebCam Eye Tracking for usability testing