The visible spectrum is likely to generate uncontrolled reflections, while illuminating the eye with infrared light – which is not perceivable by the human eye – renders the demarcation of the pupil and the iris an easy task – while the light directly enters the pupil, it just reflects from the iris. The accuracy of eye movement measurement heavily relies on a clear demarcation of the pupil and detection of corneal reflection. The light reflecting from the cornea and the center of the pupil are used to inform the eye tracker about the movement and direction of the eye. Image above: Pupil Center Corneal Reflection (PCCR). We won‘t bore you with the nature of algorithms at this point. The math behind it is …well, a bit more complex. An image of how this looks like is on the right. It essentially involves the camera tracking the pupil center, and where light reflects from the cornea. The underlying concept, commonly referred to as Pupil Center Corneal Reflection (PCCR ), is actually rather simple. Most modern eye trackers utilize near-infrared technology along with a high-resolution camera (or other optical sensor) to track gaze direction. Remote, non-intrusive methods have made eye tracking both an easy-to-use and accessible tool in human behavior research that allows objective measurements of eye movements in real-time. Modern eye trackers are hardly any larger than smart phones and provide an extremely natural experience for respondents. Long gone are the rigid experimental setups and seating arrangements you might think of. While early devices were highly intrusive and involved particularly cumbersome procedures to set up, modern eye trackers have undergone quite a technological evolution in recent years. This page is packed with all the need-to-knows and useful tools to help you get a solid grasp of eye tracking technology and best practices.Įye tracking use is on the rise. While the idea of eye tracking is quite straightforward, the technology behind it might strike you as rather complex and inaccessible. More specifically, eye tracking describes the recording of eye position and movement in an environment based on the optical tracking of corneal reflections to assess visual attention. Put simply, eye tracking refers to the measurement of eye activity. Where do we look? What do we look at, and how much time do we spend looking at it? How do our pupils react to different kinds of visual stimulation? When exactly do we blink?
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