What is Eye Tracking (Eye Tracking)?
Published: Jun 21, 2007Eye tracking is a method used in cognitive science, psychology (particularly psycholinguistics), human-computer interaction (HCI), advertising, medical research, and other areas. In eye tracking, a camera focuses on one or both eyes and records their movement as the viewer looks at a stimulus. Newest eye-trackers use contrast to find the center of the pupil and use infrared beams to create a corneal reflection. The triangulation of both is used to determine the fixation point.
There are different types of eye tracking setups. Some are head-mounted, some require the head to be stable, and some automatically track the head. Most setups use a frequency greater than 30Hz in order to capture the rapid eye movements in detail.
Typically there are two types of eye movements: fixations and saccades. When the eye gaze pauses in a certain position, it is called fixation and when it moves to another position, it is called saccade. The resulting series of fixations and saccades is known as a scan path. Most information from the eye is obtainable during a fixation. The central one or two degrees of the visual angle (the fovea) provide the majority of visual information. Larger eccentricities give less informative input. Thus, the locations of fixations along a scan path explain what information loci on the stimulus were processed during an eye tracking session. Most people cannot make a saccade voluntarily in less than 200 milliseconds.
Useful for analyzing cognitive intent, interest, and salience, scan paths may be affected by other biological factors. In HCI, eye tracking examines the scan path for usability purposes, or as a method of input in gaze-contingent displays or gaze-based interfaces.
Source: Wikipedia
