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If you’d like to learn more about eye tracking and how it could help your research, check our Eye Tracking Solutions page and blog posts. In “Pupil-CR” tracking, the change in CR position is essentially “subtracted” from the change in Pupil position, thus making it possible to disambiguate movements in the pupil center on the camera sensor that are the result of genuine rotations of the eye, from movements of the pupil center on the camera sensor that are the result of shifts in head position. Modern video-based eye trackers exploit this difference in the Pupil-CR relationship in order to compensate for head movements.
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So how do eye trackers distinguish between changes in pupil position on the camera sensor that result from rotations of the eye from those that result from movements of the head? Critically, with head movements the relationship between the center of the pupil and the center of the corneal reflection remains the same, whereas when the eye rotates, the relationship changes. Why the Corneal Reflection is so ImportantĪs you can see, in this case, both the pupil *and* the corneal reflection move on the camera sensor. 01-03-2019 06-01-2021 GazePointer Eye Tracking Challenge, online eye tracker Post navigation Previous Previous post: Webcam-Based Eye Tracking vs. The corneal reflection is simply the reflection of a fixed light source (the infrared illuminator) that sits next to the camera, as illustrated below.
EYE TRACKING SOFTWARE
So how is this done? The eye-tracking software uses image processing algorithms to identify two key locations on each of the images sent by the eye-tracking camera – the center of the pupil, and the center of the corneal reflection. Within 3 ms from the image of the eye being taken, EyeLink systems work out where on the screen the participant is looking, and relay this information back to the computer controlling stimulus presentation.
EYE TRACKING PORTABLE
Both the EyeLink 1000 Plus and EyeLink Portable Duouse single cameras that are capable of taking up to 2000 images of both eyes every second. So how do video-based eye trackers actually work?Īt the heart of all video-based eye tracking is a camera (or cameras) that takes a series of images of the eye. What is eye-tracking Eye-tracking technology helps observe and measure eye movements, pupil dilation, point of gaze, and blinking to see where subjects of. All SR Research EyeLink systems employ video-based eye-tracking, as do most other commercially available eye trackers. One of the biggest technological changes over the last couple of decades has been the near-universal adoption of video-based eye tracking as the technique of choice.