Does head movement affect eye tracking results?

Eye tracking

During an eye tracking session, the movement of the head is one of the factors that may have an impact on the gaze data accuracy. In this page we will discuss how robust Tobii Eye Trackers are to head movement. 

The  optical  sensor  of  the Tobii Eye Trackers is composed of two cameras that  capture  an  image  of  the  eyes  at  a  given  frequency (30,  60, 120 and 300 Hz). The two cameras produce  two  images  of  the  eyes  and the respective pupil and corneal reflections providing  the  eye  tracker  with  two  different  sources of information regarding the eye position. This  type  of  “stereo  data  processing”  offers  a  robust calculation of the position of

the eye in space and the point of gaze even if the position of the head changes. Additionally these two cameras increase the horizontal field of view of the sensor i.e. the horizontal size of the trackbox, increase the freedom of movement of the user.

Nevertheless head movement will still have an impact on the data if the subject moves to fast, turns his head to the side or moves to the edges of the trackbox.

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