Eye Gaze Tracking

The purpose of an eye gaze tracker is to estimate the position on the screen to where the user is fixating her/his gaze. This is accomplished by tracking the user's pupil and the corneal glint, after a brief calibration procedure, that determines the mapping from coordinates of the pupil tracker to user screen coordinates. Assuming a static head, an eye can only rotate in its socket, and the surface of the eye can be approximated by a sphere. Since the light sources are also fixed, the glint on the cornea of the eye can be taken as a reference point, thus the vector from the glint to the center of the pupil will describe the gaze direction.

To estimate the screen coordinates to where the user is looking, a simple second order polynomial transformation is used. After the calibration procedure, a simple possible application is to control the mouse using eye gaze, which provides an estimate about the accuracy of the system. We have obtained an accuracy of about 1 degree of resolution, that corresponds to about 1cm on the screen viewed from 50cm.
  

 

 

1999-07-13