Choosing An Eye Tracker
One difficulty in evaluating an eye tracking system is that the eye is never still, and it can be difficult to distinguish the tiny, but rapid and somewhat chaotic movement associated with fixation from noise sources in the eye tracking mechanism itself. One useful evaluation technique is to record from the two eyes simultaneously and compare the vertical rotation records. The two eyes of a normal subject are very tightly coordinated and vertical gaze directions typically agree to within +/- 2 minutes of arc (RMS of vertical position difference) during steady fixation. A properly functioning and sensitive eye tracking system will show this level of agreement between the two eyes, and any differences much larger than this can usually be attributed to measurement error.
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Famous quotes containing the words choosing and/or eye:
“Constantly choosing the lesser of two evils is still choosing evil.”
—Jerry Garcia (1942–1995)
“His eye had become minutely exact as to the book and its position. Then he resolved that he would not look at the book again, would not turn a glance on it unless it might be when he had made up his mind to reveal its contents.”
—Anthony Trollope (1815–1882)