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Posture considerations
writing with head mountedeye tracker
10-12 April 2012, Mshs, University of Poitiers, France
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Eye trackers primarily designed to read on screen have geometric requirements.
Participant line of sight should be perpendicular to the screen surface (more or less).
10-12 April 2012, Mshs, University of Poitiers, France
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Handwriting support can be “tilted”.
Nowadays, handwriting is usually done on a flat surface, not a vertical one.
Except in this case ! (Beware to backache)
10-12 April 2012, Mshs, University of Poitiers, France
But when seated, problems with line of sight tends to appear.
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When seated:• from the eye tracker head camera (and participant) point of view, screen
is not a square, but a trapeze
• participant moving up / down or tilting head creates parallax effect: gaze point is miscalculated.
• participant are closer to “screen” than recommended by manufacturer:because of forearm length, participant’s eye is about 35 cm from screen.
10-12 April 2012, Mshs, University of Poitiers, France
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A solution
Participant stands up, desk is elevated toward his elbow.
electrically adjustable height
10-12 April 2012, Mshs, University of Poitiers, France