Wednesday, May 13, 2009

Hi –fi eyetracking with a lo-fi eyetracker: An experimental usability study of an eyetracker built from a standard web camara (Barret, M., 2009)

Marie Barret, a masters student at the ITU Copenhagen have now finished her thesis. It evaluates eye typing performance using the ITU Gaze Tracker (low-cost web cam eye tracker) in the Stargazer and GazeTalk interfaces. The thesis in written in Danish (113 pages) but I took the freedom of translating two charts from the thesis found below. The results will be presented in English at the COGAIN 2009 conference, May 26th (session three, track one at 1:50PM) For now I quote the abstract:

"Innovation has facilitated sufficient mainstream technology to build eyetrackers from off-the-shelf-components. Prices for standard eyetrackers start at around € 4000. This thesis describes an experimental usabilty study of gazetyping with a new input device built from a standard web camera without hardware modifications. Cost: € 20. Mainstreaming of assistive technologies holds potential for faster innovation, better service, lower prices and increased accessibility. Off-the-shelf-eyetrackers must be usability competitive to standard eyetrackers in order to be adopted, as eyetracking - even with expensive hardware - presents usability issues. Usability is defined as effectiveness, efficiency and user satisfaction (ISO 9242-11, 1998).

Results from the 2 * 2 factors experiment significantly indicate how the new input device can reach the usability standards of expensive eyetrackers. This study demonstrates that the off-the-shelf-eyetracker can achieve efficiency similar to an expensive eyetracker with no significant effect from any of the tested factors. All four factors have significant impact on effectiveness. A factor that can eliminate the effectiveness difference between the standard hardware and an expensive eyetracker is identified. Another factor can additionally improve effectiveness.

Two gazetyping systems specifically designed for noisy conditions e.g. due to bad calibration and jolting are tested. StarGazer uses a zooming interface and GazeTalk uses large buttons in a static graphic user interface. GazeTalk is significantly more effective than StarGazer. The large onscreen buttons and static interface of GazeTalk with dwell time activation absorb the noise from the input device and typing speeds obtained are comparable to prior research with a regular eyetracker. Clickactivation has for years (Ware & Mikaelian 1987) proved to improve efficiency of gazebased interaction. This experiment demonstrates that this result significantly applies to off-the-shelf eyetrackers as well. The input device relies on the user to compensate for off-set with head movements. The keyboards should support this task with a static graphic user interface." Download thesis as pdf (in Danish)

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