A gaze-based virtual keyboard using a mouth switch for command selection

Portable eye-trackers provide an efficient way to access the point of gaze from a user on a computer screen. Thanks to eyetracking, gaze-based virtual keyboard can be developed by taking into account constraints related to the gaze detection accuracy. In this paper, we propose a new gaze-based virtual keyboard where all the letters can be accessed directly through a single command. In addition, we propose a USB mouth switch that is directly connected through a computer mouse, with the mouse switch replacing the left click button. This approach is considered to tackle the Midas touch problem with eye-tracking for people who are severely disabled. The performance is evaluated on 10 participants by comparing the following three conditions: gaze detection with mouth switch, gaze detection with dwell time by considering the distance to the closest command, and the gaze detection within the surface of the command box. Finally, a workload using NASA-TLX test was conducted on the different conditions. The results revealed that the proposed approach with the mouth switch provides a better performance in terms of typing speed (36.6 +/- 8.4 letters/minute) compared to the other conditions, and a high acceptance as an input device.