Text entry by gazing and smiling

Face Interface is a wearable prototype that combines the use of voluntary gaze direction and facial activations, for pointing and selecting objects on a computer screen, respectively. The aim was to investigate the functionality of the prototype for entering text. First, three on-screen keyboard layout designs were developed and tested (n =10) to find a layout that would be more suitable for text entry with the prototype than traditional QWERTY layout. The task was to enter one word ten times with each of the layouts by pointing letters with gaze and select them by smiling. Subjective ratings showed that a layout with large keys on the edge and small keys near the center of the keyboard was rated as the most enjoyable, clearest, and most functional. Second, using this layout, the aim of the second experiment (n =12) was to compare entering text with Face Interface to entering text with mouse. The results showed that text entry rate for Face Interface was 20 characters per minute (cpm) and 27 cpm for the mouse. For Face Interface, keystrokes per character (KSPC) value was 1.1 and minimum string distance (MSD) error rate was 0.12. These values compare especially well with other similar techniques.