Vision-Based Interfaces for Character-Based Text Entry: Comparison of Errors and Error Correction Properties of Eye Typing and Head Typing
Table 4
Characteristics of gaze- and head-based VBIs for hands-free text entry.
Eye typing
Head typing
Pros
Pros
Fast speed of text production (efficiency)
Possibility to freely observe text and keyboard layout
Easiness-of-use/less physical effort if large (1.5–2°) keys are used (efficiency)
Small number of errors (effectiveness) and small number of error corrections (efficiency)
Text entry is possible even for severely disabled users
Does not require extensive learning for error-free performance Can be used with small (0.4°) keys [28] Lower error correction cost (when the error rate is small)
Cons
Cons
Gaze is tied to the typing task itself
Slow speed of text entry
Requires large keys (and a keyboard takes large screen space)
Requires that control over head (and may be even torso) motion is preserved