Vision-Based Interfaces for Character-Based Text Entry: Comparison of Errors and Error Correction Properties of Eye Typing and Head Typing

Table 2

Speed and accuracy of head typing with dynamic keyboards.

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ⁱParticipants are able-bodied novices if not specified otherwise. ⁱⁱOne “word” equals five characters, including spaces and punctuation marks. ⁱⁱⁱSpeed measure (WPM) is obtained by multiplying characters per second by 60 (seconds per minute) and dividing by 5 (characters per word). ^ivMean uncorrected error rate (%) is usually calculated as a total number of errors left uncorrected in the text divided by the total number of typed characters. Note that for techniques with forced error correction, the error rate is computed using all errors made during text entry (marked as “corr” in the table). ^vKeystrokes per character (KSPC) is usually calculated as a ratio of keystrokes used to correct errors to a total number of keystrokes used to type a sentence. ^viClicking a regular mouse button or pressing a key of the physical keyboard takes 0.05 s on average [20]. ^viiThe entire word is entered by a single head gesture: two selections are used per word, one to identify the beginning of the word and another to identify the end of the word.