B#: chord-based correction for multitouch braille input

ABSTRACT

Braille has paved its way into mobile touchscreen devices, providing faster text input for blind people. This advantage comes at the cost of accuracy, as chord typing over a flat surface has proven to be highly error prone. A misplaced finger on the screen translates into a different or unrecognized character. However, the chord itself gathers information that can be leveraged to improve input performance. We present B#, a novel correction system for multitouch Braille input that uses chords as the atomic unit of information rather than characters. Experimental results on data collected from 11 blind people revealed that B# is effective in correcting errors at character-level, thus providing opportunities for instant corrections of unrecognized chords; and at word-level, where it outperforms a popular spellchecker by providing correct suggestions for 72% of incorrect words (against 38%). We finish with implications for designing chord-based correction system and avenues for future work.

References

1. Azenkot, S., Wobbrock, J., Prasain, S., Ladner, R. Input finger detection for nonvisual touch screen text entry in Perkinput. In Proc. GI (2012).
2. Deorowicz, S., & Ciura, M. G. Correcting spelling errors by modelling their causes. Int. journal of applied mathematics and computer science (2005), 15(2), 275.
3. Kane, S., Wobbrock, J., Harniss, M., & Johnson, K. TrueKeys: identifying and correcting typing errors for people with motor impairments. In Proc IUI (2008).
4. Oliveira, J., Guerreiro, T., Nicolau, H., Jorge, J., Gonçalves, D. Blind people and mobile touch-based text-entry: acknowledging the need for different flavors. In Proc. ASSETS (2011).
5. Sandnes, F. E., Huang, Y. P. Chording with spatial mnemonics: automatic error correction for eyes-free text entry. In Journal of information science and engineering, 22, 5 (2006).
6. Southern, C., Clawson, J., Frey, B., Abowd, G., Romero, M. An evaluation of BrailleTouch: mobile touchscreen text entry for the visually impaired. In Proc. Mobile HCI (2012).

Index Terms

• Human-centered computing

  • Human computer interaction (HCI)