Letterscroll: text entry using a wheel for visually impaired users

ABSTRACT

Four text entry techniques for visually impaired users are presented. LetterScroll uses a mouse wheel to maneuver a cursor across a sequence of characters, and a button for character selection. Keystrokes per character (KSPC) vary from 6.97 to 2.68. After extensive analyses and pilot testing, two variations were chosen for initial evaluation. Method 1 (M1) uses the mouse alone to enter text. Method 4 (M4) also uses the keyboard to access vowels. In a study with seven blindfolded participants, entry rates averaged 2.9 wpm for M1 and 4.4 wpm for M4. Error rates for both methods were about 3.4%.

REFERENCES

• 1: I. Scott MacKenzie, KSPC (Keystrokes per Character) as a Characteristic of Text Entry Techniques, Proceedings of the 4th International Symposium on Mobile Human-Computer Interaction, p.195-210, September 18-20, 2002
• 2: Scott MacKenzie, Mobile text entry using three keys, Proceedings of the second Nordic conference on Human-computer interaction, October 19-23, 2002, Aarhus, Denmark [doi>10.1145/572020.572025]
• 3: I. Scott MacKenzie , R. William Soukoreff, Phrase sets for evaluating text entry techniques, CHI '03 extended abstracts on Human factors in computing systems, April 05-10, 2003, Ft. Lauderdale, Florida, USA [doi>10.1145/765891.765971]
• 4: Miika Silfverberg , I. Scott MacKenzie , Panu Korhonen, Predicting text entry speed on mobile phones, Proceedings of the SIGCHI conference on Human factors in computing systems, p.9-16, April 01-06, 2000, The Hague, The Netherlands [doi>10.1145/332040.332044]

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.2 User Interfaces (D.2.2, H.1.2, I.3.6)
          Subjects: Input devices and strategies (e.g., mouse, touchscreen)

General Terms:
Human Factors

Keywords:
auditory feedback, mouse wheel, text entry, visually impaired, voice synthesis