Eyes-free text entry with error correction on touchscreen mobile devices

We present an eyes-free text entry method for mobile touchscreen devices. Input progresses by inking Graffiti strokes using a finger on a touchscreen. The system includes a word-level error correction algorithm. Auditory and tactile feedback guide eyes-free entry using speech and non-speech sounds, and by vibrations. In a study with 12 participants, three different feedback modes were tested. Entry speed, accuracy, and algorithm performance were compared between the three feedback modes. An overall entry speed of 10.0 wpm was found with a maximum rate of 21.5 wpm using a feedback mode that required a recognized stroke at the beginning of each word. Text was entered with an overall accuracy of 95.7%. The error correction algorithm performed well: 14.9% of entered text was corrected on average, representing a 70.3% decrease in errors compared to no algorithm. Where multiple candidates appeared, the intended word was 1st or 2nd in the list 94.2% of the time.

[1]  I. Scott MacKenzie,et al.  LetterWise: prefix-based disambiguation for mobile text input , 2001, UIST '01.

[2]  Ricardo A. Baeza-Yates,et al.  Fast approximate string matching in a dictionary , 1998, Proceedings. String Processing and Information Retrieval: A South American Symposium (Cat. No.98EX207).

[3]  I. Scott MacKenzie,et al.  Unipad: single stroke text entry with language-based acceleration , 2006, NordiCHI '06.

[4]  Kemal Oflazer,et al.  Error-tolerant Finite-state Recognition with Applications to Morphological Analysis and Spelling Correction , 1995, CL.

[5]  Shumin Zhai,et al.  Relaxing stylus typing precision by geometric pattern matching , 2005, IUI.

[6]  Jan O. Borchers,et al.  TypeRight: a keyboard with tactile error prevention , 2009, CHI.

[7]  Kent Lyons,et al.  Automatic whiteout++: correcting mini-QWERTY typing errors using keypress timing , 2008, CHI.

[8]  Lindsay J. Evett,et al.  Fast dictionary look-up for contextual word recognition , 1990, Pattern Recognit..

[9]  Horst Bunke,et al.  A fast algorithm for finding the nearest neighbor of a word in a dictionary , 1993, Proceedings of 2nd International Conference on Document Analysis and Recognition (ICDAR '93).

[10]  David Goldberg,et al.  Touch-typing with a stylus , 1993, INTERCHI.

[11]  Gonzalo Navarro,et al.  Flexible Pattern Matching in Strings: Practical On-Line Search Algorithms for Texts and Biological Sequences , 2002 .

[12]  Brad A. Myers,et al.  Text entry from power wheelchairs: edgewrite for joysticks and touchpads , 2004, Assets '04.

[13]  Michael D. Byrne,et al.  An Evaluation of Text-Entry in Palm OS – Graffiti and the Virtual Keyboard , 2002 .

[14]  I. Scott MacKenzie,et al.  Phrase sets for evaluating text entry techniques , 2003, CHI Extended Abstracts.

[15]  Hussain Tinwala,et al.  Eyes-free text entry on a touchscreen phone , 2009, 2009 IEEE Toronto International Conference Science and Technology for Humanity (TIC-STH).

[16]  R. Mahesh K. Sinha,et al.  On partitioning a dictionary for visual text recognition , 1990, Pattern Recognit..