An invisible keyguard

ABSTRACT

Overlap errors, in which two keys are pressed down at once, are a common typing error for people with motor disabilities. Keyguards are a commonly suggested means to may reduce overlap errors. However, they are also unpopular with many users. We present an alternative to the keyguard, a software filter which targets overlap errors. Basic, keystroke timing-based, and language-based techniques for identifying and correcting overlap errors are described. Their performance is compared using a corpus of typing data recorded by keyboard users with motor disabilities. The best filter performance was obtained by keystroke timing characteristics to identify and filter out extra characters. Accuracy of error identification was dependent on the typing style of the user. The filter accurately corrected 80% of the overlap errors presented. Combining the identification and correction techniques gave a 50--75% reduction in errors for the three study participants with the highest error rates.

REFERENCES

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INDEX TERMS

Primary Classification:
  K. Computing Milieux
  K.4 COMPUTERS AND SOCIETY
      K.4.2 Social Issues
          Subjects: Assistive technologies for persons with disabilities

Additional 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); Screen design (e.g., text, graphics, color); Interaction styles (e.g., commands, menus, forms, direct manipulation)

General Terms:
Algorithms, Documentation, Experimentation, Human Factors

Keywords:
OverlapKeys, accessibility, keyboard, keyguard, motor disabilities, typing errors