Wenxin Feng: "Dwell-free Input Methods for People with Motor Impairments" (PhD Defense)

Abstract: Millions of individuals affected by disorders or injuries that cause severe motor impairments have difficulty performing compound manipulations using traditional input devices. This thesis first explores how effective various assistive technologies are for people with motor impairments. The following questions are studied: (1) What activities are performed? (2) What tools are used? (3) What are the advantages and limitations of the tools? (4) How do users learn about and choose assistive technologies? (5) Why are some technologies abandoned? Results of a qualitative study with fifteen people with motor impairments indicate that study participants have strong needs for efficient text entry and communication that are not met.

This thesis next proposes three dwell-free input methods, designed to improve the efficacy of target selection and text entry of eye-tracking and head-tracking systems. They yielded (1) the Target Reverse Crossing selection mechanism, (2) the EyeSwipe eye-typing interface, and (3) the HGaze Typing interface. With Target Reverse Crossing, the user moves the cursor into the target and reverses over a goal to select it. This mechanism is significantly more efficient than dwell-time selection. Target Reverse Crossing is then adapted in EyeSwipe to delineate the start and end of a word that is eye-typed with a gaze path connecting the intermediate characters (as with traditional gesture typing). In comparison with a dwell-based virtual keyboard, EyeSwipe affords higher text entry rates and a more comfortable interaction. HGaze Typing adds head gestures to gaze-path-based text entry to enable simple and explicit command activations. Results from a user study demonstrate that HGaze Typing has better performance and user satisfaction than the dwell-time method.

Examining Committee: Kate Saenko (Chair of Committee) Margrit Betke (Major Professor and First Reader) Stan Sclaroff (Second Reader) Carlos Morimoto (Third Reader) Robert Jacob (Additional Member)