Smart Touch - Improving Touch Accuracy for People with Motor Impairments

Author: Martez E. Mott, Radu-Daniel Vatavu, Shaun K. Kane, Jacob O. Wobbrock

main argument

Accessibility of touch screens is hindered by implicitly ability-assumptions. Ability-based design can accommodate for a wider range of users.

findings

• User behavior
  1. Touch-down and Touch-up distances far from target center
  2. Accidental impact before they were prepared to touch
  3. Accidental lift-off
  4. Used the screen for support by sliding
  5. Previous recommended target sizes not enough to accommodate
• Current state
  1. Too much emphasis on first and last contact points
  2. Assumption that user can use fully extended finger

conclusion

Entire touch process must be considered — all touch events. Presumptions made in touch screens:

• That users can interact with a single fully extended finger
• That users possess the fine motor-control skills to land and lift within the bounds of a target

design

1. Analyze user touch process and extract most relevant data
2. Match data to training samples (templates)
3. Resolve the user’s intended (x, y) touch point

• Calculations based on shape and movement stability → indicative pose → template matcher

subjects and sites

• 10 people with motor impairments
• Paid $30 for one hour

terms and themes

• Ability-based design