Asymmetric Free-Hand Interaction on a Large Display and Inspirations for Designing Natural User Interfaces

Hand motion sensing-based interaction, abbreviated as ‘free-hand interaction’, provides a natural and intuitive method for touch-less interaction on a large display. But due to inherent usability deficiencies of the unconventional size of the large display and the kinematic limitations of the user’s arm joint movement, a large display-based free-hand interaction is suspected to have different performance across the whole areas of the large display. To verify this, a multi-directional target pointing and selection experiment was designed and conducted based on the ISO 9241-9 evaluation criteria. Results show that (1) free-hand interaction in display areas close to the center of the body had a higher accuracy than that in peripheral-body areas; (2) free-hand interaction was asymmetric at the left side and the right side of the body. More specifically, left-hand interaction in the left-sided display area was more efficient and accurate than in the right-sided display area. For the right-hand interaction, the result was converse; moreover, (3) the dominant hand generated a higher interaction accuracy than the non-dominant hand. Lessons and strategies are discussed for designing user-friendly natural user interfaces in large displays-based interactive applications