Congruent Indirect Touch vs. mouse pointing performance

We study Congruent Indirect Touch (CIT) interaction in a desktop context. CIT only differs from direct touch in that the motor and display spaces are separated: touch occurs on the horizontal desk; while users’ visual focus is on a vertical display where small pointers show the position of the fingers. We introduce an accurate fingertip tracking approach based on optical tracking and fingertip modeling as a sphere. This allows updating the pointer when the finger is hovering above the surface and implementing an efficient CIT interaction. This interaction was evaluated in a longitudinal user study. Six participants with no experience with CIT performed target acquisitions on eight different days. Throughput was measured with CIT and mouse. In the last session, two participants had similar throughput with both interactions; the four others were notably more efficient with CIT. Averaged across all participants, throughput improved by 14%. This study promotes the study of CIT as a potential efficient replacement for the mouse on the desktop.