Empirical evaluation of uni- and bimodal pen and touch interaction properties on digital tabletops

Combined bimanual pen and touch input on digital tab-letops is an appealing interaction paradigm enjoying grow-ing popularity among many HCI researchers. Due to its relative novelty, its properties are still relatively unexplored and many hypotheses emerging from intuition and extrapo-lations from studies about touch and other pointing devices remain to be verified. We present an empirical evaluation consisting of three experiments aimed at investigating a few important issues of pen and touch interaction on horizontal surfaces. Specifically, we examine the compromise between speed and accuracy for the two input modalities in position-ing and tracing contexts, the influence of palm-resting on pen precision and bimanual coordination for pen mode-switching via postures. We report on quantitative and quali-tative results obtained from these trials and discuss their potential impact on the design of pen and touch systems. Author Keywords Pen and Touch interaction; Digital tabletop