Natural use profiles for the pen: An empirical exploration of pressure, tilt, and azimuth

Inherent pen input modalities such as tip pressure, tilt and azimuth (PTA) have been extensively used as additional input channels in pen-based interactions. We conducted a study to investigate the natural use profiles of PTA, which describes the features of PTA in the course of normal pen use such as writing and drawing. First, the study reveals the ranges of PTA in normal pen use, which can distinguish pen events accidently occurring in normal drawing and writing from those used for mode switch. The natural use profiles also show that azimuth is least likely to cause false pen mode switching while tip pressure is most likely to cause false pen mode switching. Second, the study reveals correlations among various modalities, indicating that pressure plus azimuth is superior to other pairs for dualmodality control.