Is the iPad useful for sketch input? A comparison with the Tablet PC

Abstract

Despite the increasing prevalence of touch-based tablet devices, little attention has been paid to what effects, if any, this form factor has on sketch behaviours in general and on sketch recognizers in particular.We investigate the title question through an empirical study in the context of mathematical expression recognition. Using a corpus of thirty expressions drawn on Tablet PC and iPad by thirty writers, we show that characteristics of sketching and drawingdiffer depending on platform. While recognition is most accurate on the Tablet PC due to its technical superiority, recognition is feasible on mobile touch-based devices. However, there are characteristics of sketching on multitouch tablets that differ, and these physical characteristics of writing impact recognition accuracy. Together, ourobservations inform the broader Sketch Recognition community as they design systems targeted to multi-touch tablets.