KeyTime: Super-Accurate Prediction of Stroke Gesture Production Times

Abstract

We introduce KeyTime, a new technique and accompanying software for predicting the production times of users' stroke gestures articulated on touchscreens. KeyTime employs the principles and concepts of the Kinematic Theory, such as lognormal modeling of stroke gestures' velocity profiles, to estimate gesture production times significantly more accurately than existing approaches. Our experimental results obtained on several public datasets show that KeyTime predicts user-independent production times that correlate r=.99 with groundtruth from just one example of a gesture articulation, while delivering an average error in the predicted time magnitude that is 3 to 6 times smaller than that delivered by CLC, the best prediction technique up to date. Moreover, KeyTime reports a wide range of useful statistics, such as the trimmed mean, median, standard deviation, and confidence intervals, providing practitioners with unprecedented levels of accuracy and sophistication to characterize their users' a priori time performance with stroke gesture input.