Probabilistic adjustment of dwell time for eye typing

Abstract

Requiring a dwell time before selection is a common way to solve “Midas-touch problem” in gaze-based interaction. Choosing the dwell time involves a tradeoff between unintentional selection for short dwell times and slow text entry for long dwell times. We propose a probabilistic model for gaze based selection, which adjusts the dwell time based on the probability of each letter based on the past letters selected. By reformulating the entire problem of gaze-based selection probabilistically, we can naturally integrate the probability of each character naturally and with very few prior assumptions and very few free parameters. It automatically assigns shorter dwell times to more likely characters and longer dwell times to less likely characters. Our experimental results demonstrate that the proposed technique speeds up typing without loss in accuracy. The concept of this can be generalized to other dwell-based applications, leading to more efficient gaze system interaction.