Localisation of Vibrotactile Stimuli with Spatio-Temporal Inverse Filtering

A number of researchers and companies have investigated methods to improve touchscreen interaction through actuators providing vibrotactile stimuli. Wave propagation enables remote actuation but makes such stimuli perceivable all over the surface. In this paper, we report the use of an array of actuators combined with a spatio-temporal inverse filter to produce independent vibrotactile feedback at different positions on a surface. A experimental evaluation showed that this setup successfully corrects for distortion, reverberation and cross talk between piezoelectric actuators glued to a glass surface providing 300 Hz burst vibrations. A user study conducted with 10 participants demonstrated that this filtering not only improved the user's discrimination but also required less concentration when compared to a method without such filtering.