Improving the Perception of Mid-Air Tactile Shapes With Spatio-Temporally-Modulated Tactile Pointers

Ultrasound mid-air haptic (UMH) devices can remotely render vibrotactile shapes on the skin of unequipped users, e.g., to draw icons or virtual object shapes. Spatio-temporal modulation (STM), state-of-the-art UMH shape rendering method, provides large freedom in design and produces strongest possible stimuli for this technology. Yet, STM are often reported be blurry, complicating identification. Dynamic tactile pointers (DTP) were recently introduced as a technique overcome issue. By tracing contour with an amplitude-modulated focal point, they significantly improve identification accuracy over STM, but at cost much lower stimulus intensity. Building upon this, we propose Spatio-temporally-modulated Tactile Pointers (STP), novel method clearer sharper while same time producing strong sensations. We ran two human participant experiments, which show that STP perceived stronger than DTP shapes, is improved par obtained DTP. Our work has implications effective UMH, insights could inform future psychophysical investigation into perception UMH.