Vibration enhances geometry perception with tactile shape displays

Tactile displays can provide detailed spatial information to the skin, but little is known about the effects of vibrating displayed shapes. This study examines passive touch perception of flat and indented surfaces displayed on a 36 pin tactile display with 2 mm pin pitch. Subjects could not perceive a 0.1 mm deep central indentation when it was presented statically, but it was readily detected when the pattern was vibrated at 5 Hz. A central raised bar was incorrectly perceived as indented when the adjacent pins were vibrated, which is consistent with the "fishbone tactile illusion" (Nakatani et al., Proc. EuroHaptics 2006). These results suggest that tactile display devices can use vibrational stimulus to enhance perception of small differences in height.