Single Pitch Perception of Multi-frequency Textures

This study explores people’s ability to distinguish spatial complexity in tactile textures, with the eventual goal of reducing the necessary complexity of texture representation for surface display devices. To this end, we tested subjects’ ability to perceptually match a reference texture containing two spatial frequency components by adjusting the frequency and amplitude of a single frequency. All textures consisted of spatially varied friction levels on a glass display screen, where friction was modulated via amplitude of ultrasonic vibrations. Resulting chosen single frequencies were systematic, and suggest subjects can identify a single frequency, or tactile pitch, falling somewhere between those of the reference texture. Subject-adjusted frequency is modeled as a function of the reference texture’s frequency components and the ratio of their amplitudes.