Perceived Roughness of Band-Limited Noise, Single, and Multiple Sinusoids Compared to Recorded Vibration*

In this paper, perceived roughness of four types of tactile vibration was evaluated on a tactile display. The four tactile stimuli are 1) recorded vibration, 2) band-limited noise, 3) multiple sinusoids, and 4) single sinusoid. The aim was to investigate and present simplification possibilities on recorded vibration without losing its perceptual capacity since it might provide over-sophisticated information except for too fine textures. In order to test and compare several simplifications, similarity estimation experiment was conducted using continuous equal interval scaling method. During the experiment, the participants actively explored the real textures so that they could rate the roughness similarity of four tactile stimuli with respect to the real textures. The utilized textures were selected so as to contain the varying size of spatial densities to analyze the simplification approaches over fine, not too fine and coarse textures. Based on the similarity ratings and the multidimensional scaling, recorded vibration and band-limited noise stimuli were found as the most similar stimuli with fine textures while single sinusoid and multiple sinusoids were found as the most similar stimuli with coarse textures. Also based on the one-way analysis of variance tests, significant differences between the tactile stimuli were found for fine and coarse textures while a significant difference was not found between them for mid-coarse textures.