Scale Index of Vibration Signals: A Measure of Perceived Regularity of Homogeneous Textures

Regularity is a perceptual dimension that is equally important as roughness, hardness, friction, etc., for the haptic rendering of homogeneous textures. Due to the lack of an objective metric to quantify the regularity of textures, the perceptual dimension is ignored in state-of-the-art texture rendering methods, resulting in unrealistic tactile sensations. In this article, we introduce a way to use the scale index of the vibration signals as an objective measure for the perceived regularity of the textures. We use the developed platform to collect vibration signals from probe and texture surface interaction and calculate the corresponding scale index. A user study is conducted in which subjects rate the perceived regularity of textures. Experiment results suggest that the proposed measure is highly correlated with subjective regularity ratings, so it is a valid and effective measure of the perceived regularity of homogeneous textures. We present preliminary results of using the proposed metric in virtual texture rendering as an example application of it.