Perceived roughness for random surfaces

The present study seeks to find physical surface roughness parameters that are well correlated with roughness perceived by human users for complex natural surfaces. For the simple surfaces which consist of regularly spaced standard features such as dot, pyramid and truncated cone, it is well known that perceived roughness increases with the increase of spacing between two adjacent features. However, for complex natural surfaces which consist of irregularly spaced arbitrary features, it is not certain what parameter would be most suitable for representing perceived roughness. In this regard, the present study makes an attempt to evaluate suitability of the standard physical surface roughness parameters in representing roughness perceived for artificially fabricated random surfaces. These random surfaces imitate complex natural surfaces, consisting of peaks and valleys whose heights and widths are randomly given. The preliminary results show that the amplitude parameters rather than the spacing parameters have stronger correlation with perceived roughness.