Measurement of Perceptual Roughness in Fractal Surfaces

In this paper we present an investigation into visually perceived surface roughness. First we present psychophysical evidence that suggests that there is a simple relationship between perceived roughness and two well known surface parameters: fractal dimension and rms roughness. And that neither are good estimators, on there own, of perceived roughness. Second we present a measurement model for deriving the perceived roughness of a surface from its height function which is motivated by the spatial frequency channel model of the human visual system.