roughness perception is one of the multidimensional scaling of texture perception, which is the judgment of the substance and quality of an object. the studies of roughness perception demonstrate that it is unidimensional, it depends on element height, diameter, shape, compliance, and density; and that the relationship between roughness perception and the physical properties of a surface is complex and nonlinear. also, there were early observations stated that scanning velocity and contact force between the finger and a surface have minor or no effect on roughness magnitude judgments. the physical determinants of roughness perception are complex, but the evidence is that the neural mechanisms are simple. furthermore, research performed at the university of north carolina revealed that scanning velocity did not have an effect on relative roughness because the roughness for all surfaces increase by the same amount as scanning velocity increases in accordance with weber's law.