A Unified Theory of Surface Roughness

The properties of the peaks and summits of a rough surface are predicted on the assumption that the surface is two-dimensional random noise. The important result is that, in non-dimensional form, the answers depend only to a minor degree on the parameters describing the surface or on the sampling interval used: on the other hand the absolute values are strongly dependent on the sampling interval. Experimental results on a real surface agree remarkably well with the predictions.