Surface and Material Properties Perception

Objects in the environment can be described at many scales. For example, an orange has a shape [Page 939](roughly round) and, if we look more closely, we notice that the surface is smooth but irregular, composed of small bumps. If we continue to a microscopic scale, the interaction of light with the molecular structure of the surface of the orange gives it a characteristic shiny or glossy appearance and a characteristic color. From a physicist's point of view, the surface exists at many different spatial scales: megascale, mesoscale, and microscale, according to a classification adopted by Jan Koenderink and Andrea van Doorn.

The visual system provides considerable information about surfaces at different scales (small, round, rough, glossy, orange, etc.) that correspond roughly—but only roughly—to identifiable physical ...