Matching Dry to Wet Materials

When a translucent liquid is spilled over a rough surface it causes a significant change in the visual appearance of the surface. This wetting phenomenon is easily detected by humans, and an early model was devised by the physicist Andres Jonas Angstrom nearly a century ago. In this paper we investigate the problem of determining if a wet/dry relationship between two image patches explains the differences in their visual appearance. Water tends to be the typical liquid involved and therefore it is the main objective. At the same time, we consider the general problem where the liquid has some of the characteristics of water (i.e., a similar refractive index), but has an unknown spectral absorption profile (e.g., coffee, tea, wine, etc.). We report on several experiments using our own images, a publicly available dataset, and images downloaded from the web.