COLOR NAMING AND CONSTANCY OF 3D TRANSLUCENT OBJECTS

Abstract

A large body of research on color constancy and naming of colors is based on flat homogeneous patches. Even though recent studies highlight the importance of studying color in context of 3D objects and scenes, they usually address opaque objects only, whereas many objects that we interact with in the real world on a daily basis, such as wax, plastic, or various foodstuff, are translucent. Different amounts of light re-emerge from different parts of the translucent object due to thickness and other geometrical variations, which leads to high spatial variation of color in translucent objects. Little is known about how humans name colors of translucent objects and how constant color is when perceived translucency changes due to illumination direction. In this work, we generated images of chromatic translucent objects with a complex 3D shape and conducted color naming and color matching experiments. Color naming was conducted in two unrelated languages - English and Georgian. We found that the color of the translucent object substantially varies across illumination conditions, and the mean color of the object is a poor predictor of the matched color. Observers usually pick lighter and more chromatic colors than the global average. They prioritize specific spatial regions, whose exact manner remains poorly understood. If the background is highly chromatic, it may affect the hue of the translucent object. The change in illumination conditions did not cause a flip in basic categories in color naming, but we observed several curious exceptions when the background was chromatic. Future works should offer more rigorous quantitative modeling of how optical material properties and shape of the translucent object affect its color variation across the shapes and illumination conditions.

COLOR NAMING AND CONSTANCY OF 3D TRANSLUCENT OBJECTS