Tuesday 17th April

Laurence T. Maloney
Psychology & Neural Science,
New York University, USA

Title: Predicting Surface Color Perception in Three-Dimensional Scenes

Abstract:  In everyday scenes, the intensity and chromaticity of the light absorbed by a matte surface depends on its location and orientation. I will first describe recent experiments intended to investigate surface color perception in 3D rendered scenes. We found that the visual system partially compensates for changes in illumination due to changes in location and orientation of test surfaces. In carrying out these experimental tasks, observers effectively represent the spatial distribution, chromaticities and relative intensities of light sources in the scene. I’ll describe additional experiments where we assess how the visual system estimates the distribution of light in scenes (the light field) and how it used this information in estimating surface colors.

Support:  NSF1059166 from the National Science Foundation, Grant EY019889 from the National Institutes of Health.

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Wednesday 18th April

Françoise Viénot
Muséum national d’Histoire naturelle
Paris, France.

Title: Gloss Characterization: a Cyclic Approach

Abstract: Gloss is an appearance attribute related to surfaces. Its characterization is connected to several scientific domains: material science, optics, vision and cognition.

Here, we investigate how information transfers from one domain to the next, in a cyclic approach. We found gloss is connected to the physical world on the one hand and to human vision on the other hand. With respect to its connection to materials and optics, gloss is characterized by complex distributions of physical quantities however universally describable through instrumentation and uniquely transferable from one domain to the other. On the other hand, gloss is an appearance attribute appraised by human vision privately. Whereas low-level visual mechanisms operate almost automatically, gloss perception is highly linked to other appearance attributes and dependent upon the interaction of cognitive cues.

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