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Illuminant cues and surface color perception in binocularly-viewed three-dimensional scenes| old_uid | 693 |
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| title | Illuminant cues and surface color perception in binocularly-viewed three-dimensional scenes |
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| start_date | 2006/02/22 |
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| schedule | 11h |
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| online | no |
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| summary | I’ll first describe experiments that investigate human surface color perception in rendered, three-dimensional, binocularly-viewed scenes composed of simple objects, both matte and specular, and a matte test surface. The scenes were illuminated by a combination of punctate and diffuse light (‘sun’ and ‘sky’) and one punctate source. The punctate source was rendered to be behind the observer, not directly visible. The punctate and diffuse sources could differ in color and/or intensity. In such scenes the chromaticity and intensity of light incident on a matte test patch varies with surface orientation. We varied the orientation of a test surface and measured how well human observers estimate surface color and albedo. We find that observers partially discount changes in test surface orientation with respect to the punctate source.
In carrying out these experimental tasks, observers effectively estimate the spatial distribution, chromaticities and relative intensities of light sources in the scene. I’ll describe an additional experiment where we test three candidate illuminant cues that provide information about relative intensities of light sources, specular highlights, cast shadows and shading. We test each cue in isolation and all three cues combined. We find that observers used the first two cues but not the third and that when multiple cues were present, the observer combined cue information into an estimate of the distribution of light in the scene that was superior to that of any single cue. Last, I describe experiments with more than one punctate light source, intended to assess the limits of the visual system’s capability to estimate and discount the flow of light in scenes.
Support: National Institutes of Health EY08266; Human Frontiers Science Program RG0109/1999-B. |
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| oncancel | Changement d’horaire |
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| responsibles | Mamassian |
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