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Specular highlights improve color constancy when other cues are weakened

Previous studies suggest that to achieve color constancy, the human visual system makes use of multiple cues, including a priori assumptions about the illumination (“daylight priors”). Specular highlights have been proposed to aid constancy, but the evidence for their usefulness is mixed. Here, we u...

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Autores principales: Wedge-Roberts, Rebecca, Aston, Stacey, Beierholm, Ulrik, Kentridge, Robert, Hurlbert, Anya, Nardini, Marko, Olkkonen, Maria
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Association for Research in Vision and Ophthalmology 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7674000/
https://www.ncbi.nlm.nih.gov/pubmed/33170203
http://dx.doi.org/10.1167/jov.20.12.4
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author Wedge-Roberts, Rebecca
Aston, Stacey
Beierholm, Ulrik
Kentridge, Robert
Hurlbert, Anya
Nardini, Marko
Olkkonen, Maria
author_facet Wedge-Roberts, Rebecca
Aston, Stacey
Beierholm, Ulrik
Kentridge, Robert
Hurlbert, Anya
Nardini, Marko
Olkkonen, Maria
author_sort Wedge-Roberts, Rebecca
collection PubMed
description Previous studies suggest that to achieve color constancy, the human visual system makes use of multiple cues, including a priori assumptions about the illumination (“daylight priors”). Specular highlights have been proposed to aid constancy, but the evidence for their usefulness is mixed. Here, we used a novel cue-combination approach to test whether the presence of specular highlights or the validity of a daylight prior improves illumination chromaticity estimates, inferred from achromatic settings, to determine whether and under which conditions either cue contributes to color constancy. Observers made achromatic settings within three-dimensional rendered scenes containing matte or glossy shapes, illuminated by either daylight or nondaylight illuminations. We assessed both the variability of these settings and their accuracy, in terms of the standard color constancy index (CCI). When a spectrally uniform background was present, neither CCIs nor variability improved with specular highlights or daylight illuminants (Experiment 1). When a Mondrian background was introduced, CCIs decreased overall but were higher for scenes containing glossy, as opposed to matte, shapes (Experiments 2 and 3). There was no overall reduction in variability of settings and no benefit for scenes illuminated by daylights. Taken together, these results suggest that the human visual system indeed uses specular highlights to improve color constancy but only when other cues, such as from the local surround, are weakened.
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spelling pubmed-76740002020-11-20 Specular highlights improve color constancy when other cues are weakened Wedge-Roberts, Rebecca Aston, Stacey Beierholm, Ulrik Kentridge, Robert Hurlbert, Anya Nardini, Marko Olkkonen, Maria J Vis Article Previous studies suggest that to achieve color constancy, the human visual system makes use of multiple cues, including a priori assumptions about the illumination (“daylight priors”). Specular highlights have been proposed to aid constancy, but the evidence for their usefulness is mixed. Here, we used a novel cue-combination approach to test whether the presence of specular highlights or the validity of a daylight prior improves illumination chromaticity estimates, inferred from achromatic settings, to determine whether and under which conditions either cue contributes to color constancy. Observers made achromatic settings within three-dimensional rendered scenes containing matte or glossy shapes, illuminated by either daylight or nondaylight illuminations. We assessed both the variability of these settings and their accuracy, in terms of the standard color constancy index (CCI). When a spectrally uniform background was present, neither CCIs nor variability improved with specular highlights or daylight illuminants (Experiment 1). When a Mondrian background was introduced, CCIs decreased overall but were higher for scenes containing glossy, as opposed to matte, shapes (Experiments 2 and 3). There was no overall reduction in variability of settings and no benefit for scenes illuminated by daylights. Taken together, these results suggest that the human visual system indeed uses specular highlights to improve color constancy but only when other cues, such as from the local surround, are weakened. The Association for Research in Vision and Ophthalmology 2020-11-10 /pmc/articles/PMC7674000/ /pubmed/33170203 http://dx.doi.org/10.1167/jov.20.12.4 Text en Copyright 2020 The Authors https://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License.
spellingShingle Article
Wedge-Roberts, Rebecca
Aston, Stacey
Beierholm, Ulrik
Kentridge, Robert
Hurlbert, Anya
Nardini, Marko
Olkkonen, Maria
Specular highlights improve color constancy when other cues are weakened
title Specular highlights improve color constancy when other cues are weakened
title_full Specular highlights improve color constancy when other cues are weakened
title_fullStr Specular highlights improve color constancy when other cues are weakened
title_full_unstemmed Specular highlights improve color constancy when other cues are weakened
title_short Specular highlights improve color constancy when other cues are weakened
title_sort specular highlights improve color constancy when other cues are weakened
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7674000/
https://www.ncbi.nlm.nih.gov/pubmed/33170203
http://dx.doi.org/10.1167/jov.20.12.4
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