Specular highlights improve color constancy when other cues are weakened

Rebecca Wedge-Roberts, Stacey Aston, Ulrik Beierholm, Robert Kentridge, Anya Hurlbert, Marko Nardini, Maria Olkkonen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

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.
Original languageEnglish
Article number4
JournalJournal of Vision
Volume20
Issue number12
Number of pages22
ISSN1534-7362
DOIs
Publication statusPublished - Nov 2020
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 515 Psychology
  • color constancy
  • specular highlights
  • cue combination
  • daylight prior
  • SURFACE COLOR
  • CHROMATIC ADAPTATION
  • RETINEX THEORY
  • ILLUMINANT
  • PERCEPTION
  • CONTRAST
  • INFORMATION
  • MECHANISMS
  • LUMINANCE
  • VISION

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