Colour constancy and visual cues in simultaneous identification of illumination and reflectance changes.

Tutkimustuotos: ArtikkelijulkaisuKonferenssiesitelmän abstraktivertaisarvioitu


Colour constancy means the ability to perceive stable object colours under changes in illumination. We asked whether colour constancy depends on explicitly identifying the illuminant chromaticity and what kind of contextual
cues support this identification. We studied the simultaneous identification of illumination and reflectance changes with realistically rendered, abstract 3D-scenes. Two scenes were presented for 1000 ms, separated by a blank screen for 250 ms. Between the intervals, the illuminant chromaticity and/or the reflectance of a central stimulus changed towards blue, towards yellow, or remained the same. The observer’s task was to identify both changes. Different stimulus conditions had different cues for illuminant estimation: A full-screen background of uniform reflectance, or either matte or glossy neighbouring stimuli presented against a black background. We studied the patterns of errors in the responses to illumination and reflectance changes. Identification of illumination changes was reliable, and reflectance changes were rarely mis-identified as illumination changes. Illumination changes, on the other hand, were much more frequently mistaken for reflectance changes. To quantify these effects, we fit a two-dimensional signal-detection model to the data. Illuminant and reflectance mechanisms were modeled as vectors in the stimulus space. Compared to matte contextual stimuli, constancy was improved by a uniform background, and to a lesser extent by specular highlights in glossy contextual stimuli. These improvements were also confirmed by the modeling. We conclude that a failure of colour constancy does not depend on a failure to identify illumination changes, but better illumination cues still improve colour constancy.
DOI - pysyväislinkit
TilaJulkaistu - 2022
OKM-julkaisutyyppiEi sovellu


  • 515 Psykologia

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