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Updated: Sep 15, 2025
04:43
Visualizing Visual Adaptation
Published on: April 24, 2017
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Human color constancy in cast shadows
Takuma Morimoto1, Masayuki Sato2, Shoji Sunaga3
1University of Oxford, UK.
I-Perception
|July 17, 2025
Summary
Color constancy, the ability to perceive stable surface colors under varying illumination, generally holds well within cast shadows. This research confirms our everyday experience of reliably judging object colors even in shadowed areas.
Area of Science:
- Visual Perception
- Color Science
- Psychophysics
Background:
- Illumination conditions in cast shadows differ significantly in intensity and chromaticity from ambient light.
- Despite these differences, humans generally perceive surface colors stably within cast shadows.
Purpose of the Study:
- To quantitatively measure the degree of color constancy within cast shadows.
- To investigate the influence of skylight color and shadow perception on color constancy.
Main Methods:
- Experiments involved a scene with colored hexagons illuminated by simulated sunlight and skylight.
- A cast shadow area, illuminated solely by skylight, was used to measure subjective white points.
- A condition was included where the cast shadow was not perceived as such.
Main Results:
- Color constancy was found to hold well within cast shadows.
- The specific color of the skylight illumination had a variable effect on observers.
- The perception of an area as a cast shadow did not influence the results.
Conclusions:
- The findings support the robust nature of color constancy, even under challenging illumination conditions like cast shadows.
- Human visual perception effectively maintains stable color judgments in everyday scenarios involving shadows.
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