Document Detail


Color scaling of discs and natural objects at different luminance levels.
MedLine Citation:
PMID:  16962003     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Assigning a basic color name to an object and rating the amount of a particular hue is a fundamental visual capability. Traditional color scaling studies have used increment flashes or isoluminant stimuli of a homogeneous color. Natural objects, however, do not contain a single color but are characterized by a distribution of different chromatic hues. Here we study color scaling using photographs of natural fruit objects. Stimuli were either homogeneous spots, digital photographs of fruit objects (e.g., banana), or outline shapes of the fruit objects. Stimuli were displayed on a CRT monitor on a homogeneous white background; its luminance was varied above and below the medium gray. The chromaticity of the stimuli was varied in 36 equally spaced chromatic directions in the isoluminant plane of the Derrington-Krauskopf-Lennie (DKL) color space. For each stimuli, subjects rated the amount of red, green, blue, and yellow in the stimulus on a scale from 0-8. In agreement with earlier studies we found that the positions of the peak ratings for each color do not coincide with the cardinal axis of DKL color space and are largely invariant under changes of the background luminance. For the average rating we found a dependence on background luminance for all colors: yellow ratings increase with darker backgrounds, whereas ratings for the other colors, in particular green, decrease. For the fruit objects, we found a selective increase in the average color rating for the natural fruit color. For example, the average rating for yellow was 1.7 times higher for the banana images compared to disc stimuli. No such selective increase was found for outline shapes. We conclude that the distribution of hues in natural objects with a characteristic object color can have a profound effect on color scaling and color appearance.
Authors:
Thorsten Hansen; Karl R Gegenfurtner
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Visual neuroscience     Volume:  23     ISSN:  0952-5238     ISO Abbreviation:  Vis. Neurosci.     Publication Date:    2006 May-Aug
Date Detail:
Created Date:  2006-09-11     Completed Date:  2006-10-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8809466     Medline TA:  Vis Neurosci     Country:  England    
Other Details:
Languages:  eng     Pagination:  603-10     Citation Subset:  IM    
Affiliation:
Department of Psychology, University of Giessen, Giessen, Germany. thorsten.hansen@psychol.uni-giessen.de
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Ocular / physiology*
Color*
Color Perception / physiology*
Contrast Sensitivity / physiology
Female
Humans
Light*
Male
Sensory Thresholds / physiology
Space Perception / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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