Gray-world-assumption-based illuminant color estimation using color gamuts with high and low chroma

Harumi Kawamura*, Shunichi Yonemura, Jun Ohya, Akira Kojima

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


A new approach is proposed for estimating illuminant colors from color images under an unknown scene illuminant. The approach is based on a combination of a gray-world-assumption-based illuminant color estimation method and a method using color gamuts. The former method, which is one we had previously proposed, improved on the original method that hypothesizes that the average of all the object colors in a scene is achromatic. Since the original method estimates scene illuminant colors by calculating the average of all the image pixel values, its estimations are incorrect when certain image colors are dominant. Our previous method improves on it by choosing several colors on the basis of an opponent-color property, which is that the average color of opponent colors is achromatic, instead of using all colors. However, it cannot estimate illuminant colors when there are only a few image colors or when the image colors are unevenly distributed in local areas in the color space. The approach we propose in this paper combines our previous method and one using high chroma and low chroma gamuts, which makes it possible to find colors that satisfy the gray world assumption. High chroma gamuts are used for adding appropriate colors to the original image and low chroma gamuts are used for narrowing down illuminant color possibilities. Experimental results obtained using actual images show that even if the image colors are localized in a certain area in the color space, the illuminant colors are accurately estimated, with smaller estimation error average than that generated in the conventional method.

Original languageEnglish
Title of host publicationProceedings of SPIE-IS and T Electronic Imaging - Color Imaging XVIII
Subtitle of host publicationDisplaying, Processing, Hardcopy, and Applications
Publication statusPublished - 2013
EventColor Imaging XVIII: Displaying, Processing, Hardcopy, and Applications - Burlingame, CA, United States
Duration: 2013 Feb 42013 Feb 6

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceColor Imaging XVIII: Displaying, Processing, Hardcopy, and Applications
Country/TerritoryUnited States
CityBurlingame, CA


  • blackbody locus
  • color gamut
  • gray world assumption
  • illuminant color estimation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Gray-world-assumption-based illuminant color estimation using color gamuts with high and low chroma'. Together they form a unique fingerprint.

Cite this