Back to articles
Articles
Volume: 17 | Article ID: art00002
Image
Reflectance, illumination and edges
  DOI :  10.2352/CIC.2009.17.1.art00002  Published OnlineJanuary 2009
Abstract

We studied color constancy using a pair of 3-D Color Mondrian displays made of two identical sets of painted wooden shapes. There are only 6-chromatic, and 5-achromatic paints applied to nearly 100 block facets. The three-dimensional nature of these test targets adds shadows and multiple reflections not found in flat Mondrians. Observers viewed one set in uniform illumination–Low-Dynamic-Range(LDR); the other in highly directional non-uniform illumination–High-Dynamic Range(HDR). Both 3-D Mondrians, were side-by-side, in the same room, at the same time. We used two measurement techniques to evaluate how well the appearances correlated with the object's reflectances. First, we asked observers to compare the appearances of individual three-dimensional surfaces having identical reflectances, and recorded these changes in appearance using magnitude estimation. Second, an author painted a reproduction of the pair of Mondrians using watercolors. We measured the watercolor reflectances of the corresponding areas to quantify the change in appearances. Both measurements give us important data on how reflectance, illumination and image structure affect color constancy. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to non-uniform illumination.

Subject Areas :
Views 4
Downloads 0
 articleview.views 4
 articleview.downloads 0
  Cite this article 

John McCann, Carinna Parraman, Alessandro Rizzi, "Reflectance, illumination and edgesin Proc. IS&T 17th Color and Imaging Conf.,  2009,  pp 2 - 7,  https://doi.org/10.2352/CIC.2009.17.1.art00002

 Copy citation
  Copyright statement 
Copyright © Society for Imaging Science and Technology 2009
72010350
Color and Imaging Conference
color imaging conf
2166-9635
Society of Imaging Science and Technology
7003 Kilworth Lane, Springfield, VA 22151, USA