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Proceedings Paper

Illuminant color from shading
Author(s): Hsien-Che Lee
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Paper Abstract

The image of a uniform wall illuminated by a spotlight often gives a strong impression of the illuminant color. How can it be possible to know if it is a white wall illuminated by yellow light or a yellow wall illuminated by white light? If the wall is a Lambertian reflector, it would not be possible to tell the difference. However, in the real world, some amount of specular reflection is often present. An empirical reflection model describes light reflection from an inhomogeneous surface as a mixture of a specular (interface) component and a diffuse (body) component. Since the spatial scale over which the interface reflection changes significantly is much smaller than that of the body reflection, it can be shown that one can effectively exploit the scale difference to find a unique solution, which is often quite accurate. The method can also be generalized to compute the illuminant chromaticity for a nonuniform smooth surface.

Paper Details

Date Published: 1 August 1990
PDF: 9 pages
Proc. SPIE 1250, Perceiving, Measuring, and Using Color, (1 August 1990); doi: 10.1117/12.19715
Show Author Affiliations
Hsien-Che Lee, Eastman Kodak Co. (United States)

Published in SPIE Proceedings Vol. 1250:
Perceiving, Measuring, and Using Color
Michael H. Brill, Editor(s)

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