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Volume: 8 | Article ID: art00018

Illuminant Estimation: Beyond the Bases

DOI : **10.2352/CIC.2000.8.1.art00018** Published Online : **January 2000**

Abstract

We describe spectral estimation principles that are useful for color balancing, color conversion, and sensor design. The principles extend conventional estimation methods, which rely on linear models of the input data, by characterizing the distribution or structure of the linear model coefficients. When the linear model coefficients of the input data are highly structured, it is possible to improve the quality of a simple linear model by estimating coefficients that are invisible to the sensors. We illustrate these principles using the synthetic example of estimating blackbody radiator spectral power distributions. Then, we apply the principles to typical daylight illuminants that we measured over the course of twenty days in Stanford, California. We show that the distribution of the daylight linear model coefficients that approximate the daylight spectral power distributions are highly structured. We further show that from knowledge of the coefficient structure, nonlinear algorithms using N sensors estimate the data as well as linear algorithms using N+1 sensors.

Journal Title : **Color and Imaging Conference**

Publisher Name : **Society of Imaging Science and Technology**

Publisher Location : **7003 Kilworth Lane, Springfield, VA 22151, USA**

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Cite this article

Jeffrey M. DiCarlo, Brian A. Wandell, "Illuminant Estimation: Beyond the Bases" in *Proc. IS&T 8th Color and Imaging Conf.*, 2000, pp 91 - 96, https://doi.org/10.2352/CIC.2000.8.1.art00018

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Copyright © Society for Imaging Science and Technology 2000