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Proceedings Paper

Variational famework for Retinex
Author(s): Ron Kimmel; Michael Elad; Doron Shaked; Renato Keshet; Irwin E. Sobel
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Paper Abstract

Retinex theory addresses the problem of separating the illumination from the reflectance in a given image and thereby compensating for non-uniform lighting. This is in general an ill-posed problem. In this paper we propose a variational model for the Retinex problem that unifies previous methods. Similar to previous algorithms, it assumes spatial smoothness of the illumination field. In addition, knowledge of the limited dynamic range of the reflectance is used as a constraint in the recovery process. A penalty term is also included, exploiting a-priori knowledge of the nature of the reflectance image. The proposed formulation adopts a Bayesian view point of the estimation problem, which leads to an algebraic regularization term, that contributes to better conditioning of the reconstruction problem. Based on the proposed variational model, we show that the illumination estimation problem can be formulated as a Quadratic Programming optimization problem. An efficient multi-resolution algorithm is proposed. It exploits the spatial correlation in the reflectance and illumination images. Applications of the algorithm to various color images yield promising results.

Paper Details

Date Published: 30 May 2002
PDF: 10 pages
Proc. SPIE 4662, Human Vision and Electronic Imaging VII, (30 May 2002); doi: 10.1117/12.469539
Show Author Affiliations
Ron Kimmel, Hewlett-Packard Labs. (Israel)
Michael Elad, Hewlett-Packard Labs. (Israel)
Doron Shaked, Hewlett-Packard Labs. (Israel)
Renato Keshet, Hewlett-Packard Labs. (Israel)
Irwin E. Sobel, Hewlett-Packard Labs. (United States)


Published in SPIE Proceedings Vol. 4662:
Human Vision and Electronic Imaging VII
Bernice E. Rogowitz; Thrasyvoulos N. Pappas, Editor(s)

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