Using the red chromaticity for illumination estimation

Achieving color invariance to illumination is known as color constancy and it is implemented in most digital cameras. There are statistics-based and learning-based computational color constancy methods and the latter ones are known to be more accurate. For a given image these methods extract some features and since for some methods calculating and processing these features can be computationally demanding, this renders such methods slow and very often impractical for hardware implementation. In this paper simple, yet very powerful features for color constancy based on the red chromaticity are presented. A new color constancy method is proposed and it is demonstrated how an existing one can be simplified. In both cases state-of-the-art results are achieved. The results are presented and discussed and the source code is available at http://www.fer.unizg.hr/ipg/resources/color constancy/.