Colour Constancy Based on Model Selection

Colour constancy is the problem of mapping colours in a scene as the lighting environment changes. This problem has been studied for many years, and linear solutions that give excellent results are available for Lambertian scenes. More complex reflective environments demand non-linear transforms, but the models are harder to fit and in some cases bring worse results due to over-fitting. We introduce a fully non-linear colour constancy model and a method to select an optimal model from amongst a family of discrete models, including linear models. Once given a set of colour matches our model selection is fully automatic. The selection method is experimentally verified, and is put to use in two applications: scene re-lighting and environment mapping.