Human Visual Perception and Spatial Models of Colour

Colour can deeply change its characteristics when put and analyzed into its spatial context. A growing family of algorithms treat/modify/enhance colour information in its visual context, also known as spatial colour methods. There is a long lasting debate about how to judge their performance. In our opinion this is a challenging task and still an open problem. Two main variables affect the final result of these algorithm: their parameters and the visual characteristics of the image they work on. We aim at discussing the visual configurations in which a spatial colour methods show interesting or critical behaviour. A survey of the more significant visual configurations will be presented and discussed. These configurations include phenomena, such as colour constancy, colour contrast, and colour assimilation. The discussion will present strength and weakness of different algorithms, hopefully allowing a deeper understanding of their behavior and stimulating discussions about searching a common judging ground.