Computational Uses of Colour

Why do we have colour? What use is it to us? Some of the obvious answers are that we see colour so that we can recognise objects, spot objects more quickly, tell when fruit is ripe or rotten. These reasons make a lot of sense, but are there others? In this paper, we explore the things that colour makes easier for computational vision systems. In particular, we examine the role of colour in understanding specularities, processing interreflections, identifiying metals from plastics and wet surfaces from dry ones, choosing foveation points, disambiguating stereo matches, discriminating textures and identifying objects. Of course, what is easier for a computational vision system is not necessarily the same for the human visual system but it can perhaps help us create some hypotheses about the role of colour in human perception. We also consider the role of colour constancy in terms of whether or not it is required for colour to be useful to a computer vision system.