Colour displays for categorical images C.A. Glasbey ∗ Biomathematics and Statistics Scotland King’s Buildings, Edinburgh, EH9 3JZ, Scotland

We propose a method for identifying a set of colours for displaying 2-D and 3-D categorical images when the categories are unordered labels. The principle is to find maximally distinct sets of colours. We either generate colours sequentially, to maximise the dissimilarity or distance between a new colour and the set of colours already chosen, or use a simulated annealing algorithm to find a set of colours of specified size. In both cases, we use a Euclidean metric on the perceptual colour space, CIE-LAB, to specify distances. Keywords: pseudo-colour; look-up table; perceptually uniform colour space; RGB; LAB; colour quantization.