Each node of the CAG represents a single chromatic component of the image defined as a set of pixels forming a unimodal cluster in the chromatic scattergram.
Edges encode information about adjacency of colour components and their reflectance ratio.
The CAG is related to both the histogram and region adjacency graph representations. It is shown to be preserving and combining the best features of these two approaches while avoiding their drawbacks. One step further towards of local features is the solution of Matas et. The color adjacency graph representation of multi-coloured objects. J. Matas, R. Marik, and J. Kittler.