1. A system for segmenting cluster of colours within an image, the system comprising: a colour selector for identifying or selecting at least one colour within the image; a profiler for creating a colour profile curve from a reference point (x i, 0) corresponding to the at least one colour to all colours in a selected colour scheme; and an analyser for analysing the colour profile curve by detecting a closest point (s 1 ) on the colour profile curve to the reference point (x i, 0), locating a point of inflexion on the colour profile curve between the reference point (x i ,0) and the closest point (s 1 ), and segmenting a portion of the colour profile curve between the reference point (x i ,0) and the point of inflexion, the segmented portion of the colour profile curve constituting a cluster of colours corresponding to the at least one colour; wherein the colour selector is further configured for selecting a sequence of colours for assignment to the cluster of colours; and the system further comprises: an intensity determiner for determining a minimum intensity I MIN within the cluster of colours, and for determining a maximum intensity I MAX within the cluster of colours; and a relative intensity value determiner for determining a relative intensity value RIV(i) for each pixel or voxel i within the cluster of colours according to: RIV ⁡ ( i ) = f ⁡ ( I ⁡ ( i ) - I M ⁢ ⁢ IN I M ⁢ ⁢ AX - I M ⁢ ⁢ I ⁢ ⁢ N ) where I(i) is an intensity of pixel or voxel i, and ƒ is a preselected function; and a colour assignor for assigning colours to at least some of the pixels or voxels based on the relative intensity values and an order of each of the colours in the sequence.