Patent ID: 7366348

Claim:
A method for segmenting a digital image formed from an array of pixels, visual characteristics of each pixel being defined by a set of n parameters, each possible unique set of parameter values being representable as a node on an n-dimensional lattice, the method comprising steps of: storing frequency of each said unique set of parameter values occurring in a set of pixels forming the image; assigning a label to each said unique set of parameter values, taken in order of frequency; and determining an image segment comprising a set of pixels whose visual characteristics are defined by those sets of parameter values which have been assigned one or more specified labels; wherein said assigning of the label to each said unique set of parameter values comprises sub-steps of: assigning a first label to a set of parameter values if the node representing that set of parameter values is adjacent to at least one node representing a set of parameter values which has been assigned the first label, but which is not adjacent to any nodes representing sets of parameter values which have been assigned other labels; wherein sets of parameter values having a common frequency are reprocessed according to this sub-step until none of the nodes representing unlabelled sets of parameter values is adjacent to at least one node representing a set of parameter values which has been assigned the first label but which is not adjacent to any nodes representing sets of parameter values which have been assigned other labels; and assigning a new label to a set of parameter values if the node representing that set of parameter values is not adjacent to any node representing a labelled set of parameter values.