GetClusters

Identify contiguous clusters of pixels in a binary 2D image.

Takes a 2D matrix of binary data (e.g. {0,1} or {true,false} and returns a labeled map of all sets of contigues "1" pixels with each cluster identified by a different numer.
This will only be useful to you if you don't have the image processing toolbox. Otherwise the bwconncomp function does the same thing faster.