spm_clusters.m
8a186cd82567master

spm_clusters.m
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			function A = spm_clusters(L,n)
			% Return the cluster index for a point list
			% FORMAT A = spm_clusters(L,n)
			% L - locations [x y x]' {in voxels} ([3 x m] matrix)
			% n - connectivity criterion (see spm_bwlabel) [Default: 18]
			%
			% A - cluster index or region number ([1 x m] vector)
			%__________________________________________________________________________
			%
			% spm_clusters characterises a point list of voxel values defined with
			% their locations (L) in terms of edge, face and vertex connected
			% subsets, returning a list of indices in A, such that the ith location
			% belongs to cluster A(i) (using an 18 connectivity scheme).
			%__________________________________________________________________________
			% Copyright (C) 1994-2012 Wellcome Trust Centre for Neuroimaging

			% Jesper Andersson
			% $Id: spm_clusters.m 4929 2012-09-17 14:21:01Z guillaume $


			if isempty(L), A = []; return; end
			if nargin < 2, n = 18; end

			% Turn location list to binary 3D volume
			%--------------------------------------------------------------------------
			dim = [max(L(1,:)) max(L(2,:)) max(L(3,:))];
			vol = zeros(dim(1),dim(2),dim(3));
			indx = sub2ind(dim,L(1,:)',L(2,:)',L(3,:)');
			vol(indx) = 1;

			% Label each cluster in 3D volume with its own label using an 18
			% connectivity criterion
			%--------------------------------------------------------------------------
			cci = spm_bwlabel(vol,n);

			% Map back to list
			%--------------------------------------------------------------------------
			A = cci(indx);
			A = A(:)';