Daniel@0: % NONMAXSUP - Non-maximal Suppression
Daniel@0: %
Daniel@0: % Usage:  cim = nonmaxsup(im, radius)
Daniel@0: %
Daniel@0: % Arguments:   
Daniel@0: %            im     - image to be processed.
Daniel@0: %            radius - radius of region considered in non-maximal
Daniel@0: %                     suppression (optional). Typical values to use might
Daniel@0: %                     be 1-3.  Default is 1.
Daniel@0: %
Daniel@0: % Returns:
Daniel@0: %            cim    - image with pixels that are not maximal within a 
Daniel@0: %                     square neighborhood zeroed out.
Daniel@0: 
Daniel@0: % Copyright (C) 2002 Mark A. Paskin
Daniel@0: %
Daniel@0: % This program is free software; you can redistribute it and/or modify
Daniel@0: % it under the terms of the GNU General Public License as published by
Daniel@0: % the Free Software Foundation; either version 2 of the License, or
Daniel@0: % (at your option) any later version.
Daniel@0: %
Daniel@0: % This program is distributed in the hope that it will be useful, but
Daniel@0: % WITHOUT ANY WARRANTY; without even the implied warranty of
Daniel@0: % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Daniel@0: % General Public License for more details.
Daniel@0: %
Daniel@0: % You should have received a copy of the GNU General Public License
Daniel@0: % along with this program; if not, write to the Free Software
Daniel@0: % Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
Daniel@0: % USA.
Daniel@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Daniel@0: 
Daniel@0: function cim = nonmaxsup(m, radius)
Daniel@0:   if (nargin == 1) radius = 1; end
Daniel@0:   % Extract local maxima by performing a grey scale morphological
Daniel@0:   % dilation and then finding points in the corner strength image that
Daniel@0:   % match the dilated image and are also greater than the threshold.
Daniel@0:   sze = 2 * radius + 1;                   % Size of mask.
Daniel@0:   mx = ordfilt2(m, sze^2, ones(sze));   % Grey-scale dilate.
Daniel@0:   cim = sparse(m .* (m == mx));
Daniel@0: 
Daniel@0: