Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / image-1.0.15 / mmgradm.m

diff --git a/octave_packages/image-1.0.15/mmgradm.m b/octave_packages/image-1.0.15/mmgradm.m
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+## Copyright (C) 2010 Carnë Draug <carandraug+dev@gmail.com>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} @var{grad} = mmgradm(@var{A}, @var{se})
+## @deftypefnx {Function File} @var{grad} = mmgradm(@var{A}, @var{se_dil}, @var{se_ero})
+## Calculates the morphological gradient @var{grad} of a given image @var{A}.
+##
+## In the first form, the same structuring element @var{se} is used for dilation
+## and erosion. In the second form, @var{se_dil} and @var{se_ero} are the
+## corresponding structuring elements used for dilation and erosion
+##
+## The image @var{A} must be a grayscale or a binary image.
+##
+## The morphological gradient of a image corresponds to its erosion subtracted
+## to its dilation.
+##
+## @seealso{imerode, imdilate, imopen, imclose, imtophat}
+## @end deftypefn
+
+function grad = mmgradm (im, se_dil, se_ero)
+
+  ## sanity checks
+  if (nargin == 1)
+    error ("Structuring element must be specified");
+  elseif (nargin == 2)              # if only one SE is specified, use it for both erosion and dilation
+    se_ero  = se_dil;
+  elseif (nargin == 3)
+    # all is good
+  else
+    print_usage;
+  endif
+
+  dilated   = imdilate  (im, se_dil);
+  eroded    = imerode   (im, se_ero);
+
+  grad      = dilated - eroded;
+endfunction