Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/image-1.0.15/bwhitmiss.m b/octave_packages/image-1.0.15/bwhitmiss.m
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+## Copyright (C) 2008 Soren Hauberg
+## 
+## 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 2
+## 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.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} @var{bw2} = bwhitmiss (@var{bw1}, @var{se1}, @var{se1})
+## @deftypefnx{Function File} @var{bw2} = bwhitmiss (@var{bw1}, @var{interval})
+## Perform the binary hit-miss operation.
+##
+## If two structuring elements @var{se1} and @var{se1} are given, the hit-miss
+## operation is defined as
+## @example
+## bw2 = erode(bw1, se1) & erode(!bw1, se2);
+## @end example
+## If instead an 'interval' array is given, two structuring elements are computed
+## as
+## @example
+## se1 = (interval ==  1)
+## se2 = (interval == -1)
+## @end example
+## and then the operation is defined as previously.
+## @seealso{bwmorph}
+## @end deftypefn
+
+function bw = bwhitmiss(im, varargin)
+  ## Checkinput
+  if (nargin != 2 && nargin != 3)
+    print_usage();
+  endif
+  if (!ismatrix(im) || !isreal(im))
+    error("bwhitmiss: first input argument must be a real matrix");
+  endif
+
+  ## Get structuring elements
+  if (nargin == 2) # bwhitmiss (im, interval)
+    interval = varargin{1};
+    if (!isreal(interval))
+      error("bwhitmiss: second input argument must be a real matrix");
+    endif
+    if (!all( (interval(:) == 1) | (interval(:) == 0) | (interval(:) == -1) ))
+      error("bwhitmiss: second input argument can only contain the values -1, 0, and 1");
+    endif
+    se1 = (interval ==  1);
+    se2 = (interval == -1);
+  else # bwhitmiss (im, se1, se2)
+    se1 = varargin{1};
+    se2 = varargin{2};
+    if (!all((se1(:) == 1) | (se1(:) == 0)) || !all((se2(:) == 1) | (se2(:) == 0)))
+      error("bwhitmiss: structuring elements can only contain zeros and ones.");
+    endif
+  endif
+  
+  ## Perform filtering
+  bw = erode(im, se1) & erode(!im, se2);
+
+endfunction