Mercurial > hg > octave-image
view inst/bwperim.m @ 915:8c8ed7c4ab83 default tip
* bwlabeln.cc (bwlabel_nd): Fix small bug in comment
| author | Jordi Gutiérrez Hermoso <jordigh@octave.org> |
|---|---|
| date | Tue, 18 Nov 2014 11:30:57 -0500 |
| parents | 355bd9c476d9 |
| children |
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## Copyright (C) 2013 Carnë Draug <carandraug@octave.org> ## ## 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} {} bwperim (@var{bw}) ## @deftypefnx {Function File} {} bwperim (@var{bw}, @var{conn}) ## Find perimeter of objects in binary images. ## ## Values from the matrix @var{bw} are considered part of an object perimeter ## if their value is non-zero and is connected to at least one zero-valued ## element. ## ## Element connectivity @var{conn}, to define the size of objects, can be ## specified with a numeric scalar (number of elements in the neighborhood): ## ## @table @samp ## @item 4 or 8 ## for 2 dimensional matrices; ## @item 6, 18 or 26 ## for 3 dimensional matrices; ## @end table ## ## or with a binary matrix representing a connectivity array. Defaults to ## @code{conndef (ndims (@var{bw}), "minimal")} which is equivalent to ## @var{conn} of 4 and 6 for 2 and 3 dimensional matrices respectively. ## ## @seealso{bwarea, bwboundaries, imerode, mmgrad} ## @end deftypefn function varargout = bwperim (bw, conn) if (nargin < 1 || nargin > 2) print_usage (); elseif (! ismatrix (bw) || ! (isnumeric (bw) || islogical (bw))) error("bwperim: BW must be a numeric matrix"); endif nDims = ndims (bw); if (nargin < 2) ## Defining default connectivity here because it's dependent ## on the first argument conn = conndef (nDims, "minimal"); else conn = make_conn ("bwperim", 2, nDims, conn); endif ## Make sure bw is logical; bw = logical (bw); ## Recover the elements that would get removed by erosion perim = (! imerode (bw, conn)) & bw; ## Get the borders back (they are removed during erosion tmp_idx = repmat ({":"}, [1 nDims]); p_size = size (perim); for dim = 1:nDims idx = tmp_idx; idx{dim} = [1 p_size(dim)]; perim(idx{:}) = bw(idx{:}); endfor if (nargout > 0) varargout{1} = perim; else imshow (perim); endif endfunction %!shared in, out %! in = [ 1 1 1 1 0 1 1 0 1 1 %! 1 1 0 1 1 1 1 1 1 0 %! 1 1 1 0 1 1 1 1 1 1 %! 1 1 1 1 0 1 1 1 0 1 %! 1 1 1 0 1 1 1 1 1 0 %! 1 1 1 1 1 1 0 1 0 1 %! 1 1 1 1 1 1 1 1 1 0 %! 1 1 1 1 1 1 1 1 1 1 %! 1 1 1 1 1 1 0 0 1 1 %! 1 1 1 1 0 1 0 1 1 0]; %! %! out = [1 1 1 1 0 1 1 0 1 1 %! 1 1 0 1 1 0 0 1 1 0 %! 1 0 1 0 1 0 0 0 1 1 %! 1 0 0 1 0 1 0 1 0 1 %! 1 0 1 0 1 0 1 0 1 0 %! 1 0 0 1 0 1 0 1 0 1 %! 1 0 0 0 0 0 1 0 1 0 %! 1 0 0 0 0 0 1 1 0 1 %! 1 0 0 0 1 1 0 0 1 1 %! 1 1 1 1 0 1 0 1 1 0]; %!assert (bwperim (in), logical (out)); %!assert (bwperim (in, 4), logical (out)); %! %! out = [1 1 1 1 0 1 1 0 1 1 %! 1 1 0 1 1 1 1 1 1 0 %! 1 1 1 0 1 1 0 1 1 1 %! 1 0 1 1 0 1 0 1 0 1 %! 1 0 1 0 1 1 1 1 1 0 %! 1 0 1 1 1 1 0 1 0 1 %! 1 0 0 0 0 1 1 1 1 0 %! 1 0 0 0 0 1 1 1 1 1 %! 1 0 0 1 1 1 0 0 1 1 %! 1 1 1 1 0 1 0 1 1 0]; %!assert (bwperim (in, 8), logical (out)); %! %! out = [1 1 1 1 0 1 1 0 1 1 %! 1 0 0 0 0 1 0 0 1 0 %! 1 0 0 0 0 0 0 1 0 1 %! 1 0 1 0 0 0 0 0 0 1 %! 1 0 0 0 0 1 0 1 0 0 %! 1 0 0 0 1 0 0 0 0 1 %! 1 0 0 0 0 0 0 1 0 0 %! 1 0 0 0 0 1 1 0 0 1 %! 1 0 0 1 0 1 0 0 1 1 %! 1 1 1 1 0 1 0 1 1 0]; %!assert (bwperim (in, [1 0 0; 0 1 0; 0 0 1]), logical (out)); ## test that any non-zero value is valid (even i and Inf) %!shared in, out %! in = [ 0 0 0 0 0 0 0 %! 0 0 5 0 0 1 9 %! 0 Inf 9 7 0 0 0 %! 0 1.5 5 7 1 0 0 %! 0 0.5 -1 89 i 0 0 %! 0 4 10 15 1 0 0 %! 0 0 0 0 0 0 0]; %! out = [0 0 0 0 0 0 0 %! 0 0 1 0 0 1 1 %! 0 1 0 1 0 0 0 %! 0 1 0 0 1 0 0 %! 0 1 0 0 1 0 0 %! 0 1 1 1 1 0 0 %! 0 0 0 0 0 0 0]; %!assert (bwperim (in), logical (out)); ## test for 3D %!shared in, out %! in = reshape (magic(16), [8 8 4]) > 50; %! out(:,:,1) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 1 1 1 0 1 %! 0 1 1 1 1 1 0 1 %! 1 1 0 1 1 1 1 1 %! 1 1 1 1 1 1 1 1 %! 1 1 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %! out(:,:,2) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 0 1 1 0 1 %! 0 1 0 0 0 1 0 1 %! 1 0 1 0 0 0 1 1 %! 1 0 0 1 0 1 0 1 %! 1 0 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %! out(:,:,3) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 0 1 1 0 1 %! 0 1 0 0 0 1 0 1 %! 1 0 0 0 0 0 1 1 %! 1 0 0 1 0 1 0 1 %! 1 0 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %! out(:,:,4) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 1 1 1 0 1 %! 0 1 1 1 1 1 0 1 %! 1 1 1 1 1 1 1 1 %! 1 1 1 1 1 1 1 0 %! 1 1 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %!assert (bwperim (in), logical (out)); %! %! out(:,:,1) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 1 1 1 0 1 %! 0 1 1 1 1 1 0 1 %! 1 1 0 1 1 1 1 1 %! 1 1 1 1 1 1 1 1 %! 1 1 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %! out(:,:,2) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 1 1 1 0 1 %! 0 1 1 0 0 1 0 1 %! 1 1 1 1 0 1 1 1 %! 1 0 1 1 1 1 1 1 %! 1 0 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %! out(:,:,3) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 1 1 1 0 1 %! 0 1 0 0 0 1 0 1 %! 1 1 0 0 0 1 1 1 %! 1 0 1 1 1 1 1 1 %! 1 0 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %! out(:,:,4) = [ %! 1 1 0 1 0 1 1 1 %! 0 1 1 1 1 1 0 1 %! 0 1 1 1 1 1 0 1 %! 1 1 1 1 1 1 1 1 %! 1 1 1 1 1 1 1 0 %! 1 1 1 0 1 0 1 1 %! 1 1 1 0 1 0 1 1 %! 1 0 1 1 1 1 1 0]; %!assert (bwperim (in, 18), logical (out)); %!error bwperim ("text") %!error bwperim (rand (10), 5) %!error bwperim (rand (10), "text")