/usr/share/octave/packages/image-2.6.1/imclearborder.m is in octave-image 2.6.1-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | ## Copyright (C) 2014 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} {} imclearborder (@var{im})
## @deftypefnx {Function File} {} imclearborder (@var{im}, @var{conn})
## Clear borders of objects or ligher structures.
##
## On the simplest case of binary images, this function removes objects
## that touch the image borders. In the case of grayscale images, lighter
## regions (higher intensity values) that touch the image border get removed.
##
## To be more exact, this is equivalent to use @code{imreconstruct} using
## the @var{im} borders as marker, and setting all unchanged elements to
## a background value.
##
## 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}), "maximal")} which is equivalent to
## @var{conn} of 8 and 26 for 2 and 3 dimensional matrices respectively.
##
## @seealso{imreconstruct}
## @end deftypefn
function im = imclearborder (im, conn)
if (nargin < 1 || nargin > 2)
print_usage ();
elseif (! isimage (im))
error ("imclearborder: IM must be an image");
endif
if (nargin < 2)
conn = conndef (ndims (im), "maximal");
else
conn = conndef (conn);
endif
bg_val = cast (getrangefromclass (im)(1), class (im));
marker = get_borders (im, conn, bg_val);
border_elems = imreconstruct (marker, im, conn) == im;
im(border_elems) = bg_val;
endfunction
function borders = get_borders (im, conn, val)
im_size = size (im);
borders = repmat (val, im_size);
tmp_idx = repmat ({":"}, [1 ndims(im)]);
tmp_conn_idx = repmat ({":"}, [1 ndims(conn)]);
for dim = 1:min (ndims (im), ndims (conn))
conn_idx = tmp_conn_idx;
conn_idx{dim} = [1 3];
if (im_size(dim) == 1 || ! any (conn(conn_idx{:})(:)))
continue
endif
idx = tmp_idx;
idx{dim} = [1 im_size(dim)];
borders(idx{:}) = im(idx{:});
endfor
endfunction
## TODO check what exactly does Matlab do with in grayscale images, specially
## in the case of signed integers and floating point with negative values.
## We are different from the Matlab documentation suggests but that's
## because Matlab documentation sounds wrong to me.
%!test
%! a = logical ([
%! 0 1 0 0 1 0 0 0 0 1
%! 1 0 0 0 0 1 0 0 0 0
%! 0 1 0 0 0 0 0 0 0 0
%! 1 0 1 0 1 0 1 0 0 1
%! 0 0 0 0 0 0 0 1 1 0
%! 0 0 1 0 0 1 0 1 0 0
%! 0 1 0 1 0 1 1 0 0 0
%! 0 0 0 1 0 0 0 0 0 0
%! 0 0 0 1 0 1 1 0 0 0
%! 0 0 0 1 1 0 0 0 1 0]);
%!
%! a4 = logical ([
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 1 0 0 0 0
%! 0 1 0 0 0 0 0 0 0 0
%! 0 0 1 0 1 0 1 0 0 0
%! 0 0 0 0 0 0 0 1 1 0
%! 0 0 1 0 0 1 0 1 0 0
%! 0 1 0 0 0 1 1 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 1 1 0 0 0
%! 0 0 0 0 0 0 0 0 0 0]);
%!
%! a8 = logical ([
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 1 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0
%! 0 0 0 0 0 0 0 0 0 0]);
%!
%! assert (imclearborder (a, 4), a4)
%! assert (imclearborder (a, [0 1 0; 1 1 1; 0 1 0]), a4)
%! assert (imclearborder (a), a8)
%! assert (imclearborder (a, 8), a8)
%! assert (imclearborder (a, ones (3)), a8)
%!test
%! a = false (5, 5, 3);
%! a(2:4,2:4,:) = true;
%! assert (imclearborder (a, 4), a)
%!
%! a(1,2) = true;
%! a4 = a;
%! a4(:,:,1) = false;
%! assert (imclearborder (a, 4), a4)
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