[Octave-bug-tracker] [bug #51884] bwmorph(blackNwhiteMatrix, "thicken", 1) returns negated result (+ strange behavior at border)

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?51884>

                 Summary: bwmorph(blackNwhiteMatrix, "thicken", 1) returns
negated result (+ strange behavior at border)
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 29 Aug 2017 01:40:39 PM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: hans messner
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.1
        Operating System: GNU/Linux

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Details:




Problem Environment: 
---------------------

octave:41> ver
--------------------------------------------------
GNU Octave Version: 4.2.1
GNU Octave License: GNU General Public License
Operating System: Linux 2.6.32.54-0.3-default 
                  #2 SMP Fri Nov 29 16:05:00 CET 2013 x86_64
--------------------------------------------------
Package Name   | Version | Installation directory
---------------+---------+-----------------------
      general  |   2.0.0 | /octave/general-2.0.0
        image *|   2.6.1 | /octave/image-2.6.1
           io *|   2.4.7 | /octave/io-2.4.7
miscellaneous  |   1.2.1 | /octave/miscellaneous-1.2.1
     parallel  |   3.1.1 | /octave/parallel-3.1.1
      sockets  |   1.2.0 | /octave/sockets-1.2.0
   statistics *|   1.3.0 | /octave/statistics-1.3.0
       struct  |  1.0.14 | /octave/struct-1.0.14


Problematic Code fragment:
---------------------------


octave:44> a0 = false(5);
octave:45> a0(3,3) = true;
octave:47> a0
a0 =

  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

octave:46> bb=bwmorph(a0, "thicken", 1)
bb =

  0  0  1  0  0
  0  1  1  1  0
  1  1  0  1  1
  0  1  1  1  0
  0  0  1  0  0


%% ======= We expected (not negated; margin not growing):
%
%  0  0  0  0  0
%  0  0  1  0  0
%  0  1  1  1  0
%  0  0  1  0  0
%  0  0  0  0  0
%


%% ======== and can be achieved by some kind of "workaround":
octave:50> m_border = false(size(a0,1)+4);
octave:51> m_border(3:(size(a0,1)+2),3:(size(a0,1)+2)) = a0;
octave:52> bb = !bwmorph(m_border, 'thicken', 1) ...
                        (3:(size(a0,1)+2), 3:(size(a0,1)+2))
bb =

  0  0  0  0  0
  0  0  1  0  0
  0  1  1  1  0
  0  0  1  0  0
  0  0  0  0  0

%% however, I guess this needs a fix in the source code.





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