[Octave-bug-tracker] [bug #46570] Image package: wrong result with edge

[Avinoam Kalma]

URL:
  <http://savannah.gnu.org/bugs/?46570>

                 Summary: Image package: wrong result with edge
                 Project: GNU Octave
            Submitted by: avinoam
            Submitted on: Sun 29 Nov 2015 08:39:00 PM GMT
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Avinoam
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

    _______________________________________________________

Details:


Start working on BIST for edge, I have found this:


A = ones(5,5);
A(3,3) = 0;

B = edge(A)

B =

   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


the correct result is:


B =

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


If we replace lines 175-176


        strength = sqrt( conv2(im, h1, "same").^2 + ...
                           conv2(im, h3, "same").^2 );



        strength = sqrt( imfilter(im, h1, "replicate").^2 + ...
                           imfilter(im, h3, "replicate").^2 );


We get the correct result, tough I do not know if this is the correct fix. The
problem is that the borders get high values, so
the threshold is wrong.

BTW, this simple example can be served as first test for edge.




    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?46570>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/