[Octave-bug-tracker] [bug #52029] Compatibility MATLAB and Octave code

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?52029>

                 Summary: Compatibility MATLAB and Octave code
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Fri 15 Sep 2017 07:18:41 AM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: r2d3
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.1
        Operating System: Microsoft Windows

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Details:

I just installed Octave 4.2.1 and tried this example code that uses Image
Processing package to visualize the ellipse-based measurements produced by
regionprops
(http://blogs.mathworks.com/steve/2010/07/30/visualizing-regionprops-ellipse-measurements/):

url='http://blogs.mathworks.com/images/steve/2010/rice_binary.png';
bw = imread(url);
imshow(bw)
hold on

pkg load image

s = regionprops(bw, 'Orientation', 'MajorAxisLength', ...
    'MinorAxisLength', 'Eccentricity', 'Centroid');

phi = linspace(0,2*pi,50);
cosphi = cos(phi);
sinphi = sin(phi);

for k = 1:length(s)
    xbar = s(k).Centroid(1);
    ybar = s(k).Centroid(2);

    a = s(k).MajorAxisLength/2;
    b = s(k).MinorAxisLength/2;

    theta = pi*s(k).Orientation/180;
    R = [ cos(theta)   sin(theta)
         -sin(theta)   cos(theta)];

    xy = [a*cosphi; b*sinphi];
    xy = R*xy;

    x = xy(1,:) + xbar;
    y = xy(2,:) + ybar;

    plot(x,y,'r','LineWidth',2);
end
hold off


The result I have obtained, shown in attached file ("wrong_result.JPG") - all
ellipses are arranged horizontally.
"Orientation" does not work?
How it possible to workaround this problem?




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File Attachments:


-------------------------------------------------------
Date: Fri 15 Sep 2017 07:18:41 AM UTC  Name: wrong_result.JPG  Size: 61KiB  
By: None

<http://savannah.gnu.org/bugs/download.php?file_id=41804>

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