Hi Charl,<br><br><br> That looks like a bug.<br><br><br>The filter should produce identical images, <br>when called with identical parameters.<br><br>Could your please file a bug report in the bug tracker ?<br><br>
Also, in the meantime, you may want to try the modified<br>CannyEdge detection filter that we improved for the <br>Lesion Sizing Toolkit:<br><br><a href="https://www.kitware.com/svn/LesionSizingKit/trunk/Sandbox/Source/">https://www.kitware.com/svn/LesionSizingKit/trunk/Sandbox/Source/</a><br>
<br>You may want to take the files:<br><br><li><a href="https://www.kitware.com/svn/LesionSizingKit/trunk/Sandbox/Source/itkCannyEdgeDetectionRecursiveGaussianImageFilter2.h">itkCannyEdgeDetectionRecursiveGaussianImageFilter2.h</a></li>
<li><a href="https://www.kitware.com/svn/LesionSizingKit/trunk/Sandbox/Source/itkCannyEdgeDetectionRecursiveGaussianImageFilter2.txx">itkCannyEdgeDetectionRecursiveGaussianImageFilter2.txx</a></li><br><br>Regards,<br><br>
<br> Luis<br><br><br>-------------------------------------<br><div class="gmail_quote">On Mon, Aug 10, 2009 at 12:33 PM, Charl Botha <span dir="ltr"><<a href="mailto:c.p.botha@tudelft.nl">c.p.botha@tudelft.nl</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Dear all,<br>
<br>
Running the attached Python script on<br>
Insight/Testing/Data/Input/cthead1.png yields 4 images on disc, of<br>
which canny_t0.png and canny_t0_after.png should be identical, as they<br>
are using the same thresholds, and otherwise identical parameters.<br>
However, they are wildly different, see the attached images.<br>
<br>
In short, the canny filter's behaviour changes depending on whether it<br>
has been freshly instantiated or whether it has been used with a<br>
different parameter setting before. Setting the threshold back to a<br>
previous value after having executed the filter with different values<br>
will yield incorrect results.<br>
<br>
Is this a bug, or am I expecting too much from this filter? :)<br>
<br>
Thanks,<br>
<font color="#888888">Charl<br>
</font><br>_____________________________________<br>
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