[Insight-developers] Flat structuring element issues with polygons.

[Bradley Lowekamp]

Bill,

Have you used the poly line structuring element?

I ran into the segfault while adding this feature to SimpleITK[1]. GDB lead me deep into the innards of the VanHerkGilWerman algorithm[2] and other common morphology utilities[3].

This was the SimpleITK code I was using:
import SimpleITK as sitk

img = img = sitk.Image(100,100, sitk.sitkUInt8); img[50,50]=1
sitk.Show(sitk.BinaryDilate(img, 20, sitk.sitkPolygon6)*255)

I added a good test which can be used to verify the structuring elements. Unlike the current test which just prints to to std out.

http://review.source.kitware.com/#/c/13845/

Unfortunately, I was not able to reproduce the segfault with the test. Although the output for the 6-line SE is visibly wrong.


[1] http://itk.org/gitweb?p=stage/SimpleITK.git;a=shortlog;h=refs/heads/SIMPLEITK-431_AddMorphologyKernelEnum
[2] https://github.com/Kitware/ITK/blob/master/Modules/Filtering/MathematicalMorphology/include/itkFlatStructuringElement.hxx#L1006
[3] https://github.com/Kitware/ITK/blob/master/Modules/Filtering/MathematicalMorphology/include/itkSharedMorphologyUtilities.hxx#L79

Brad


On Dec 17, 2013, at 12:40 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:

> Brad,
> 
> If you can post a small compilable C++ example that illustrates the problem, I'll take a look.
> 
> Bill
> 
> 
> 
> On Tue, Dec 17, 2013 at 12:04 PM, Bradley Lowekamp <blowekamp at mail.nih.gov> wrote:
> Hello,
> 
> I have gotten a couple segfaults when creating when creating Polygon faceted structuring elements. Specifically creating a 6 line 2D element with 12 threads on linux. There were many other combinations which caused a segault.
> 
> 
> Also many of the of the structuring elements don't look right, this is a poly from 5 lines or 10 side:
> 
> <poly5.png>
> 
> Any one familiar with this code? Or have used it? Perhaps it's a recent regression?
> 
> 
> Thanks,
> Brad
> 
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