[ITK-users] Strange coordinates output by itk::ContourExtractor2DImageFilter

[Dženan Zukić]

Hi Shen,

using a recent version of ITK
<https://github.com/InsightSoftwareConsortium/ITK/commit/90b04fba49007c300caba06f796fff6976424c40>
(and
using the attached C++ version of your code) I could not reproduce this
problem. For me the output is:
[197, 378]
[196, 378]
[195, 379]
[194, 379]
[193, 379]
[192, 380]
[191, 380]
[190, 380]
[189, 380]
[188, 380]
[187, 381]

Regards,
Dženan

On Mon, Mar 14, 2016 at 11:00 PM, 沈庄明 <zhuangming.shen at sphic.org.cn> wrote:

> Hi all,
>
>
> I used itk::ContourExtractor2DImageFilter to extract contours from a
> binary image (i.e. only 0 or 255 for pixel intensity). Mostly, the code can
> work correctly. However, the code sometimes outputs very strange
> coordinates (e.g. (194.0, 5.36011819173e-320) ), which should represent the
> path of the contour. When I change the contour value from 0 to other number
> no less than 255 (i.e. 250), I got more strange coordinates. My code and
> results are listed as below. Has anyone met the same situation?​
>
>
>
> Regards,
>
>
> Zhuangming Shen
>
>
>
>
> Here is my code
>
>
> =======================================================================================
> import itk
>
> reader = itk.ImageFileReader[itk.Image.UC2].New()
> reader.SetFileName("test.nii")
> reader.Update()
>
> contour_extractor = itk.ContourExtractor2DImageFilter[itk.Image.UC2].New()
> contour_extractor.SetInput(reader.GetOutput())
> contour_extractor.SetContourValue(0)
> contour_extractor.Update()
>
> contour_number = contour_extractor.GetNumberOfOutputs()
>
> print("There are "+str(contour_number)+" contours")
>
> for k in xrange(contour_number):
>     print("================  Contour "+str(k)+" ================")
>
>     point_number = contour_extractor.GetOutput(k).GetVertexList().Size()
>     print("Point number: "+str(point_number))
>
>     for i in xrange(point_number):
>
> print("("+str(contour_extractor.GetOutput(k).GetVertexList().GetElement(i)[0])+","+str(contour_extractor.GetOutput(0).GetVertexList().GetElement(i)[1])+")")
>
>
>
>
> Here is my results
>
>
> =========================================================================================
> There are 2 contours
> ================  Contour 0 ================
> Point number: 670
> (373.0,380.0)
> (372.0,380.0)
> (371.0,380.0)
> (370.0,380.0)
> (369.0,380.0)
> (368.0,380.0)
> (367.0,380.0)
> ...
> (375.0,379.0)
> (374.0,379.0)
> (373.0,380.0)
> ================  Contour 1 ================
> Point number: 677
> (188.0,380.0)
> (187.0,380.0)
> (186.0,380.0)
> (185.0,380.0)
> ...
> (198.0,379.0)
> (197.0,379.0)
> (196.0,379.0)
> (195.0,380.0)
> (194.0,5.36011819173e-320)
> (193.0,382.0)
> (192.0,382.0)
> (191.0,382.0)
> (190.0,382.0)
> (189.0,382.0)
> (188.0,382.0)
>
>
>
>
> Here is the input test.nii
>
> =============================================================================================
> ​
>
>
>
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