[vtkusers] Closed vtkPolyLine to binary image

Mon Jul 12 10:34:59 EDT 2010

Hey Lars,

Nope it didn't. I can't find the error ^^

dirk

> Dirk,
>
> try to place the stripper between polyreader->GetOutput() and circle, i.e.
> vtkSmartPointer<vtkPolyData> circle = stripper->GetOutput();
> Let me know whether it helped.
>
> lars
>
>
> -------- Original-Nachricht --------
>> Datum: Mon, 12 Jul 2010 16:16:49 +0200
>> Von: "Dirk Boye" <body at nabla.org>
>> An: "Lars Friedrich Lars" <lars-friedrich at gmx.net>
>> CC: "Dirk Boye" <body at nabla.org>, vtkusers at vtk.org
>> Betreff: Re: [vtkusers] Closed vtkPolyLine to binary image
>
>> I ran your example and the only difference between stripper->GetOutput()
>> and my outline were the normals.
>>
>> My code is as follows: (your code but with a readin of my circle
>> and given image dimensions etc.)
>>
>> The vtk File can be found here:
>> http://www.nabla.org/circle.vtk
>>
>> The resulting image is black only.
>>
>>
>> #include <vtkSmartPointer.h>
>> #include <vtkPolyData.h>
>> #include <vtkImageData.h>
>> #include <vtkSphereSource.h>
>> #include <vtkMetaImageWriter.h>
>> #include <vtkPolyDataToImageStencil.h>
>> #include <vtkImageStencil.h>
>> #include <vtkPointData.h>
>> #include <vtkCutter.h>
>> #include <vtkPlane.h>
>> #include <vtkStripper.h>
>> #include <vtkLinearExtrusionFilter.h>
>> #include <vtkXMLPolyDataWriter.h>
>> #include <vtkPolyDataReader.h>
>>
>> int main(int argc, char **argv)
>> {
>> vtkSmartPointer< vtkPolyDataReader > polyreader=vtkSmartPointer<
>> vtkPolyDataReader >::New();
>> 	polyreader->SetFileName("circle.vtk");
>> 	polyreader->Update();
>>
>> 	vtkSmartPointer<vtkPolyData> circle = polyreader->GetOutput();
>>
>> 	// prepare the binary image's voxel grid
>> 	vtkSmartPointer<vtkImageData> whiteImage =
>> 	  vtkSmartPointer<vtkImageData>::New();
>> 	double spacing[3]; // desired volume spacing
>> 	spacing[0] = 2.0;
>> 	spacing[1] = 2.0;
>> 	spacing[2] = 2.0;
>> 	whiteImage->SetSpacing(spacing);
>>
>> 	// compute dimensions
>> 	int dim[3]={256,256,1};
>> 	whiteImage->SetDimensions(dim);
>> 	whiteImage->SetExtent(0, dim[0] - 1, 0, dim[1] - 1, 0, dim[2] - 1);
>> 	double origin[3]={0,0,0};
>> 	whiteImage->SetOrigin(origin);
>> 	whiteImage->SetScalarTypeToUnsignedChar();
>> 	whiteImage->AllocateScalars();
>> 	// fill the image with foreground voxels:
>> 	unsigned char inval = 255;
>> 	unsigned char outval = 0;
>> 	vtkIdType count = whiteImage->GetNumberOfPoints();
>> 	for (vtkIdType i = 0; i < count; ++i)
>> 	{
>> 		whiteImage->GetPointData()->GetScalars()->SetTuple1(i, inval);
>> 	}
>>
>> 	// sweep polygonal data (this is the important thing with contours!)
>> 	vtkSmartPointer<vtkLinearExtrusionFilter> extruder =
>> 	  vtkSmartPointer<vtkLinearExtrusionFilter>::New();
>> 	extruder->SetInput(circle);
>> 	extruder->SetScaleFactor(1.);
>> 	extruder->SetExtrusionTypeToNormalExtrusion();
>> 	extruder->SetVector(0, 0, 1);
>> 	extruder->Update();
>>
>> 	// polygonal data --> image stencil:
>> 	vtkSmartPointer<vtkPolyDataToImageStencil> pol2stenc =
>> 	vtkSmartPointer<vtkPolyDataToImageStencil>::New();
>> 	pol2stenc->SetTolerance(0); // important if extruder->SetVector(0, 0,
>> 1)
>> !!!
>> 	pol2stenc->SetInputConnection(extruder->GetOutputPort());
>> 	pol2stenc->SetOutputOrigin(origin);
>> 	pol2stenc->SetOutputSpacing(spacing);
>> 	pol2stenc->SetOutputWholeExtent(whiteImage->GetExtent());
>> 	pol2stenc->Update();
>>
>> 	// cut the corresponding white image and set the background:
>> 	vtkSmartPointer<vtkImageStencil> imgstenc =
>> 	vtkSmartPointer<vtkImageStencil>::New();
>> 	imgstenc->SetInput(whiteImage);
>> 	imgstenc->SetStencil(pol2stenc->GetOutput());
>> 	imgstenc->ReverseStencilOff();
>> 	imgstenc->SetBackgroundValue(outval);
>> 	imgstenc->Update();
>>
>> 	vtkSmartPointer<vtkMetaImageWriter> imageWriter =
>> 	vtkSmartPointer<vtkMetaImageWriter>::New();
>> 	imageWriter->SetFileName("labelImage.mhd");
>> 	imageWriter->SetInput(imgstenc->GetOutput());
>> 	imageWriter->Write();
>>
>> 	return 0;
>> };
>>
>>
>> >
>> > vtkPolyDataNormals
>> >
>> > just to satisfy my curiosity:
>> > why are you of the opinion that missing normals are a problem for that
>> > approach? I copied the piece of example code more or less from an old
>> > application I programmed some months ago; as far as I can remember, my
>> > input polygons did not have any normals defined, and it worked though
>> ...
>> >
>> > regards,
>> > lars
>> >
>> > -------- Original-Nachricht --------
>> >> Datum: Mon, 12 Jul 2010 15:30:01 +0200
>> >> Von: "Dirk Boye" <body at nabla.org>
>> >> An: "Lars Friedrich Lars" <lars-friedrich at gmx.net>
>> >> CC: "Dirk Boye" <body at nabla.org>, vtkusers at vtk.org
>> >> Betreff: Re: [vtkusers] Closed vtkPolyLine to binary image
>> >
>> >> Hi Lars,
>> >>
>> >> Thank you for your help. My problem now seems to be, that my contour
>> >> lines
>> >> don't have any normals.
>> >>
>> >> Do you know if there's some function to generate the normals?
>> >>
>> >> Cheers,
>> >> Dirk
>> >>
>> >> > Hi,
>> >> >
>> >> > I added a small example:
>> >> >
>> >> >
>> >>
>> http://www.cmake.org/Wiki/VTK/Examples/PolyData/PolyDataContourToImageData
>> >> >
>> >> > Hope that helps you.
>> >> >
>> >> > However, please read the NOTE in the description. Maybe you could
>> fix
>> >> /
>> >> > verify the image origin problem.
>> >> >
>> >> > regards,
>> >> > lars
>> >> >
>> >> > -------- Original-Nachricht --------
>> >> >> Datum: Mon, 12 Jul 2010 08:36:32 +0200
>> >> >> Von: "Dirk Boye" <body at nabla.org>
>> >> >> An: vtkusers at vtk.org
>> >> >> Betreff: [vtkusers] Closed vtkPolyLine to binary image
>> >> >
>> >> >> Dear list,
>> >> >>
>> >> >> let's say I have a closed vtkPolyLine in 2D and points are
>> >> >> ordered clockwise and last point=first point.
>> >> >> The resulting Polygon is non-convex.
>> >> >>
>> >> >> I'd like to create a binary image
>> >> >> from that. Ones inside the line, zeros outside. See picture:
>> >> >> http://www.nabla.org/circlecontour.png
>> >> >>
>> >> >> Is there an filter to do that? Or do I have to check all pixels,
>> >> >> if they are inside?
>> >> >>
>> >> >>
>> >> >> Cheers,
>> >> >> Dirk
>> >> >>
>> >> >>
>> >> >>
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