[vtkusers] Closed vtkPolyLine to binary image

Mon Jul 12 10:40:04 EDT 2010

Strange.
Does the circle-polydata define a continuous closed line after stripper?

-------- Original-Nachricht --------
> Datum: Mon, 12 Jul 2010 16:34:59 +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

> 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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> >
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