[vtkusers] Region Growing (Volume Rendering) Cropping Problem

[Luis Ibanez]

Hi Yusuf,

The output of the Region Growing filters in ITK are binary images.

The fist thing you should do is to make sure that your camera is
looking in the right direction.

To this end, you could simply introduce first a surface-based visualization
of the binary image, by passing it through the vtkContour filter, as illustrated
in the examples :

           InsightApplications/Auxiliary/vtk/
                     itkReadITKImage3DExtractContourVTK.cxx
                     ExtractIsoSurface.cxx
                     ScreenShotGenerator.cxx

http://public.kitware.com/cgi-bin/viewcvs.cgi/Auxiliary/vtk/?root=InsightApplications


Once you have made sure that your spatial coordinates are correct,
you could proceed to setup a volume rendering visualization.

You should then make sure that you use a transfer function suitable
for an image whose pixel values are only { 0, 255 }. The transfer
function that you may have used for the original values of the DICOM
image, will probably not be appropriate for the binary values of the
segmented image.


Also, please note that Volume Rendering (although it is an extremly
useful visualization method) is not a substitute for image segmentation
methods.



    Regards,


         Luis



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On Mon, Mar 29, 2010 at 6:10 AM, Yusuf OEZBEK <nasil122002 at yahoo.de> wrote:
> Hello All.
>
> I have a problem with to cut (cropping) a 3D object, which I produced by the
> segmentation-method “region growing”. In the beginning I read the DICOM (.
> dcm) images with itkImageSeriesReader then I run region growing -algorithm,
> in order to connect itk with vtk and a 3D object produce, I use
> ImageToVTKImageFilter and volume rendering (ray casting). And after
> segmentation of cutting the images I give below
> vtkFixedPointVolumeRayCastMapper (SetCroppingRegionPlanes) the Xmin, Xmax,
> Ymin, Ymax, Zmin and Zmax coordinates, but the result is a black screen. But
> when I read the images with vtkDICOMImageReader and then segmented with
> volume rendering, then it works completely well. The problem arises only for
> region growing -algorithm. Where is my mistake in the code? What should I
> do?
>
> Thank you.
>
>
>