[Insight-users] What's wrong with this code?

[Luis Ibanez]

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Hi Tsai,

A couple of things were wrong with
the example that you sent.



A) The threshold parameter for the
   Watershed filter is too high:

    Watershed.SetThreshold(1.0)

   It is supposed to be a fraction
   of 1.0, and typically should be
   something like 1/10 of the water
   level that you want to extract.
   This line has been changed to

    Watershed.SetThreshold( 0.1 )


B) The output of the Watershed filter
   is an image of labels. This image
   has pixel type = "unsigned long".
   Therefore the writer that you need
   is not of type:

    writer = itkImageFileWriterF2_New()

   It should be of type:

    writer = itkImageFileWriterUL2_New()


C) The filename that you provide for the
   output has extension .png.  However,
   the PNG format only supports unsigned
   char and unsigned short pixel types.
   For F2 or UL2 you should rather use a
   fileformat like MetaImage. That is, use
   an extension like ".mhd"


Please fine attached the modified version
of your code, that is now working fine.



Note also that a variant of this example
has now been commited under

   Insight/Examples/Segmenation/
             WatershedSegmentation1.py




Regards,


   Luis



---------------
tsai wrote:
> Hello,insight-usersŁĄ
> 
> import sys,os
> import paths
> from InsightToolkit import *
> from vtkMINCReader  import *
> from ConnectVTKITK import *
> 
> reader =itkImageFileReaderF2_New()
> reader.SetFileName("d:/Life/photo/genius.jpg")
> 
> diffusion = itkGradientAnisotropicDiffusionImageFilterF2F2_New()
> diffusion.SetInput(reader.GetOutput())
> diffusion.SetTimeStep(0.0625)
> diffusion.SetConductanceParameter(9.0)
> diffusion.SetNumberOfIterations(  5 );
> ##        
> gradient = itkGradientMagnitudeImageFilterF2F2_New()
> gradient.SetInput(diffusion.GetOutput())
> 
> Watershed = itkWatershedImageFilterF2_New()
> Watershed.SetInput(gradient.GetOutput())
> Watershed.SetThreshold(1.0)
> Watershed.SetLevel(0.6)
> #print Watershed.GetOutput()
> 
> writer = itkImageFileWriterF2_New()
> writer.SetFileName("e:/xjf.png")
> writer.SetInput( Watershed.GetOutput()  )
> writer.Write()
> 
> 
> Best Regards,                    
> 
> tsai
> tsai at sjtu.edu.cn
> 
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
> 
> 
======================================================





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