[Insight-users] Python Wrapping: Return an itkImage Object

[Hua Qian]

Hi Glen,

Yes, a deep copy would solve my problem. However, I didn't
find anything like that for itk::Image.

For you VTK to ITK connection problem, you can try to put
"self." before all the filters you use, I bet the "seg. fault"
will disappear. This "trick" works for both ITK to VTK and VTK
to ITK connection. I don't know why, and I am still look for
an answer. I guess it has something to do with reference counting.
We have to keep references to all the filters to keep the image
data pipeline alive.
   
Hua

 
Glen Lehmann wrote:

> Hi Hua,
>
> I avoid this when converting from itk::Image to vtkImageData by doing 
> the following;
>
>    def ITK2VTK(self, itkImage):
>        # this will form the end-point of the ITK pipeline segment
>        itkExporter = itk.itkVTKImageExportF2_New()
>        itkExporter.SetInput( itkImage )
>
>        # the vtkImageImport will bring our data back into VTK-land
>        vtkImporter = vtk.vtkImageImport()
>
>        # do the magic connection call (once again: only available if 
> you built
>        # ITK with ITK_CSWIG_CONNECTVTKITK set to ON)
>        CVIPy.ConnectITKF2ToVTK(itkExporter.GetPointer(), vtkImporter)
>
>        imageData = vtk.vtkImageData()
>        imageData.DeepCopy( vtkImporter.GetOutput() )
>
>        return imageData
>
> However, when converting from vtkImageData to itk::Image I get the 
> same seg. faults that you do because I can't preform a deep copy 
> operation on the itk::Image.  Is there an equivilant operation in itk?
>
> Glen
>
> Hua Qian wrote:
>
>> Hello,
>>
>> Here are two little python classes to test returning an
>> itkImage object. One class works and the other gives
>> segmentation fault. Could someone confirm that and
>> explain why?
>>
>> Regards,
>> Hua
>>
>> from InsightToolkit import *
>>
>> class testReturnImage1:
>>    def __init__(self):
>>        self._reader = itkImageFileReaderF2_New()
>>        self._reader.SetFileName("../../Testing/Data/Input/cthead1.png")
>>        self._image = self._reader.GetOutput()
>>
>>    def GetImage(self):
>>        return self._image
>>
>> class testReturnImage2:
>>    def __init__(self):
>>        reader = itkImageFileReaderF2_New()
>>        reader.SetFileName("../../Testing/Data/Input/cthead1.png")
>>        self._image = reader.GetOutput()
>>          def GetImage(self):
>>        return self._image
>>
>> app1 = testReturnImage1()
>> image = app1.GetImage()
>> print "app1: updating image ... "
>> image.Update()
>> print "     Done."
>>
>> app2 = testReturnImage2()
>> image2 = app2.GetImage()
>> print "app2: updating image ... "
>> image2.Update()
>> print "      Done."
>>
>>
>>