Convert VTK image to ITK image without itk-vtkglue

finetjul · April 27, 2020, 8:07am

How can I convert a VTK image into an ITK image without itk-vtkglue in Python ? (see current issue)

Is there a solution as simple as converting from ITK to VTK ?

        data = itk.GetArrayViewFromImage(myITKImage).tostring()

        dataImporter = vtk.vtkImageImport()
        dataImporter.CopyImportVoidPointer(data, len(data))
        dataImporter.SetDataExtent(volumeExtent)
        dataImporter.SetWholeExtent(volumeExtent)
        dataImporter.SetDataOrigin(volumeOrigin)
        dataImporter.SetDataScalarType(volumeDataType)
        dataImporter.SetDataSpacing(spacing)
        dataImporter.SetNumberOfScalarComponents(volumeComponents)
        dataImporter.Update()

Thanks,
Julien.

dchen · April 27, 2020, 1:28pm

There’s a corresponding function itk.GetImageViewFromArray that converts a numpy array to an ITK image. Here’s a blog post about that:

To get from a VTK image to NumPy array you can use the vtk_to_numpy in numpy_support. Here’s stackoverflow thread describing that process:

I wrote a function that goes from VTK to SimpleITK that is essentially the same thing:

github.com

dave3d/dicom2stl/blob/master/utils/vtk2sitk.py

#!/usr/bin/env python

import SimpleITK as sitk
import numpy
import vtk
from vtk.util.numpy_support import *

def vtk2sitk(vtkimg, debug=False):
    """Takes a VTK image, returns a SimpleITK image."""
    sd = vtkimg.GetPointData().GetScalars()
    npdata = vtk_to_numpy(sd)

    dims = list(vtkimg.GetDimensions())
    origin = vtkimg.GetOrigin()
    spacing=vtkimg.GetSpacing()

    if debug:
        print("dims:", dims)
        print("origin:", origin)
        print("spacing:", spacing)

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matt.mccormick · April 28, 2020, 3:27pm

Yes, NumPy can be used as a bridge.

Here is a patch to add itk.vtk_image_from_image and itk.image_from_vtk_image:

without itk-vtkglue.