[Insight-users] How to convert SimpleITK image to VTK data

[Samuel Pichardo]

Hi

You convert first from a VTK array to numpy array (using "from vtk.util 
import numpy_support") then to SimpleITK array. This is the way I read 
Dicom files with VTK, in my case a 3D MRI dataset,

  reader = vtk.vtkDICOMImageReader()
  reader.SetDirectoryName(dirpath) #dirpath is the directory with group 
of dicom files
  reader.Update();

  origin     = reader.GetImagePositionPatient()
  dimensions = reader.GetDataExtent()
  spacing    = reader.GetPixelSpacing()

  data = reader.GetOutput().GetPointData() # get VTK-formatted data
  data = numpy_support.vtk_to_numpy(data.GetArray(0)) # convert VTK 
data to numpy data
  data = 
data.reshape((dimensions[5]+1,dimensions[3]+1,dimensions[1]+1)) # 
reshape data from 1D -> 3D

then to convert to simpleITK,

dataITK = sitk.GetImageFromArray(data)

You'd need to adapt it to NRRD reader but it should be similar. 
Personally, I'd stop in converting to numpy array and from there use 
matplotlib or chaco for the display, depending on if you are looking 
for GUI or a simple display.  From there, you can figure out for the 
inverse process from SimpleITK  (GetArrayFromImage) to Numpy  and then 
to VTK using an object vtk.vtkImageImport() (there is a lot of examples 
for this)

good luck


Sam




On Sun 15 Sep 2013 11:59:49 AM EDT, jmerkow wrote:
> I am looking to do something similar.  I have an NRRD that I read in VTK.  I
> am using ImageReslice to obtain slices along a path (3D path along
> vasculature).  I want to reslice the image and display a single slice. Since
> display is significantly easier in SimpltITK, I wanted to convert the
> vtkImageData to a format that SimpleITK can read.  I would also love to do
> be able to do this for various other reasons.  Since this post is about 2
> years old, are there any updated methods in SimpleITK or VTK6 to convert VTK
> -> SimpleITK, SimpleITK -> VTK?
>
>
>
> --
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