[vtkusers] how to append two image data with different extent?

[Grace Chen]

Hi there, 

I have been a faithful user of VTK for the past year.  But lately, I ran into this problem I cannot solve, so I subscribe myself to this list asking for help for the first time!  

I try to extract a slice from a 3D image data.  The original data (data) has an extent of (0,  511, 0, 511, 0, 3) , and I want to extract different slices from a volumn (in "data") and store them in two vtkImageData.  So, my code goes:

         extractS1 = vtk.vtkExtractVOI( )    
         extractS1.SetInput(data)
         extractS1.SetVOI(0, 511, 0, 511, 0, 0)
         extractS1.Update( )
         slice1 = extractS1.GetOutput( )  <-- slice1 has extent (0, 511, 0, 511, 0, 0)

         extractS2 = vtk.vtkExtractVOI( )
         extractS2.SetInput(data)
         extractS2.SetVOI(0, 511, 0, 511, 2, 2)
         extractS2.Update( ) 
         slice2 = extractS2.GetOutput( )  <-- slice1 has extent (0, 511, 0, 511, 2, 2)

I append these two slices in z direction in different order to create two image data:

        filter = vtk.vtkImageAppend()
        filter.AddInput(slice1)
        filter.AddInput(slice2)
        filter.AddInput(slice1)
        filter.SetAppendAxis(2)
        filter.Update()
        image1 = filter.GetOutput() <-- has extent (0, 511, 0, 511, 0, 2)
  
        filter1 = vtk.vtkImageAppend()    
        filter1.AddInput(slice2)
        filter1.AddInput(slice1)
        filter1.AddInput(slice2)
        filter1.SetAppendAxis(2)
        filter1.Update()       
        image2 = filter1.GetOutput() <-- has extent(0, 511, 0, 511, 2,4)

When I combine those two image data into one by the following code:

        filter2 = vtk.vtkImageAppendComponents()
        filter2.AddInput(image2)
        filter2.AddInput(image1)
        filter2.Update()
        image3 = filter2.GetOutput()

I get error message that tells me the extents of the data doesn't lie within the whole extent: 
       
ERROR: In \OCCIviewerSDK10\Vtk42\Common\vtkDataObject.cxx, line 548
vtkImageData (1B2DBC68): Update extent does not lie within whole extent

ERROR: In \OCCIviewerSDK10\Vtk42\Common\vtkDataObject.cxx, line 555
vtkImageData (1B2DBC68): Update extent is: 0, 511, 0, 511, 2, 4

ERROR: In \OCCIviewerSDK10\Vtk42\Common\vtkDataObject.cxx, line 562
vtkImageData (1B2DBC68): Whole extent is: 0, 511, 0, 511, 0, 2

ERROR: In \OCCIviewerSDK10\Vtk42\Common\vtkDataObject.cxx, line 548
vtkImageData (1B2DBC68): Update extent does not lie within whole extent

ERROR: In \OCCIviewerSDK10\Vtk42\Common\vtkDataObject.cxx, line 555
vtkImageData (1B2DBC68): Update extent is: 0, 511, 0, 511, 2, 4

ERROR: In \OCCIviewerSDK10\Vtk42\Common\vtkDataObject.cxx, line 562
vtkImageData (1B2DBC68): Whole extent is: 0, 511, 0, 511, 0, 2


How do I fix this problem???  Thanx!!

Grace
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