    constantPad = vtkImageConstantPad()
    constantPad.SetInputConnection(reader.GetOutputPort())
    constantPad.SetConstant(800)
    constantPad.SetOutputWholeExtent(-127, 383, -127, 383, 22, 22)

    mirrorPad = vtkImageMirrorPad()
--
    pad = vtkImageConstantPad()
    pad.SetInputConnection(polar.GetOutputPort())
    pad.SetOutputNumberOfScalarComponents(3)
    pad.SetConstant(200.0)

    # At this point we have Hue, Value, Saturation.
--
    grey_padder = vtkImageConstantPad()
    grey_padder.SetInputConnection(grey_reader.GetOutputPort())
    grey_padder.SetOutputWholeExtent(0, 511, 0, 511, slice_number, slice_number)
    grey_padder.SetConstant(0)

    grey_plane = vtkPlaneSource()
--
    segment_padder = vtkImageConstantPad()
    segment_padder.SetInputConnection(segment_reader.GetOutputPort())
    segment_padder.SetOutputWholeExtent(0, 511, 0, 511, slice_number, slice_number)
    segment_padder.SetConstant(0)

    segment_plane = vtkPlaneSource()
