    sumFilter = vtkImageWeightedSum()
    sumFilter.SetWeight(0, 0.8)
    sumFilter.SetWeight(1, 0.2)
    sumFilter.AddInputConnection(source1Double.GetOutputPort())
    sumFilter.AddInputConnection(source2.GetOutputPort())
    sumFilter.Update()
--
    SumFilter = vtkImageWeightedSum()
    for x in range(0, NumOfImages, 1):
        SumFilter.AddInputConnection(ImageSets[x])
        SumFilter.SetWeight(x, Weights[x])
    SumFilter.Update()

