[ITK] Gaussian Filtering using SimpleITK + Python

import SimpleITK as sitk
import sys

reader = sitk.ImageFileReader()
reader.SetFileName ( sys.argv[1] )
image = reader.Execute()

pixelID=image.GetPixelIDValue()

gaussian=sitk.SmoothingRecursiveGaussianImageFilter()
gaussian.SetSigma(float(sys.argv[2]))
image=gaussian.Execute(image) 

caster=sitk.CastImageFilter()
caster.SetOutputPixelType(pixelID)
image=caster.Execute(image)

writer=sitk.ImageFileWriter()
writer.SetFileName(sys.argv[3])
writer.Execute(image);