Resampling an itk image object with SimpleITK

resample_itk_image.py

def resample_img(itk_image, out_spacing=[2.0, 2.0, 2.0], is_label=False):
    
    # Resample images to 2mm spacing with SimpleITK
    original_spacing = itk_image.GetSpacing()
    original_size = itk_image.GetSize()

    out_size = [
        int(np.round(original_size[0] * (original_spacing[0] / out_spacing[0]))),
        int(np.round(original_size[1] * (original_spacing[1] / out_spacing[1]))),
        int(np.round(original_size[2] * (original_spacing[2] / out_spacing[2])))]

    resample = sitk.ResampleImageFilter()
    resample.SetOutputSpacing(out_spacing)
    resample.SetSize(out_size)
    resample.SetOutputDirection(itk_image.GetDirection())
    resample.SetOutputOrigin(itk_image.GetOrigin())
    resample.SetTransform(sitk.Transform())
    resample.SetDefaultPixelValue(itk_image.GetPixelIDValue())

    if is_label:
        resample.SetInterpolator(sitk.sitkNearestNeighbor)
    else:
        resample.SetInterpolator(sitk.sitkBSpline)

    return resample.Execute(itk_image)

# Assume to have some sitk image (itk_image) and label (itk_label)
resampled_sitk_img = resample_img(itk_image, out_spacing=[2.0, 2.0, 2.0], is_label=False)
resampled_sitk_lbl = resample_img(itk_label, out_spacing=[2.0, 2.0, 2.0], is_label=True)

thanks for sharing!! been back here 3+ times now! 🚀

is that different from

sitk.Resample(input, reference,)

?

thanks a lot!! i've been working on this over quite a few hours.