code: def smooth_image(image, sigma, sigma_in_physical_coordinates=True, FWHM=False, max_kernel_width=32):
      
      if image.components == 1:
          return _smooth_image_helper(image, sigma, sigma_in_physical_coordinates, FWHM, max_kernel_width)
      else:
          imagelist = utils.split_channels(image)
          newimages = []
          for image in imagelist:
              newimage = _smooth_image_helper(image, sigma, sigma_in_physical_coordinates, FWHM, max_kernel_width)
              newimages.append(newimage)
          return utils.merge_channels(newimages)
docs: Smooth an image
  
      ANTsR function: `smoothImage`
  
      Arguments
      ---------
      image   
          Image to smooth
      
      sigma   
          Smoothing factor. Can be scalar, in which case the same sigma is applied to each dimension, or a vector of length dim(inimage) to specify a unique smoothness for each dimension.
      
      sigma_in_physical_coordinates : boolean  
          If true, the smoothing factor is in millimeters; if false, it is in pixels.
      
      FWHM : boolean    
          If true, sigma is interpreted as the full-width-half-max (FWHM) of the filter, not the sigma of a Gaussian kernel.
      
      max_kernel_width : scalar    
          Maximum kernel width
      
      Returns
      -------
      ANTsImage
      
      Example
      -------
      >>> import ants
      >>> image = ants.image_read( ants.get_ants_data('r16'))
      >>> simage = ants.smooth_image(image, (1.2,1.5))