code: def ps_ball(radius):
      r
      rad = int(sp.ceil(radius))
      other = sp.ones((2 * rad + 1, 2 * rad + 1, 2 * rad + 1), dtype=bool)
      other[rad, rad, rad] = False
      ball = spim.distance_transform_edt(other) < radius
      return ball
docs: r"""
      Creates spherical ball structuring element for morphological operations
  
      Parameters
      ----------
      radius : float or int
          The desired radius of the structuring element
  
      Returns
      -------
      strel : 3D-array
          A 3D numpy array of the structuring element