code: def isotropic_opening(image, radius, out=None, spacing=None):
      """Return binary morphological opening of an image.
  
      This function returns the same result as :func:`skimage.morphology.binary_opening`
      but performs faster for large circular structuring elements.
      This works by thresholding the exact Euclidean distance map [1]_, [2]_.
      The implementation is based on: func:`scipy.ndimage.distance_transform_edt`.
  
      Parameters
      ----------
      image : ndarray
          Binary input image.
      radius : float
          The radius with which the regions should be opened.
      out : ndarray of bool, optional
          The array to store the result of the morphology. If None
          is passed, a new array will be allocated.
      spacing : float, or sequence of float, optional
          Spacing of elements along each dimension.
          If a sequence, must be of length equal to the input's dimension (number of axes).
          If a single number, this value is used for all axes.
          If not specified, a grid spacing of unity is implied.
  
      Returns
      -------
      opened : ndarray of bool
          The result of the morphological opening.
  
      References
      ----------
      .. [1] Cuisenaire, O. and Macq, B., "Fast Euclidean morphological operators
          using local distance transformation by propagation, and applications,"
          Image Processing And Its Applications, 1999. Seventh International
          Conference on (Conf. Publ. No. 465), 1999, pp. 856-860 vol.2.
          :DOI:`10.1049/cp:19990446`
  
      .. [2] Ingemar Ragnemalm, Fast erosion and dilation by contour processing
          and thresholding of distance maps, Pattern Recognition Letters,
          Volume 13, Issue 3, 1992, Pages 161-166.
          :DOI:`10.1016/0167-8655(92)90055-5`
      """
  
      eroded = isotropic_erosion(
          image, radius, out=out, spacing=spacing
      )
      return isotropic_dilation(
          eroded, radius, out=out, spacing=spacing
      )
  
imports: import numpy
  from scipy import ndimage
label_desc: Use image node_id 3 for calling a global function with example usage: isotropic_opening(image, radius, out, spacing) and returns: isotropic_dilation