code: def chord_counts(im):
      r
      labels, N = spim.label(im > 0)
      props = regionprops(labels, coordinates='xy')
      chord_lens = sp.array([i.filled_area for i in props])
      return chord_lens
docs: r"""
      Finds the length of each chord in the supplied image and returns a list
      of their individual sizes
  
      Parameters
      ----------
      im : ND-array
          An image containing chords drawn in the void space.
  
      Returns
      -------
      result : 1D-array
          A 1D array with one element for each chord, containing its length.
  
      Notes
      ----
      The returned array can be passed to ``plt.hist`` to plot the histogram,
      or to ``sp.histogram`` to get the histogram data directly. Another useful
      function is ``sp.bincount`` which gives the number of chords of each
      length in a format suitable for ``plt.plot``.