def areas(self):
        """
        A 1D array of areas (in pixel**2) of the non-zero labeled
        regions.

        The `~numpy.ndarray` starts with the *non-zero* label.  The
        returned array has a length equal to the number of labels and
        matches the order of the ``labels`` attribute.
        """

        return np.array([area
                         for area in np.bincount(self.data.ravel())[1:]
                         if area != 0])