def most_free_pixel(self):
        """ Find the black pixel with the largest distance from the white pixels.

        Returns
        -------
        :obj:`numpy.ndarray`
            2-vector containing the most free pixel
        """
        dist_tf = self.to_distance_im()
        max_px = np.where(dist_tf == np.max(dist_tf))
        free_pixel = np.array([max_px[0][0], max_px[1][0]])
        return free_pixel