@techreport{TR-IC-98-22,
  number = {IC-98-22},
  author = {Francisco Nivando Bezerra and Neucimar Jerônimo Leite},
  title = {Some Comments on Thinning Algorithms for 3-D Images},
  month = {May},
  year = {1998}, 
  institution = {Institute of Computing, University of Campinas},
  note = {In English, 9 pages.
    \par\selectlanguage{english}\textbf{Abstract}
      The problem of defining simple points in a two-dimensional binary
      image was extensively discussed in the literature. This definition is
      more complicated for 3-d images due to the introduction of a new
      topological component, namely, the tunnel. Recently, some simple-point
      characterizations for these images have been proposed. In this paper
      we show the equivalences between these new characterizations and
      discuss the implementation problems concerned with their use in
      thinning algorithms. An extension of the 2-d gray-level thinning
      algorithm to the 3-d case is also presented.
  }
}