@techreport{TR-IC-99-24,
  number = {IC-99-24},
  author = {Helena C. G. Leitão and Jorge Stolfi},
  title = {Information Contents of Fracture Lines},
  month = {December},
  year = {1999}, 
  institution = {Institute of Computing, University of Campinas},
  note = {In English, 15 pages.
    \par\selectlanguage{english}\textbf{Abstract}
      Reassembling unknown broken objects from a large collection
      of fragments is a common problem in archaeology and other fields.
      Computer tools have recently been developed, by the authors and by
      others, which try to help by identifying pairs of fragments with matching
      outline shapes. These tools have been succesfully tested on small
      collections of fragments; here we address the question of whether 
      they can be expected to work also for practical instances of the problem
      ($10^3$ to $10^5$ fragments). To that end, we describe here a method
      to measure the average amount of information contained in the shape of
      a fracture line of given length. This parameter tells us how many
      false matches we can expect to find for that fracture among a given
      set of fragments.  In particular, the numbers we obtained for 
      ceramic fragments indicate that fragment outline comparison should
      give useful results even for large instances.
  }
}