@TechReport{TR092,
  author =	 "Walter G. Kropatsch and Yll Haxhimusa and Zygmunt
                  Pizlo",
  title =	 "Integral Trees: Subtree Depth and Diameter",
  institution =	 "PRIP, TU Wien",
  number =	 "PRIP-TR-092",
  year =	 "2004",
  url =		 "https://www.prip.tuwien.ac.at/pripfiles/trs/tr92.pdf",
  abstract =	 "Regions in an image graph can be described by their
                  spanning tree. A graph pyramid is a stack of image
                  graphs at different granularities. Integral features
                  capture important properties of these regions and
                  the associated trees. We compute the depth of a
                  rooted tree, its diameter and the center which
                  becomes the root in the top-down decomposition of a
                  region. The integral tree is an intermediate
                  representation labeling each vertex of the tree with
                  the integral feature(s) of the subtree. Parallel
                  algorithms efficiently compute the integral trees
                  for subtree depth and diameter enabling local
                  decisions with global validity in subsequent
                  top-down processes.",
}