Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site utai.UUCP Path: utzoo!utcsrgv!utai!gh From: gh@utai.UUCP (Graeme Hirst) Newsgroups: ont.events Subject: A.I. seminar, Univ Toronto: Chris Brown (Rochester) Message-ID: <254@utai.UUCP> Date: Thu, 4-Oct-84 09:56:23 EDT Article-I.D.: utai.254 Posted: Thu Oct 4 09:56:23 1984 Date-Received: Thu, 4-Oct-84 10:44:28 EDT Distribution: ont Organization: CSRI, University of Toronto Lines: 29 . ARTIFICIAL INTELLIGENCE SEMINAR DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF TORONTO Skewed symmetry: Its physiology and technique Chris Brown University of Rochester Tuesday 9 October, 3pm, Sandford Fleming 1105 ABSTRACT Symmetric planar shapes viewed under orthography from an arbitrary position have a (skewed) symmetry axis and a skew (transverse) axis. If thye are known, th plane's orientation may be constrained to a one-dimensional locus in the spherical space of orientations. The second moments of skew-symmetric image shapes constrain the axes to a one-dimensional locus in the toroidal space of axis-angle pairs. Then finding skew and symmetry axes involves searching this locus for a pair of angles that in fact specify satisfactory axes. In a quantized image, this calls for robust symmetry evaluators. The analytic constraints will be developed, several symmetry evaluators considered, and experimental results shown. -- \\\\ Graeme Hirst University of Toronto Computer Science Department //// utcsrgv!utai!gh / gh.toronto@csnet-relay / 416-978-8747