[Colloquium] Reminder: Purdy/Dissertation Defense/Feb 19, 2013

[Margaret Jaffey]

This is a reminder about Eric's defense tomorrow morning.

       Department of Computer Science/The University of Chicago

                     *** Dissertation Defense ***


Candidate:  Eric Purdy

Date:  Tuesday, February 19, 2013

Time:  10:00 AM

Place:  Ryerson 251

Title: Grammatical Methods in Computer Vision

Abstract:
In computer vision, grammatical models are models that represent
objects hierarchically as compositions of sub-objects. This allows us
to specify rich object models in a standard Bayesian probabilistic
framework. In this thesis, we formulate shape grammars, a
probabilistic model of curve formation that allows for both continuous
variation and structural variation. We derive an EM-based training
algorithm for shape grammars. We demonstrate the effectiveness of
shape grammars for modeling human silhouettes, and also demonstrate
their effectiveness in classifying curves by shape. We also give a
general method for heuristically speeding up a large class of dynamic
programming algorithms. We provide a general framework for discussing
coarse-to-fine search strategies, and provide proofs of correctness.
Our method can also be used with inadmissible heuristics.

Finally, we give an algorithm for doing approximate parsing of long
strings in linear time. We define a notion of approximate parsing in
terms of restricted families of decompositions, and construct small
families which can approximate arbitrary parses.

Eric's advisor is Prof. Pedro Felzenszwalb

Login to the Computer Science Department website for details,
including a draft copy of the dissertation:

 https://www.cs.uchicago.edu/phd/phd_announcements#epurdy

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Margaret P. Jaffey            margaret at cs.uchicago.edu
Department of Computer Science
Student Support Rep (Ry 156)               (773) 702-6011
The University of Chicago      http://www.cs.uchicago.edu
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