[Colloquium] Reminder: Girshick/MS Presentation/May 29, 2009

[Margaret Jaffey]

This is a reminder about Ross Girshick's MS Presentation tomorrow.

------------------------------------------------------------------------------
Date:  Friday, May 29, 2009

Time:  11:30 AM

Place:  Ryerson 251

M.S. Candidate:  Ross Girshick

M.S. Paper Title: Object Detection with Heuristic Coarse-to-Fine
Search

Abstract:
We consider the task of localizing and labeling instances of a generic
object class within real-world images. Our focus is on a generalized
class of pictorial structure models that are defined in terms of
visual grammars. In particular, we address the challenging problem of
performing detection efficiently even as model complexity grows within
this class. Our proposed solution is a blend of heuristic best-first
search and a coarse-to-fine detection process. This paper demonstrates
that our algorithm can be successfully applied to two special cases of
visual grammars: multiscale star models and mixtures of multiscale
star models. We show that for problems where the desired output is the
local optima of a thresholded function, best-first search gives
additional pruning power to coarse-to-fine processes. Unfortunately,
admissible heuristics that also provide good best-first search
behavior can be difficult or impossible to find in practice. To
resolve this deficiency, we provide theoretical results demonstrating
that inadmissible heuristics can be used to increase detection speed
while only slightly increasing the likelihood of suffering mistakes.
The theoretical results are bolstered by strong experimental evidence
obtained by applying inadmissible heuristic coarse-to-fine detection
to our object recognition system during both training and testing. We
increase testing speed by a factor of 2-3 for some classes while
maintaining comparable average precision scores on the challenging
PASCAL 2007 dataset. Ultimately we expect to see even more significant
speed gains when we explore more complex grammar models in future
work.

Advisor: Prof. Pedro Felzenszwalb

Login to the Computer Science Department website for details:
 https://www.cs.uchicago.edu/phd/ms_announcements#rbg

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=