[Colloquium] Talk by Ronen Basri, Weizmann Inst and TTI-C, May 4, 2009

[Katie Casey]

DEPARTMENT OF COMPUTER SCIENCE

UNIVERSITY OF CHICAGO

Date: Monday, May 4, 2009
Time: 3:45 p.m.
Place: RY 251

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Speaker:	Ronen Basri

From:		Weizmann Institute and TTI- C

Website: 	http://www.tti-c.org/basri.php

Title:       Visibility Constraints on Features of 3D Objects

Abstract:        To recognize three-dimensional objects it is  
important to model how their appearances can change due to changes in  
viewpoint. A key aspect of this involves understanding which object  
features can be simultaneously visible under different viewpoints. We  
address this problem in an image based framework, in which we use a  
limited number of images of an object taken from unknown viewpoints to  
determine which subsets of features might be simultaneously visible in  
other views. This leads to the problem of determining whether a set of  
images, each containing a set of features, is consistent with a single  
3D object. We assume that each feature is visible from a disk of  
viewpoints on the viewing sphere. In this case we show the problem is  
NP-hard in general, but can be solved efficiently when all views come  
from a circle on the viewing sphere. We also give iterative algorithms  
that can handle noisy data and converge to locally optimal solutions  
in the general case. Our techniques can also be used to recover  
viewpoint information from the set of features that are visible in  
different images. We show that these algorithms perform well both on  
synthetic data and images from the COIL dataset. Joint work with Pedro  
Felzenszwalb, Ross Grishick, David Jacobs and Caroline Klivans.

Refreshments will be served prior to the talk in RY 255.
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