Seminars at the Faculty of Informatics

Visual Computing Techniques in Inter- and Intra-Class 3D Object Retrieval

The Faculty of Informatics is pleased to announce a seminar given by Theoharis Theoharis

DATE: Thursday, October 1st, 2009
PLACE: USI Università della Svizzera italiana, room SI-006, Informatics building (Via G. Buffi 13)
TIME: 15.30

ABSTRACT:
As the size of information repositories increases, the importance of retrieval operations rises. This partly explains the success of internet search engines.
The type of information object gradually changes and becomes more complex. Starting from huge text collections, we have moved to large image collections. More recently, aided by the proliferation of three-dimensional scanners and modeling software, collections of three-dimensional models (referred to as 'objects' here) are also expanding in size. Some collections contain objects of various classes (e.g. furniture) while some are more specialized and contain objects of a single class (e.g. human faces for biometric applications).

In this talk we present recent work on accurate and efficient inter-class object retrieval, based on both two-dimensional (depth buffers) and three-dimensional (spherical harmonics) characteristics of objects. Experiments show that when such inter-class retrieval methods are applied to intra-class problems, the results are quite poor. In intra-class retrieval it is necessary to exploit the specific characteristics of the class in order to distinguish the small differences that exist between objects belonging to the same class. An intra-class retrieval method, based on a parameterized and annotated class model, is also presented. Its very encouraging results in face and ear recognition are given. Our intra-class method took part in the Face Recgnition Grand Challenge and achieved the top accuracy score in the shape-only class of the Face Recognition Vendor Test.


BIO:
Theoharis Theoharis received the BSc. degree in Computer Science from the University of London in 1984, the MSc. Degree in Computation from the University of Oxford in 1985 and the Ph.D. degree in Computer Graphics and Parallel processing from the University of Oxford in 1988. He served as a Research Fellow at the University of Cambridge between 1987 and 1990 and as a Consultant with Andersen Consulting between 1992 and 1993.
He is with the Department of Informatics, University of Athens and has an Adjunct appointment at the University of Houston. His main research interests lie in 3D Shape Similarity (with applications in Biometrics, Object Retrieval, Archaeological Reconstruction) and Computer Graphics.

HOST: Prof. Evanthia Papadopoulou

URL 1: http://www.inf.usi.ch