LAW Marc

PhD graduated
Team : MLIA
Departure date : 05/27/2016

Supervision : Matthieu CORD

Co-supervision : GANÇARSKI Stéphane

Distance metric learning for image and webpage comparison

This thesis focuses on distance metric learning for image and webpage comparison. Distance metrics are used in many machine learning and computer vision contexts such as k-nearest neighbors classification, clustering, support vector machine, information/image retrieval, visualization etc. In this thesis, we focus on Mahalanobis-like distance metric learning where the learned model is parametered by a symmetric positive semidefinite matrix. It learns a linear tranformation such that the Euclidean distance in the induced projected space satisfies learning constraints.
First, we propose a method based on comparison between relative distances that takes rich relations between data into account, and exploits similarities between quadruplets of examples. We apply this method on relative attributes and hierarchical image classification.
Second, we propose a new regularization method that controls the rank of the learned matrix, limiting the number of independent parameters and overfitting. We show the interest of our method on synthetic and real-world recognition datasets.
Eventually, we propose a novel Webpage change detection framework in a context of archiving. For this purpose, we use temporal distance relations between different versions of a same Webpage. The metric learned in a totally unsupervised way detects important regions and ignores unimportant content such as menus and advertisements. We show the interest of our method on different Websites.

Defence : 01/20/2015 - 10h30

Jury members :

Patrick Pérez, Technicolor (Rennes), Rapporteur
Alain Rakotomamonjy, Université de Rouen (Rouen), Rapporteur
Francis Bach, Inria - Ecole Normale Supérieure (Paris), Examinateur
Patrick Gallinari, UPMC (Paris), Examinateur
Jean Ponce, Ecole Normale Supérieure (Paris), Examinateur
Frédéric Précioso, Polytech'Nice-Sophia, Examinateur
Matthieu Cord, UPMC (Paris), Directeur de thèse
Stéphane Gançarski, UPMC (Paris), Co-directeur de thèse
Nicolas Thome, UPMC (Paris), Invité

2012-2016 Publications