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Classification on the Grassmannians: theory and applications

dc.contributor.authorChang, Jen-Mei, author
dc.contributor.authorKirby, Michael, advisor
dc.date.accessioned2024-03-13T18:50:57Z
dc.date.available2024-03-13T18:50:57Z
dc.date.issued2008
dc.description.abstractThis dissertation consists of four parts. It introduces a novel geometric framework for the general classification problem and presents empirical results obtained from applying the proposed method on some popular classification problems. An analysis of the robustness of the method is provided using matrix perturbation theory, which in turn motivates an optimization problem to improve the robustness of the classifier. Lastly, we illustrate the use of compressed data representations based on Karcher mean.
dc.description.abstractThe success of this geometric framework builds upon the facts that the geometry and statistics of the Grassmannians are well-understood and families of patterns with a common characterization possesses discriminatory variations that are useful for classification. Under the right conditions, these families of patterns can be viewed as points on the Grassmannian where distances are available for classification. In this dissertation, we will make precise this connection, review various ways these metrics arise, and how to efficiently compute distances between points on this manifold.
dc.description.abstractUnder this framework, we achieve excellent classification results for a variety of applications in face recognition and offer new insights to the problem in general. Attempting to break the method, we consider nonlinear data sets and images of extremely low resolutions. We are pleased to learn that the Grassmann method is robust against resolution reductions.
dc.description.abstractIn order to understand how robust the Grassmann method is against perturbation, we draw support from matrix perturbation theory where we exploit the natural correspondence between linear subspaces and points on the Grassmannians. We are then led to formulate an optimization problem using these characteristics as an objective function and further connect this optimization criterion to the idea of Fisher Linear Discriminant on general image sets. Numerical solutions obtained show promising improvements on the separability criterion.
dc.description.abstractThe thesis is concluded by providing a novel algorithm that computes subject prototypical points using the Karcher mean on the Grassmannian. A lot of new ideas for geometric data analysis are generated through studies of old ideas. We hope that the suite of these frameworks and algorithms can collectively provide useful insights in studying geometric aspects of large data sets.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierETDF_Chang_2008_3321265.pdf
dc.identifier.urihttps://hdl.handle.net/10217/237637
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.rights.licensePer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.
dc.subjectclassification
dc.subjectface recognition
dc.subjectgeometric data analysis
dc.subjectGrassmannians
dc.subjectmanifolds
dc.subjectset-to-set
dc.subjectmathematics
dc.subjectcomputer science
dc.titleClassification on the Grassmannians: theory and applications
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineMathematics
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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