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Globally Maximizing Locally Minimizing unsupervised discriminant projection with applications to face and palm biometrics PAMI 2007. Bo Yang 6/7/2014. Motivation. Shortage of existing manifold algorithms for Classification: Locality : has no direct connection to classification
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Globally Maximizing Locally Minimizing unsupervised discriminant projection with applications to face and palm biometricsPAMI 2007 Bo Yang 6/7/2014
Motivation • Shortage of existing manifold algorithms for Classification: Locality: has no direct connection to classification • non-locality: modeling multi-manifolds the inter-cluster scatter, may provide crucial information for discrimination • seeks to maximize the ratio of the nonlocal scatter to the local scatter.
Review • PCA • LDA
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
Determine a Criterion: Maximizing the Ratio ofNonlocal Scatter to Local Scatter
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
Algorithmic Derivations of UDP in Small Sample Size Cases (cont’d)
Algorithmic Derivations of UDP in Small Sample Size Cases (cont’d)
Algorithmic Derivations of UDP in Small Sample Size Cases (cont’d)
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
LINKS TO LPP • UDP maximizes the ratio of the nonlocal scatter (or the global scatter) to the local scatter whereas LPP minimizes the local scatter
LINKS TO LDA • LDA can be regarded as a special case of UDP if we assume that each class has the same number of training samples
UNSUPERVISED DISCRIMINANT PROJECTION (UDP) • Basic Idea of UDP • Algorithmic Derivations of UDP in Small Sample Size Cases • UDP Algorithm • EXTENSION: UDP WITH KERNEL WEIGHTING • LINKS TO OTHER LINEAR PROJECTION TECHNIQUES: LDA AND LPP • BIOMETRICS APPLICATIONS: EXPERIMENTS AND ANALYSIS
EXPERIMENTS • Yale Database • FERET Database • AR Database • PolyU Palmprint Database
FERET Database This subset includes 1,000 images of 200 individuals (each one has five images). It is composed of the images whose names are marked with two-character strings: “ba,” “bj,” “bk,” “be,” “bf.”
Comment • LPP • UDP • UDP and LPP essentially share the same basic idea: simultaneously minimizing the local quantity and maximizing the global quantity.
Comment • the numerators in (1) and (2), are two equivalent • the denominators in (1) and (2), are two similar scatters • the projections derived from UDP and LPP are identical under the assumption that the local density is uniform
Comment • we would like to conclude that UDP is an effective algorithm as a simplified, or regularized, version of LPP, but there is no reason to prefer UDP over LPP for the general classification and clustering tasks.