Issue No. 06 - June (2012 vol. 34)
F. De la Torre , Robot. Inst., Carnegie Mellon Univ., Pittsburgh, PA, USA
Over the last century, Component Analysis (CA) methods such as Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), Canonical Correlation Analysis (CCA), Locality Preserving Projections (LPP), and Spectral Clustering (SC) have been extensively used as a feature extraction step for modeling, classification, visualization, and clustering. CA techniques are appealing because many can be formulated as eigen-problems, offering great potential for learning linear and nonlinear representations of data in closed-form. However, the eigen-formulation often conceals important analytic and computational drawbacks of CA techniques, such as solving generalized eigen-problems with rank deficient matrices (e.g., small sample size problem), lacking intuitive interpretation of normalization factors, and understanding commonalities and differences between CA methods. This paper proposes a unified least-squares framework to formulate many CA methods. We show how PCA, LDA, CCA, LPP, SC, and its kernel and regularized extensions correspond to a particular instance of least-squares weighted kernel reduced rank regression (LS--WKRRR). The LS-WKRRR formulation of CA methods has several benefits: 1) provides a clean connection between many CA techniques and an intuitive framework to understand normalization factors; 2) yields efficient numerical schemes to solve CA techniques; 3) overcomes the small sample size problem; 4) provides a framework to easily extend CA methods. We derive weighted generalizations of PCA, LDA, SC, and CCA, and several new CA techniques.
regression analysis, correlation methods, data visualisation, feature extraction, learning (artificial intelligence), least squares approximations, matrix algebra, pattern classification, pattern clustering, principal component analysis, small sample size problem, least-squares framework, principal component analysis, linear discriminant analysis, canonical correlation analysis, locality preserving projections, spectral clustering, feature extraction step, modeling, classification, visualization, CA techniques, eigen-problems, data nonlinear representation learning, eigen-formulation, rank deficient matrices, normalization factor intuitive interpretation lackness, least-squares weighted kernel reduced rank regression, numerical schemes, Principal component analysis, Kernel, Equations, Mathematical model, Covariance matrix, Algorithm design and analysis, Analytical models, dimensionality reduction., Principal component analysis, linear discriminant analysis, canonical correlation analysis, k-means, spectral clustering, reduced rank regression, kernel methods
F. De la Torre, "A Least-Squares Framework for Component Analysis," in IEEE Transactions on Pattern Analysis & Machine Intelligence, vol. 34, no. , pp. 1041-1055, 2012.