Quadtree principal component analysis and its application to facial expression classification

This paper presents a method called quadtree principal components analysis for facial expression classification. The quadtree principal components analysis is an image transformation that takes its name from the quadtree partition scheme on which it is based. The quadtree principal components analysis method implements a global-local decomposition of the input face image. This solves the problems associated with the existing principal components analysis and local principal components analysis methods when applied to facial expression classification.