1/27/04: Rich Zemel, University of Toronto

Learning Parts

Many collections of data exhibit a common underlying structure: they consist of a number of parts or factors, each with a range of possible states. For example, in a collection of facial images, every image contains eyes, a nose, and a mouth, each of which has a number of possible appearances. I will present a new method for the unsupervised learning of parts-based representations of high-dimensional data. Our technique automates the segmentation of data dimensions into parts, while simultanously learning a model of part appearances. Inference and learning are carried out efficiently via variational algorithms. I will describe applications of this approach to problems in image decomposition, text modeling, and collaborative filtering.
Time permitting, I'll briefly describe other current work on learning multiscale random fields for image labeling.