Using Expectation-Maximisation to Learn Dynamical Models from Visual Data

Ben North and Andrew Blake,
Department of Engineering Science,
University of Oxford,
Oxford.   OX1 3PJ
UK
north@robots.ox.ac.uk, ab@robots.ox.ac.uk

Abstract

Tracking with deformable contours in a filtering framework requires a dynamical model for prediction. For any given application, tracking is improved by having an accurate model, learnt from training data. We develop a method for learning dynamical models from training sequences, explicitly taking account of the fact that our data are measurements and not true states. By introducing an `augmented-state smoothing filter', we show how the technique of Expectation-Maximisation can be applied to this problem, and show that the resulting algorithm produces more robust and accurate tracking.

PostScript

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Ben North
north@robots.ox.ac.uk