Physically based and probabilistic models for computer vision

Models of 2-D and 3-D objects are an essential aspect of computer vision. Physically-based models represent object shape and motion through dynamic differential equations and provide mechanisms for fitting and tracking visual data using simulated forces. Probabilistic models allow the incorporation of prior knowledge about shape and the optimal extraction of information from noisy sensory measurements. In this paper we propose a framework for combining the essential elements of both the physically-based and probabilistic approaches. The combined model is a Kalman filter which incorporates physically-based models as part of the prior and system dynamics and is able to integrate noisy data over time. In particular, through a suitable choice of parameters models can be built which either return to a rest shape when external data are removed or remember shape cues seen previously. The proposed framework shows promise in a number of computer vision applications.