Influence of an explicitly modelled 3D scene on the tracking of partially occluded vehicles

Model-based tracking of vehicles in real world image sequences of traffic may fail due to different reasons. A careful analysis of failed tracking experiments brought to light that one of these phenomena consists in an incorrect match of parts of the vehicle model to image features belonging to other scene components. This effect appears in particular if the vehicle is occluded by either stationary scene components or by another moving vehicle. Although we got some encouraging results when we modeled the occluding scene components explicitly, we still encountered cases in which we did not succeed in tracking partially occluded vehicles properly. In this contribution we show some successful tracking results obtained from real world image sequences and discuss the cases of failures. Additionally, we present a framework for the conceptual characterization of occurring occlusions which became amenable to experimental analysis in the course of our investigations.