Towards Realtime Visual Based Tracking in Cluttered Traffic Scenes
Joseph Weber , and
In Proc. of the Intelligent Vehicles Symposium 1994, pp. 201-206,
October 24-26, 1994, Paris, France
Automatic traffic scene analysis has gained great interest in the context of Advanced
Transportation Management Systems. Major improvements in performance and
quality of results of machine vision based traffic surveillance systems
allow connections to symbolic reasoning components that attain a level of accuracy
and reliability well above previous proposed systems.
We apply a new approach for detecting and
tracking vehicles in road traffic scenes with high accuracy and reliability.
High accuracy and reliability are obtained by using an
explicit occlusion reasoning step. For that purpose we represent moving vehicles by
closed contours and employ a
contour tracker based on intensity and motion boundaries. Motion and contour
estimation is performed by linear Kalman Filters based on an affine motion model.
Occlusion detection is performed by intersecting the depth ordered regions associated
to the objects. The intersection is then excluded in the motion and shape update.
A contour associated to a moving region is initialized using a
motion segmentation step which is based on differences between filter outputs of
an acquired image and a continuously updated background image.
Symbolic reasoning of the traffic scene based on the extracted car tracks is
performed using a belief network. Belief networks
provide a flexible and theoretically sound framework for traffic scene
analysis because of their inherent ability to model uncertainties.
We show the validity of our approach and present results of experiments with real
world traffic scenes.
Preliminary results of an implementation on special purpose hardware
using C-40 Digital Signal Processors show that near real-time performance
can be achieved without further improvements.
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