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Green Image
Issue No. 09 - September (2011 vol. 33)
ISSN: 0162-8828
pp: 1758-1775
S. Sclaroff , Dept. of Comput. Sci., Boston Univ., Boston, MA, USA
V. Ablavsky , Dept. of Comput. Sci., Boston Univ., Boston, MA, USA
ABSTRACT
We propose a representation for scenes containing relocatable objects that can cause partial occlusions of people in a camera's field of view. In many practical applications, relocatable objects tend to appear often; therefore, models for them can be learned offline and stored in a database. We formulate an occluder-centric representation, called a graphical model layer, where a person's motion in the ground plane is defined as a first-order Markov process on activity zones, while image evidence is aggregated in 2D observation regions that are depth-ordered with respect to the occlusion mask of the relocatable object. We represent real-world scenes as a composition of depth-ordered, interacting graphical model layers, and account for image evidence in a way that handles mutual overlap of the observation regions and their occlusions by the relocatable objects. These layers interact: Proximate ground-plane zones of different model instances are linked to allow a person to move between the layers, and image evidence is shared between the observation regions of these models. We demonstrate our formulation in tracking pedestrians in the vicinity of parked vehicles. Our results compare favorably with a sprite-learning algorithm, with a pedestrian tracker based on deformable contours, and with pedestrian detectors.
INDEX TERMS
object tracking, image representation, Markov processes, depth-ordered graphical model layer, layered graphical model, partially occluded object tracking, relocatable object, occluder-centric representation, first-order Markov process, image evidence, proximate ground-plane zone, pedestrian tracking, sprite-learning algorithm, Computational modeling, Cameras, Graphical models, Target tracking, Three dimensional displays, Pattern analysis, Image representation, graphical models., Computer vision, image representation, tracking
CITATION
S. Sclaroff, V. Ablavsky, "Layered Graphical Models for Tracking Partially Occluded Objects", IEEE Transactions on Pattern Analysis & Machine Intelligence, vol. 33, no. , pp. 1758-1775, September 2011, doi:10.1109/TPAMI.2011.43
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