11. An article of manufacture comprising: a non-transitory machine readable storage medium; and executable program instructions embodied in the machine readable storage medium that when executed by a processor of a programmable computing device configures the programmable computing device to control an image processing system receiving a plurality of images, to perform functions for object tracking within image frames, including instructions to: perform a first level of association between detection responses in image frames, including forming one or more tracklets between pairs of detection responses having suitable link probabilities, wherein the detection responses include a vector having position, size, and frame index components; receive the one or more tracklets formed as a result of the first level of association, and perform a second level of association, including producing a tracklet association between tracklets; perform a third level of association, including estimating a scene structure model from the second level of association; and provide as an output a trajectory set of the tracklets.
11. An article of manufacture comprising: a non-transitory machine readable storage medium; and executable program instructions embodied in the machine readable storage medium that when executed by a processor of a programmable computing device configures the programmable computing device to control an image processing system receiving a plurality of images, to perform functions for object tracking within image frames, including instructions to: perform a first level of association between detection responses in image frames, including forming one or more tracklets between pairs of detection responses having suitable link probabilities, wherein the detection responses include a vector having position, size, and frame index components; receive the one or more tracklets formed as a result of the first level of association, and perform a second level of association, including producing a tracklet association between tracklets; perform a third level of association, including estimating a scene structure model from the second level of association; and provide as an output a trajectory set of the tracklets. 12. The article of manufacture of claim 11 , wherein the executable program instructions further comprise instruction to: for the second level of association, transform a maximum a posteriori (MAP) problem into an assignment problem in a way that distinguishes between true trajectories and false alarm trajectories using a Hungarian algorithm.