Simultaneous Object Detection, Tracking, and Event Recognition
  The common internal structure and algorithmic organization of object detection, detection-based tracking, and event recognition facilitates a general approach to integrating these three components. This supports multidirectional information flow between these components allowing object detection to influence tracking and event recognition and event recognition to influence tracking and object detection. The performance of the combination can exceed the performance of the components in isolation. This can be done with linear asymptotic complexity. 
Andrei Barbu, Aaron Michaux, Siddharth Narayanaswamy, and Jeffrey Mark   Siskind
cs.CV cs.AI