Modeling complex temporal composition of actionlets for activity prediction

  • Authors:

  • Kang Li;Jie Hu;Yun Fu

  • Affiliations:

  • Department of ECE and College of CIS, Northeastern University, Boston, MA;Department of CSE, State University of New York, Buffalo, NY;Department of ECE and College of CIS, Northeastern University, Boston, MA

  • Venue:
  • ECCV'12 Proceedings of the 12th European conference on Computer Vision - Volume Part I
  • Year:
  • 2012

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Abstract

Early prediction of ongoing activity has been more and more valuable in a large variety of time-critical applications. To build an effective representation for prediction, human activities can be characterized by a complex temporal composition of constituent simple actions. Different from early recognition on short-duration simple activities, we propose a novel framework for long-duration complex activity prediction by discovering the causal relationships between constituent actions and the predictable characteristics of activities. The major contributions of our work include: (1) we propose a novel activity decomposition method by monitoring motion velocity which encodes a temporal decomposition of long activities into a sequence of meaningful action units; (2) Probabilistic Suffix Tree (PST) is introduced to represent both large and small order Markov dependencies between action units; (3) we present a Predictive Accumulative Function (PAF) to depict the predictability of each kind of activity. The effectiveness of the proposed method is evaluated on two experimental scenarios: activities with middle-level complexity and activities with high-level complexity. Our method achieves promising results and can predict global activity classes and local action units.