Social Scene Understanding: End-to-End Multi-Person Action Localization   and Collective Activity Recognition
  We present a unified framework for understanding human social behaviors in raw image sequences. Our model jointly detects multiple individuals, infers their social actions, and estimates the collective actions with a single feed-forward pass through a neural network. We propose a single architecture that does not rely on external detection algorithms but rather is trained end-to-end to generate dense proposal maps that are refined via a novel inference scheme. The temporal consistency is handled via a person-level matching Recurrent Neural Network. The complete model takes as input a sequence of frames and outputs detections along with the estimates of individual actions and collective activities. We demonstrate state-of-the-art performance of our algorithm on multiple publicly available benchmarks. 
Timur Bagautdinov, Alexandre Alahi, Fran\c{c}ois Fleuret, Pascal Fua,   Silvio Savarese
cs.CV