Deep Fully Connected Model for Collective Activity Recognition

Group activity recognition is a challenging task because there is an exponentially large number of semantic and geometrical relationships among individuals. This makes it difficult to model these interactions and merge them as a whole for group activity classification. In this paper, we propose a deep fully-connected model for group recognition, first we use the spatial-temporal model based on convolution neural network (CNN) and long short-term memory networks (LSTM) network to capture the dynamic features of each person. Then, we use the fully-connected conditional random field (FCCRF) to learn the interactions between people. Finally, with FCCRF potential functions we re-fine the activity recognition predicted by the spatial-temporal model. The experimental results on collective activity data-set and collective activity extended data-set show that our model improves recognition accuracy over baseline methods and gets competitive results in comparison to the state-of-the-art models.