Group Activity Recognition by Gaussian Processes Estimation

Human action recognition has been well studied recently, but recognizing the activities of more than three persons remains a challenging task. In this paper, we propose a motion trajectory based method to classify human group activities. Gaussian Processes are introduced to represent human motion trajectories from a probabilistic perspective to handle the variability of people´s activities in group. With respect to the relationships of persons in group activities, three discriminative descriptors are designed, which are Individual, Dual and Unitized Group Activity Pattern. We adopt the Bag of Words approach to solve the problem of unbalanced number of persons in different activities. Experiments are conducted on the human group-activity video database, and the results show that our approach outperforms the state-of-the-art.