Storyboard relational model for group activity recognition

This work concerns how to effectively recognize the group activity performed by multiple persons collectively. As known, Storyboards (i.e., medium shot, close shot) jointly describe the whole storyline of a movie in a compact way. Likewise, the actors in small subgroups (similar to Storyboards) of a group activity scene contribute a lot to such group activity and develop more compact relationships among them within subgroups. Inspired by this, we propose a Storyboard Relational Model (SRM) to address the problem of Group Activity Recognition by splitting and reintegrating the group activity based on the small yet compact Storyboards. SRM mainly consists of a Pose-Guided Pruning (PGP) module and a Dual Graph Convolutional Networks (Dual-GCN) module. Specifically, PGP is designed to refine a series of Storyboards from the group activity scene by leveraging the attention ranges of individuals. Dual-GCN models the compact relationships among actors in a Storyboard. Experimental results on two widely-used datasets illustrate the effectiveness of the proposed SRM compared with the state-of-the-art methods.