Title
Detector-Free Weakly Supervised Group Activity Recognition
Abstract
Group activity recognition is the task of understanding the activity conducted by a group of people as a whole in a multiperson video. Existing models for this task are often impractical in that they demand ground-truth bounding box labels of actors even in testing or rely on off-the-shelf object detectors. Motivated by this, we propose a novel model for group activity recognition that depends neither on bounding box labels nor on object detector. Our model based on Transformer localizes and encodes partial contexts of a group activity by leveraging the attention mechanism, and represents a video clip as a set of partial context embeddings. The embedding vectors are then aggregated to form a single group representation that reflects the entire context of an activity while capturing temporal evolution of each partial context. Our method achieves outstanding performance on two benchmarks, Volleyball and NBA datasets, surpassing not only the state of the art trained with the same level of supervision, but also some of existing models relying on stronger supervision.
Year
DOI
Venue
2022
10.1109/CVPR52688.2022.01945
IEEE Conference on Computer Vision and Pattern Recognition
Keywords
DocType
Volume
Action and event recognition, Scene analysis and understanding, Video analysis and understanding
Conference
2022
Issue
Citations 
PageRank 
1
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Dongkeun Kim100.34
Jinsung Lee200.34
Minsu Cho367735.74
Suha Kwak439720.33