Papers › 3C-Net: Category Count and Center Loss for Weakly-Supervised Action Localization
3C-Net: Category Count and Center Loss for Weakly-Supervised Action Localization
Sanath Narayan, Hisham Cholakkal, Fahad Shahbaz Khan, Ling Shao
Temporal action localization is a challenging computer vision problem with numerous real-world applications. Most existing methods require laborious frame-level supervision to train action localization models. In this work, we propose a framework, called 3C-Net, which only requires video-level supervision (weak supervision) in the form of action category labels and the corresponding count. We introduce a novel formulation to learn discriminative action features with enhanced localization capabilities. Our joint formulation has three terms: a classification term to ensure the separability of learned action features, an adapted multi-label center loss term to enhance the action feature discriminability and a counting loss term to delineate adjacent action sequences, leading to improved localization. Comprehensive experiments are performed on two challenging benchmarks: THUMOS14 and ActivityNet 1.2. Our approach sets a new state-of-the-art for weakly-supervised temporal action localization on both datasets. On the THUMOS14 dataset, the proposed method achieves an absolute gain of 4.6% in terms of mean average precision (mAP), compared to the state-of-the-art. Source code is available at https://github.com/naraysa/3c-net.
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Tasks
Results from the paper archive 2025-07-28
| Task | Dataset | Model | Metric | Value | Rank at snapshot | Leaderboard | Report |
|---|---|---|---|---|---|---|---|
| Action Classification | ActivityNet-1.2 | 3C-Net | mAP | 92.4 | #2 of 3 | Archive leaderboard | report |
| Action Classification | THUMOS'14 | 3C-Net | mAP | 86.9 | #1 of 1 | Archive leaderboard | report |
| Action Classification | THUMOS’14 | 3C-Net | mAP | 86.9 | #1 of 3 | Archive leaderboard | report |
| Weakly Supervised Action Localization | ActivityNet-1.2 | 3C-Net | Mean mAP | 21.7 | #13 of 19 | Archive leaderboard | report |
| Weakly Supervised Action Localization | ActivityNet-1.2 | 3C-Net | mAP@0.5 | 37.2 | #13 of 19 | Archive leaderboard | report |
| Weakly Supervised Action Localization | THUMOS 2014 | 3C-Net | mAP@0.5 | 26.6 | #24 of 30 | Archive leaderboard | report |
| Weakly Supervised Action Localization | THUMOS’14 | 3C-Net | mAP@0.5 | 26.6 | #13 of 13 | Archive leaderboard | report |
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