Papers › CDC: Convolutional-De-Convolutional Networks for Precise Temporal Action Localization...

CDC: Convolutional-De-Convolutional Networks for Precise Temporal Action Localization in Untrimmed Videos

4 Mar 2017CVPR 2017 7arXiv:1703.01515archive 2025-07-28

Zheng Shou, Jonathan Chan, Alireza Zareian, Kazuyuki Miyazawa, Shih-Fu Chang

Temporal action localization is an important yet challenging problem. Given a long, untrimmed video consisting of multiple action instances and complex background contents, we need not only to recognize their action categories, but also to localize the start time and end time of each instance. Many state-of-the-art systems use segment-level classifiers to select and rank proposal segments of pre-determined boundaries. However, a desirable model should move beyond segment-level and make dense predictions at a fine granularity in time to determine precise temporal boundaries. To this end, we design a novel Convolutional-De-Convolutional (CDC) network that places CDC filters on top of 3D ConvNets, which have been shown to be effective for abstracting action semantics but reduce the temporal length of the input data. The proposed CDC filter performs the required temporal upsampling and spatial downsampling operations simultaneously to predict actions at the frame-level granularity. It is unique in jointly modeling action semantics in space-time and fine-grained temporal dynamics. We train the CDC network in an end-to-end manner efficiently. Our model not only achieves superior performance in detecting actions in every frame, but also significantly boosts the precision of localizing temporal boundaries. Finally, the CDC network demonstrates a very high efficiency with the ability to process 500 frames per second on a single GPU server. We will update the camera-ready version and publish the source codes online soon.

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bitbucket.org/columbiadvmm/cdc officialmentioned in paper report

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Action LocalizationTemporal Action Localization

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Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Temporal Action Localization THUMOS’14 CDC mAP IOU@0.3 40.1 #40 of 42 Archive leaderboard report
Temporal Action Localization THUMOS’14 CDC mAP IOU@0.4 29.4 #40 of 42 Archive leaderboard report
Temporal Action Localization THUMOS’14 CDC mAP IOU@0.5 23.3 #40 of 42 Archive leaderboard report
Temporal Action Localization THUMOS’14 CDC mAP IOU@0.6 13.1 #40 of 42 Archive leaderboard report
Temporal Action Localization THUMOS’14 CDC mAP IOU@0.7 7.9 #40 of 42 Archive leaderboard report

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