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A Hybrid Video Anomaly Detection Framework via Memory-Augmented Flow Reconstruction and Flow-Guided Frame Prediction

16 Aug 2021ICCV 2021 10arXiv:2108.06852archive 2025-07-28

Zhian Liu, Yongwei Nie, Chengjiang Long, Qing Zhang, Guiqing Li

In this paper, we propose HF²-VAD, a Hybrid framework that integrates Flow reconstruction and Frame prediction seamlessly to handle Video Anomaly Detection. Firstly, we design the network of ML-MemAE-SC (Multi-Level Memory modules in an Autoencoder with Skip Connections) to memorize normal patterns for optical flow reconstruction so that abnormal events can be sensitively identified with larger flow reconstruction errors. More importantly, conditioned on the reconstructed flows, we then employ a Conditional Variational Autoencoder (CVAE), which captures the high correlation between video frame and optical flow, to predict the next frame given several previous frames. By CVAE, the quality of flow reconstruction essentially influences that of frame prediction. Therefore, poorly reconstructed optical flows of abnormal events further deteriorate the quality of the final predicted future frame, making the anomalies more detectable. Experimental results demonstrate the effectiveness of the proposed method. Code is available at \href{https://github.com/LiUzHiAn/hf2vad}{https://github.com/LiUzHiAn/hf2vad}.

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aggregate_kl_loss LiUzHiAn/hf2vad/losses/loss.py official repository unverified MIT (permissive) · 38d8b97b928f93a2 · report
delCoverBboxes LiUzHiAn/hf2vad/pre_process/extract_bboxes.py official repository unverified MIT (permissive) · a653b45bfcbe2b95 · report
getFgBboxes LiUzHiAn/hf2vad/pre_process/extract_bboxes.py official repository unverified MIT (permissive) · b3698ab6fca12450 · report
get_inputs LiUzHiAn/hf2vad/datasets/dataset.py official repository unverified MIT (permissive) · 8d81b09e9f81cc4b · report
hard_shrink_relu LiUzHiAn/hf2vad/models/ml_memAE_sc.py official repository unverified MIT (permissive) · 22ed0e6535db75a1 · report
img_batch_tensor2numpy LiUzHiAn/hf2vad/datasets/dataset.py official repository unverified MIT (permissive) · c33c92a32cd64fd4 · report
img_tensor2numpy LiUzHiAn/hf2vad/datasets/dataset.py official repository unverified MIT (permissive) · b6912e844379ed70 · report
latent_kl LiUzHiAn/hf2vad/losses/loss.py official repository unverified MIT (permissive) · 46f0670b0df56146 · report
loader LiUzHiAn/hf2vad/utils/model_utils.py official repository unverified MIT (permissive) · bc27df2e0a58fe31 · report
mem_loader LiUzHiAn/hf2vad/utils/model_utils.py official repository unverified MIT (permissive) · 79bed0a0515af148 · report
only_model_loader LiUzHiAn/hf2vad/utils/model_utils.py official repository unverified MIT (permissive) · 75bb71577a8469ba · report

Tasks

Anomaly DetectionOptical Flow EstimationVideo Anomaly Detection

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Video Anomaly Detection CUHK Avenue HF2-VAD AUC 91.1% #5 of 7 Archive leaderboard report
Video Anomaly Detection Ped2 HF2-VAD AUC 0.993 #1 of 1 Archive leaderboard report
Video Anomaly Detection ShanghaiTech Campus HF2-VAD AUC 76.2 #4 of 4 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

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