Inter-Clip Feature Similarity Based Weakly Supervised Video Anomaly Detection via Multi-Scale Temporal MLP

Abstract

The major paradigm of weakly supervised video anomaly detection (WSVAD) is treating it as a multiple instance learning (MIL) problem, with only video-level labels available for training. Due to the rarity and ambiguity of anomaly, the selection of potential abnormal training sample is the prime challenge for WSVAD. Considering the temporal relevance and length variation of anomaly events, how to integrate the temporal information is also a controversial topic in WSVAD area. To address forementioned problems, we propose a novel method named Inter-clip Feature Similarity based Video Anomaly Detection (IFS-VAD). In the proposed IFS-VAD, to make use of both the global and local temporal relation, a Multi-scale Temporal MLP (MT-MLP) is leveraged. To better capture the ambiguous abnormal instances in positive bags, we introduce a novel anomaly criterion based on the Inter-clip Feature Similarity (IFS). The proposed IFS criterion can assist in discerning anomaly, as an additional anomaly score in the prediction process of anomaly classifier. Extensive experiments show that IFS-VAD demonstrates state-of-the-art performance on ShanghaiTech with an AUC of 97.95%, UCF-Crime with an AUC of 86.57% and XD-Violence with an AP of 83.14%. Our code implementation is accessible at https://github.com/Ria5331/IFS-VAD.