Multi-Normal Prototypes Learning for Weakly Supervised Anomaly Detection
This addresses the challenge of weakly supervised anomaly detection for domains with complex normal data distributions, though it is incremental in improving existing approaches.
The paper tackles the problem of anomaly detection when normal data consists of multiple subgroups and unlabeled samples may include anomalies, proposing a framework that learns multi-normal prototypes and estimates sample normality likelihood. The method demonstrates superior performance compared to state-of-the-art methods in experiments on various datasets.
Anomaly detection is a crucial task in various domains. Most of the existing methods assume the normal sample data clusters around a single central prototype while the real data may consist of multiple categories or subgroups. In addition, existing methods always assume all unlabeled samples are normal while some of them are inevitably being anomalies. To address these issues, we propose a novel anomaly detection framework that can efficiently work with limited labeled anomalies. Specifically, we assume the normal sample data may consist of multiple subgroups, and propose to learn multi-normal prototypes to represent them with deep embedding clustering and contrastive learning. Additionally, we propose a method to estimate the likelihood of each unlabeled sample being normal during model training, which can help to learn more efficient data encoder and normal prototypes for anomaly detection. Extensive experiments on various datasets demonstrate the superior performance of our method compared to state-of-the-art methods.