1. Memoryless Multimodal Anomaly Detection via Student–Teacher Network and Signed Distance Learning.
- Author
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Sun, Zhongbin, Li, Xiaolong, Li, Yiran, and Ma, Yue
- Subjects
ANOMALY detection (Computer security) ,COMPUTER vision ,POINT cloud ,THREE-dimensional imaging ,DISTANCE education - Abstract
Unsupervised anomaly detection is a challenging computer vision task, in which 2D-based anomaly detection methods have been extensively studied. However, multimodal anomaly detection based on RGB images and 3D point clouds requires further investigation. The existing methods are mainly inspired by memory bank-based methods commonly used in 2D-based anomaly detection, which may cost extra memory for storing multimodal features. In the present study, a novel memoryless method MDSS is proposed for multimodal anomaly detection, which employs a lightweight student–teacher network and a signed distance function to learn from RGB images and 3D point clouds, respectively, and complements the anomaly information from the two modalities. Specifically, a student–teacher network is trained with normal RGB images and masks generated from point clouds by a dynamic loss, and the anomaly score map could be obtained from the discrepancy between the output of student and teacher. Furthermore, the signed distance function learns from normal point clouds to predict the signed distances between points and surfaces, and the obtained signed distances are used to generate an anomaly score map. Subsequently, the anomaly score maps are aligned to generate the final anomaly score map for detection. The experimental results indicate that MDSS is comparable but more stable than SOTA methods and, furthermore, performs better than other baseline methods. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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