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Unsupervised anomaly detection (UAD) is a key ingredient of automated visual inspection in modern manufacturing. The reconstruction-based methods appeal because they have basic architectural design and they process data quickly but they…

Computer Vision and Pattern Recognition · Computer Science 2026-02-03 Dmytro Filatov , Valentyn Fedorov , Vira Filatova , Andrii Zelenchuk

It is hard to collect enough flaw images for training deep learning network in industrial production. Therefore, existing industrial anomaly detection methods prefer to use CNN-based unsupervised detection and localization network to…

Computer Vision and Pattern Recognition · Computer Science 2024-08-16 Jianfeng Huang , Chenyang Li , Yimin Lin , Shiguo Lian

Recent advances in unsupervised anomaly detection (UAD) have shifted from single-class to multi-class scenarios. In such complex contexts, the increasing pattern diversity has brought two challenges to reconstruction-based approaches: (1)…

Computer Vision and Pattern Recognition · Computer Science 2025-04-22 Jingyu Xing , Chenwei Tang , Tao Wang , Rong Xiao , Wei Ju , Ji-Zhe Zhou , Liangli Zhen , Jiancheng Lv

Semi-supervised video anomaly detection (VAD) methods formulate the task of anomaly detection as detection of deviations from the learned normal patterns. Previous works in the field (reconstruction or prediction-based methods) suffer from…

Computer Vision and Pattern Recognition · Computer Science 2022-05-05 Mohammad Baradaran , Robert Bergevin

Accuracy anomaly detection in user-level network traffic is crucial for network security. Compared with existing models that passively detect specific anomaly classes with large labeled training samples, user-level network traffic contains…

Cryptography and Security · Computer Science 2025-01-16 Tongtong Feng , Qi Qi , Lingqi Guo , Jingyu Wang

Anomaly detection aims to recognize samples with anomalous and unusual patterns with respect to a set of normal data. This is significant for numerous domain applications, such as industrial inspection, medical imaging, and security…

Machine Learning · Computer Science 2020-03-30 Shuo Wang , Tianle Chen , Shangyu Chen , Carsten Rudolph , Surya Nepal , Marthie Grobler

Traditional reconstruction-based methods have struggled to achieve competitive performance in anomaly detection. In this paper, we introduce Denoising Diffusion Anomaly Detection (DDAD), a novel denoising process for image reconstruction…

Computer Vision and Pattern Recognition · Computer Science 2025-04-29 Arian Mousakhan , Thomas Brox , Jawad Tayyub

Deep neural networks are known to be vulnerable to unseen data: they may wrongly assign high confidence stcores to out-distribuion samples. Recent works try to solve the problem using representation learning methods and specific metrics. In…

Computer Vision and Pattern Recognition · Computer Science 2022-06-07 Haowei He , Jiaye Teng , Yang Yuan

Anomaly detection on attributed networks aims at finding nodes whose patterns deviate significantly from the majority of reference nodes, which is pervasive in many applications such as network intrusion detection and social spammer…

Machine Learning · Computer Science 2020-02-13 Haoyi Fan , Fengbin Zhang , Zuoyong Li

In the realm of diverse high-dimensional data, images play a significant role across various processes of manufacturing systems where efficient image anomaly detection has emerged as a core technology of utmost importance. However, when…

Computer Vision and Pattern Recognition · Computer Science 2025-12-24 Ji Song , Xing Wang , Jianguo Wu , Xiaowei Yue

This work studies a challenging and practical issue known as multi-class unsupervised anomaly detection (MUAD). This problem requires only normal images for training while simultaneously testing both normal and anomaly images across…

Computer Vision and Pattern Recognition · Computer Science 2024-08-13 Jiangning Zhang , Xuhai Chen , Yabiao Wang , Chengjie Wang , Yong Liu , Xiangtai Li , Ming-Hsuan Yang , Dacheng Tao

Unsupervised graph anomaly detection (GAD) has received increasing attention in recent years, which aims to identify data anomalous patterns utilizing only unlabeled node information from graph-structured data. However, prevailing…

Machine Learning · Computer Science 2025-11-14 Jiazhen Chen , Xiuqin Liang , Sichao Fu , Zheng Ma , Weihua Ou

Unsupervised anomaly detection (UAD) seeks to localize the anomaly mask of an input image with respect to normal samples. Either by reconstructing normal counterparts (reconstruction-based) or by learning an image feature embedding space…

Image and Video Processing · Electrical Eng. & Systems 2025-10-06 Zhe Zhang , Mingxiu Cai , Hanxiao Wang , Gaochang Wu , Tianyou Chai , Xiatian Zhu

Existing anomaly detection (AD) methods often treat the modality and class as independent factors. Although this paradigm has enriched the development of AD research branches and produced many specialized models, it has also led to…

Computer Vision and Pattern Recognition · Computer Science 2026-03-17 Yuan Zhao , Youwei Pang , Lihe Zhang , Hanqi Liu , Jiaming Zuo , Huchuan Lu , Xiaoqi Zhao

Conventional unsupervised anomaly detection (UAD) methods build separate models for each object category. Recent studies have proposed to train a unified model for multiple classes, namely model-unified UAD. However, such methods still…

Computer Vision and Pattern Recognition · Computer Science 2024-04-17 Jia Guo , Haonan Han , Shuai Lu , Weihang Zhang , Huiqi Li

Current state-of-the-art multi-class unsupervised anomaly detection (MUAD) methods rely on training encoder-decoder models to reconstruct anomaly-free features. We first show these approaches have an inherent fidelity-stability dilemma in…

Computer Vision and Pattern Recognition · Computer Science 2026-02-03 Xingwu Zhang , Guanxuan Li , Paul Henderson , Gerardo Aragon-Camarasa , Zijun Long

Unsupervised Continuous Anomaly Detection (UCAD) is gaining attention for effectively addressing the catastrophic forgetting and heavy computational burden issues in traditional Unsupervised Anomaly Detection (UAD). However, existing UCAD…

Computer Vision and Pattern Recognition · Computer Science 2026-03-24 Mingle Zhou , Jiahui Liu , Jin Wan , Gang Li , Min Li

Anomaly detection (AD) aims to identify defective images and localize their defects (if any). Ideally, AD models should be able to detect defects over many image classes; without relying on hard-coded class names that can be uninformative…

Computer Vision and Pattern Recognition · Computer Science 2024-04-01 Chih-Hui Ho , Kuan-Chuan Peng , Nuno Vasconcelos

Unsupervised Anomaly Detection (UAD) is a key data mining problem owing to its wide real-world applications. Due to the complete absence of supervision signals, UAD methods rely on implicit assumptions about anomalous patterns (e.g.,…

Machine Learning · Computer Science 2023-12-27 Hangting Ye , Zhining Liu , Xinyi Shen , Wei Cao , Shun Zheng , Xiaofan Gui , Huishuai Zhang , Yi Chang , Jiang Bian

Unsupervised Anomaly Detection (UAD) with incremental training is crucial in industrial manufacturing, as unpredictable defects make obtaining sufficient labeled data infeasible. However, continual learning methods primarily rely on…

Computer Vision and Pattern Recognition · Computer Science 2024-01-03 Jiaqi Liu , Kai Wu , Qiang Nie , Ying Chen , Bin-Bin Gao , Yong Liu , Jinbao Wang , Chengjie Wang , Feng Zheng