Unsupervised Anomaly Detection

169 papers with code • 15 benchmarks • 23 datasets

The objective of Unsupervised Anomaly Detection is to detect previously unseen rare objects or events without any prior knowledge about these. The only information available is that the percentage of anomalies in the dataset is small, usually less than 1%. Since anomalies are rare and unknown to the user at training time, anomaly detection in most cases boils down to the problem of modelling the normal data distribution and defining a measurement in this space in order to classify samples as anomalous or normal. In high-dimensional data such as images, distances in the original space quickly lose descriptive power (curse of dimensionality) and a mapping to some more suitable space is required.

Source: Unsupervised Learning of Anomaly Detection from Contaminated Image Data using Simultaneous Encoder Training

Libraries

Use these libraries to find Unsupervised Anomaly Detection models and implementations

Latest papers with no code

Dual-Student Knowledge Distillation Networks for Unsupervised Anomaly Detection

no code yet • 1 Feb 2024

In terms of classification, we obtain pixel-wise anomaly segmentation maps by measuring the discrepancy between the output feature maps of the teacher and student networks, from which an anomaly score is computed for sample-wise determination.

UP-CrackNet: Unsupervised Pixel-Wise Road Crack Detection via Adversarial Image Restoration

no code yet • 28 Jan 2024

Subsequently, a generative adversarial network is trained to restore the corrupted regions by leveraging the semantic context learned from surrounding uncorrupted regions.

MAEDiff: Masked Autoencoder-enhanced Diffusion Models for Unsupervised Anomaly Detection in Brain Images

no code yet • 19 Jan 2024

To address these two issues, we propose a novel Masked Autoencoder-enhanced Diffusion Model (MAEDiff) for unsupervised anomaly detection in brain images.

Generating and Reweighting Dense Contrastive Patterns for Unsupervised Anomaly Detection

no code yet • 26 Dec 2023

Recent unsupervised anomaly detection methods often rely on feature extractors pretrained with auxiliary datasets or on well-crafted anomaly-simulated samples.

Deep Anomaly Detection in Text

no code yet • 14 Dec 2023

Deep anomaly detection methods have become increasingly popular in recent years, with methods like Stacked Autoencoders, Variational Autoencoders, and Generative Adversarial Networks greatly improving the state-of-the-art.

Adversarial Denoising Diffusion Model for Unsupervised Anomaly Detection

no code yet • 7 Dec 2023

With the addition of explicit adversarial learning on data samples, ADDM can learn the semantic characteristics of the data more robustly during training, which achieves a similar data sampling performance with much fewer sampling steps than DDPM.

How Low Can You Go? Surfacing Prototypical In-Distribution Samples for Unsupervised Anomaly Detection

no code yet • 6 Dec 2023

Additionally, we show that the prototypical in-distribution samples identified by our proposed methods translate well to different models and other datasets and that using their characteristics as guidance allows for successful manual selection of small subsets of high-performing samples.

Bagged Regularized $k$-Distances for Anomaly Detection

no code yet • 2 Dec 2023

We consider the paradigm of unsupervised anomaly detection, which involves the identification of anomalies within a dataset in the absence of labeled examples.

DISYRE: Diffusion-Inspired SYnthetic REstoration for Unsupervised Anomaly Detection

no code yet • 26 Nov 2023

Such a score function is potentially relevant for UAD, since $\nabla_x \log p(x)$ is itself a pixel-wise anomaly score.

Leveraging healthy population variability in deep learning unsupervised anomaly detection in brain FDG PET

no code yet • 20 Nov 2023

Unsupervised anomaly detection is a popular approach for the analysis of neuroimaging data as it allows to identify a wide variety of anomalies from unlabelled data.