Rethinking Unsupervised Outlier Detection via Multiple Thresholding

Fuente: arXiv
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Main Authors: Liu, Zhonghang, Lu, Panzhong, Xie, Guoyang, Lu, Zhichao, Lin, Wen-Yan
Format: Preprint
Published: 2024
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author Liu, Zhonghang
Lu, Panzhong
Xie, Guoyang
Lu, Zhichao
Lin, Wen-Yan
author_facet Liu, Zhonghang
Lu, Panzhong
Xie, Guoyang
Lu, Zhichao
Lin, Wen-Yan
contents In the realm of unsupervised image outlier detection, assigning outlier scores holds greater significance than its subsequent task: thresholding for predicting labels. This is because determining the optimal threshold on non-separable outlier score functions is an ill-posed problem. However, the lack of predicted labels not only hiders some real applications of current outlier detectors but also causes these methods not to be enhanced by leveraging the dataset's self-supervision. To advance existing scoring methods, we propose a multiple thresholding (Multi-T) module. It generates two thresholds that isolate inliers and outliers from the unlabelled target dataset, whereas outliers are employed to obtain better feature representation while inliers provide an uncontaminated manifold. Extensive experiments verify that Multi-T can significantly improve proposed outlier scoring methods. Moreover, Multi-T contributes to a naive distance-based method being state-of-the-art.
format Preprint
id arxiv_https___arxiv_org_abs_2407_05382
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Rethinking Unsupervised Outlier Detection via Multiple Thresholding
Liu, Zhonghang
Lu, Panzhong
Xie, Guoyang
Lu, Zhichao
Lin, Wen-Yan
Computer Vision and Pattern Recognition
In the realm of unsupervised image outlier detection, assigning outlier scores holds greater significance than its subsequent task: thresholding for predicting labels. This is because determining the optimal threshold on non-separable outlier score functions is an ill-posed problem. However, the lack of predicted labels not only hiders some real applications of current outlier detectors but also causes these methods not to be enhanced by leveraging the dataset's self-supervision. To advance existing scoring methods, we propose a multiple thresholding (Multi-T) module. It generates two thresholds that isolate inliers and outliers from the unlabelled target dataset, whereas outliers are employed to obtain better feature representation while inliers provide an uncontaminated manifold. Extensive experiments verify that Multi-T can significantly improve proposed outlier scoring methods. Moreover, Multi-T contributes to a naive distance-based method being state-of-the-art.
title Rethinking Unsupervised Outlier Detection via Multiple Thresholding
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2407.05382