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Main Authors: Abbas, Momin, Falahati, Ali, Goli, Hossein, Amiri, Mohammad Mohammadi
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2510.06505
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author Abbas, Momin
Falahati, Ali
Goli, Hossein
Amiri, Mohammad Mohammadi
author_facet Abbas, Momin
Falahati, Ali
Goli, Hossein
Amiri, Mohammad Mohammadi
contents Out-of-distribution (OOD) detection plays a crucial role in ensuring the robustness and reliability of machine learning systems deployed in real-world applications. Recent approaches have explored the use of unlabeled data, showing potential for enhancing OOD detection capabilities. However, effectively utilizing unlabeled in-the-wild data remains challenging due to the mixed nature of both in-distribution (InD) and OOD samples. The lack of a distinct set of OOD samples complicates the task of training an optimal OOD classifier. In this work, we introduce Medix, a novel framework designed to identify potential outliers from unlabeled data using the median operation. We use the median because it provides a stable estimate of the central tendency, as an OOD detection mechanism, due to its robustness against noise and outliers. Using these identified outliers, along with labeled InD data, we train a robust OOD classifier. From a theoretical perspective, we derive error bounds that demonstrate Medix achieves a low error rate. Empirical results further substantiate our claims, as Medix outperforms existing methods across the board in open-world settings, confirming the validity of our theoretical insights.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06505
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Median Perspective on Unlabeled Data for Out-of-Distribution Detection
Abbas, Momin
Falahati, Ali
Goli, Hossein
Amiri, Mohammad Mohammadi
Machine Learning
Artificial Intelligence
Optimization and Control
Out-of-distribution (OOD) detection plays a crucial role in ensuring the robustness and reliability of machine learning systems deployed in real-world applications. Recent approaches have explored the use of unlabeled data, showing potential for enhancing OOD detection capabilities. However, effectively utilizing unlabeled in-the-wild data remains challenging due to the mixed nature of both in-distribution (InD) and OOD samples. The lack of a distinct set of OOD samples complicates the task of training an optimal OOD classifier. In this work, we introduce Medix, a novel framework designed to identify potential outliers from unlabeled data using the median operation. We use the median because it provides a stable estimate of the central tendency, as an OOD detection mechanism, due to its robustness against noise and outliers. Using these identified outliers, along with labeled InD data, we train a robust OOD classifier. From a theoretical perspective, we derive error bounds that demonstrate Medix achieves a low error rate. Empirical results further substantiate our claims, as Medix outperforms existing methods across the board in open-world settings, confirming the validity of our theoretical insights.
title A Median Perspective on Unlabeled Data for Out-of-Distribution Detection
topic Machine Learning
Artificial Intelligence
Optimization and Control
url https://arxiv.org/abs/2510.06505