Revisiting Logit Distributions for Reliable Out-of-Distribution Detection

Fuente: arXiv
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Autores principales: Liang, Jiachen, Hou, Ruibing, Hu, Minyang, Chang, Hong, Shan, Shiguang, Chen, Xilin
Formato: Preprint
Publicado: 2025
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author Liang, Jiachen
Hou, Ruibing
Hu, Minyang
Chang, Hong
Shan, Shiguang
Chen, Xilin
author_facet Liang, Jiachen
Hou, Ruibing
Hu, Minyang
Chang, Hong
Shan, Shiguang
Chen, Xilin
contents Out-of-distribution (OOD) detection is critical for ensuring the reliability of deep learning models in open-world applications. While post-hoc methods are favored for their efficiency and ease of deployment, existing approaches often underexploit the rich information embedded in the model's logits space. In this paper, we propose LogitGap, a novel post-hoc OOD detection method that explicitly exploits the relationship between the maximum logit and the remaining logits to enhance the separability between in-distribution (ID) and OOD samples. To further improve its effectiveness, we refine LogitGap by focusing on a more compact and informative subset of the logit space. Specifically, we introduce a training-free strategy that automatically identifies the most informative logits for scoring. We provide both theoretical analysis and empirical evidence to validate the effectiveness of our approach. Extensive experiments on both vision-language and vision-only models demonstrate that LogitGap consistently achieves state-of-the-art performance across diverse OOD detection scenarios and benchmarks. Code is available at https://github.com/GIT-LJc/LogitGap.
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spellingShingle Revisiting Logit Distributions for Reliable Out-of-Distribution Detection
Liang, Jiachen
Hou, Ruibing
Hu, Minyang
Chang, Hong
Shan, Shiguang
Chen, Xilin
Computer Vision and Pattern Recognition
Out-of-distribution (OOD) detection is critical for ensuring the reliability of deep learning models in open-world applications. While post-hoc methods are favored for their efficiency and ease of deployment, existing approaches often underexploit the rich information embedded in the model's logits space. In this paper, we propose LogitGap, a novel post-hoc OOD detection method that explicitly exploits the relationship between the maximum logit and the remaining logits to enhance the separability between in-distribution (ID) and OOD samples. To further improve its effectiveness, we refine LogitGap by focusing on a more compact and informative subset of the logit space. Specifically, we introduce a training-free strategy that automatically identifies the most informative logits for scoring. We provide both theoretical analysis and empirical evidence to validate the effectiveness of our approach. Extensive experiments on both vision-language and vision-only models demonstrate that LogitGap consistently achieves state-of-the-art performance across diverse OOD detection scenarios and benchmarks. Code is available at https://github.com/GIT-LJc/LogitGap.
title Revisiting Logit Distributions for Reliable Out-of-Distribution Detection
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2510.20134