Rethinking Out-of-Distribution Detection on Imbalanced Data Distribution

Fuente: arXiv
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Autori principali: Liu, Kai, Fu, Zhihang, Jin, Sheng, Chen, Chao, Chen, Ze, Jiang, Rongxin, Zhou, Fan, Chen, Yaowu, Ye, Jieping
Natura: Preprint
Pubblicazione: 2024
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author Liu, Kai
Fu, Zhihang
Jin, Sheng
Chen, Chao
Chen, Ze
Jiang, Rongxin
Zhou, Fan
Chen, Yaowu
Ye, Jieping
author_facet Liu, Kai
Fu, Zhihang
Jin, Sheng
Chen, Chao
Chen, Ze
Jiang, Rongxin
Zhou, Fan
Chen, Yaowu
Ye, Jieping
contents Detecting and rejecting unknown out-of-distribution (OOD) samples is critical for deployed neural networks to void unreliable predictions. In real-world scenarios, however, the efficacy of existing OOD detection methods is often impeded by the inherent imbalance of in-distribution (ID) data, which causes significant performance decline. Through statistical observations, we have identified two common challenges faced by different OOD detectors: misidentifying tail class ID samples as OOD, while erroneously predicting OOD samples as head class from ID. To explain this phenomenon, we introduce a generalized statistical framework, termed ImOOD, to formulate the OOD detection problem on imbalanced data distribution. Consequently, the theoretical analysis reveals that there exists a class-aware bias item between balanced and imbalanced OOD detection, which contributes to the performance gap. Building upon this finding, we present a unified training-time regularization technique to mitigate the bias and boost imbalanced OOD detectors across architecture designs. Our theoretically grounded method translates into consistent improvements on the representative CIFAR10-LT, CIFAR100-LT, and ImageNet-LT benchmarks against several state-of-the-art OOD detection approaches. Code is available at https://github.com/alibaba/imood.
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id arxiv_https___arxiv_org_abs_2407_16430
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Rethinking Out-of-Distribution Detection on Imbalanced Data Distribution
Liu, Kai
Fu, Zhihang
Jin, Sheng
Chen, Chao
Chen, Ze
Jiang, Rongxin
Zhou, Fan
Chen, Yaowu
Ye, Jieping
Computer Vision and Pattern Recognition
Detecting and rejecting unknown out-of-distribution (OOD) samples is critical for deployed neural networks to void unreliable predictions. In real-world scenarios, however, the efficacy of existing OOD detection methods is often impeded by the inherent imbalance of in-distribution (ID) data, which causes significant performance decline. Through statistical observations, we have identified two common challenges faced by different OOD detectors: misidentifying tail class ID samples as OOD, while erroneously predicting OOD samples as head class from ID. To explain this phenomenon, we introduce a generalized statistical framework, termed ImOOD, to formulate the OOD detection problem on imbalanced data distribution. Consequently, the theoretical analysis reveals that there exists a class-aware bias item between balanced and imbalanced OOD detection, which contributes to the performance gap. Building upon this finding, we present a unified training-time regularization technique to mitigate the bias and boost imbalanced OOD detectors across architecture designs. Our theoretically grounded method translates into consistent improvements on the representative CIFAR10-LT, CIFAR100-LT, and ImageNet-LT benchmarks against several state-of-the-art OOD detection approaches. Code is available at https://github.com/alibaba/imood.
title Rethinking Out-of-Distribution Detection on Imbalanced Data Distribution
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2407.16430