An Embarrassingly Simple Baseline for Imbalanced Semi-Supervised Learning

Fuente: arXiv
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Autori principali: Chen, Hao, Fan, Yue, Wang, Yidong, Wang, Jindong, Schiele, Bernt, Xie, Xing, Savvides, Marios, Raj, Bhiksha
Natura: Preprint
Pubblicazione: 2022
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author Chen, Hao
Fan, Yue
Wang, Yidong
Wang, Jindong
Schiele, Bernt
Xie, Xing
Savvides, Marios
Raj, Bhiksha
author_facet Chen, Hao
Fan, Yue
Wang, Yidong
Wang, Jindong
Schiele, Bernt
Xie, Xing
Savvides, Marios
Raj, Bhiksha
contents Semi-supervised learning (SSL) has shown great promise in leveraging unlabeled data to improve model performance. While standard SSL assumes uniform data distribution, we consider a more realistic and challenging setting called imbalanced SSL, where imbalanced class distributions occur in both labeled and unlabeled data. Although there are existing endeavors to tackle this challenge, their performance degenerates when facing severe imbalance since they can not reduce the class imbalance sufficiently and effectively. In this paper, we study a simple yet overlooked baseline -- SimiS -- which tackles data imbalance by simply supplementing labeled data with pseudo-labels, according to the difference in class distribution from the most frequent class. Such a simple baseline turns out to be highly effective in reducing class imbalance. It outperforms existing methods by a significant margin, e.g., 12.8%, 13.6%, and 16.7% over previous SOTA on CIFAR100-LT, FOOD101-LT, and ImageNet127 respectively. The reduced imbalance results in faster convergence and better pseudo-label accuracy of SimiS. The simplicity of our method also makes it possible to be combined with other re-balancing techniques to improve the performance further. Moreover, our method shows great robustness to a wide range of data distributions, which holds enormous potential in practice. Code will be publicly available.
format Preprint
id arxiv_https___arxiv_org_abs_2211_11086
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle An Embarrassingly Simple Baseline for Imbalanced Semi-Supervised Learning
Chen, Hao
Fan, Yue
Wang, Yidong
Wang, Jindong
Schiele, Bernt
Xie, Xing
Savvides, Marios
Raj, Bhiksha
Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
Semi-supervised learning (SSL) has shown great promise in leveraging unlabeled data to improve model performance. While standard SSL assumes uniform data distribution, we consider a more realistic and challenging setting called imbalanced SSL, where imbalanced class distributions occur in both labeled and unlabeled data. Although there are existing endeavors to tackle this challenge, their performance degenerates when facing severe imbalance since they can not reduce the class imbalance sufficiently and effectively. In this paper, we study a simple yet overlooked baseline -- SimiS -- which tackles data imbalance by simply supplementing labeled data with pseudo-labels, according to the difference in class distribution from the most frequent class. Such a simple baseline turns out to be highly effective in reducing class imbalance. It outperforms existing methods by a significant margin, e.g., 12.8%, 13.6%, and 16.7% over previous SOTA on CIFAR100-LT, FOOD101-LT, and ImageNet127 respectively. The reduced imbalance results in faster convergence and better pseudo-label accuracy of SimiS. The simplicity of our method also makes it possible to be combined with other re-balancing techniques to improve the performance further. Moreover, our method shows great robustness to a wide range of data distributions, which holds enormous potential in practice. Code will be publicly available.
title An Embarrassingly Simple Baseline for Imbalanced Semi-Supervised Learning
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2211.11086