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arXiv 2501.06004cs.CV
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SeMi:当不平衡半监督学习遇上难例挖掘

SeMi: When Imbalanced Semi-Supervised Learning Meets Mining Hard Examples

Zhejiang University(浙江大学);The Hong Kong University of Science and Technology(香港科技大学);Central South University(中南大学);Zhejiang Gongshang University(浙江工商大学)

Yin Wang, Zixuan Wang, Hao Lu, Zhen Qin, Hailiang Zhao, Guanjie Cheng, Ge Su, Li Kuang, Mengchu Zhou, Shuiguang Deng

AI总结:

针对类别不平衡半监督学习忽视难例价值的问题,提出 SeMi,通过 logits 熵差异识别难例并结合带置信度衰减的类别平衡记忆库,在多个基准上取得最优性能。

摘要:

半监督学习(SSL)能够利用大量无标签数据来提升模型性能。然而,现实场景中的类别不平衡数据分布给 SSL 带来了巨大挑战,导致性能下降。现有的类别不平衡半监督学习(CISSL)方法主要关注重新平衡数据集,却忽视了利用难例来增强性能的潜力,因此即使采用复杂算法,也难以充分发挥无标签数据的作用。为解决这一问题,我们提出了一种通过挖掘难例来增强不平衡半监督学习性能的方法(SeMi)。该方法区分难例与简单例 logits 之间的熵差异,从而识别难例并提高无标签数据的效用,更好地应对 CISSL 中的不平衡问题。此外,我们维护一个带有置信度衰减的类别平衡记忆库,用于存储高置信度嵌入,以增强伪标签的可靠性。尽管我们的方法简单,但它有效且可与现有方法无缝集成。我们在标准 CISSL 基准上进行了全面实验,并通过实验证明,所提出的 SeMi 在多个基准上优于现有最先进方法,尤其是在反转场景中,我们的最佳结果相较基线方法显示出约 54.8% 的提升。

英文摘要:

Semi-Supervised Learning (SSL) can leverage abundant unlabeled data to boost model performance. However, the class-imbalanced data distribution in real-world scenarios poses great challenges to SSL, resulting in performance degradation. Existing class-imbalanced semi-supervised learning (CISSL) methods mainly focus on rebalancing datasets but ignore the potential of using hard examples to enhance performance, making it difficult to fully harness the power of unlabeled data even with sophisticated algorithms. To address this issue, we propose a method that enhances the performance of Imbalanced Semi-Supervised Learning by Mining Hard Examples (SeMi). This method distinguishes the entropy differences among logits of hard and easy examples, thereby identifying hard examples and increasing the utility of unlabeled data, better addressing the imbalance problem in CISSL. In addition, we maintain a class-balanced memory bank with confidence decay for storing high-confidence embeddings to enhance the pseudo-labels' reliability. Although our method is simple, it is effective and seamlessly integrates with existing approaches. We perform comprehensive experiments on standard CISSL benchmarks and experimentally demonstrate that our proposed SeMi outperforms existing state-of-the-art methods on multiple benchmarks, especially in reversed scenarios, where our best result shows approximately a 54.8\% improvement over the baseline methods.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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