When Classes Evolve: A Benchmark and Framework for Stage-Aware Class-Incremental Learning

Fuente: arXiv
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Main Authors: Zhang, Zheng, Hu, Tao, Li, Xueheng, Wang, Yang, Li, Rui, Zhang, Jie, Xie, Chengjun
Format: Preprint
Published: 2026
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author Zhang, Zheng
Hu, Tao
Li, Xueheng
Wang, Yang
Li, Rui
Zhang, Jie
Xie, Chengjun
author_facet Zhang, Zheng
Hu, Tao
Li, Xueheng
Wang, Yang
Li, Rui
Zhang, Jie
Xie, Chengjun
contents Class-Incremental Learning (CIL) aims to sequentially learn new classes while mitigating catastrophic forgetting of previously learned knowledge. Conventional CIL approaches implicitly assume that classes are morphologically static, focusing primarily on preserving previously learned representations as new classes are introduced. However, this assumption neglects intra-class evolution: a phenomenon wherein instances of the same semantic class undergo significant morphological transformations, such as a larva turning into a butterfly. Consequently, a model must both discriminate between classes and adapt to evolving appearances within a single class. To systematically address this challenge, we formalize Stage-Aware CIL (Stage-CIL), a paradigm in which each class is learned progressively through distinct morphological stages. To facilitate rigorous evaluation within this paradigm, we introduce the Stage-Bench, a 10-domain, 2-stages dataset and protocol that jointly measure inter- and intra-class forgetting. We further propose STAGE, a novel method that explicitly learns abstract and transferable evolution patterns within a fixed-size memory pool. By decoupling semantic identity from transformation dynamics, STAGE enables accurate prediction of future morphologies based on earlier representations. Extensive empirical evaluation demonstrates that STAGE consistently and substantially outperforms existing state-of-the-art approaches, highlighting its effectiveness in simultaneously addressing inter-class discrimination and intra-class morphological adaptation.
format Preprint
id arxiv_https___arxiv_org_abs_2602_00573
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle When Classes Evolve: A Benchmark and Framework for Stage-Aware Class-Incremental Learning
Zhang, Zheng
Hu, Tao
Li, Xueheng
Wang, Yang
Li, Rui
Zhang, Jie
Xie, Chengjun
Machine Learning
Computer Vision and Pattern Recognition
Class-Incremental Learning (CIL) aims to sequentially learn new classes while mitigating catastrophic forgetting of previously learned knowledge. Conventional CIL approaches implicitly assume that classes are morphologically static, focusing primarily on preserving previously learned representations as new classes are introduced. However, this assumption neglects intra-class evolution: a phenomenon wherein instances of the same semantic class undergo significant morphological transformations, such as a larva turning into a butterfly. Consequently, a model must both discriminate between classes and adapt to evolving appearances within a single class. To systematically address this challenge, we formalize Stage-Aware CIL (Stage-CIL), a paradigm in which each class is learned progressively through distinct morphological stages. To facilitate rigorous evaluation within this paradigm, we introduce the Stage-Bench, a 10-domain, 2-stages dataset and protocol that jointly measure inter- and intra-class forgetting. We further propose STAGE, a novel method that explicitly learns abstract and transferable evolution patterns within a fixed-size memory pool. By decoupling semantic identity from transformation dynamics, STAGE enables accurate prediction of future morphologies based on earlier representations. Extensive empirical evaluation demonstrates that STAGE consistently and substantially outperforms existing state-of-the-art approaches, highlighting its effectiveness in simultaneously addressing inter-class discrimination and intra-class morphological adaptation.
title When Classes Evolve: A Benchmark and Framework for Stage-Aware Class-Incremental Learning
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2602.00573