Balanced Contrast Class‐Incremental Learning

ABSTRACT Continual learning aims to empower a model to learn new tasks continuously while reducing forgetting to retain previously learnt knowledge. In the context of receiving streaming data that are not constrained by the independent and identically distributed (IID) assumption, continual learning efficiently transforms and leverages previously learnt knowledge through various methodologies and completes the learning of new tasks. The generalisation performance and learning efficiency of the model are enhanced in a sequence of tasks. However, the class imbalance in continual learning scenarios critically undermines model performance. In particular, in the class‐incremental scenario, the class imbalance results in a bias towards new task classes while degrading the performance on previous learnt classes, leading to catastrophic forgetting. In this paper, a novel method based on balanced contrast is proposed to solve the class‐incremental continual learning. The method utilises gradient balancing to mitigate the impact of class imbalance in the class‐incremental scenario. The method leverages contrastive learning and gradient modifications to facilitate balanced processing of data across different classes in continual learning. The method proposed in this paper surpasses the existing baseline approaches in the class‐incremental learning scenario on standard image datasets such as CIFAR‐100, CIFAR‐10 and mini‐ImageNet. The research results reveal that the proposed method effectively mitigates catastrophic forgetting of previously learnt classes, markedly improving the efficacy of continual learning and offering a powerful solution for further advancing continual learning performance.