Dynamic Confidence Variance for Generalized Coreset in Active Learning

Active Learning (AL) aims to reduce data annotation costs by selecting the most informative samples from an unlabeled data pool. Traditional AL methods often rely on a single snapshot to identify uncertain or representative samples, often overlooking the poor generalization of a single model. Recent AL studies have attempted to address this issue by tracking a broader range of training dynamics for data selection, typically using averaging or accumulating manner. However, both our theoretical and experimental analyses reveal that these methods obscure the variability inherent in the training process, potentially prioritizing hard-to-learn samples that result in poor generalization. In this paper, we propose a novel AL method termed as Dynamic Confidence Variance (DCoV), that seamlessly integrates variability with the training dynamic to effectively identify a well-generalized Coreset. DCoV leverages the variance of the model’s prediction confidence throughout the training process for active sampling and model training. Our theoretical analysis demonstrates that DCoV provides a lower bound on the population risk of the model learned from selected labeled subset, spanning the entire training process. Extensive experiments demonstrate that our approach significantly outperforms existing state-of-the-art AL methods on various balanced and imbalanced benchmark datasets across various modalities.