Improving Knowledge Distillation Under Unknown Covariate Shift Through Confidence-Guided Data Augmentation
Journal:
arXiv
Published Date:
Jun 2, 2025
Abstract
Large foundation models trained on extensive datasets demonstrate strong
zero-shot capabilities in various domains. To replicate their success when data
and model size are constrained, knowledge distillation has become an
established tool for transferring knowledge from foundation models to small
student networks. However, the effectiveness of distillation is critically
limited by the available training data. This work addresses the common
practical issue of covariate shift in knowledge distillation, where spurious
features appear during training but not at test time. We ask the question: when
these spurious features are unknown, yet a robust teacher is available, is it
possible for a student to also become robust to them? We address this problem
by introducing a novel diffusion-based data augmentation strategy that
generates images by maximizing the disagreement between the teacher and the
student, effectively creating challenging samples that the student struggles
with. Experiments demonstrate that our approach significantly improves worst
group and mean group accuracy on CelebA and SpuCo Birds as well as the spurious
mAUC on spurious ImageNet under covariate shift, outperforming state-of-the-art
diffusion-based data augmentation baselines
