Distilling Out-of-Distribution Robustness from Vision-Language Foundation Models
Andy Zhou, Jindong Wang, Yu-Xiong Wang, Haohan Wang
TL;DR
This work tackles robust generalization for vision models under distribution shifts by marrying knowledge distillation with diverse data augmentation. It introduces Discrete Adversarial Distillation (DAD), which uses a robust foundation-model teacher (e.g., CLIP) and discretizes teacher-generated adversarial samples with a VQGAN to create informative augmentations, all within a KD objective augmented by the teacher's representations. A Wasserstein-distance based theory formalizes why diverse augmentations that resemble test distributions improve robustness, and empirical results on ViT-B/16 and ResNet50 show substantial gains on natural shifts (e.g., ImageNet-Sketch, ImageNet-Rendition) with modest overhead and compatibility with existing augmentations. The work provides a practical pathway to transfer foundation-model robustness to smaller students, albeit with limitations such as teacher bias toward the teacher and the need for broader semantic-shift evaluation.
Abstract
We propose a conceptually simple and lightweight framework for improving the robustness of vision models through the combination of knowledge distillation and data augmentation. We address the conjecture that larger models do not make for better teachers by showing strong gains in out-of-distribution robustness when distilling from pretrained foundation models. Following this finding, we propose Discrete Adversarial Distillation (DAD), which leverages a robust teacher to generate adversarial examples and a VQGAN to discretize them, creating more informative samples than standard data augmentation techniques. We provide a theoretical framework for the use of a robust teacher in the knowledge distillation with data augmentation setting and demonstrate strong gains in out-of-distribution robustness and clean accuracy across different student architectures. Notably, our method adds minor computational overhead compared to similar techniques and can be easily combined with other data augmentations for further improvements.
