  Data mixing augmentation has been widely applied to improve the
generalization ability of deep neural networks. Recently, offline data mixing
augmentation, e.g. handcrafted and saliency information-based mixup, has been
gradually replaced by automatic mixing approaches. Through minimizing two
sub-tasks, namely, mixed sample generation and mixup classification in an
end-to-end way, AutoMix significantly improves accuracy on image classification
tasks. However, as the optimization objective is consistent for the two
sub-tasks, this approach is prone to generating consistent instead of diverse
mixed samples, which results in overfitting for target task training. In this
paper, we propose AdAutomixup, an adversarial automatic mixup augmentation
approach that generates challenging samples to train a robust classifier for
image classification, by alternatively optimizing the classifier and the mixup
sample generator. AdAutomixup comprises two modules, a mixed example generator,
and a target classifier. The mixed sample generator aims to produce hard mixed
examples to challenge the target classifier, while the target classifier's aim
is to learn robust features from hard mixed examples to improve generalization.
To prevent the collapse of the inherent meanings of images, we further
introduce an exponential moving average (EMA) teacher and cosine similarity to
train AdAutomixup in an end-to-end way. Extensive experiments on seven image
benchmarks consistently prove that our approach outperforms the state of the
art in various classification scenarios. The source code is available at
https://github.com/JinXins/Adversarial-AutoMixup.
