Despite the clear performance benefits of data augmentations, little is known about why they are so effective. In this paper, we disentangle several key mechanisms through which data augmentations operate. Establishing an exchange rate between augmented and additional real data, we find that in out-of-distribution testing scenarios, augmentations which yield samples that are diverse, but inconsistent with the data distribution can be even more valuable than additional training data. Moreover, we find that data augmentations which encourage invariances can be more valuable than invariance alone, especially on small and medium sized training sets. Following this observation, we show that augmentations induce additional stochasticity during training, effectively flattening the loss landscape.
翻译:尽管数据增强的性能优势明显,但对于其为什么如此有效的原因知之甚少。在本文中,我们分离了数据增强发挥作用的几个关键机制。通过建立增强数据和额外真实数据之间的兑换率,我们发现在离分布外的测试场景中,产生多样性但与数据分布不一致的样本的增强技术可以比额外的训练数据更有价值。此外,我们发现鼓励不变性的数据增强技术比仅仅追求不变性在中小型训练集上更有价值。根据这个观察结果,我们展示了数据增强技术在训练期间引入了额外的随机性,有效地降低了损失函数的复杂度。