During the past decade, deep neural networks have led to fast-paced progress
and significant achievements in computer vision problems, for both academia and
industry. Yet despite their success, state-of-the-art image classification
approaches fail to generalize well in previously unseen visual contexts, as
required by many real-world applications. In this paper, we focus on this
domain generalization (DG) problem and argue that the generalization ability of
deep convolutional neural networks can be improved by taking advantage of
multi-layer and multi-scaled representations of the network. We introduce a
framework that aims at improving domain generalization of image classifiers by
combining both low-level and high-level features at multiple scales, enabling
the network to implicitly disentangle representations in its latent space and
learn domain-invariant attributes of the depicted objects. Additionally, to
further facilitate robust representation learning, we propose a novel objective
function, inspired by contrastive learning, which aims at constraining the
extracted representations to remain invariant under distribution shifts. We
demonstrate the effectiveness of our method by evaluating on the domain
generalization datasets of PACS, VLCS, Office-Home and NICO. Through extensive
experimentation, we show that our model is able to surpass the performance of
previous DG methods and consistently produce competitive and state-of-the-art
results in all datasets.

通过结合多层和多尺度的特征，利用深度卷积神经网络来提高图像分类器的领域泛化能力，并提出了一种新颖的目标函数，使用对比学习的方法约束提取的特征在分布转移下保持不变，实验证明该方法在多个数据集上均表现出与之前方法相比更好的性能。