Aggregation of Disentanglement: Reconsidering Domain Variations in Domain Generalization

Domain Generalization (DG) is a fundamental challenge for machine learning models, which aims to improve model generalization on various domains. Previous methods focus on generating ___domain invariant features from various source domains. However, we argue that the ___domain variantions also contain useful information, ie, classification-aware information, for downstream tasks, which has been largely ignored. Different from learning ___domain invariant features from source domains, we decouple the input images into Domain Expert Features and noise. The proposed ___domain expert features lie in a learned latent space where the images in each ___domain can be classified independently, enabling the implicit use of classification-aware ___domain variations. Based on the analysis, we proposed a novel paradigm called Domain Disentanglement Network (DDN) to disentangle the ___domain expert features from the source ___domain images and aggregate the source ___domain expert features for representing the target test ___domain. We also propound a new contrastive learning method to guide the ___domain expert features to form a more balanced and separable feature space. Experiments on the widely-used benchmarks of PACS, VLCS, OfficeHome, DomainNet, and TerraIncognita demonstrate the competitive performance of our method compared to the recently proposed alternatives.