Progressive Diversity Generation for Single Domain Generalization

Single domain generalization (single-DG) is a realistic yet challenging domain generalization scenario where a model trained on a single domain generalization scenario where a model trained on a single domain generalizes well to multiple unseen domains. Unlike typical single-DG methods that are essentially supervised data augmentation and focus mainly on the novelty of images, we propose a simple adversarial augmentation method, termed Progressive Diversity Generation (PDG), to synthesize novel and diverse images in a fully unsupervised manner. Specifically, PDG minimizes the uncertainty coefficient to ensure that synthesized images are novel. By modeling conditional probabilities with an auxiliary network, we transfer the adversarial process from semantics to images, thus eliminating dependency on labels. To enhance diversity, we propose the f-diversity, a collection of correlation or similarity measures, to allow our model to generate potential images from diverse perspectives. The proposed architecture combines a multi-attribute generator with a progressive generation framework to improve model performance. PDG is the unsupervised and easy-to-implement method that solves single-DG with only synthesized (source) images. Extensive experiments on multiple single-DG benchmarks show that PDG achieves remarkable results and outperforms existing supervised and unsupervised methods by a large margin in single domain generalization.