Cross-Domain Few-Shot Classification via Inter-Source Stylization

Cross-Domain Few Shot Classification (CDFSC) leverages prior knowledge learned from a supervised auxiliary dataset to solve a target task with limited supervised information available, where the auxiliary and target datasets come from the different domains. It is challenging due to the domain shift between these datasets. Inspired by Multisource Domain Adaptation (MDA), the recent works introduce the multiple domains to improve the performance. However, they, on the one hand, evaluate only on the benchmark with natural images, and on the other hand, they need many annotations even in the source domains can be costly. To address the above mentioned issues, this paper explore a new Multisource CDFSC setting (MCDFSC) where only one source domain is fully labeled while the rest source domains remain unlabeled. These sources are from different fileds, means they are not only natural images. Considering the inductive bias of CNNs, this paper proposed Inter-Source stylization network (ISSNet) for this new MCDFSC setting. It transfers the styles of unlabeled sources to labeled source, which expands the distribution of labeled source and further improves the model generalization ability. Experiments on 8 target datasets demonstrate ISSNet effectively suppresses the performance degradation caused by different domains.