Cross-Level Distillation and Feature Denoising for Cross-Domain Few-Shot
  Classification
Hao Zheng Runqi Wang Jianzhuang Liu Asako Kanezaki
The conventional few-shot classification aims at learning a model on a large
labeled base dataset and rapidly adapting to a target dataset that is from the
same distribution as the base dataset. However, in practice, the base and the
target datasets of few-shot classification are usually from different domains,
which is the problem of cross-domain few-shot classification. We tackle this
problem by making a small proportion of unlabeled images in the target domain
accessible in the training stage. In this setup, even though the base data are
sufficient and labeled, the large domain shift still makes transferring the
knowledge from the base dataset difficult. We meticulously design a cross-level
knowledge distillation method, which can strengthen the ability of the model to
extract more discriminative features in the target dataset by guiding the
network's shallow layers to learn higher-level information. Furthermore, in
order to alleviate the overfitting in the evaluation stage, we propose a
feature denoising operation which can reduce the feature redundancy and
mitigate overfitting. Our approach can surpass the previous state-of-the-art
method, Dynamic-Distillation, by 5.44% on 1-shot and 1.37% on 5-shot
classification tasks on average in the BSCD-FSL benchmark. The implementation
code will be available at https://github.com/jarucezh/cldfd.