Rise by Lifting Others: Interacting Features to Uplift Few-Shot Fine-Grained Classification

Few-shot fine-grained classification entails notorious subtle inter-class variation. Recent works address this challenge by developing attention mechanisms, such as the task discrepancy maximization (TDM) that can highlight discriminative channels. This paper, however, aims to reveal that, besides designing sophisticated attention modules, a well-designed input scheme, which simply blends two types of features and their interactions capturing different properties of the target object, can also greatly promote the quality of the learnt weights. To illustrate, we design a bi-feature interactive TDM (BiFI-TDM) module to serve as a strong foundation for TDM to discover the most discriminative channels with ease. Specifically, we design a novel mixing strategy to produce four sets of channel weights with different focuses, reflecting the properties of the corresponding input features and their interactions, as well as a proper feature re-weighting scheme. Extensive experiments on four benchmark fine-grained image datasets showcase superior performance of BiFI-TDM in metric-based few-shot methods. Our codes are available at https://github.com/Peiy-Lu/BiFI-TDM.