IU-Module: Intersection and Union Module for Fine-Grained Visual Classification

A predominant viewpoint in previous works of fine-grained visual classification (FGVC) is to the localize discriminative parts by auxiliary networks and extract the part-based finegrained features for classification. In this paper, we propose a simple yet effective approach by introducing an intersection and union module (IU-Module). The IU-Module aims to capture more discriminative features by 1) dividing features into distinct groups, 2) sharing parts of interests within each group, and 3) adding a differentiation loss to reduce the similarity among those grouped feature channels. Without adding any new learnable parameters, the proposed approach imposes two straightforward operations, namely channel intersection (CI) and channel union (CU) operations, on the convolutional features and achieves competitive results compared with the state-of-the-art methods. Experimental results on three publicly available FGVC datasets show the effectiveness of the IU-Module. Ablation studies and visualizations are also provided to make further demonstrations.