Fine-grained recognition is challenging mainly because the inter-class differences between fine-grained classes are usually local and subtle while intra-class differences could be large due to pose variations. In order to distinguish them from intra-class variations, it is essential to zoom in on highly discriminative local regions. In this work, we introduce a reinforcement learning-based fully convolutional attention localization network to adaptively select multiple task-driven visual attention regions. We show that zooming in on the selected attention regions significantly improves the performance of fine-grained recognition. Compared to previous reinforcement learning-based models, the proposed approach is noticeably more computationally efficient during both training and testing because of its fully-convolutional architecture, and it is capable of simultaneous focusing its glimpse on multiple visual attention regions. The experiments demonstrate that the proposed method achieves notably higher classification accuracy on three benchmark fine-grained recognition datasets: Stanford Dogs, Stanford Cars, and CUB-200-2011.

本文提出了一种基于全卷积注意力网络（FCANs）的强化学习框架，用于优化细粒度识别中的局部区域，并避免耗费昂贵的部件注释和定义困难的细粒度类别，该方法在包括CUB-200-2011、斯坦福狗、斯坦福汽车和Food-101等四个基准数据集上得到了证明。

用于细粒度识别的全卷积注意力网络