The Smaller The Better: Fine-grained Image Classification with Compressed Networks

Fine-grained image classification is a challenging problem, due to the small inter-class variance caused by highly similar subordinate categories and large intra-class variance in poses, viewpoints and rotations. In this paper, we propose a novel end-to-end model for fine-grained image classification(FGIC). The proposed model consists of two sub-networks: detection sub-network and classification sub-network. The detection sub-network is constructed on the basis of R-FCN, and the classification sub-network contains a two-steam CNN for feature extraction and three fully connected layers for object classification. In addition, the network compression technology is adopted in both of the sub-networks to improve efficiency and reduce storage space. Experimental results on the CUB-200-2011 shows that the accuracy of our method is close to state-of-the-art with higher efficiency and lower storage requirement than the other compared methods (10 frames/sec during inference on TitanX). The proposed high-efficiency framework is believed to be effective in some of the practical applications, especially in the applications of mobile terminals.