Channel enhanced cross-modality relation network for visible-infrared person re-identification

Visible-infrared person re-identification (VI Re-ID) is designed to perform pedestrian retrieval on non-overlapping visible-infrared cameras, and it is widely employed in intelligent surveillance. For the VI Re-ID task, one of the main challenges is the huge modality discrepancy between the visible and infrared images. Therefore, mining more shared features in the cross-modality task turns into an important issue. To address this problem, this paper proposes a novel framework for feature learning and feature embedding in VI Re-ID, namely Channel Enhanced Cross-modality Relation Network (CECR-Net). More specifically, the network contains three key modules. In the first module, to shorten the distance between the original modalities, a channel selection operation is applied to the visible images, the robustness against color variations is improved by randomly generating three-channel R/G/B images. The module also exploits the low- and mid-level information of the visible and auxiliary modal images through a feature parameter-sharing strategy. Considering that the body sequences of pedestrians are not easy to change with modality, CECR-Net designs two modules based on relation network for VI Re-ID, namely the intra-relation learning and the cross-relation learning modules. These two modules help to capture the structural relationship between body parts, which is a modality-invariant information, disrupting the isolation between local features. Extensive experiments on the two public benchmarks indicate that CECR-Net is superior compared to the state-of-the-art methods. In particular, for the SYSU-MM01 dataset, the Rank1 and mAP reach 76.83% and 71.56% in the "All Search" mode, respectively.