FA-Net: A Feature Alignment Network for Video-Based Visible-Infrared Person Re-Identification

Video-based visible-infrared person re-identification (VVI-ReID) aims to match target pedestrians between visible and infrared videos, which is significantly applied in 24-hour surveillance systems. The key of VVI-ReID is to learn modality invariant and spatio-temporal invariant sequence-level representation to solve the challenges such as modality differences, spatio-temporal misalignment, and domain shift noise. However, existing methods predominantly emphasize on reducing modality discrepancy while relatively neglect temporal misalignment and domain shift noise reduction. To this end, this paper proposes a VVI-ReID framework called Feature Alignment Network (FA-Net) from the perspective of feature alignment, aiming to mitigate temporal misalignment. FA-Net comprises two main alignment modules: Spatial-Temporal Alignment Module (STAM) and Modality Distribution Constraint (MDC). STAM integrates global and local features to ensure individuals' spatial representation alignment. Additionally, STAM also establishes temporal relationships by exploring inter-frame features to address cross-frame person feature matching. Furthermore, we introduce the Modality Distribution Constraint (MDC), which utilizes a symmetric distribution loss to align the distributions of features from different modalities. Besides, the SAM Guidance Augmentation (SAM-GA) strategy is designed to transform the image space of RGB and IR frames to provide more informative and less noisy frame information. Extensive experimental results demonstrate the effectiveness of the proposed method, surpassing existing state-of-the-art methods. Our code will be available at: https://github.com/code/FANet.