Robust Vehicle Re-identification via Rigid Structure Prior

Abstract

Vehicle re-identification (re-id) is one of the most important components in the current intelligence transport system, benefiting both the smart traffic management and the optimal path planning. In this paper, we focus on developing a robust part-aware structure-based vehicle re-id system against the massive appearance changes due to the pose and illumination variants. Specifically, we apply the strong convolutional neural networks to extract the visual representation, which is based on the detected vehicle images. Taking one step further, we deploy a part detector to recognize different vehicle parts, such as front, back, left, and right, which explicitly introduce the prior knowledge on the structure of the rigid objective, i.e., vehicle. With the geometry information, we further harness different part feature extractors to filter wrong matches. By using this simple but effective strategy, we remove the hard negative candidates while maintaining high recall accuracy, combing general global-level coarse-grained re-id feature models with part-level fine-grained features. We achieved 71.51% mAP in the vehicle re-id track of the AI City Challenge 2021, which verified the effectiveness and scalability of the proposed structure-based method. The code will be available at https://github.com/XuanmengZhang/AICITY2021-Track2.