Diversity-Representativeness Replay and Knowledge Alignment for Lifelong Vehicle Re-identification

Lifelong Vehicle Re-Identification (LVReID) aims to match a target vehicle across multiple cameras, considering non-stationary and continuous data streams, which fits the needs of the practical application better than traditional vehicle re-identification. Nonetheless, this area has received relatively little attention. Recently, methods for Lifelong Person Re-Identification (LPReID) have been emerging, with replay-based methods achieving the best results by storing a small number of instances from previous tasks for retraining, thus effectively reducing catastrophic forgetting. However, these methods cannot be directly applied to LVReID because they fail to simultaneously consider the diversity and representativeness of replayed data, resulting in biases between the subset stored in the memory buffer and the original data. They randomly sample classes, which may not adequately represent the distribution of the original data. Additionally, these methods fail to consider the rich variation in instances of the same vehicle class due to factors such as vehicle orientation and lighting conditions. Therefore, preserving more informative classes and instances for replay helps maintain information from previous tasks and may mitigate the model's forgetting of old knowledge. In view of this, we propose a novel Diversity-Representativeness Dual-Stage Sampling Replay (DDSR) strategy for LVReIDthat constructs an effective memory buffer through two stages, i.e.,Cluster-Centric Class Selection andDiverse Instance Mining. Specifically, we first perform class-level sampling based on density in the clusteredclass-centered feature space and then further mine the diverse, high-quality instances within the selectedclasses. In addition, we introduce Maximum Mean Discrepancy loss to align the feature distribution betweenreplay data and the new arrivals and apply L2 regularization in the parameter space to facilitate knowledgetransfer, thus enhancing the model's generalization ability to new tasks. Extensive experiments demonstrateeffective improvements of our method compared to current state-of-the-art lifelong ReID methods on theVeRi-776, VehicleID, and VERI-Wild datasets