Mitigate Catastrophic Remembering via Continual Knowledge Purification for Noisy Lifelong Person Re-Identification

Current Lifelong Person Re-Identification (LReID) methods focus on tackling a clean data stream with accurate labels. When noisy data with incorrect labels are given, their performance is severely degraded since the model inevitably and continually remembers erroneous knowledge induced by the label noises. Moreover, the well-known issue of catastrophic forgetting in LReID is exacerbated by noisy labels, which disrupt the retention of correct knowledge from previous models. Such a practical noisy LReID task is important but challenging, and rare works have attempted to handle it. In this paper, we initially investigate noisy LReID and propose a Continual Knowledge Purification (CKP) method to address the catastrophic remembering of erroneous knowledge and catastrophic forgetting of correct knowledge simultaneously. Specifically, a Cluster-aware Data Purification module (CDP) is designed to select clean labels based on clustering-guided label confidence estimation. Besides, an Iterative Label Rectification (ILR) pipeline is proposed to rectify wrong labels by fusing the prediction and label information throughout the training epochs. To handle the catastrophic remembering problem, an Erroneous Knowledge Filtering (EKF) algorithm is proposed to estimate and transfer the correct old knowledge to the new model. Finally, a Noisy LReID benchmark is constructed for performance evaluation and extensive experimental results demonstrate that our proposed CKP method achieves state-of-the-art performance. Our code is available at https://github.com/zhoujiahuan1991/MM2024-CKP