Optimizing Label Assignment for Weakly Supervised Person Search

Weakly supervised person search aims to detect and match individuals using only bounding box annotations jointly. The existing methods mainly alternate between the clustering stage and the training stage, where the former is responsible for instance level label allocation tasks and the latter needs to undertake proposal level label allocation tasks. In the clustering phase, the conventional use of the DBSCAN algorithm for clustering pedestrian instance features often neglects key contextual information such as scene context and relative positioning of individuals. During the training phase, the Region Proposal Network assigns labels based on the MaxIoU, which tends to produce locally ambiguous labels. Finally, the proposals updated to the memory bank with extensive background information tend to interfere with the task of pseudo-label generation. To address these issues, this paper proposes an Optimizing Label Assignment (OLA) for weakly supervised person search. Firstly, in the clustering phase, Context Aware Clustering is introduced to integrate contextual information and constraints, enhancing the accuracy of clustering. Secondly, in the training phase, we adopt Prototype Matching based on Optimal Transport theory to optimize label distribution from a global perspective. Furthermore, we propose Dual Memory Bank Enhancement that effectively enhances the accuracy of label assignment. Extensive experiments conducted on the CUHK-SYSU and PRW datasets demonstrate that our method achieves state-of-the-art performance in weakly supervised person search.