UPAR Challenge 2024: Pedestrian Attribute Recognition and Attribute-Based Person Retrieval - Dataset, Design, and Results.

Attribute-based person retrieval enables individuals to be searched and retrieved using their soft biometric features, for instance, gender, accessories, and clothing colors. The process has numerous practical use cases, such as surveillance, retail, or smart cities. Notably, attribute-based person retrieval empowers law enforcement agencies to efficiently comb through vast volumes of surveillance footage from extensive multi-camera networks, facilitating the swift localization of missing persons or criminals. However, for real-world application, attribute-based person retrieval is required to generalize to multiple settings in indoor and outdoor scenarios with their respective challenges. For its second edition, the WACV 2024 Pedestrian Attribute Recognition and Attribute-based Person Retrieval Challenge (UPAR-Challenge) aimed once again to spotlight the current challenges and limitations of existing methods to bridge the domain gaps in real-world surveillance contexts. Analogous to the first edition, two tracks are offered: pedestrian attribute recognition and attribute-based person retrieval. The UPAR-Challenge 2024 dataset extends the UPAR dataset with the introduction of harmonized annotations for the MEVID dataset, which is used as a novel test domain. To this aim, 1.1M additional annotations were manually labeled and validated. Each track evaluates the robustness of the competing methods to domain shifts by training and evaluating on data from entirely different domains. The challenge attracted 82 registered participants, which was considered a success from the organiz ers' perspective. While ten competing teams surpassed the baseline for track 1, no team managed to outperform the baseline on track 2, emphasizing the task's difficulty. This work describes the challenge design, the adopted dataset, obtained results, as well as future directions on the topic. The UPAR-Challenge dataset is available on GitHub: https:/github.com/speckean/upar_challenge.