SEAS: ShapE-Aligned Supervision for Person Re-Identification

Haidong Zhu, Pranav Budhwant, Zhaoheng Zheng, Ram Nevatia; Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024, pp. 164-174

We introduce SEAS using ShapE-Aligned Supervision to enhance appearance-based person re-identification. When recognizing an individual's identity existing methods primarily rely on appearance which can be influenced by the background environment due to a lack of body shape awareness. Although some methods attempt to incorporate other modalities such as gait or body shape they encode the additional modality separately resulting in extra computational costs and lacking an inherent connection with appearance. In this paper we explore the use of implicit 3-D body shape representations as pixel-level guidance to augment the extraction of identity features with body shape knowledge in addition to appearance. Using body shape as supervision rather than as input provides shape-aware enhancements without any increase in computational cost and delivers coherent integration with pixel-wise appearance features. Moreover for video-based person re-identification we align pixel-level features across frames with shape awareness to ensure temporal consistency. Our results demonstrate that incorporating body shape as pixel-level supervision reduces rank-1 errors by 1.4% for frame-based and by 2.5% for video-based re-identification tasks respectively and can also be generalized to other existing appearance-based person re-identification methods.