Neural Image Parts Group Search for Person Re-Identification
Zhipu Liu, Lei Zhang, David Zhang · IEEE Transactions on Circuits and Systems for Video Technology · 2022
Employing partition strategy to explore fine-grained features has been verified to be beneficial for person re-identification in recent literature. However, existing methods primarily rely on expert experience to manually design various partition strategies, which may lead to a sub-optimal solution for fine-grained features exploration. In this paper, we propose a Neural Parts Group Search (NPGS) strategy that auto-searches the optimal parts group via evolutionary algorithm (EA) to facilitate the network to exploit the local details. And during search process, designing a high-quality search space is especially crucial for an efficient optimization. Considering the human top-down structure and the semantic coherence of parts, we design a coarse-to-fine parts search space (C2F-PSP) in NPGS, which effectively reduce the search complexity without the loss of parts expressivity. Additionally, since only employing the high-level semantic features is insufficient for the NPGS to search effective parts, we further develop an efficient feature aggregation strategy named hierarchical low-rank bilinear pooling that progressively integrates the high-level semantic property and the low-level fine-grained details to facilitate the NPGS to explore the fine-grained features. Furthermore, to relieve the interference of background during parts search process, we propose a novel Relational Attention Module (RAM) by exploiting the channel and spatial structural interdependence of pixels to strengthen the discriminative regions. Extensive experiments on the mainstream evaluation datasets demonstrate that our method outperforms the recent state-of-the-art Re-ID models.