IMH-MOT: Interactive Multi-Hierarchical Image and Point Cloud Fusion for Multi-Object Tracking

Abstract

Multi-object tracking (MOT) plays a critical role in applications such as autonomous driving and surveillance. Camera-based approaches offer rich texture features for object association, while LiDAR-based methods provide accurate geometric information for spatial reasoning. Although each modality addresses different challenges, their intrinsic discrepancies hinder effective cross-modal fusion and unified representation learning. To overcome these limitations, we propose IMH-MOT, an interactive multi-hierarchical MOT framework comprising three key modules. The Multi-modality~Alignment~Module~(MMAM) enhances spatial representations by sampling and clustering instance-level point clouds. From different modalities are motion cues integrated by the Multi-modality~Motion~Estimation~Module~(MMEM) to build a unified motion model. To mitigate the impact of occlusion on single-frame appearance features, the Long-term~Appearance~Module~(LAM) captures temporal appearance consistency by constructing a long-term appearance embedding. Guided by modality-aware cues from MMAM, MMEM generates reliable spatial representations, while LAM encodes robust long-term appearance features. These components are jointly integrated through a Multi-hierarchical~Data~Association~(MHDA) strategy, enabling stable and accurate tracking. Extensive experiments on the KITTI MOT benchmark demonstrate the effectiveness of our framework, achieving 80.90% HOTA, 89.73% MOTA, and 470 IDSW, outperforming state-of-the-art methods in both standard and challenging scenarios.