Cross-Modal Representation Alignment in Intelligent Traffic Systems via Mutual Information Maximization
摘要
Modern Intelligent Traffic Systems (ITS) rely on diverse data sources such as vehicle mobility, wireless communication signals, and environmental configurations to support real-time decisions. However, in practice, this data is often incomplete, unsynchronized, or noisy, which poses challenges for accurate traffic analysis. This paper presents a cross-modal alignment framework that brings together these heterogeneous data sources into a shared representation space without requiring labeled or perfectly synchronized inputs. The method leverages mutual information maximization using a contrastive InfoNCE loss to align different modalities. Evaluation on the TiHanX_V2X dataset shows that the proposed approach achieves retrieval accuracies of 91.7% between mobility and communication modalities, 75.0% between mobility and scenario data, and 58.3% between communication and scenario inputs. Alternate training strategies such as regression loss and intra-modal contrastive learning, both implemented for comparative analysis in this study, showed limited effectiveness in achieving cross-modal alignment, with retrieval accuracies not exceeding 3.12%. The performance of a random selection strategy, used as a lower bound baseline, was measured at 1.56%, aligning with expectations for untrained models. Visualizations further confirm that the learned latent representations are semantically consistent across modalities. The empirical evidence highlights that mutual information maximization offers a scalable and effective approach for aligning asynchronous and incomplete modalities in Intelligent Traffic Systems, substantially outperforming baseline and alternative methods under realistic constraints.