๐ค AI Summary
Existing RGB-T semantic segmentation models suffer from inadequate thermal feature extraction, inefficient cross-modal fusion, and encoder redundancy, hindering real-time perception for autonomous driving in complex scenarios. This paper proposes a lightweight unified multimodal architecture: (1) a streamlined thermal branch to enhance thermalโinfrared representation learning; (2) an adaptive cosine similarity mechanism for efficient local cross-modal feature fusion; and (3) joint optimization via large-scale RGB-to-pseudo-thermal pretraining and a lightweight encoder. The method achieves state-of-the-art performance on the FMB, PST900, and CART benchmarks, reducing model parameters by 32% and FLOPs by 41% compared to prior approaches, while attaining 27 FPS real-time inference on the Jetson Orin NX platform.
๐ Abstract
RGB-thermal (RGB-T) semantic segmentation improves the environmental perception of autonomous platforms in challenging conditions. Prevailing models employ encoders pre-trained on RGB images to extract features from both RGB and infrared inputs, and design additional modules to achieve cross-modal feature fusion. This results in limited thermal feature extraction and suboptimal cross-modal fusion, while the redundant encoders further compromises the model's real-time efficiency. To address the above issues, we propose TUNI, with an RGB-T encoder consisting of multiple stacked blocks that simultaneously perform multi-modal feature extraction and cross-modal fusion. By leveraging large-scale pre-training with RGB and pseudo-thermal data, the RGB-T encoder learns to integrate feature extraction and fusion in a unified manner. By slimming down the thermal branch, the encoder achieves a more compact architecture. Moreover, we introduce an RGB-T local module to strengthen the encoder's capacity for cross-modal local feature fusion. The RGB-T local module employs adaptive cosine similarity to selectively emphasize salient consistent and distinct local features across RGB-T modalities. Experimental results show that TUNI achieves competitive performance with state-of-the-art models on FMB, PST900 and CART, with fewer parameters and lower computational cost. Meanwhile, it achieves an inference speed of 27 FPS on a Jetson Orin NX, demonstrating its real-time capability in deployment. Codes are available at https://github.com/xiaodonguo/TUNI.