A weight-sharing based RGB-T image semantic segmentation network with hierarchical feature enhancement and progressive feature fusion

RGB-T image segmentation algorithms have been widely adopted in various fields, such as surveillance and autonomous driving. These algorithms typically employ separate encoders to ensure each branch extracts modality-specific features. Nevertheless, this design increases parameters and potential conflicts between multimodal features. An alternative solution is using a weight-sharing encoder, which facilitates consistent encoding across different data types, reducing the number of training parameters and enhancing the encoder’s generalization capability. However, a weight-sharing encoder tends to extract modality-shared features but under-represent modality-specific features, thereby limiting segmentation performance under heterogeneous sensor conditions. To preserve the modality-shared features of multimodal data while simultaneously enhancing modality-specific features, we propose a novel Weight-Sharing based RGB-T image semantic segmentation network (WSRT) with a Hierarchical Feature Enhancement Module (HFEM) and Progressive Fusion Decoder (PFD). HFEM first integrates the modality-shared information from the weight-sharing encoded feature maps to generate enhanced modality-shared feature maps. Subsequently, it utilizes these enhanced feature maps to generate relative modality-specific feature maps of the RGB and thermal modalities. PFD is proposed to progressively integrate multi-scale features from different stages to decode these enhanced features more effectively. Experimental results on multiple RGB-T image semantic segmentation datasets demonstrate that our method achieves top-ranking performance or competitive results. The code is available at: https://github.com/bearxwm/WSRT.