Virtual Visual-Guided Domain-Shadow Fusion via Modal Exchanging for Domain-Specific Multi-Modal Neural Machine Translation

Incorporating domain-specific visual information into text poses one of the critical challenges for domain-specific multi-modal neural machine translation (DMNMT). While most existing DMNMT methods often borrow multi-modal fusion frameworks from multi-modal neural machine translation (MNMT) in the general domain, they overlook the domain gaps between general and specific domains. Visual-to-textual interaction in a specific domain frequently exhibits multi-focus characteristics, making it difficult to consistently focus on domain-specific multi-visual details using traditional multi-modal fusion frameworks. This challenge can lead to a decrease in machine translation performance for domain-specific terms. To tackle this problem, this paper presents a virtual visual scene-guided domain-shadow multi-modal fusion mechanism to simultaneously integrate multi-grained domain visual details and text with the guidance of modality-agnostic virtual visual scene, thereby enhancing machine translation performance for DMNMT, especially for domain terms. Specifically, we first adopt a modality-mixing selection-voting strategy to generate modality-mixed domain representations through layer-by-layer intra-modality selection and inter-modality exchanging. Then, we gradually aggregate modality-mixed domain representations and text across modality boundaries with the guidance of a modality-agnostic virtual visual scene to enhance the collaboration between domain characteristics and textual semantics. The experimental results on three benchmark datasets demonstrate that our proposed approach outperforms the state-of-the-art (SOTA) methods in all machine translation tasks. The in-depth analysis further highlights the robustness and generalizability of our approach across various scenarios. Our code is available on https://github.com/HZY2023/VVDF.