Multimodal sentiment analysis(MSA) is mostly used to understand human emotional states through multimodal. However, due to the fact that the effective information carried by multimodal is not balanced, the modality containing less effective information cannot fully play the complementary role between modalities. Therefore, the goal of this paper is to fully explore the effective information in modalities and further optimize the under-optimized modal representation.To this end, we propose a novel Modal Feature Optimization Network (MFON) with a Modal Prompt Attention (MPA) mechanism for MSA. Specifically, we first determine which modalities are under-optimized in MSA, and then use relevant prompt information to focus the model on these features. This allows the model to focus more on the features of the modalities that need optimization, improving the utilization of each modality’s feature representation and facilitating initial information aggregation across modalities. Subsequently, we design an intra-modal knowledge distillation strategy for under-optimized modalities. This approach preserves the integrity of the modal features. Furthermore, we implement inter-modal contrastive learning to better extract related features across modalities, thereby optimizing the entire network. Finally, sentiment prediction is carried out through the effective fusion of multimodal information. Extensive experimental results on public benchmark datasets demonstrate that our proposed method outperforms existing state-of-the-art models.

Emotion recognition in conversation (ERC) involves identifying emotional labels associated with utterances within a conversation, a task that is essential for developing empathetic robots. Current research emphasizes contextual factors, the speaker’s influence, and extracting complementary information across different modalities. However, it often overlooks the cross-modal noise at the semantic level and the redundant information brought by the features themselves. This study introduces a diffusion-based approach designed to effectively address the challenges posed by redundant information and unexpected noise while robustly capturing shared semantics, thus facilitating the learning of compact and representative features from multimodal data. Specifically, we present the Multi-Condition Guided Diffusion Network (McDiff). McDiff employs a modal prior knowledge extraction strategy to derive the prior distribution for each modality, thereby enhancing the regional attention of each modality and applying the generated prior distribution at each diffusion step. Furthermore, we propose a method to learn the mutual information of each modality through a specific objective constraints approach prior to the forward process, which aims to improve inter-modal interaction and mitigate the effects of noise and redundancy. Comprehensive experiments conducted on two multimodal datasets, IEMOCAP and MELD, demonstrate that McDiff significantly surpasses existing state-of-the-art methodologies, thereby affirming the generalizability and efficacy of the proposed model.