ESTJ: Enhancing Structured Tendency Judgment in Hybrid-Modal Table Understanding

Hybrid-modal table understanding (HMTU), which targets leveraging multi-modal table evidence for multi-hop reasoning, has garnered widespread attention. Existing models primarily focus on effectively integrating multi-modal table evidence to enhance the table understanding capabilities of multi-modal large language models (MLLMs). However, these models ignore the fact that different types of table understanding questions lean toward different modalities of table evidence. Consequently, these models suffer from low utilization efficiency and poor interpretability. To address these issues, in this paper, we propose a modality preference alignment model, called ESTJ, which Enhances Structured Tendency Judgment in HMTU. Specifically, ESTJ first samples modality preference data from the responses generated by MLLMs. Then, it alleviates modality preference imbalance by adhering to the principle of least modality priority. Finally, ESTJ performs direct preference optimization (DPO) training based on structured tendency judgment to align modality preference effectively. Experimental results on TableQA and TableFV tasks demonstrate that our proposed model outperforms state-of-the-art baselines. Additionally, these results present fascinating phenomena and unveil profound insights into modality preference for table understanding.