Describe-then-Reason: Improving Multimodal Mathematical Reasoning through Visual Comprehension Training
Mengzhao Jia, Zhihan Zhang, Wenhao Yu, Fangkai Jiao, Meng Jiang
TL;DR
Open-source MLLMs struggle with multimodal mathematical reasoning due to weak visual comprehension. VCAR introduces a two-step training pipeline that first strengthens visual understanding through image description generation and then enhances reasoning with description-assisted rationales, using separate LoRA adapters. The method achieves significant improvements on MathVista and MathVerse, especially for visually demanding problems, and gains are observed across different base models. Ablation studies confirm the necessity of both components and the proposed training order, underscoring the importance of visual-centric supervision for multimodal math.
Abstract
Open-source multimodal large language models (MLLMs) excel in various tasks involving textual and visual inputs but still struggle with complex multimodal mathematical reasoning, lagging behind proprietary models like GPT-4V(ision) and Gemini-Pro. Although fine-tuning with intermediate steps (i.e., rationales) elicits some mathematical reasoning skills, the resulting models still fall short in visual comprehension due to inadequate visual-centric supervision, which leads to inaccurate interpretation of math figures. To address this issue, we propose a two-step training pipeline VCAR, which emphasizes the Visual Comprehension training in Addition to mathematical Reasoning learning. It first improves the visual comprehension ability of MLLMs through the visual description generation task, followed by another training step on generating rationales with the assistance of descriptions. Experimental results on two popular benchmarks demonstrate that VCAR substantially outperforms baseline methods solely relying on rationale supervision, especially on problems with high visual demands.
