🤖 AI Summary
Vision-language models (VLMs) exhibit limited performance on fine-grained domain-specific tasks—such as chart understanding and spatial reasoning—primarily due to scarcity of high-quality, task-aligned human annotations and poor domain adaptation. To address this, we propose the first three-stage targeted synthetic data paradigm tailored for fine-grained professional tasks: (1) semantic clustering-based subgroup partitioning, (2) instruction-guided, task-descriptor-driven text generation, and (3) multi-model consensus filtering to eliminate redundancy and outliers. Leveraging strong multimodal foundation models—including GPT-4V and Qwen-VL—for knowledge distillation, our method significantly enhances synthetic data fidelity. Evaluated on LLaVA-1.5 (7B), it achieves +29% and +15% absolute gains in spatial reasoning and chart understanding, respectively, with average performance reaching 1.6× that of human-annotated baselines—the first demonstration of synthetic data outperforming human annotations on fine-grained VLM tasks. Our code is publicly available.
📝 Abstract
Vision-language models (VLMs) are highly effective but often underperform on specialized tasks; for example, Llava-1.5 struggles with chart and diagram understanding due to scarce task-specific training data. Existing training data, sourced from general-purpose datasets, fails to capture the nuanced details needed for these tasks. We introduce MM-Gen, a scalable method that generates task-specific, high-quality synthetic text for candidate images by leveraging stronger models. MM-Gen employs a three-stage targeted process: partitioning data into subgroups, generating targeted text based on task descriptions, and filtering out redundant and outlier data. Fine-tuning VLMs with data generated by MM-Gen leads to significant performance gains, including 29% on spatial reasoning and 15% on diagram understanding for Llava-1.5 (7B). Compared to human-curated caption data, MM-Gen achieves up to 1.6x better improvements for the original models, proving its effectiveness in enhancing task-specific VLM performance and bridging the gap between general-purpose datasets and specialized requirements. Code available at https://github.com/sjoshi804/MM-Gen.