RegionDoc-R1: Reinforcing Semantic Layout-Aware Reasoning for Document Understanding

Chao Wang, Hehe Fan, Huichen Yang, Zhengdong Hu, Sarvnaz Karimi, Lina Yao, Yi Yang


Abstract
Reinforcement Learning (RL) has proven effective in eliciting reasoning abilities of Multimodal Large Language Models (MLLMs) and is emerging in document understanding. However, existing approaches usually lack fine-grained region-level grounding supervision, while the key challenge in document reasoning lies in linking visual evidence within precise regions directly to question–answer semantics. We introduce RegionDoc-R1, a novel framework for document understanding that enhances MLLMs’ reasoning with step-wise feedback. Instead of previous OCR-based text positions, we encourage the model to predict question-relevant Regions of Interest (RoIs) and ground the answer in these regions. Specifically, we first propose the Region-Aware Group Relative Policy Optimization (RA-GRPO), which encourages models to utilize region-level spatial information in documents for reasoning. Correspondingly, we construct a hybrid training corpus, named SR-Doc, containing Semantic Reasoning (SR) examples enriched with cross-page and region-level reasoning layout annotations. Meanwhile, we also introduce an Adaptive Chain-of-Thought (Ada-CoT) strategy, which dynamically adjusts the reasoning process according to different tasks, enabling more efficient and flexible step-wise document understanding. Experiments on several document reasoning benchmarks demonstrate that RegionDoc-R1 achieves state-of-the-art performance across tasks such as form document understanding, table-based QA, and layout-sensitive information extraction.
Anthology ID:
2026.emnlp-main.965
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
22260–22282
Language:
URL:
https://aclanthology.org/2026.emnlp-main.965/
DOI:
Bibkey:
Cite (ACL):
Chao Wang, Hehe Fan, Huichen Yang, Zhengdong Hu, Sarvnaz Karimi, Lina Yao, and Yi Yang. 2026. RegionDoc-R1: Reinforcing Semantic Layout-Aware Reasoning for Document Understanding. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 22260–22282, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
RegionDoc-R1: Reinforcing Semantic Layout-Aware Reasoning for Document Understanding (Wang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.965.pdf