A Multi-Stage System for Ancient Chinese OCR and Layout Understanding in the EvaHan2026 Shared Task

KeYan Liang, Meiling Liu


Abstract
This paper presents a multi-stage system for the EvaHan2026 shared task, addressing the complex challenges of ancient Chinese optical character recognition (OCR) and layout understanding. For text recognition (Tasks A and C), we adopt parameter-efficient LoRA fine-tuning on the Qwen2.5-VL-7B-Instruct vision-language model (VLM). By directly processing full-resolution long-column images, we preserve critical spatial and contextual integrity without heuristic region cropping. For document layout analysis (Task B), we propose a novel hybrid perception-reasoning paradigm. Instead of relying solely on scaling visual detectors, we decouple localization and understanding: utilizing a YOLO-based ensemble for precise spatial bounding, and casting the VLM as a semantic verifier to eliminate spurious detections. Evaluated on the official unseen test set, our system achieves substantial improvements over the provided baselines, obtaining a 0.0441 Character Error Rate (CER) for printed OCR, a 0.0793 CER for handwritten OCR (including variants), and a 0.5118 mAP@[0.5:0.95] for layout detection. These results demonstrate that integrating VLM-based semantic reasoning into traditional visual detection pipelines is highly effective for multimodal historical document analysis.
Anthology ID:
2026.lt4hala-1.24
Volume:
Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages (LT4HALA 2026) @ LREC 2026
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Rachele Sprugnoli, Marco Passarotti
Venues:
LT4HALA | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
263–267
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-lt4hala-24
DOI:
10.63317/4tmmz89iawet
Bibkey:
Cite (ACL):
KeYan Liang and Meiling Liu. 2026. A Multi-Stage System for Ancient Chinese OCR and Layout Understanding in the EvaHan2026 Shared Task. In Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages (LT4HALA 2026) @ LREC 2026, pages 263–267, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
A Multi-Stage System for Ancient Chinese OCR and Layout Understanding in the EvaHan2026 Shared Task (Liang & Liu, LT4HALA 2026)
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