Abstract
Historical Manchu OCR must accommodate various visually distinct writing styles, including regular script, running script, and the semi-cursive chancery hand used in palace memorials, despite limited labeled data. We study a multi-expert system that reuses checkpoints from an iterative fine-tuning process as domain specialists and uses a lightweight page-level image classifier to dispatch pages by visual style.
When the checkpoint pool lacks a suitable specialist, we train an additional expert for that domain. On three frozen test sets, the routed system matches the selected specialist for each style at two-decimal precision: 0.30 percent CER on regular script, 1.57 percent on memorials, and 4.83 percent on running script. The router achieves 99.3 percent page-level domain accuracy and matches the domain-label oracle at the same precision. Two of the three selected specialists were not trained specifically for their final domain; only the running-script expert was trained with that domain as its target.
We report the evaluation protocol, router design, and per-page predictions to make the comparison reproducible.
Blogger's Review: This study highlights the potential of effectively handling diverse writing styles through a multi-expert system in resource-constrained scenarios, particularly for historical text OCR tasks. The checkpoint reuse strategy not only enhances accuracy but also provides new insights for future low-resource OCR fields.