Enhancement of text recognition for hanja handwritten documents of Ancient Korea

We implemented a high-performance optical character recognition model for classical handwritten documents using data augmentation with highly variable cropping within the document region. Optical character recognition in handwritten documents, especially classical documents, has been a challenging topic in many countries and research organizations due to its difficulty. Although many researchers have conducted research on this topic, the quality of classical texts over time and the unique stylistic characteristics of various authors have made it difficult, and it is clear that the recognition of hanja handwritten documents is a meaningful and special challenge, especially since hanja, which has been developed by reflecting the vocabulary, semantic, and syntactic features of the Joseon Dynasty, is different from classical Chinese characters. To study this challenge, we used 1100 cursive documents, which are small in size, and augmented 100 documents per document by cropping a randomly sized region within each document for training, and trained them using a two-stage object detection model, High resolution neural network (HRNet), and applied the resulting model to achieve a high inference recognition rate of 90% for cursive documents. Through this study, we also confirmed that the performance of OCR is affected by the simplified characters, variants, variant characters, common characters, and alternators of Chinese characters that are difficult to see in other studies, and we propose that the results of this study can be applied to optical character recognition of modern documents in multiple languages as well as other typefaces in classical documents.

Ancient Korean Archive Translation: Comparison Analysis on Statistical phrase alignment, LLM in-context learning, and inter-methodological approach

This study aims to compare three methods for translating ancient texts with sparse corpora: (1) the traditional statistical translation method of phrase alignment, (2) in-context LLM learning, and (3) proposed inter methodological approach - statistical machine translation method using sentence piece tokens derived from unified set of source-target corpus. The performance of the proposed approach in this study is 36.71 in BLEU score, surpassing the scores of SOLAR-10.7B context learning and the best existing Seq2Seq model. Further analysis and discussion are presented.

Punctuation restoration Model and Spacing Model for Korean Ancient Document

In Korean ancient documents, there is no spacing or punctuation, and they are written in classical Chinese characters. This makes it challenging for modern individuals and translation models to accurately interpret and translate them. While China has models predicting punctuation and spacing, applying them directly to Korean texts is problematic due to data differences. Therefore, we developed the first models which predict punctuation and spacing for Korean historical texts and evaluated their performance. Our punctuation restoration model achieved an F1 score of 0.84, and Spacing model achieved a score of 0.96. It has the advantage of enabling inference on low-performance GPUs with less VRAM while maintaining quite high accuracy.

Transfer Learning across Several Centuries: Machine and Historian Integrated Method to Decipher Royal Secretary's Diary

A named entity recognition and classification plays the first and foremost important role in capturing semantics in data and anchoring in translation as well as downstream study for history. However, NER in historical text has faced challenges such as scarcity of annotated corpus, multilanguage variety, various noise, and different convention far different from the contemporary language model. This paper introduces Korean historical corpus (Diary of Royal secretary which is named SeungJeongWon) recorded over several centuries and recently added with named entity information as well as phrase markers which historians carefully annotated. We fined-tuned the language model on history corpus, conducted extensive comparative experiments using our language model and pretrained muti-language models. We set up the hypothesis of combination of time and annotation information and tested it based on statistical t test. Our finding shows that phrase markers clearly improve the performance of NER model in predicting unseen entity in documents written far different time period. It also shows that each of phrase marker and corpus-specific trained model does not improve the performance. We discuss the future research directions and practical strategies to decipher the history document.