Comparative analysis of optical character recognition methods for Sámi texts from the National Library of Norway

Fuente: arXiv
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Auteurs principaux: Enstad, Tita, Trosterud, Trond, Røsok, Marie Iversdatter, Beyer, Yngvil, Roald, Marie
Format: Preprint
Publié: 2025
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author Enstad, Tita
Trosterud, Trond
Røsok, Marie Iversdatter
Beyer, Yngvil
Roald, Marie
author_facet Enstad, Tita
Trosterud, Trond
Røsok, Marie Iversdatter
Beyer, Yngvil
Roald, Marie
contents Optical Character Recognition (OCR) is crucial to the National Library of Norway's (NLN) digitisation process as it converts scanned documents into machine-readable text. However, for the Sámi documents in NLN's collection, the OCR accuracy is insufficient. Given that OCR quality affects downstream processes, evaluating and improving OCR for text written in Sámi languages is necessary to make these resources accessible. To address this need, this work fine-tunes and evaluates three established OCR approaches, Transkribus, Tesseract and TrOCR, for transcribing Sámi texts from NLN's collection. Our results show that Transkribus and TrOCR outperform Tesseract on this task, while Tesseract achieves superior performance on an out-of-domain dataset. Furthermore, we show that fine-tuning pre-trained models and supplementing manual annotations with machine annotations and synthetic text images can yield accurate OCR for Sámi languages, even with a moderate amount of manually annotated data.
format Preprint
id arxiv_https___arxiv_org_abs_2501_07300
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Comparative analysis of optical character recognition methods for Sámi texts from the National Library of Norway
Enstad, Tita
Trosterud, Trond
Røsok, Marie Iversdatter
Beyer, Yngvil
Roald, Marie
Computation and Language
Computer Vision and Pattern Recognition
Optical Character Recognition (OCR) is crucial to the National Library of Norway's (NLN) digitisation process as it converts scanned documents into machine-readable text. However, for the Sámi documents in NLN's collection, the OCR accuracy is insufficient. Given that OCR quality affects downstream processes, evaluating and improving OCR for text written in Sámi languages is necessary to make these resources accessible. To address this need, this work fine-tunes and evaluates three established OCR approaches, Transkribus, Tesseract and TrOCR, for transcribing Sámi texts from NLN's collection. Our results show that Transkribus and TrOCR outperform Tesseract on this task, while Tesseract achieves superior performance on an out-of-domain dataset. Furthermore, we show that fine-tuning pre-trained models and supplementing manual annotations with machine annotations and synthetic text images can yield accurate OCR for Sámi languages, even with a moderate amount of manually annotated data.
title Comparative analysis of optical character recognition methods for Sámi texts from the National Library of Norway
topic Computation and Language
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2501.07300