Jochre 3 and the Yiddish OCR corpus

TL;DR

This paper introduces Jochre 3, an open-source OCR tool suite, and a comprehensive Yiddish OCR corpus, demonstrating high accuracy and enabling searchable Yiddish texts for research and digitization efforts.

Contribution

The paper presents a new open-source OCR system tailored for Yiddish, along with a sizable annotated corpus, improving OCR accuracy and accessibility for Yiddish language materials.

Findings

Achieved 1.5% CER on Yiddish OCR corpus

Created a publicly available Yiddish OCR corpus with 658 pages

Enabled searchable Yiddish texts through the Yiddish Book Center

Abstract

We describe the construction of a publicly available Yiddish OCR Corpus, and describe and evaluate the open source OCR tool suite Jochre 3, including an Alto editor for corpus annotation, OCR software for Alto OCR layer generation, and a customizable OCR search engine. The current version of the Yiddish OCR corpus contains 658 pages, 186K tokens and 840K glyphs. The Jochre 3 OCR tool uses various fine-tuned YOLOv8 models for top-down page layout analysis, and a custom CNN network for glyph recognition. It attains a CER of 1.5% on our test corpus, far out-performing all other existing public models for Yiddish. We analyzed the full 660M word Yiddish Book Center with Jochre 3 OCR, and the new OCR is searchable through the Yiddish Book Center OCR search engine.