Datasets:
language:
- si
- pi
license: cc-by-4.0
task_categories:
- image-to-text
tags:
- ocr
- sinhala
- pali
- historical-documents
- buddhism
pretty_name: Sinhala and Pali OCR (old prints)
size_categories:
- 1K<n<10K
Sinhala and Pali OCR: old prints
These are scanned pages of Sinhala and Pali books, mostly Buddhist texts printed between the 1870s and 2000s, each paired with a corrected transcription. They were collected to fine-tune a page-level OCR model (e.g. LightOnOCR-2) for old Sinhala-script print, made by Path Nirvana.
Target format
Each target is the page text as UTF-8 Unicode Sinhala (NFC):
- Lines: one printed line becomes one line of text. A word split by the printer across a line end keeps its hyphen (
word-\n). - Paragraphs: a blank line separates paragraphs, headings, verses and footnotes.
- Bold: printed bold is marked
**bold**. - Footnotes: reference numbers are superscript digits (¹ ² ³).
- Left out: running headers, page numbers and printer's footer codes.
The prompt column says when a target falls short of this format. The image is then given to the model with that prompt as a text instruction, so that pages with no prompt keep the full format:
| prompt | meaning |
|---|---|
| null | full format |
nobold |
the source transcription has no bold markup (the acts pages) |
crop is [x0, y0, x1, y1] to apply to the image before use, or null for the full page. A crop is used where the page holds text that the transcription lacks.
Files
The data is in Parquet shards, data/{train,validation,test}-*.parquet, with one row per page. The columns are id, image (the original JPEG bytes), crop, text, prompt, source, stratum, lang and year.
from datasets import load_dataset
ds = load_dataset("pathnirvana/sinhala-pali-ocr", split="train")
row = ds[0]
img = row["image"].crop(row["crop"]) if row["crop"] else row["image"]
Sources
| source | pages | images | text |
|---|---|---|---|
bjt |
3,301 | Buddha Jayanti Tripitaka (Sri Lanka government edition, 1960s–80s), Pali and facing Sinhala translation | typed text from tipitaka.lk. Printed line breaks were recovered by aligning Tesseract line boxes. 30 pages per volume and language |
pitaka-books |
4,795 | old scanned prints in the tipitaka.lk library | corrected editions from pitaka.lk/books, cut into pages by alignment. At most 150 pages per print, from 32 books |
acts |
410 | Sri Lankan acts, 1981–1989 | the pre-2000 pages of avishadilhara/sinhala-ocr-lk-acts-1010 (CC BY 4.0), with headers removed |
opus-lib |
92 | single pages of library books printed 1870s–1980s | transcribed by Claude Opus. Not human-checked, so expect a few % character errors and imperfect bold |
The page transcriptions come from corrected editions, which can differ from the printed page in places: spelling, punctuation, small edits. Expect a floor of about 1–2% character differences.
Splits
- test: whole books never trained on. These are BJT volumes 12, 29 and 47, and the pitaka.lk books suvisi-gunaya (1964 print) and chathurarya-sathya (2007).
- test, other sources: the acts follow the source dataset's split, and 10% of the
opus-libpages are test. - validation: a small set of pages from all sources, used to track loss.
Credits
The acts pages come from Sinhala OCR – Sri Lankan Acts Dataset by avishadilhara (CC BY 4.0). The BJT text is from tipitaka.lk, and the book texts and scans are from pitaka.lk and the tipitaka.lk library.