| --- |
| 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](https://pitaka.lk). |
|
|
| ## 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`. |
|
|
| ```python |
| 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](https://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](https://tipitaka.lk/library) | corrected editions from [pitaka.lk/books](https://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](https://huggingface.co/datasets/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-lib` pages 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. |
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|
