README.md

---
license: cc0-1.0
task_categories:
- image-to-text
language:
- bo
tags:
- ocr
- tibetan
- benchmark
- evaluation
pretty_name: "BDRC Tibetan OCR Evaluation Benchmark"
size_categories:
- n<1K
configs:
- config_name: default
  data_files:
  - split: test
    path: "data/test-*.parquet"
---

# BDRC Tibetan OCR Benchmark (open subset)

<!-- DRAFT public card for BDRC/tibetan-ocr-benchmark. The full benchmark is 1,071
     hand-transcribed pages; this open release is the 472 that can be shared. -->

A hand-transcribed benchmark for evaluating Tibetan OCR across writing styles and
technologies. This is an **open-access set of 472 page images** with ground-truth
transcriptions and per-page metadata (script, technology, legibility).

Companion to the model [`BDRC/tibetan-ocr`](https://huggingface.co/BDRC/tibetan-ocr)
and the **[leaderboard](https://huggingface.co/spaces/BDRC/tibetan-ocr-leaderboard)**
(dozens of OCR systems scored on this benchmark).

The transcriptions were produced by [Dharmaduta](dharmaduta.in).

The images were selected through detailed research on Tibetan writing styles in collaboration
with Pentsok W. Rtsang who selected and cataloged the images. Most writing styles are represented
in the benchmark, except those only present in images that cannot be made fully open access.

## Contents & schema

One row per page. We deliberately keep **only fully-documentable** metadata; the
internal fine-grained numeric script id and the 8-class script label are **not**
published here.

| column | description |
|---|---|
| `image` | the page scan (embedded bytes; anonymized filename) |
| `transcription` | Tibetan Unicode ground truth (main text box only), botok-normalized |
| `id` | stable per-page id (the anonymized page number, e.g. `0002`) |
| `technology` | how the page was produced: `manuscripts` / `blockprints` / `modern` / `metal_type` / `typewriter` / … |
| `script` | coarse writing system: `Uchen` / `Ume` |
| `script_4` | writing-style family: `Uchen` / `Pedri` / `Gyuyig` / `Druma` / `Tsugdri` / `Danyig` / `Non-applicable` |
| `period` | palaeographic period of the writing style (e.g. *Medieval (15)-present*) |
| `rarity` | how common the writing style is (e.g. *4 - very common*) |
| `legibility` | annotator legibility grade of the page (e.g. *2 - Fair*, *4 - Excellent*) |

```python
from datasets import load_dataset
ds = load_dataset("BDRC/tibetan-ocr-benchmark", split="test")
```

## Transcription conventions

- Only the **main text box** is transcribed (no marginalia or pagination).
- Orthographic **shorthands are kept** as written.
- Placeholders in ground truth: `I` illegible · `B` broken paper · `S` struck-through
  · `D`/`K` dakini script · `O` ornamental. Scribal inserts are marked with `()`.

See `transcription_conventions.md` and `analysis_conventions.md` in this repo for
the full manuals.

## How CER is computed

Character Error Rate is computed after normalization, both sides:

1. Normalize with **botok** (hypothesis; ground truth is pre-normalized).
2. Strip all whitespace.
3. Fold repeated tsheg (`U+0F0B`) to one.
4. Remove placeholder characters (`K O B I S`).
5. `CER = Levenshtein(hyp, ref) / len(ref)` (rapidfuzz).

Aggregate CER is an **unweighted mean over pages**.

## License

- **CC0-1.0** for the transcriptions and metadata. Image-rights: BDRC claims no
  copyright over the scans; verifying the underlying works' copyright is the user's
  responsibility.

## Citation

```bibtex
@misc{bdrc_tibetan_ocr_benchmark_2026,
  title  = {BDRC Tibetan OCR Benchmark},
  author = {Buddhist Digital Resource Center},
  year   = {2026},
  howpublished = {Hugging Face},
  note   = {https://huggingface.co/datasets/BDRC/tibetan-ocr-benchmark}
}
```

Funded by the **Khyentse Foundation** ("The BDRC Etext Corpus").