---
license: cc-by-4.0
language:
- sv
- de
- en
- fr
- da
- 'no'
tags:
- ocr
- htr
- page-xml
- libraries
- cultural-heritage
configs:
- config_name: default
  data_files:
  - split: train
    path: data/train-*.parquet
---

# Kat57 ground truth

Hugging Face conversion of Lund University Library's
[Kat57 ground-truth release](https://zenodo.org/records/14679534): 10,695 scanned catalogue
cards with manually corrected PAGE XML transcriptions.

The cards come from Catalogue -1957, Lund University Library's alphabetical
catalogue of holdings published through 1957. They contain a mixture of
typewritten and handwritten text in several languages.

## Fields

- `image`: original PNG card scan
- `reference`: line transcriptions joined in PAGE XML document order
- `lines`: individual PAGE XML line transcriptions
- `page_xml`: original PAGE XML, including line geometry
- `id`, `drawer_id`, `card_id`, `source_image`: source identifiers

## Conversion

The source archive contains 10,695 matched PNG/XML pairs. This copy
is stored in 84 Parquet shards and was produced by the reproducible
Kat57 converter in [`tadad/ocr-bench`](https://github.com/tadad/ocr-bench/tree/feat/cer-wer-kat57/experiments/kat57).
No OCR or synthetic labels were introduced: `reference`, `lines`, and
`page_xml` are derived directly from Lund's human-transcribed PAGE XML.

Source ZIP MD5: `0895d5785cd0ddf9f9c6488484ac447e`.

## License and attribution

The source dataset is CC BY 4.0. Credit Maria Hedberg and Lund University
Library, and cite the [Zenodo record](https://zenodo.org/records/14679534) when using this
conversion. This repository is a convenience conversion and is not an
official Lund University Library publication.