biglam/horae-lsv2-layout

HORAE-LSv2 — layout segmentation for Books of Hours

555 annotated page images from 334 medieval and early-modern Books of Hours, manuscript and printed, marked up for page layout analysis. Created by the HORAE project at the Institut de Recherche et d'Histoire des Textes (IRHT-CNRS) with Teklia, and deposited on Zenodo in August 2025 as HORAE-LSv2 (10.5281/zenodo.16919911).

This repository is a format conversion of that deposit. Same images, same annotations, repackaged so it loads with datasets instead of requiring four zip files and three text encodings.

Two annotation systems over the same pages

The deposit ships two independent markup schemes for the same 555 pages, and they do not map onto each other. Both are carried here rather than picking one.

Column	Scheme	Geometry	Count
objects	14-class YOLO taxonomy	bounding boxes, COCO [x, y, w, h] in absolute pixels	22,878
regions	7-type Arkindex taxonomy plus subclasses	polygons	22,964

regions types and their subclasses:

Type	Count	Subclasses
text_line	13,879	calendar
initial	3,542	simple_initial, decorated_initial, historiated_initial
decoration	2,412	line_filler, ornament, music_notation, decorated_border, illustrated_border
rubrication	1,224	red, blue, gold
text	896	border_text
single_page	852	calendar
miniature	159	—

text_line is 60% of the polygon annotations. Filter it out if you are after decorative or structural elements rather than lines.

Structure

Field	Type	Notes
image	image	JPEG at maximum available IIIF resolution
file_name	string	source filename; institution and shelfmark are encoded in it
width, height	int32	as declared upstream; verified to match the decoded image
iiif_url	string	the IIIF source URL, preserved for provenance
objects	list of struct	bbox, category_id, category_name
regions	list of struct	polygon, type, class_name

Caveats

Not every page is annotated. 555 images, but only 545 carry YOLO labels and 542 carry polygon regions. Roughly 13 pages have an image and nothing else. This is in the source deposit, not introduced by the conversion. Filter on len(objects) > 0 or len(regions) > 0 before training.

There are no splits. The upstream README documents metadata/train.csv, val.csv and test.csv; none of those files exist in the published archive, including in extras.zip. Everything is in a single train split. Make your own splits — and group by manuscript, not by page, since 555 pages come from only 334 books and pages from the same book are highly correlated.

No transcriptions. The upstream documentation describes text_line elements as carrying transcription data. The published elements.csv has no transcription column, so none is present here. This is a layout dataset only.

Dating is unknown per item. The deposit does not ship per-manuscript dates, so there is no date field. "Medieval and early modern" is the collection-level description, not something you can filter on.

If you go back to the original deposit

The three annotation files are in three different text encodings, which is worth knowing before you parse them yourself:

File	Encoding
extras/HORAE_LSv2.csv	UTF-8
metadata/HORAE_LSv2_elements.csv	latin-1
metadata/HORAE_LSv2_image_data.csv	UTF-7 (+AF8- for _)

Reading any of them as UTF-8 either raises or silently mangles every accented library name. The conversion here decodes each with its own encoding.

The 2019 first release (HORAE_LS) referenced images by IIIF URL rather than shipping them; those URLs rotted, which is why v2 exists with images included.

Load

from datasets import load_dataset

ds = load_dataset("biglam/horae-lsv2-layout", split="train")

# pages with decorative elements only — text_line is 60% of the polygons
decorated = ds.filter(
    lambda r: any(x["type"] in {"miniature", "initial", "decoration"} for x in r["regions"])
)

Licence

CC BY 4.0, following the upstream deposit. Attribution to the HORAE project creators, below.

Note that the source institutions holding the digitised manuscripts apply their own terms to the underlying images; the Zenodo deposit is the layer licensed CC BY 4.0. Where you need to go back to an institution's own copy, iiif_url points at it.

Credit

Data created by Dominique Stutzmann and Lise Bernard Leterme (Institut de Recherche et d'Histoire des Textes), Mélodie Boillet and Christopher Kermorvant (Teklia), and Marie-Laurence Bonhomme. Converted and repackaged for the Hub by Daniel van Strien.

@dataset{stutzmann_2025_horae_lsv2,
  author    = {Stutzmann, Dominique and Bernard Leterme, Lise and Boillet, M{\'e}lodie and
               Bonhomme, Marie-Laurence and Kermorvant, Christopher},
  title     = {{HORAE-LSv2. Layout Segmentation Dataset for Medieval Books of Hours}},
  year      = {2025},
  version   = {2.0},
  publisher = {Zenodo},
  doi       = {10.5281/zenodo.16919911}
}