BrailleLens/Annotated_braille_page_dataset

Annotated Braille Page Dataset

Page-level photos of Braille book pages, hand-annotated with axis-aligned bounding boxes around every Braille cell (2x3 raised-dot pattern), in LabelMe JSON format. Collected and annotated for BrailleLens, a camera-based Braille reading/learning system.

Contents

12 physical pages from a Sinhala Braille book, each shot twice under different lighting:

Folder	Description
High quality dataset/	12 pages (pg-1.jpeg ... pg-12.jpeg), good lighting, each with a matching pg-N.json LabelMe annotation
Low quality dataset/	The same 12 physical pages, re-photographed under weaker/uneven lighting, each with its own pg-N.json annotation
symbols guide.jpeg	Reference chart: the Sinhala Braille dot-pattern-to-character table used while annotating
ANNOTATION_GUIDELINES.md	The annotation spec used to produce this dataset (box convention, label format, train/val/test split)

48 images, 24 LabelMe JSON annotation files.

Annotation format

Each pg-N.json is a standard LabelMe file: shapes is a list of axis-aligned rectangles, one per physical Braille cell. points gives the box corners in pixel coordinates; label is the cell's raised dot pattern, written as the concatenated dot numbers (not a Sinhala character):

Raised dots	Label
none (blank cell)	0
dots 1, 2	12
dots 1, 3, 4, 5	1345
all six	123456

Dot numbering:

1  4
2  5
3  6

This is the same 0-63 encoding used for the Sri Lankan Sinhala Braille alphabet (code = sum(1 << (dot-1)) over raised dots); symbols guide.jpeg maps each code to its printed Sinhala glyph.

Known gaps

• Decorative divider/ruler rows (used for section breaks) are intentionally not boxed -- they aren't Braille cells.
• Hand-transcribed plain-text ground truth exists for 6 of the 12 pages but isn't included in this release yet (incomplete); may be added in a future version once all 12 are done.

Recommended split

Both lighting variants of a page should stay in the same split (don't separate High/Low quality versions of the same physical page across splits):

Pages	Split
1-8	train
9-10	val
11-12	test

License

CC BY 4.0.