Licensing

Licensing

This repository holds three kinds of material with different rights, so one licence over everything would misdescribe at least one of them. Copyright in the code and documentation is held jointly by Stephen Masters and Yvette Mankerian.

The corpus images

Every image in evaluation/corpus/images/ is in the public domain in the United States. We did not create them and hold no copyright in them, so there is nothing here for us to license — a licence file covering them would overclaim. Provenance, source institution and rights status for each item are recorded in evaluation/corpus/SOURCES.md.

Public domain status is jurisdictional. These items are public domain in the US; if you are republishing elsewhere, check your own position.

The transcripts

The ground-truth transcripts in evaluation/corpus/expected/ were generated by Claude from the corpus images and are released under CC BY 4.0. They are the reference the whole benchmark is scored against, and the most directly reusable artefact here — if you use them, attribution is the only condition.

Bear in mind what they are: a strong vision model’s reading of these images, not a human-verified transcription. The method page sets out the limits.

Attribution

For the documentation, the benchmark results or the transcripts:

Tetrak OCR (Stephen Masters and Yvette Mankerian), CC BY 4.0. https://github.com/scattercode/tetrak

Dependencies

The core dependencies are permissively licensed — Pillow, pytesseract (Apache-2.0), pdf2image (MIT) and python-dotenv (BSD-3-Clause) — so installing tetrak-ocr on its own carries no copyleft obligation.

The optional backends are a different matter, and one is worth knowing about before you build on it: marker-pdf and its Surya models are, as of writing, GPL-3.0 with a commercial-use exception offered by their author. That does not affect this project’s licence — the extras are optional dependencies, resolved at install time and never vendored here — but it does affect anyone redistributing a bundle that includes them. Check the current terms upstream rather than relying on this note; licence terms change.