Description

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kraken is a turn-key OCR system optimized for historical and non-Latin script material.

kraken's main features are:

• Fully trainable layout analysis, reading order, and character recognition
• Right-to-Left <https://en.wikipedia.org/wiki/Right-to-left>, BiDi <https://en.wikipedia.org/wiki/Bi-directional_text>, and Top-to-Bottom script support
• ALTO <https://www.loc.gov/standards/alto/>_, PageXML, abbyyXML, and hOCR output
• Word bounding boxes and character cuts
• Multi-script recognition support
• Public repository <https://zenodo.org/communities/ocr_models>_ of model files
• Variable recognition network architecture

Installation

kraken only runs on Linux or Mac OS X. Windows is not supported.

The latest stable releases can be installed either from PyPi <https://pypi.org>_:

::

$ pip install kraken

or through conda <https://anaconda.org>_:

::

$ conda install -c conda-forge -c mittagessen kraken

If you want direct PDF and multi-image TIFF/JPEG2000 support it is necessary to install the pdf extras package for PyPi:

::

$ pip install kraken[pdf]

or install pyvips manually with pip:

::

$ pip install pyvips

Conda environment files are provided for the seamless installation of the main branch as well:

::

$ git clone https://github.com/mittagessen/kraken.git $ cd kraken $ conda env create -f environment.yml

or:

::

$ git clone https://github.com/mittagessen/kraken.git $ cd kraken $ conda env create -f environment_cuda.yml

for CUDA acceleration with the appropriate hardware.

Finally you'll have to scrounge up a model to do the actual recognition of characters. To download the default model for printed French text and place it in the kraken directory for the current user:

::

$ kraken get 10.5281/zenodo.10592716

A list of libre models available in the central repository can be retrieved by running:

::

$ kraken list

Quickstart

Recognizing text on an image using the default parameters including the prerequisite steps of binarization and page segmentation:

::

$ kraken -i image.tif image.txt binarize segment ocr

To binarize a single image using the nlbin algorithm:

::

$ kraken -i image.tif bw.png binarize

To segment an image (binarized or not) with the new baseline segmenter:

::

$ kraken -i image.tif lines.json segment -bl

To segment and OCR an image using the default model(s):

::

$ kraken -i image.tif image.txt segment -bl ocr -m catmus-print-fondue-large.mlmodel

All subcommands and options are documented. Use the help option to get more information.

Documentation

Have a look at the docs <https://kraken.re>_.

Related Software

These days kraken is quite closely linked to the eScriptorium <https://gitlab.com/scripta/escriptorium/>_ project developed in the same eScripta research group. eScriptorium provides a user-friendly interface for annotating data, training models, and inference (but also much more). There is a gitter channel <https://gitter.im/escripta/escriptorium>_ that is mostly intended for coordinating technical development but is also a spot to find people with experience on applying kraken on a wide variety of material.

Funding

kraken is developed at the École Pratique des Hautes Études <https://www.ephe.psl.eu>, Université PSL <https://www.psl.eu>.

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    .. image:: https://raw.githubusercontent.com/mittagessen/kraken/main/docs/_static/normal-reproduction-low-resolution.jpg
      :width: 100
      :alt: Co-financed by the European Union

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    This project was partially funded through the RESILIENCE project, funded from
    the European Union’s Horizon 2020 Framework Programme for Research and
    Innovation.

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  .. image:: https://projet.biblissima.fr/sites/default/files/2021-11/biblissima-baseline-sombre-ia.png
     :width: 400
     :alt: Received funding from the Programme d’investissements d’Avenir

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    Ce travail a bénéficié d’une aide de l’État gérée par l’Agence Nationale de la
    Recherche au titre du Programme d’Investissements d’Avenir portant la référence
    ANR-21-ESRE-0005 (Biblissima+).