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Pretrained mixed models to be used with Calamari.

Short description of the available models

  • gt4histocr was trained on the entire GT4HistOCR corpus
  • antiqua/fraktur_historical used the corresponding data from the GT4HistOCR corpus
  • The ligs versions used the same data as the standard antiqua/fraktur_historical models but were refined on an manually enriched subset (afair 100 lines per book) containing ligatures etc.
  • fraktur19 is based on the DTA19 sub set of the GT4HistOCR corpus; and other Fraktur19 data; see here for further details
  • uw3-modern-english (formerly antiqua_modern) was trained on the UW3 dataset (link seems to be down)
  • idiotikon originated from a cooperation with Schweizerisches Idiotikon in an effort to OCR the entire dictionary. The model is based on the UW3 model and its codec contains a wide variety of mostly Latin-based characters including many diacritics. Consequently, it may be a good choice to recognize many modern languages.
  • 18th_century_french was trained in cooperation with the MiMoText project of the University of Trier. It is based on double-keyed transcriptions of french novels published between 1750 and 1800.
  • historical_french used data from 17/18/19. century French printings collected by Simon Gabay

General comments

  • All models are provided as a voting ensemble trained via calamari-cross-fold-train and containing five individual voters.
  • Most models have been trained (exclusively) on the output of the OCRopus nlbin script (gt4histocr used grayscale images, the rest binary ones) and will consequently work best on similar data.
  • All models have been trained using NFC normalization except the idiotikon one (NFD).

Future work

We are planning to considerably increase the number of available models in the somewhat near future, including more time-specific models and spezialized or at least more robust models regarding different binarization techniques. Furthermore, a student work (hopefully) will deal with the task of training various models for modern scripts and languages using (mainly) synthetic data.

If you want to contribute your own models or have any questions / model requests please don't hesitate to contact us.