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ocrtesseract

Limit characters tesseract is looking for

Is it possible to limit the set of characters that tesseract is looking for (e.g. search only for letters a-z)? That would improve my results greatly.

Solution

  • Create a config file (e.g "letters") in tessdata/configs directory - usually /usr/share/tesseract/tessdata/configs
    or
    /usr/share/tesseract-ocr/tessdata/configs

    And add this line to the config file:

    tessedit_char_whitelist abcdefghijklmnopqrstuvwxyz

    ...or maybe [a-z] works. I don't know. Then call tesseract similar to this:

    tesseract input.tif output nobatch letters

    That will limit tesseract to recognize only the wanted characters.