114 lines
3.8 KiB
ReStructuredText
114 lines
3.8 KiB
ReStructuredText
OCRmyPDF
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========
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OCRmyPDF adds an OCR text layer to scanned PDF files, allowing them to
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be searched.
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Main features
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-------------
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- Generates a searchable
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`PDF/A <https://en.wikipedia.org/?title=PDF/A>`__ file from a PDF
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file containing only images
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- Places OCRed text accurately below the image to ease copy / paste
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- Keeps the exact resolution of the original embedded images
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- or if requested oversamples the images before OCRing so as to get
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better results
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- If requested deskews and/or cleans the image before performing OCR
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- Validates the generated file against the PDF/A-1b specification using
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`JHOVE <http://jhove.sourceforge.net/>`__
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- Provides debug mode to enable easy verification of the OCR results
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- Processes several pages in parallel when more than one CPU core is
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available
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- Uses Tesseract OCR engine
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For details: please consult the `release notes <RELEASE_NOTES.rst>`__
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Motivation
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----------
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I searched the web for a free command line tool to OCR PDF files on
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Linux/UNIX: I found many, but none of them were really satisfying.
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- Either they produced PDF files with misplaced text under the image (making copy/paste impossible)
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- Or they did not display correctly some escaped HTML characters located in the hOCR file produced by the OCR engine
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- Or they changed the resolution of the embedded images
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- Or they generated PDF files having a ridiculous big size
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- Or they crashed when trying to OCR some of my PDF files
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- Or they did not produce valid PDF files (even though they were readable with my current PDF reader)
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- On top of that none of them produced PDF/A files (format dedicated for long time storage)
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... so I decided to develop my own tool (using various existing scripts
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as an inspiration)
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Install
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-------
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Download OCRmyPDF here: https://github.com/fritz-hh/OCRmyPDF/releases
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You can install it within a virtual environment or system-wide.
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To install the HEAD revision from sources in development mode::
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git clone -b master https://github.com/fritz-hh/OCRmyPDF.git
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cd OCRmyPDF
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pip3 install -e .
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On certain Linux/UNIX platforms such as Ubuntu, you may need to use
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run the install command as superuser::
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sudo pip3 install -e .
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Note that this will alter your system's Python distribution. If you prefer
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to not install as superuser, you can install the package in a Python virtual environment::
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git clone -b master https://github.com/fritz-hh/OCRmyPDF.git
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pyvenv venv
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source venv/bin/activate
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cd OCRmyPDF
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pip3 install -e .
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If your platform does not have ``pip3``, make sure that Python 3.4+ and the `pip`
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package are installed.
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To run the program::
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ocrmypdf --help
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If not yet installed, the script will notify you about dependencies that
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need to be installed. The script requires specific versions of the
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dependencies. Older version than the ones mentioned in the release notes
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are likely not to be compatible to OCRmyPDF.
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Support
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-------
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In case you detect an issue, please:
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- Check if your issue is already known
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- If no problem report exists on github, please create one here:
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https://github.com/fritz-hh/OCRmyPDF/issues
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- Describe your problem thoroughly
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- Append the console output of the script when running the debug mode
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(-v 1 option)
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- If possible provide your input PDF file as well as the content of the
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temporary folder (using a file sharing service like
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www.file-upload.net)
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Press & Media
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-------------
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- `c't 1-2014, page 59 <http://www.heise.de/ct/inhalt/2014/1/58/>`__:
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Detailed presentation of OCRmyPDF v1.0 in the leading German IT
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magazine c't
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- `heise Open Source, 09/2014: Texterkennung mit
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OCRmyPDF <http://www.heise.de/-2356670>`__
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Disclaimer
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----------
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The software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied.
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