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OCRmyPDF

ocrmypdf

Top / ocrmypdf

https://ocrmypdf.readthedocs.io/en/latest/cookbook.html

インストール

• brew install ocrmypdf

ocrmypdf --mode?

ocrmypdf --mode strip

help

• usage: OCRmyPDF [-h] [-l LANGUAGES] [--image-dpi DPI] [--output-type {auto,pdfa,pdf,pdfa-1,pdfa-2,pdfa-3,none}] [--sidecar [FILE]] [-n] [--version] [-j N] [-q] [-v [VERBOSE]] [--title TITLE]
                  [--author AUTHOR] [--subject SUBJECT] [--keywords KEYWORDS] [-r] [--remove-background] [-d] [-c] [-i] [--unpaper-args UNPAPER_ARGS] [--oversample DPI] [--remove-vectors]
                  [-m {default,force,skip,redo,strip}] [-f] [-s] [--redo-ocr] [--skip-big MPixels] [--invalidate-digital-signatures] [--tagged-pdf-mode {default,ignore}] [--pages PAGES]
                  [--max-image-mpixels MPixels] [--pdf-renderer {auto,hocr,sandwich,hocrdebug,fpdf2}] [--ocr-engine {auto,tesseract,none}] [--rasterizer {auto,ghostscript,pypdfium}]
                  [--rotate-pages-threshold CONFIDENCE] [--fast-web-view MEGABYTES] [--continue-on-soft-render-error] [--plugin PLUGINS] [-k] [--tesseract-config CFG] [--tesseract-pagesegmode PSM]
                  [--tesseract-oem MODE] [--tesseract-thresholding TESSERACT_THRESHOLDING] [--tesseract-timeout SECONDS] [--tesseract-non-ocr-timeout SECONDS]
                  [--tesseract-downsample-large-images | --no-tesseract-downsample-large-images] [--tesseract-downsample-above TESSERACT_DOWNSAMPLE_ABOVE] [--user-words FILE] [--user-patterns FILE]
                  [-O {0,1,2,3}] [--jpeg-quality Q] [--png-quality Q] [--jbig2-threshold T] [--color-conversion-strategy {CMYK,Gray,LeaveColorUnchanged,RGB,UseDeviceIndependentColor}]
                  [--pdfa-image-compression {auto,jpeg,lossless}] [--ghostscript-jpeg-quality Q] [--ghostscript-jpeg-maxdpi DPI]
                  input_pdf_or_image output_pdf
  
  Generates a searchable PDF or PDF/A from a regular PDF.
  
  OCRmyPDF rasterizes each page of the input PDF, optionally corrects page
  rotation and performs image processing, runs the Tesseract OCR engine on the
  image, and then creates a PDF from the OCR information.
  
  positional arguments:
    input_pdf_or_image    PDF file containing the images to be OCRed (or '-' to read from standard input)
    output_pdf            Output searchable PDF file (or '-' to write to standard output). Existing files will be overwritten (use --no-overwrite to prevent this). If same as input file, the input file
                          will be updated only if processing is successful.
  
  options:
    -h, --help            show this help message and exit
    -l, --language LANGUAGES
                          Language(s) of the file to be OCRed (see tesseract --list-langs for all language packs installed in your system). Use -l eng+deu for multiple languages.
    --image-dpi DPI       When the input file is an image, not a PDF, use this DPI instead of the DPI claimed by the input file. If the input does not claim a sensible DPI, this option will be required.
    --output-type {auto,pdfa,pdf,pdfa-1,pdfa-2,pdfa-3,none}
                          Choose output type. 'auto' (default) produces best-effort PDF/A without requiring Ghostscript - uses verapdf validation when available, otherwise passes through as PDF/A if
                          safe (input already PDF/A or force-ocr was used), or falls back to regular PDF. 'pdfa' creates a PDF/A-2b compliant file for long term archiving (requires Ghostscript as
                          fallback). 'pdf' minimizes changes to the input file. 'pdfa-1' creates a PDF/A-1b file. 'pdfa-2' is equivalent to 'pdfa'. 'pdfa-3' creates a PDF/A-3b file. 'none' will produce
                          no output, which may be helpful if only the --sidecar is desired.
    --sidecar [FILE]      Generate sidecar text files that contain the same text recognized by Tesseract. This may be useful for building a OCR text database. If FILE is omitted, the sidecar file be
                          named {output_file}.txt; the next argument must NOT be the name of the input PDF. If FILE is set to '-', the sidecar is written to stdout (a convenient way to preview OCR
                          quality). The output file and sidecar may not both use stdout at the same time.
    -n, --no-overwrite    If the output file already exists, exit with an error instead of overwriting it.
    --version             Print program version and exit
  
  Job control options:
    -j, --jobs N          Use up to N CPU cores simultaneously (default: use all).
    -q, --quiet           Suppress INFO messages
    -v, --verbose [VERBOSE]
                          Print more verbose messages for each additional verbose level. Use `-v 1` typically for much more detailed logging. Higher numbers are probably only useful in debugging.
  
  Metadata options:
    Set output PDF/A metadata (default: copy input document's metadata)
  
    --title TITLE         Set document title (place multiple words in quotes)
    --author AUTHOR       Set document author
    --subject SUBJECT     Set document subject description
    --keywords KEYWORDS   Set document keywords
  
  Image preprocessing options:
    Options to improve the quality of the final PDF and OCR
  
    -r, --rotate-pages    Automatically rotate pages based on detected text orientation
    --remove-background   Attempt to remove background from gray or color pages, setting it to white
    -d, --deskew          Deskew each page before performing OCR
    -c, --clean           Clean pages from scanning artifacts before performing OCR, and send the cleaned page to OCR, but do not include the cleaned page in the output
    -i, --clean-final     Clean page as above, and incorporate the cleaned image in the final PDF. Might remove desired content.
    --unpaper-args UNPAPER_ARGS
                          A quoted string of arguments to pass to unpaper. Requires --clean. Example: --unpaper-args '--layout double'.
    --oversample DPI      Oversample images to at least the specified DPI, to improve OCR results slightly
    --remove-vectors      EXPERIMENTAL. Mask out any vector objects in the PDF so that they will not be included in OCR. This can eliminate false characters.
  
  OCR options:
    Control how OCR is applied
  
    -m, --mode {default,force,skip,redo,strip}
                          Processing mode for pages with existing text. 'default' errors if text is found. 'force' rasterizes all content and runs OCR (same as --force-ocr). 'skip' skips pages with
                          existing text (same as --skip-text). 'redo' re-OCRs pages, replacing old invisible text (same as --redo-ocr). 'strip' removes the invisible OCR text layer without rasterizing
                          or running OCR, producing a smaller file; only text drawn as invisible (render mode 3) is removed, so text from some OCR engines cannot be removed this way.
    -f, --force-ocr       Rasterize any text or vector objects on each page, apply OCR, and save the rastered output (this rewrites the PDF). Equivalent to --mode force.
    -s, --skip-text       Skip OCR on any pages that already contain text, but include the page in final output; useful for PDFs that contain a mix of images, text pages, and/or previously OCRed pages.
                          Equivalent to --mode skip.
    --redo-ocr            Attempt to detect and remove the hidden OCR layer from files that were previously OCRed with OCRmyPDF or another program. Apply OCR to text found in raster images. Existing
                          visible text objects will not be changed. If there is no existing OCR, OCR will be added. Equivalent to --mode redo.
    --skip-big MPixels    Skip OCR on pages larger than the specified amount of megapixels, but include skipped pages in final output
    --invalidate-digital-signatures
                          Normally, OCRmyPDF will refuse to OCR a PDF that has a digital signature. This option allows OCR to proceed, but the digital signature will be invalidated.
    --tagged-pdf-mode {default,ignore}
                          Control behavior when a Tagged PDF is encountered. 'default' errors if --mode is default, otherwise warns. 'ignore' always warns but continues processing.
  
  Advanced:
    Advanced options to control OCRmyPDF
  
    --pages PAGES         Limit OCR to the specified pages (ranges or comma separated), skipping others. The token 'end' is an alias for the last page, so e.g. '3-end' OCRs from page 3 to the last page.
    --max-image-mpixels MPixels
                          Set maximum number of megapixels to unpack before treating an image as a decompression bomb
    --pdf-renderer {auto,hocr,sandwich,hocrdebug,fpdf2}
                          Choose OCR PDF renderer. 'auto' (recommended) uses fpdf2, which provides full international language support including RTL scripts, proper text positioning, and invisible text
                          that becomes visible when selected. 'sandwich' renders text as a background layer. Legacy 'hocr' and 'hocrdebug' options are deprecated and will use fpdf2.
    --ocr-engine {auto,tesseract,none}
                          OCR engine to use. 'auto' (default) selects the best available engine. 'tesseract' uses Tesseract OCR. 'none' skips OCR entirely, useful for PDF/A conversion or image
                          processing without text recognition.
    --rasterizer {auto,ghostscript,pypdfium}
                          Choose PDF page rasterizer. 'auto' (the default) prefers pypdfium2 when the pypdfium2 package is installed, falling back to Ghostscript otherwise. pypdfium2 anti-aliases page
                          content and generally produces better input for OCR than Ghostscript 10.x, which can render aliased glyphs that OCR misreads as extra word breaks. 'pypdfium' forces the
                          pypdfium2 rasterizer (requires the pypdfium2 package); 'ghostscript' forces the traditional Ghostscript rasterizer.
    --rotate-pages-threshold CONFIDENCE
                          Only rotate pages when confidence is above this value (arbitrary units reported by tesseract)
    --fast-web-view MEGABYTES
                          If the size of file is more than this threshold (in MB), then linearize the PDF for fast web viewing. This allows the PDF to be displayed before it is fully downloaded in web
                          browsers, but increases the space required slightly. By default we skip this for small files which do not benefit. If the threshold is 0 it will be apply to all files. Set the
                          threshold very high to disable.
    --continue-on-soft-render-error
                          Continue processing pages after a recoverable PDF rendering error. A recoverable error is one that does not prevent the page from being rendered, but may result in visual
                          differences compared to the input file. Missing fonts are a typical source of these errors.
    --plugin PLUGINS      Name of plugin to import. Argument may be issued multiple times to import multiple plugins. Plugins may be specified as module names in Python syntax, provided they are
                          installed in the same Python (virtual) environment as ocrmypdf; or you may give the path to the Python file that contains the plugin. Plugins must conform to the specification
                          in the OCRmyPDF documentation.
  
  Debugging:
    Arguments to help with troubleshooting and debugging
  
    -k, --keep-temporary-files
                          Keep temporary files (helpful for debugging)
  
  Tesseract:
    Advanced control of Tesseract OCR
  
    --tesseract-config CFG
                          Additional Tesseract configuration files -- see documentation.
    --tesseract-pagesegmode PSM
                          Set Tesseract page segmentation mode (see tesseract --help).
    --tesseract-oem MODE  Set Tesseract 4+ OCR engine mode: 0 - original Tesseract only; 1 - neural nets LSTM only; 2 - Tesseract + LSTM; 3 - default.
    --tesseract-thresholding TESSERACT_THRESHOLDING
                          Set Tesseract 5.0+ input image thresholding mode. This may improve OCR results on low quality images or those that contain high contrast color. Options: auto, otsu, adaptive-
                          otsu, sauvola. auto/otsu is the Tesseract default (legacy Otsu); adaptive-otsu is an improved Otsu algorithm with improved sort for background color changes; sauvola is based
                          on local standard deviation.
    --tesseract-timeout SECONDS
                          Give up on OCR after the timeout, but copy the preprocessed page into the final output. This timeout is only used when using Tesseract for OCR. When Tesseract is used for other
                          operations such as deskewing and orientation, the timeout is controlled by --tesseract-non-ocr-timeout.
    --tesseract-non-ocr-timeout SECONDS
                          Give up on non-OCR operations such as deskewing and orientation after timeout. This is a separate timeout from --tesseract-timeout because these operations are not as expensive
                          as OCR.
    --tesseract-downsample-large-images, --no-tesseract-downsample-large-images
                          Downsample large images before OCR. Tesseract has an upper limit on the size images it will support. If this argument is given, OCRmyPDF will downsample large images to fit
                          Tesseract. This may reduce OCR quality, on large images the most desirable text is usually larger. If this parameter is not supplied, Tesseract will error out and produce no
                          OCR on the page in question. This argument should be used with a high value of --tesseract-timeout to ensure Tesseract has enough to time.
    --tesseract-downsample-above TESSERACT_DOWNSAMPLE_ABOVE
                          Downsample images larger than this size pixel size (either dimension) before OCR. --tesseract-downsample-large-images downsamples when an image exceeds Tesseract's internal
                          limits. This argument causes downsampling to occur when an image exceeds the given size. This may reduce OCR quality, but on large images the most desirable text is usually
                          larger.
    --user-words FILE     Specify the location of the Tesseract user words file. This is a list of words Tesseract should consider while performing OCR in addition to its standard language dictionaries.
                          This can improve OCR quality especially for specialized and technical documents.
    --user-patterns FILE  Specify the location of the Tesseract user patterns file.
  
  Optimization options:
    Control how the PDF is optimized after OCR
  
    -O, --optimize {0,1,2,3}
                          Control how PDF is optimized after processing:0 - do not optimize; 1 - do safe, lossless optimizations (default); 2 - do lossy JPEG and JPEG2000 optimizations; 3 - do more
                          aggressive lossy JPEG and JPEG2000 optimizations. To enable lossy JBIG2, see --jbig2-lossy.
    --jpeg-quality Q      Adjust JPEG quality level for JPEG optimization. 100 is best quality and largest output size; 1 is lowest quality and smallest output; 0 uses the default.
    --png-quality Q       Adjust PNG quality level to use when quantizing PNGs. Values have same meaning as with --jpeg-quality
    --jbig2-threshold T   Adjust JBIG2 symbol code classification threshold (default 0.85), range 0.4 to 0.9.
  
  Ghostscript:
    Advanced control of Ghostscript
  
    --color-conversion-strategy {CMYK,Gray,LeaveColorUnchanged,RGB,UseDeviceIndependentColor}
                          Set Ghostscript color conversion strategy
    --pdfa-image-compression {auto,jpeg,lossless}
                          Specify how to compress images in the output PDF/A. 'auto' lets OCRmyPDF decide: at -O0 it uses lossless image compression so Ghostscript does not transcode lossless images to
                          JPEG; at -O1 and above it defers to Ghostscript's heuristic, which may recompress images lossily. 'jpeg' changes all grayscale and color images to JPEG compression. 'lossless'
                          uses PNG-style lossless compression for non-JPEG images and passes existing JPEGs through unchanged (re-encoding them losslessly would only inflate them). Monochrome images are
                          always compressed using a lossless codec. Compression settings are applied to all pages, including those for which OCR was skipped. Not supported for --output-type=pdf ; that
                          setting preserves the original compression of all images.
    --ghostscript-jpeg-quality Q
                          Advanced: Set Ghostscript's -dJPEGQ for images that Ghostscript transcodes to JPEG during PDF/A generation. 0 is maximum compression; 100 is best quality. If omitted,
                          Ghostscript's default is used. This only affects images Ghostscript chooses to recompress; for general JPEG quality tuning prefer --jpeg-quality, which is applied by the
                          OCRmyPDF optimizer.
    --ghostscript-jpeg-maxdpi DPI
                          Advanced: Force Ghostscript to downsample color, grayscale, and monochrome images in PDF/A output to the given maximum DPI. Reducing JPEG quality usually gives better results
                          than downsampling at the same file size, and can degrade quality of high-resolution monochrome masks.
  
  OCRmyPDF attempts to keep the output file at about the same size.  If a file
  contains losslessly compressed images, and images in the output file will be
  losslessly compressed as well.
  
  PDF is a page description file that attempts to preserve a layout exactly.
  A PDF can contain vector objects (such as text or lines) and raster objects
  (images).  A page might have multiple images.  OCRmyPDF is prepared to deal
  with the wide variety of PDFs that exist in the wild.
  
  When a PDF page contains text, OCRmyPDF assumes that the page has already
  been OCRed or is a "born digital" page that should not be OCRed.  The default
  behavior is to exit in this case without producing a file.  You can use the
  option --skip-text to ignore pages with text, or --force-ocr to rasterize
  all objects on the page and produce an image-only PDF as output.
  
      ocrmypdf --skip-text file_with_some_text_pages.pdf output.pdf
  
      ocrmypdf --force-ocr word_document.pdf output.pdf
  
  If you are concerned about long-term archiving of PDFs, use the default option
  --output-type pdfa which converts the PDF to a standardized PDF/A-2b.  This
  removes some features from the PDF such as Javascript or forms. If you want to
  minimize the number of changes made to your PDF, use --output-type pdf.
  
  If OCRmyPDF is given an image file as input, it will attempt to convert the
  image to a PDF before processing.  For more control over the conversion of
  images to PDF, use the Python package img2pdf or other image to PDF software.
  
  For example, this command uses img2pdf to convert all .png files beginning
  with the 'page' prefix to a PDF, fitting each image on A4-sized paper, and
  sending the result to OCRmyPDF through a pipe.
  
      img2pdf --pagesize A4 page*.png | ocrmypdf - myfile.pdf
  
  Online documentation is located at:
      https://ocrmypdf.readthedocs.io/en/latest/introduction.html