ocrmypdf --help
usage: ocrmypdf [-h] [-l LANGUAGE] [--image-dpi DPI]
[--output-type {pdfa,pdf,pdfa-1,pdfa-2,pdfa-3}]
[--sidecar [FILE]] [--version] [-j N] [-q] [-v [VERBOSE]]
[--title TITLE] [--author AUTHOR] [--subject SUBJECT]
[--keywords KEYWORDS] [-r] [--remove-background] [-d] [-c]
[-i] [--oversample DPI] [--remove-vectors] [--mask-barcodes]
[--threshold] [-f] [-s] [--redo-ocr] [--skip-big MPixels]
[-O {0,1,2,3}] [--jpeg-quality Q] [--png-quality Q]
[--jbig2-lossy] [--max-image-mpixels MPixels]
[--tesseract-config CFG] [--tesseract-pagesegmode PSM]
[--tesseract-oem MODE] [--pdf-renderer {auto,hocr,sandwich}]
[--tesseract-timeout SECONDS]
[--rotate-pages-threshold CONFIDENCE]
[--pdfa-image-compression {auto,jpeg,lossless}]
[--user-words FILE] [--user-patterns FILE] [-k]
[--flowchart FLOWCHART]
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 ovewritten.
If same as input file, the input file will be updated
only if processing is successful.
optional arguments:
-h, --help show this help message and exit
-l LANGUAGE, --language LANGUAGE
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 For input image instead of PDF, use this DPI instead
of file's.
--output-type {pdfa,pdf,pdfa-1,pdfa-2,pdfa-3}
Choose output type. 'pdfa' creates a PDF/A-2b
compliant file for long term archiving (default,
recommended) but may not suitable for users who want
their file altered as little as possible. 'pdfa' also
has problems with full Unicode text. 'pdf' attempts to
preserve file contents as much as possible. 'pdf-a1'
creates a PDF/A1-b file. 'pdf-a2' is equivalent to
'pdfa'. 'pdf-a3' creates a PDF/A3-b file.
--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 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.
--version Print program version and exit
Job control options:
-j N, --jobs N Use up to N CPU cores simultaneously (default: use
all).
-q, --quiet Suppress INFO messages
-v [VERBOSE], --verbose [VERBOSE]
Print more verbose messages for each additional
verbose level
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.
--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.
--mask-barcodes EXPERIMENTAL. Mask out any barcodes that appear in the
PDF so they are not considered during OCR. Barcodes
can introduce false characters into OCR.
--threshold EXPERIMENTAL. Threshold image to 1bpp before sending
it to Tesseract for OCR. Can improve OCR quality
compared to Tesseract's thresholder.
OCR options:
Control how OCR is applied
-f, --force-ocr Rasterize any text or vector objects on each page,
apply OCR, and save the rastered output (this rewrites
the PDF)
-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
--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.
--skip-big MPixels Skip OCR on pages larger than the specified amount of
megapixels, but include skipped pages in final output
Optimization options:
Control how the PDF is optimized after OCR
-O {0,1,2,3}, --optimize {0,1,2,3}
Control how PDF is optimized after processing:0 - do
not optimize; 1 - do safe, lossless optimizations
(default); 2 - do some lossy optimizations; 3 - do
aggressive lossy optimizations (including lossy JBIG2)
--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-lossy Enable JBIG2 lossy mode (better compression, not
suitable for some use cases - see documentation).
Advanced:
Advanced options to control Tesseract's OCR behavior
--max-image-mpixels MPixels
Set maximum number of pixels to unpack before treating
an image as a decompression bomb
--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 4.0 OCR engine mode: 0 - original
Tesseract only; 1 - neural nets LSTM only; 2 -
Tesseract + LSTM; 3 - default.
--pdf-renderer {auto,hocr,sandwich}
Choose OCR PDF renderer - the default option is to let
OCRmyPDF choose. See documentation for discussion.
--tesseract-timeout SECONDS
Give up on OCR after the timeout, but copy the
preprocessed page into the final output
--rotate-pages-threshold CONFIDENCE
Only rotate pages when confidence is above this value
(arbitrary units reported by tesseract)
--pdfa-image-compression {auto,jpeg,lossless}
Specify how to compress images in the output PDF/A.
'auto' lets OCRmyPDF decide. 'jpeg' changes all
grayscale and color images to JPEG compression.
'lossless' uses PNG-style lossless compression for all
images. 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.
--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.
Debugging:
Arguments to help with troubleshooting and debugging
-k, --keep-temporary-files
Keep temporary files (helpful for debugging)
--flowchart FLOWCHART
Generate the pipeline execution flowchart
OCRmyPDF attempts to keep the output file at about the same size. If a file
contains losslessly compressed images, and 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
converts images to sRGB colorspace, 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 is a dependency of
ocrmypdf so it is already installed.
img2pdf --pagesize A4 page*.png | ocrmypdf - myfile.pdf
Online documentation is located at:
https://ocrmypdf.readthedocs.io/en/latest/introduction.html
