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Add stop on soft render errors and option to override

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This commit is contained in:
James R. Barlow
2023-06-01 23:49:34 -07:00
parent 22d35c199d
commit e8ed510543
13 changed files with 68 additions and 20 deletions
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docs/advanced.rst
+12 -1
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@@ -104,7 +104,7 @@ was requested, the preprocessed image layer will be inserted.
If you want to adjust the amount of time spent on OCR, change
``--tesseract-timeout``. You can also automatically skip images that
exceed a certain number of megapixels with ``--skip-big``. (A 300 DPI,
8.5×11" page is 8.4 megapixels.)
8.5×11" page image is 8.4 megapixels.)
.. code-block:: bash
@@ -241,6 +241,17 @@ PDF.js viewer.
This works in all versions of Tesseract.
Rendering and rasterizing options
=================================
.. versionadded:: 14.3.0
The ``--continue-on-soft-render-error`` option allows OCRmyPDF to
proceed if a page cannot be rasterized rendered. This is useful if you are
trying to get the best possible OCR from a PDF that is not well-formed,
and you are willing to accept some pages that may not visually match the
input, and that may not OCR well.
Return code policy
==================
docs/pdfsecurity.rst
+7 -11
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@@ -29,13 +29,9 @@ attack vectors.
In short, PDFs `may contain
viruses <https://security.stackexchange.com/questions/64052/can-a-pdf-file-contain-a-virus>`__.
This
`article <https://theinvisiblethings.blogspot.ca/2013/02/converting-untrusted-pdfs-into-trusted.html>`__
describes a high-paranoia method which allows potentially hostile PDFs
to be viewed and rasterized safely in a disposable virtual machine. A
trusted PDF created in this manner is converted to images and loses all
information making it searchable and losing all compression. OCRmyPDF
could be used to restore searchability.
If you do not trust a PDF or its source, do not open it or use OCRmyPDF
on it. Consider using a Docker container or virtual machine to isolate
an untrusted PDF from your system.
How OCRmyPDF processes PDFs
===========================
@@ -43,11 +39,11 @@ How OCRmyPDF processes PDFs
OCRmyPDF must open and interpret your PDF in order to insert an OCR
layer. First, it runs all PDFs through
`pikepdf <https://github.com/pikepdf/pikepdf>`__, a library based on
`qpdf <https://github.com/qpdf/qpdf>`__, a program that repairs PDFs
`QPDF <https://github.com/qpdf/qpdf>`__, a program that repairs PDFs
with syntax errors. This is done because, in the author's experience, a
significant number of PDFs in the wild, especially those created by
scanners, are not well-formed files. qpdf makes it more likely that
OCRmyPDF will succeed, but offers no security guarantees. qpdf is also
scanners, are not well-formed files. QPDF makes it more likely that
OCRmyPDF will succeed, but offers no security guarantees. QPDF is also
used to split the PDF into single page PDFs.
Finally, OCRmyPDF rasterizes each page of the PDF using
@@ -133,7 +129,7 @@ The author also provides professional services that include OCR and
building databases around PDFs, and is happy to provide consultation.
Abbyy Cloud OCR is viable commercial alternative with a web services
API. Amazon Textract, Google Cloud Vision, and Microsoft Azure
API. Amazon Textract, Google Cloud Vision, and Microsoft Azure
Computer Vision provide advanced OCR but have less PDF rendering capability.
Password protection, digital signatures and certification