![]() ![]() ![]() PDF is a horrible format for scanned images, but quite often used because it can include multiple pages in one file. Print to PDF (with PDF support from cups-pdf) You can use pdfimages for the extraction (from the poppler-utils package) and convert (from imagemagick) to convert them back: pdfimages toc.pdf toctmp There are multiple ways to get rid of the OCRed text in the file.Įxport the scanned images from the PDF and recombine them. Since Ghostscript does not "understand" the re-named operators, it will simply skip them by default. The input still had the text, albeit in an "unusable" form, because the operator renaming. The output will have removed all traces of text. This final step uses editable.pdf as input. This command should achieve what you want: gs \ The renamed text operators do not have any meaning any more for the PDF viewer, nor for any PDF interpreter. ![]() (Be careful not to change the number of bytes when replacing stuff in PDF source code, because otherwise you may cause it to become "corrupted".) This will change them into 'no-ops': they have no meaning at all in the PDF source code no PDF viewer or processor will "understand" them. Whenever a text string is prepared for being rendered, the actual operator that is responsible for doing so is named Tj or TJ. Change Tj and TJ text stroking operators to 'no-ops' Glyphs will appear in thick outlines, overlaying the original scanned page images. This should make the previously hidden text visible. neither filled nor stroked) text is marked by an initial definition of 3 Tr Search for spots where PDF code contains 3 TrĪll spots in the editable.pdf where there is 'invisible' (a.k.a. Qpdf is a beautiful command line tool to transform most PDFs into a form that makes it easier to manipulate through a text editor (or through sed): qpdf \Ģ. Use qpdf to un-compress most of the PDF objects "How can we make the invisible text visible?".The following screenshot from the official PDF specification lists all available text rendering modes:įor more background, please see these answers of mine on StackOverflow: Here is how I would remove the OCR-ed text should I have to.įirst, you need to know, that OCR-ed text in a PDF is not a layer, but a special text rendering mode. ![]()
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