Make existing PDF searchable ( OCR ) via command line / script

ocrpdf

I am looking for an offline scriptable tool that makes an existing PDF file searchable by running OCR on it, replacing the original non-searchable file with the searchable version, and can run unattended.

E.g., www.pdfscannerapp.com – does exactly what I need, but it's GUI only – not scriptable.

I am aware that Evernote makes PDF files searchable, but they remain searchable only when within Evernote.

I am not looking for perfect OCR, even a moderately acceptable OCR is fine, but I would prefer a small utility rather than a bulky software package.

(I am aware of a similar, but different question on AD: Looking for Software to Scan or Convert to Searchable and Signable PDF – however, I don't need to sign or fill PDFs, and my requirement is that the solution is scriptable)

EDIT:

1) Several utilities allow structured text extraction, however in order to be extracted, the text must be there; I am mainly referring to PDFs that are wrapped bitmaps, as is the case with plain PDFs generated by scanners.

2) I am not necessarily looking for a free solution, and I would be more than happy to pay for a good utility that just does what I need, but I am not looking for bulky applications with a million features that include an OCR feature but whose cost does not justify buying them just for the OCR functionality.

3) As stated above, I am not looking for perfect OCR, just a moderately acceptable OCR. Unfortunately, in my experience, tesseract is really below that threshold. I define "moderately acceptable" an OCR that can, say, OCR an utility bill so that at least the account number (customer number) is recognized correctly.

EDIT: "scriptable" or "automatable", that is, able to be triggered automatically and run unattended without human input whatsoever.

Best Answer

It's not entirely clear to me what your requirements are for being able to "script" this from the "command line".

If you are talking about automation, then that is possible with any number of utilities.

ABBYY FineReader Express + Keyboard Maestro + Hazel

I use ABBYY FineReader Express + Keyboard Maestro + Hazel like so:

  1. Hazel monitors a given folder for any new PDFs

  2. if a PDF is found, it is opened in "ABBYY FineReader Express"

  3. Keyboard Maestro then automates the process of turning the PDF into a Searchable PDF (OCR) and saves the file to a different directory.

Now, if you don't own Hazel and Keyboard Maestro already, your initial costs are going to rise pretty quickly (although I depend on both so much I consider them a bargain).

PDFPen + AppleScript + Folder Actions

You could do something similar with PDFPen (or PDFPenPro) and folder actions and AppleScript. See https://gist.github.com/prenagha/1355037 for one example.

Marco Arment did a survey of OCR apps for Mac and found that PDFPen had great results and was easy to automate.

A google search for "PDFpen applescript OCR" will turn up a number of alternatives.

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