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Dan337
Dan337
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How do you convert a searchable (OCR) PDF to a PDF/A-2b compiant file?

Mar 30, 2012 8:41 AM

Categories: Windows Tags: #ocr #searchable #actions #preflight #pdf/a

Hello all,

 

My first ever post here so please be gentle!

 

I am trying to work out how to convert a scanned PDF document into a PDF/A-2b document with OCR.

 

I have thousands of scanned PDFs that i am compressing and converting to PDF/A-2b. I am using actions within Adobe Acrobat Pro x. I have converted a few thousand so far with no problems.

 

However, what I now want to do additionally is not only compress and convert to PDF/A-2b but compress, OCR and convert to PDF/A-2b to make a searchable PDF/A-2b compliant file.

 

At the moment when I try to do this using Actions within Acrobat X Pro and using the searchable image output style it produces an error at the preflight stage. The error is: Character references .notdef glyph

 

Now I am assuming this because within the OCR text layer it is obviously detecting / picking up bits of text/rubbish that it cannot convert / embed into the document as a font.

 

When doing the same but using the clearscan output style (which I don’t want to use anyway as compression is disabled when using this) it also produces an error at the preflight stage. The error is: Width information for rendered glyphs is inconsistent

 

My question therefore is how do you convert an OCR’ed PDF to a PDF/A-2b compliant PDF?

 

Note: It doesn’t HAVE to be PDF/A-2b, PDF/A-2u would be fine as well (but same problems when trying to do this).

 

What am I doing wrong?

 

The complete action of the batched job I have configured is as follows:

 

Step 1 – Remove Hidden Information (everything checked).

Step 2 – Add Document Description (Title, Subject, Author Keywords filled in).

Step 3 – Optimised Scanned PDF (JPEG2000 / JBIG2 Compression, Text Sharpening High, OCR – Searchable Image)

Step 4 – Preflight (Convert to PDF/A-2b)

Save To: Output Format – PDF Optimiser (compatible 1.7 version (acrobat 8) + various settings here, too many to mention)

 

Is it even possible to have a PDF/A-2a/b/u compliant PDF that is searchable? I am assuming it is?!

 

Any help and assistance would be greatly appreciated!

 

Cheers

 

Dan

 

2412 Views   6 Replies   Latest reply: Dan337, Jun 14, 2012 10:47 AM
 
Replies
  • CtDave
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    1. CtDave,
    Mar 30, 2012 10:45 AM   in reply to Dan337
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    This article may be useful.

    http://www.pdfa.org/2011/08/pdfa-%E2%80%93-a-look-at-the-technical-sid e/ 

     

    As the "a" and "b" mean the same as in PDF/A-1 & "u" relates to Unicode mapping I suspect that, from a approach of practicality, you can attempt to obtain "b".

    Trying to get "a" from OCR output is rather problematic.

    Trying for "u" means you'd have to get the OCR output to properly map to Unicode.

    That's not to say something workable is not possible if you are willing to spend the money to obtain one of the high-end third party applications.

     

    Be well...

     
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  • Dan337
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    2. Dan337,
    Mar 30, 2012 11:20 AM   in reply to CtDave
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    Hi Dave,

     

    Many thanks for your reply.

     

    Getting a searchable PDF/A-2b compliant PDF is exactly what i am trying to achieve.

     

    Do you know how to do this with Adobe Acrobat Pro X?

     

    Cheers

     

    Dan

     
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  • CtDave
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    3. CtDave,
    Mar 30, 2012 2:26 PM   in reply to Dan337
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    Just a guess, but you might be facing the 2-ton in a 1-ton pickup truck scenario what with everything the Action is doing.

    Are you back fitting PDFs you have already processed to 2b?

    Doing the OCR of such after the fact might be contributing to the issue(s).

     

    fwiw, On a small sample of PDF of scanned textual content that had already be processed with Searchable Image (Exact) the Acrobat X Pro Preflight "Convert to PDF/A-2b (sRGB)" analyze and fix provided valid "2b".

     

    Be well...

     
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  • jwwiegley
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    4. jwwiegley,
    May 7, 2012 12:16 AM   in reply to Dan337
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    I too am experiencing the exact same thing that you are.  I can turn a scanned document into PDF/A-2b, but if I then use OCR to recognize text in the document, I can't turn that OCR'd document into PDF/A-2b.  If I use Searchable Image (exact) I get the .notdef problem; and if I use ClearScan I get the Width information problem.

     

    Is there any way to convert scanned OCR documents into PDF/A with Acrobat X?

     

    Thanks,

      John

     
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  • Dregen1980
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    5. Dregen1980,
    Jun 11, 2012 1:39 PM   in reply to jwwiegley
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    I halso have this problem and I'm a little bit confused, that Acrobat X Pro seems to be unable to make its own OCR compatible to PDF/A-2b.

    I'd be very thankful for any hints and workarounds!

     
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  • Dan337
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    6. Dan337,
    Jun 14, 2012 10:47 AM   in reply to jwwiegley
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    Hi all,

     

    Sorry for my the lateness in this reply.

     

    I managed to fix / solve my problem by doing something that in my humble opinion is illogical.

     

    What i did essentially is change the order of the OCR and PDF/A steps.

     

    Originally i had the Preflight (Convert to PDF/A-2b) as the very last step, as in my mind that is logical and where you would want to do it.

     

    I however as mentioned changed the order of the steps so the Preflight (Convert to PDF/A-2b) step i put BEFORE the Reconise Text (OCR) step, i.e you OCR the document AFTER you convert it to PDF/A2b. (i know.. weird!! how can be PDF/A2b compliant still?? but it is!!)

     

    So my complete batched processing action is now as follows:

     

    Step 1 - Remove Hidden Information (everything checked!)

    Step 2 - Add Document Description

    Step 3 - Preflight (Convert to PDF/A-2b)

    Step 4 - Recognize Text (using OCR) (English UK, Searchable Image (Exact)

     

    Save to (step 5 essentially) I have made it add "_Processed" to the original file name and used PDF Optimizer on the Output Format (loads of settings here, too many to mention).

     

    Thats it!

     

    This now compresses my PDF's by a good 50-60%, OCR's them and makes them fully PDF/A-2b compliant.

     

    I have processed in the region of 3000 PDF's (another 5000 to go!) with no issues.

     

    I hope this helps.

     

    Cheers

     

    Dan

     
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