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T
Tanquen
Participating Frequently
July 15, 2022
Question

Recognize Text not working well with CAD drawings in PDF

  • July 15, 2022
  • 2 replies
  • 4150 views

I have some PDFs with CAD drawings in them and would like to be able to seach the text.

Searchable Image - Sort of works but a lot of smaller text enevnthough you can zoom in and the text looks great as its vector.

I think ClearScan or Searchable image may be better but 600dpi is not enough for the size of the drawings so they find almost no text and the drawings then look really bad.

 

Befor scan.

After ClearScan at 600dpi.

 

 

 

Is there a way to just turn the PDF with the CAD drawings in bitmaps at a much higher PDI and then run the Recognize Text?

This topic has been closed for replies.

2 replies

M
marthed60789977
Participant
August 1, 2023

I have the same problem. I enhanced the image in Photoshop, but the OCR does not recognize the -apparantly- random text in an autocad P&ID like yours.
Some text is indeed converted, other text not. Especially with P&ID this would be a real help if it could recognize anywhere on the page. 

T
TanquenAuthor
Participating Frequently
October 27, 2023

Unfortunetly there seems to be no fix for this in Acrobat. When it conversts the drawing to a bitmap to then do the OCR the dpi is too low and it can not read most of the text. Maybe there is a way to overide the dpi used in the Acrobat Recognize Text OCR function.

gary_sc
Community Expert
gary_scCommunity Expert
Community Expert
July 15, 2022

Do you have access to the software that generated the CAD?

 

What format is the CAD image currently in?

 

Thanks

T
TanquenAuthor
Participating Frequently
July 15, 2022

I don't know what it is in the PDF but there were DWG files so AutoCAD files maybe? We just have the PDFs and the text is vector but is made up of more that one object.

 

 

T
TanquenAuthor
Participating Frequently
July 15, 2022

HI Tanquen,

 

Not knowing what I'm looking at here, exactly what am I looking at. Also, if this is the PDF, I would not call that a vector object; it looks like it has been bitmapped.

 


The pic is from the PDF using the edit object option in Acrobat. It's not a bitmap but a vector. When it converted the DWG CAD file into a PDF it did not make it a bitmap. The letters are not single objects though, it's some kind of odd converstion. In AutoCAD you can work with text as shapes and that is kind of what this looks like.

 

So an N is like this:

Then is Acrobat I can select a part of it and move it.

and if you look at the OP, ClearScan will convert it to a bitmap and then do OCR but maxed at 600dpi and it is not enought, it cant make out the letters correctly. 

 

I know the file would be large but if ClearScan let me select 1200dpi it would then be abel to make out all the letters when using OCR.

 

Searchable Image was able to get this:

G-1960

PEDS TANK AGITATOR

n'PE: PBT

MOC: 318L 55

MOTOR: 0.5HP/460/3P/6<JHZ

 

out of this:

 

But only this

U-1961

out of this

 

 

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