I was wondering if anyone has any software recommendations to mass OCR about 1000 PDF files. It could be; converting to text, to word Doc or making the PDF searchable. I just need an efficient way to analyze the converted documents.

I've tried Abby FineReader and it's not necessarily up to the speed I would like, so I was wondering if there were any faster methods.

Thank you!

EDIT: I'm essentially looking for a method to convert 5000~ scanned PDF's to searchable PDFs or even a text file.

  • Thank you everyone for your responses. My biggest problem right now is the OCR processing of these documents, essentially converting the scanned images into readable text.
    – AyronH
    May 7, 2019 at 12:48

5 Answers 5


It rather depends on the nature of the PDF files - some contain the text while others contain images of the text. In the former case pdfminer3 can do an excellent job. In the latter case you will need to perform OCR (Optical Character Recognition) on the images which is almost always an uncertain proposition.


I don't know if it's faster, but because you say you want to analyze the converted documents, you might take a look at Apache Tika (https://tika.apache.org/). It will extract both text and metadata, and can produce output in the 'tsvector' format used by PostgreSQL, allowing you to store the text of your 1,000+ documents and search them efficiently.


Nuance OmniPage Ultimate is generally faster. It depends on what settings you use in the software, what version you use, etc.

If you have not already, you could try the "Fast Reading" option in Abbyy FineReader. However, it may lead to more slight discrepancies in the resulting files.

You can also change the OCR task priority in Windows for a potential small boost. (Your amount of boost will depend on how many cores your computer has, etc.) I would look to reduce what other processes are running on the computer, including background processes, use a computer with multiple cores, use an SSD local hard disk, and look into other methods such as possibly overclocking your CPU.


You should note that there are different versions of ABBY Finereader (or Acrobat Pro...etc). The batch pdf feature is available only in some versions. You should maybe use for instance Abby "Hotfolder" features (batch pdf files) which is included into "Abby FineReader 12 Corporate edition".


You can use the LEADTOOLS Recognition SDK technology in your application. https://www.leadtools.com/sdk/products/recognition You can leverage the IOcrEngine interface to convert batch files to searchable PDF's.

DISCLOSURE: I am an employee of the company offering this toolkit.

Here is some sample code:

string dir = @"C:\LEADTOOLS21\Resources\Images";
string[] files = Directory.GetFiles(dir, "*.tif");
using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD))
    foreach (string file in files)
        DocumentWriter writer = new DocumentWriter();
        string output = Path.Combine(@"C:\Temp\Batch Processed\" + $"{Path.GetFileNameWithoutExtension(file)}" + ".pdf");
        PdfDocumentOptions options = writer.GetOptions(DocumentFormat.Pdf) as PdfDocumentOptions;
        options.ImageOverText = true;
        writer.SetOptions(DocumentFormat.Pdf, options);
        //Startup the LEADTOOLS OCR Engine 
        ocrEngine.Startup(null, writer, null, null);
        //Run the AutoRecognizeManager and specify PDF format 
        ocrEngine.AutoRecognizeManager.Run(file, output, DocumentFormat.Pdf, null, null);
        Console.WriteLine($"OCR output saved to {output}\n");
  • 1) Can the LEADTOOLS script you mentioned be modified to recursively look in a folder structure (including subfolders) for PDF files? 2) The folder structure I'm referring to will have a mix of searchable PDF's and non-searchable. Will LEADTOOLS properly skip files that are already searchable?
    – BobH
    Oct 2 at 23:37

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