Search tool for scanned PDF documents and images

Question

I am looking for a tool that is able to search for text in scanned PDF documents and images. I have tried Evernote and really liked it, but I do not want to have personal documents on someone elses cloud.

I am a developer so I could do some minor things myself, but parsing PDF files for text is way out of my league.

Important features

1. No cloud service
2. Ability to deal with scanned PDF documents and images
3. Should be able to work reliably with up to 100,000 documents.
4. Must run on either Linux or Windows 10 with 8GB RAM
5. Preferably has a secure Web interface that allows me to add Documents and search for documents
6. Must support large documents >50MB

Less important features

7. Supports encryption of documents (e.g. searching requires authentication)
8. Can deal with other document types (raw, docx, pptx, etc.)
9. Ability to add multiple users

Budget

Either about 50€/year or about 200€ one time.

Answer 1

You may be able to make some headway with the python pdfminer/pdfminer3k but the big problem is that scanned pdf files only contain text as a result of any OCR, (Optical Character Recognition), performed by the scanner. This varies enormously in quality depending on the original document font & quality and on the scanner.

If the text is present and good quality in the pdf you can use pdfminer to extract it and index your files from it but otherwise you are going to have to perform OCR on the images of the pages first using something like Aprise or Abby (both charged for) or Tesseract (free and with a number of front-ends including pyTesseract).

If your pdf files include hand written or poor scan quality documents you are probably going to struggle.