Ask HN: What OCR tool do you use in your project?

[vikasr111]

I am working on a project where I want to extract data from PDF document. Sometimes these are scanned PDF or forms.

I am looking for for an OCR tool (paid or open source) which can effectively extract data from poorly scanned documents and forms. What do you use?

[sandreas]

It depends on what input amount, format and quality you have.

There are free / open source tools (like Tesseract), but if you would like to use them, some manual or (semi-)auto preprocessing steps are very important (threshold / binarization, deskew, noise removal[1]) too get nearly comparable results to commercial tools.

Some tesseract based solutions are better integrated with automatic preprocessing, you could take a look at Papermerge or other self hosted document management solutions[2].

There are also commercial SDKs around tesseract with good price point, like Vintasoft OCR[5], which supports automatic preprocessing and delivers a decent quality.

If you don't mind having a (free) clicking adventure with small amounts of documents, you could also try the free verson of PDF X-Change viewer[3], which has a small but pretty good OCR to embedded PDF-Layer option which makes PDFs "searchable". But the embedded OCR data cannot be easily extracted.

The best "no cloud" / offline solution I found, was Abbyy FineReader[4] which also has a command line tool, but if you really want a ready to use, easy and good quality solution, I would go with Google Lens (if you don't mind google)

[1] https://towardsdatascience.com/pre-processing-in-ocr-fc231c6...

[2] https://github.com/awesome-selfhosted/awesome-selfhosted#doc...

[3] https://www.tracker-software.com/product/pdf-xchange-editor

[4] https://www.pdf-xchange.de/pdf-xchange-viewer/

[5] https://www.vintasoft.com/vsocr-dotnet-index.html

[beardyw]

A bit off topic but I've just started using Google Lens to extract whole pages from books with my phone. Near perfect conversion to text is great for taking notes.

[vikasr111]

Google Lens works great in individual use cases, wonder what they are using behind the scene.

In my case I need to extract data on server side, so a library/API will be most suitable.

[smoldesu]

I still use Tesseract. It's not the fastest or most-accurate anymore, but it gets what I need off of PDF files.

[vikasr111]

Does it work well with scanned PDF? In my experiments it was not giving the correct output.

[james-revisoai]

Explore different page segmentation modes and make sure you are using v4 (it's a massive step up)

[is_true]

We started using tesseract for a project that needed to extract text from video frames. But in the end we moved to easyocr, as it needed less preprocessing for our use case.

[itake]

What languages do you need to support? Off the shelf models don't work well on non-Latin languages. You may need to train your own.