Windows 7 OCR API

Question

I have been reviewing replacements for the Office 2007 MODI OCR (OneNote's 2010 solution has lesser quality/results than 2007 :-( ). I notice that Windows 7 contains an OCR library once you install the optional tiff filter

The OCR component gets installed to

%programfiles%\Common Files\microsoft shared\OCR\7.0\xocr3.psp.dll 

but I don't see any API for it?

Does anyone see how this can be interfaced preferably in C#?

ANSWER: Found the soluation, once the optional tiff ifilter win7 feature is installed, i can then get a textoutput of a screenshot using the code/exe on http://www.codeproject.com/KB/cs/IFilter.aspx. Also if add the same [HKEY_CLASSES_ROOT.tiff\PersistentHandler] for .png and .jpg then OCR also works for jpg and png's.

Stonecutter

The main API seems defined in thocrapi.dll. But good luck with programming against an undocument, possibly changing target. You'd better spend some money and get a commercial library instead of wasting your time here. – Cordoba

Answer 1

1. Tessnet OCR is a good solution, but pretty old (last release from 2009). There are couple of very good free OCR solutions available for .NET:
2. Asprise C# OCR SDK. Very good and fast one.
3. Microsoft Research Project Hawaii Web-based (cloud) OCR solution with full docs and samples (discontinued 2013)
4. Bing OCR Web based (cloud) OCR replacement for above. (discontinued March 2014)

Omega

taught me something, I only knew about tessnet (on my budget, at least ;-). Forewarning: It doesn't look like you can distribute software with the 'free' Aprise OCR - so 'free' probably belongs in quotes: asprise.com/product/ocr/faq.php?lang=vb – Leatherwood

Havent' read their license fully, as used that in non-commercial, personal project a while ago. Have to recheck it. There was also a third library I used the most. It was the nicest one, but forgot it's name. Will post you with info on that if I manage to find it somewhere:) – Omega

Piotr, thank you for mentioning Asprise C# OCR Component Library. Our dev team has spent a lot effort to improve the accuracy and speed of the OCR. Let us know if you have any suggestion to make it even better :) – Isomerous

At $5k for the cheapest version, Asprise appears to be anything but free: asprise.com/royalty-free-library/… – Pianoforte

@Pianoforte Well, there was one at the time of writing (there is a free trial now though). And OP didn't specifically ask for free libraries so I included it. – Omega

Answer 2

Try TessNet, using the suggestions I made to the Poster in this post (enlarge image, use separate process):
c# OCR can't recognize digits (tesseract 2)

Leatherwood

Answer 3

I was exploring the windows 7 dlls and I found 3 libraries that might be useful: thocr.psp.dll ,xocr3.psp.dll, and ximage3b.dll. In this website and other similar websites I found out that ximage3b is a Windows system ocr engine. I have been looking for documentation online but I have not been succesful, but hey! at least I know that it's there, I will give you guys an update if I find out how to use it with C#/C/C++.

Coprolite