I am looking for open source c++ ocr library. I want use it for Symbian/Meego application. Can you recommend any? I've found http://code.google.com/p/tesseract-ocr/. But i don't know whether it is a good choice and how to use it in my Qt app. Can you advise me?
There's a number of approaches:
Tesseract (http://code.google.com/p/tesseract-ocr/), it's opensource and considered to be the best among free OCR engines. It's rather hard to set up, requires font training and develpment of image preprocessing on your side (OCR from phone camera often requires noise reduction, perspective correction, warps&skews handling etc.)
ABBYY Mobile OCR Engine refer this question for details: ABBYY Mobile OCR Engine for Iphone
One more solution could be a Cloud SDK – it's a website that lets you upload an image and sends you back OCRed data through web API, take a look at www.ocrsdk.com for mobile ocr. It may be useful when you work with mid-level and low-end mobile devices (which are likely to have symbian), because image preprocessing and OCR is very resource consuming processes, so i'd suggest you try it out as well.
Tesseract engine is opensource while ABBYY provides unmatchable OCR quality and is much easier to use. If you're planning a commercial project - try ABBYY, it would add a serious value to your product. If you're developing a free/opensource/study project - tesseract is your choice. I work @ ABBYY and can provide you additional info in necessary.