OpenCV-Python + python-tesseract real-time image preprocess and OCR.
Trained data for 7 segments font avaliable under letsgodigital folder.
Web-app using trained data: http://ocr.sytes.net (Not always up, due to the low cost server)
Reference: https://code.google.com/p/python-tesseract/
Tips to achieve better results:
License: GPL v2