If you are using character matching the my guess would be that you are using the wrong font - some fonts are very similar where some characters match but others are subtly different. Unfortunately often the only solution to finding the right font is brute force, although usually apps tend to use common fonts like Tahoma, Arial, Segoe UI etc.Alternatively try the OCR option - you don't need a font but you have accept the fact that the OCR engine (Google Tesseract) will 'work out' the result rather than give you a 100% match like Character matching does.
