Author iOS application "iHowMuch" - 135.000 Downloads at the last year.
"Directly through the screen of your smartphone, allows you to see the prices during travel in other countries in currencies you normally use. Direct the camera at the [price tag digits] in the other currency and see how much it costs for you at home, according to exchange rates. The application is very simple to use and works without an internet connection. It’s like a magic! Forget about calculators and currency converters. You simply wish to know - «how much?» "
On technical language this application is "REALTIME OCR-Engine+Currency-converter/calculator-in-one-piece"