I'm trying to read a credit card number to text. Using the sample WP8 app, I can read text from a document, but I can't get anything from a credit card number (nothing nefarious going on here, I have an app that needs to read a CC).

I've tried it with some very sharp, very contrasty images and cropped down just to the numbers, but no luck. Is this even possible?

Hello Don,
Thank you for your message.
As this is a special case, i believe that the cc image will need special "treatment" in order to ne recognized.
Are the numbers on the card in black or are they embossed?
The OCR engine will try to find Black components so that it can later match it against the characters.
First you should limit the OCR to numbers only and then you should try with diferent image resolutions and sizes.
Remember that the engine will be expecting an image with at least 200 dpi.
Also have you tried with different OCR modes? like single block of character or single line?

best regards.