I wonder, is this something you yourself use? Are you blind? In which case, I'm sure you're aware that this is not how assistive software works. Sorry, I just don't get it.
That said, this isn't an entirely unique concept, and you're right, positioning the camera is challenging. There are tools to help with this--arms and stands that position devices at the correct height to photograph a standard-sized sheet of paper. It may strike you as entirely impractical, but I remember the days when scanners were huge and bulky things, and even now when they aren't, I don't necessarily have the desk space to keep one out, or the desire to hook it up and store it when not in use. A reliable camera-based OCR solution for my Android phone and an arm/paper guide calibrated to the S III would rock, and assuming reasonable material prices and standard markup (I.e. not the absolutely huge markups of AT) it'd be competitive with dedicated OCR solutions and hardware.
Source: I'm blind.
You're blind and a developer? As I noted in my comment ( https://news.ycombinator.com/item?id=8138937 ), I used to write software for awesome folks like you. I'd love to chat with you for a bit if you don't mind? What's your email?
Thanks!
- Jonathan