Search a photo for drawing

I w开发者_如何转开发ant to be able to do something like take a picture of a chalkboard and search for what the teacher wrote and then delete the chalkboard and make like a CGContext Path of what the teacher wrote, or just have what the teacher wrote

OCR is tricky with the iPhone camera. If you just want to pull out edges and save those you might try a Canny edge detector followed by a little edge linking to get larger features. You'll get some noise though, off a chalk board.

Easiest approach to that would be to use OpenCV. You can grab a version that's already been ported and compiled from this guy's site: http://niw.at/articles/2009/03/14/using-opencv-on-iphone/en

My sense is that this approach is probably not quite right for what you want. I'd sit down and think a bit more about what you're trying to do.

You might want to look at OCR.

Here is one option: Mobile OCR Engine for iPhone app