Image processing n00b

[Zak J]

Hi-

I'm hoping someone can give me some pointers. I am working on a
project that is doing OCR of forms. I want to be able to do some
image assessment on the device before sending the image to the
server. I want to check for a few things, namely dark images and
blurry images. I'm hoping I can use this library to help. I'm
reading up on all of the different algorithms implemented, but I'm not
sure how to connect them together to do what I want. For example,
once I do edge detection how do I find out if there are enough sharp
edges to consider the image not blurry? Or how can I tell if there's
enough contrast to call it not dark?

What are the best books on this subject? Are there more simplistic
algorithms I can use?

Thanks for any help or pointers.
- Zak