i mean scanning only, not correcting.

I've tried playing with a camera and AMC but it's hard to get a usable image. You have to consider keystone, alignment, good lighting, macro-settings etc.
It can be done, but to get consistently reliable images you would probably need a tripod or a makeshift stand. Even then, the speed is not much greater than using a flatbed scanner, because you have to align every new page carefully and will probably lose extra time in post-processing (deskewing, scaling, adjusting contrast etc.).

If you can afford a mobile phone with a decent camera you could probably afford a low-end flatbed scanner as well, in my experience camera idea was a failure.

thanks
now i used "gradecam" to correcting the monthly quiz.
scan and correct in the same time without saving the images (ram only).
60 pages in 1 minute.
free for "the teachers".
http://www.gradecam.com
regards,

Hi, I took a look at this. It has an impressive OMR engine, but 'free' version is limited to 10 multiple choice questions and doesn't allow export of reports to gradebooks. Full version for schools costs $2 per student per year, that would set my school back about $2000 per year.

Anyway, if it works for you, go ahead. Regardless of financial issues, now that I have picked up a bit of LaTex I have come to greatly appreciate the fine control LaTex and AMC give me in the exam making and grading process.

To answer the original question, YES, actually you can use the mobile phones to capture usable images for AMC. Recently I have been playing with CamScan and Mobile Document Scanner (MD Scan) on Android and Apple phones, and they actually do a decent job of capturing useful images (or processing imported images that were taken by another camera). MD Scan had a 100% accuracy rate. I had a few missed marks when using CamScan, but the person taking those pictures was quite sloppy and the camera resolution at a very low setting. CamScan is free, MD Scan costs $5 for a full version, both support batch processing.

So far I tried this on a sample of some 60 papers. For midterm exams we plan to process a few hundred papers using mobile phone cameras (that's a very small percentage of exams at my school) to obtain a better sample. We also plan to process a couple hundred more using images captures by standard cameras and then processed on tablets or mobile phones to see does it influence accuracy. We are considering to use them instead of procuring costly ADF scanners. I was quite pleasantly surprised at the speed of work obtained by using lower end smartphones in batch mode processing.

As a side note, Ubuntu 14.10 will reportedly be able to run Android apps natively, so hopefully CamScan, MD Scan and other such software could be run on a laptop. The key is in the software, images can be taken with standard cameras. It's kind of odd I couldn't find similar software that would run on a desktop or a laptop at this time. Somebody please chime in if you know of any such desktop software.