Recently I was faced with the task of quickly scanning quite a few books. There was a scanner at home I decided to use. A hp scanner; which I thought will do the job just fine. The last time I had such a requirement, I borrowed a scanner from a friend and did the job. 3 days later (with intermittent breaks) I had completed scanning 101 pages of my first book.
I soon realized that using a camera to take a picture of each of the pages would get the job done just as well. Whipped out the camera, and completed 5 books in one day (actually not even a day, more like an evening). What's the difference in quality? Well, the scans are definitely better that the photos, but my main requirement was that the text be legible. The camera was more than enough for the task. Moreover the difference in quality was due to uneven light sources for the photos (which I'm sure can be alleviated once the technology is perfected).
It then got me thinking about Google's task of creating a searchable archive of books. I sure hope they didn't use a scanner to scan all the pages of all the books. A photo of the pages and then using a OCR software should get the job done faster (I think). My next thought is, why don't they make scanners based on camera technology? Wouldn't scanning time then be reduced to a fraction of what it currently is?
Maybe its a cost factor, but hopefully the next generation of scanners will perform much faster (or be based off of photographic technology)