BEFORE WE BEGIN... Reasons you might want to do this include the following:
ALSO... We've done this book scanning Instructable thing before. And answered many questions in the comments! And we love you guys completely, but sometimes (well, actually, all the time) we get the same questions over and over! So we've compiled a Fairly Annoying Questions (FAQ) Here are some answers before we get started!
1. Why not just take a picture with the book on the table.
2. Why use a camera instead of a flatbed scanner?
3. Why not use a sheet-feed scanner like the ScanSnap?
4. Can't I use a webcam?
Find a box that is roughly this shape. We got this box from a comic book shop. It's nearly perfect. 7x14x10.5". Box size really isn't that critical but after cutting ~10 boxes this one seemed to work best. Of course, you could make your own box.
Tape the box completely shut (we neglected to do this starting out; learn from our mistakes!)
Take your piece of glass and use it as a ruler to mark the diagonal line from corner to corner.
Cut across the diagonal.
Do the same thing on the other side.
If there are any remaining parts of the box hanging free, tape 'em up. If you taped your box completely shut at the beginning, you shouldn't have these kinds of problems.
Unfold the box so you have two wedges.
Good job so far. Question: What are you scanning?
If the thing you are scanning is very thin, like a magazine or composition book or lab notebook, leave the two wedges connected. Same if it is a spiral-bound notebook. These things all work well without further cutting. If the diagonal you cut across was not square, however, you might want to cut anyway. Like in our case, because the angles weren't equal, we had to flip one of the wedges around.
OK, now for some lighting. You want your camera to be taking pictures nice and quick, so you need to give it plenty of light. We used a simple desk lamp. $3.99 at Savers, a local thrift store. Though this is not the world's most even or perfect light, it is GOOD ENOUGH and, most importantly, the camera has a white balance setting for it (called "Incandescent" -- set your WB to incandescent, PLZ!). Doing so ensures the colors come out perfectly. Consult the manual for your camera for instructions.
After you set up your camera in the next step, you may have to adjust your lamp because it will show up as a reflection in the glass. It's easy, just move it up or down to get it out of the picture. But you can't do it until we set up the camera, so... let's set up the camera!
Here's the thing. You need a camera to look at your stuff and take pictures. And I guess you could hold it in your hands, but the shake, moving position, and so on would reall complicate the post-processing of your images. What you need is a stand to put your camera on. We used a tripod, but of course you don't really need a tripod. In fact, there are dozens of tripod-like objects on Instructables. If you don't have a tripod, check 'em out.
Ideally, you want your camera to be facing the page so that the screen on the back of the camera is parallel to the page. If things are straight-on, there is less correction to do in software. It's worth playing around a bit to get your camera perfectly positioned. Once you have it set up, you might find, as we did, that it's ready to fall over! In this case, tape the back leg of the tripod to your table.
This part is easy. From the previous step, you should have ensured that you have some slop aroud the image of the page you are interested. This allows you to crop later, which is especially important if it is a thick book or magazine.
The way we prefer to do this is to shoot all the right-side pages first, and all the left-side pages second. Shooting all the pages this way simplifies post-processing later.
Below, you can see Matti shooting all the right-side pages of a book. He places the glass, presses the shutter button, replaces the glass, presses the shutter button... ad nauseam. Do this until you have reached the end of whatever you are interested in scanning.
Then flip the book.
Continue as before, but now shooting all the left-side pages.