Here's the scanner first being assembled:
The completed scanner ready to scan:
The original LED light was replaced with a larger LED array. To avoid glare, the array is mounted perpendicularly so the long side is parallel with the spine of the book. All of the interior surfaces of the book scanner are painted black, to avoid casting reflections on the glass.
We use two Canon cameras connected with USB to a computer and remote-controlled with the gphoto2 library. The pictures are transferred to the computer as soon as they are taken, rather than stored on an SD card.
The cameras are triggered by a button mounted next to the handle on the scanner. The button is connected to a circuit board from a USB keyboard, so it behaves like pressing the "enter" key on the computer.