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. The glass was taken from two flatbed scanners and cut down to size by hand.
We use two Canon Digital Rebel T3 cameras, attaching the scanner frame to the body with a screw that resembles what you would find in a tripod head. Each is connected via USB to a computer and remote-controlled with a Python script that uses the gphoto2 library. There is no battery or persistent storage in either camera. Pictures are transferred to the controller computer after the shutter is triggered. If you would like to use different cameras, there is a list of cameras supported by gphoto2 .
The settings as of this revision are the following
mode: M aperture: F14 shutter: 1/20 ISO: auto zoom: 24mm stabilizer: on manual focus
All manual settings
- The zoom is adjusted by turning the ring around the lens and looking at the numbers, which indicate millimeters.
- The mode is indicated by turning the circular knob on the upper left, so the letter M is facing the arrow.
- The stabilizer is a physical switch on the lens. It is marked "stabilizer".
- The focus is adjusted by turning the ring on the far end of the lens. This will require you see down the viewfinder. This camera supports live viewfinder mode. Open Darktable in tethering mode.
The cameras are triggered by pressing the enter key on the computer keyboard.
A cool upgrade would be a foot switch to trigger the shutter. This would free up the operator's hands to be dedicated to the book parts. This could be a cheap MIDI keyboard sustain pedal or a guitar pedal type switch.
(See also: Book Scanner Software)
The scanning is handled by a Python script that uses gphoto2 to connect with the cameras and displays images of the scanned pages in an HTML view. Three USB ports are required for the monitoring computer: One each for the two cameras, and one for the keyboard or triggering mechanism. Post-processing is handled with ScanTailor, an OCR script using Tessaract, and various other scripts.
Live View is obtained through a utility called Darktable. It supports "tethering mode". It may even be possible to use Darktable as a complete book assembly application. Not sure yet.
Alternative for liveview from a python library http://magiclantern.wikia.com/wiki/Remote_control_with_PTP_and_Python
There is a firmware upgrade for Canon DSLR cameras like the 5D Mk II called Magic Lantern which is popular. The supported models of cameras have a high resale value.
Infos on building a transcoding cluster http://media.bemyapp.com/develop-video-render-farm/
Bookscanner Instructions are available, these are most likely obsolete.
The red book scanner has been archived. As of 2017-04-01 it exists as a kit with all parts necessary for re-assembly on a shelf in the south-west wall.
This device has a deep emotional connection with many members of the noisebridge community. It represents more than the sum of its parts. Here is some of the documented history.
Here's the red scanner first being assembled:
The completed scanner ready to scan:
The scanner on its new rolling stand: