Scanning Overview

The actual scanning is controlled with Pi Scan, a scanning appliance that runs on a Raspberry Pi. Pi Scan is optimized to run with the official Raspberry Pi display and touchscreen. The Pi is connected via USB cables to the two cameras. The cameras run unofficial software called CHDK which allows them to be controlled and configured remotely via USB cables. The Pi is also connected to an SD Card reader where scans and settings are saved.

The physical process of scanning consists of pulling on the handle to press the cradle up against the glass platen. While a pair of pages if flat against the glass platen, the operator taps the touch screen to trigger the cameras. The cameras trigger and send photos to the Pi in one step and the photographs are never stored on the cameras.

The Pi itself saves the photographs to the card in the SD Card reader immediately. Once a book is scanned, the user is left with a folder full of page photographs to copy from the SD Card to their computer. Turning the photographs into a single ebook is called post-processing and discussed below.