Piano Roll Scanner

This short video shows how the scanner operates. While the scanner is capable of faster speeds, the operator gradually increases the speed to a level that seems safe for this old, fragile roll. The paper of many of these older rolls can be quite brittle and susceptible to tearing especially along the edges.

The Stanford piano roll scanner is based on a design by Anthony Robinson, a piano roll expert in England. Tony Calavano, Stanford Libraries Digitization Lab Manager, identified a gigE, line scanning camera that scans in color to create the images. Swope Design Solutions engineers Robyn Nariyoshi and Brett Swope adapted the Robinson design to scan in color at 300 dpi and to accept rolls up to 17 inches wide. Ethan Ruffing, a software systems engineer at Active Inspection, worked with Swope to write the software that allows the camera and scanner hardware to function together.

Achieving the optimum foreground and background lighting was a major issue to be resolved. It is critical for computer analysis to have good definition of the edges of the individual perforations, which is only possible if the lighting is properly balanced. The final images are slightly darker than they appear under most lighting conditions. This was necessary to ensure that the holes appear with sufficient brightness to be read to convert the notes and expression perforations into MIDI coding. The brightness of the image can be adjusted by the user in the Mirador viewer to come closer to the actual color and brightness of the original roll. To achieve this, use the brightness control found in the upper left corner of the Mirador viewer by about 22 percent. The brightness control is found in the upper left corner of the Mirador viewer along with the other image controls such as rotation, contrast, etc.

A video of Anthony Robinson’s scanner shows the scanner design upon which the Stanford piano roll scanner was based.