Piano roll scanner update

October 23, 2018
Jerry L McBride
Piano roll scanner

The Stanford piano roll scanner has progressed from a prototype to a functional, production level machine since the last report in spring of 2017. As reported earlier, the scanner is based on a design by Anthony Robinson, a piano roll expert in England. Swope Design Solutions engineers Robyn Nariyoshi and Brett Swope adapted the Robinson design to scan wider rolls and in color at 300 dpi. Tony Calavano, Stanford Libraries Digitization Lab Manager, identified a gigE, line scanning camera that scans in color to provide the images for the scanner. Ethan Ruffing was the software systems engineer at Active Inspection working with Swope to write the software that allows the camera and scanner hardware to function together.

Piano roll scanner (detail)

In fall of 2017 the scanner was ready for delivery and testing. Craig Sapp, Adjunct Professor of Music, advised the scanner project from the beginning and agreed to conduct the onsite testing of the scanner at Stanford. Craig, in consultation with Tony Calavano, the camera manufacturer Teledyne Dalsa, and SDS, spent innumerable hours adjusting and fine tuning the scanner and camera so that the resulting scans would meet the specifications needed to obtain the data to produce MIDI files that accurately represent the music encoded on the rolls and that also would meet preservation archival standards for the digital images. Sapp’s progress and his analysis of the scans is recorded on his web page, Craig’s Piano Roll Resources. 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.

Scanner with roll inserted

By December 2017 most of the issues had been worked out, and the scanner was producing full color scans that met the goals of the project. Small refinements and adjustments continued to be made to the camera settings and scanner through the winter and spring of 2018 in anticipation of the Reactions the Record symposium on piano rolls held in April 2018.

It is incredibly exciting to see these high-resolution scans of red Welte rolls of over 100 years ago appear on the screen, where every minute detail is clearly visible from the opening title label

Piano roll label

to the handwritten date at the end with the technician’s initials. 

Piano roll detail with date and technician's initials

Even more exciting is to be able to hear the realization of the rolls in sound, which will be the subject of a future posting.

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