Reconstruction of Recorded Sound from an Edison Cylinder Using Three-Dimensional Noncontact Optical Surface Metrology

摘要

Audio information stored in the undulations of a groove in a mechanical sound carrier such as a cylinder or disk phonograph record may be reconstructed, without contact, by measuring the groove shape using precision optical metrology methods and digital image processing. The viability of this approach was recently demonstrated on a 78-rpm shellac disk using two-dimensional image acquisition and analysis methods. The first three-dimensional reconstruction of recorded sound from a mechanical carrier is reported. The source material, a celluloid cylinder, was scanned using color-coded confocal microscopy techniques and resulted in a faithful playback of the recorded information.