Groove Extraction of Phonographic Records

Historical sound documents are of high importance for our cultural heritage. The sound of phonographic records is usually extracted by a stylus following the groove, but many old records are in such bad shape that no mechanical contact is possible. The only way to read them is by a contactless reading system. A phonographic document analysis system was developed using an optical technique to retrieve the sound from old records. The process is straightforward: we take a picture of each side of the disc using a dedicated analog camera, we store the film as our working copy, and when needed, we scan the film and process the image in order to extract the sound. In this paper, we analyze the imaging issues and present the algorithm for extracting the groove position and therefore the sound of the records.