Using Computer Vision Technology to Play Gramophone Records
Baozhong Tian, John A. Barron · Journal of the Audio Engineering Society · 2011
We present a non-contact optical flow based method to reproduce the sound signal from gramophone records using 3D robust scene reconstruction of the surface orientation of the walls of the grooves. The conversion of analogue data to digital data is an important task for the preservation of historic sound recordings. We digitally viewed the grooves of a record using a microscope that was modified to overcome the limitation of a shallow depth of field by using a thin glass plate to obtain part of the image at a second focal length to gain better overall quality images of the groove. The sound signal was recovered from the groove surface orientation. The overall algorithm has been tested and found to be working correctly using undamaged and damaged real records.