Sound from Gramophone Record Groove Surface Orientation

Preserving historic recording on gramophone records is an important task because the traditional record play back system damages/wears out records eventually. We present an optical flow based method to reproduce the sound signal from gramophone records using 3 D robust scene reconstruction of the surface orientation of the walls of the grooves. The imaging setup was modified to overcome a shallow depth of field by using a thin glass plate to obtain additional in-focus parts of the image at a second focal length. The sound signal was recovered from the surface orientation and processed further using the industry standard RIAA filter. The overall algorithm has been tested and found to be working correctly using both undamaged and damaged SP records. The algorithm is a "proof of concept" in that it shows sound can be recovered from time-varying 3 D orientation of groove walls.