(26) Reproduction of sound of old records by means of incoherent illumination and image processing
Jun Uozumi
Technical Digest of the Eighth Japan-Finland Joint Symposium on Optics in Engineering (OIE'09), pp.43-44, 2009-9
A non-contact method for reproducing sound from monaural SP discs is developed on the basis of incoherent illumination of disc surface and digital processing of images captured by CCD camera. Light from a halogen lamp, guided by a fiber bundle, illuminates the surface of a disc with an adequate illumination angle, reducing a sound groove to a distinct dark or bright band. A sequence of magnified images of the grooves are captured and subjected to a sequence of digital processing on a computer. At present, images containing a groove of 31 rotations were processed and the sound signal of about 24 seconds of good quality was reproduced successfully.
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