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(30) 画像処理によるモノラル円盤レコードからの音声再生

魚住 純
北海学園大学工学部研究報告, 第35号, pp.119-129, 2008-2


 A method for reproducing sound from old monaural discs is developed on the basis of digital image processing. In this method, the surface of a disc is illuminated with a large illumination angle and a sequence of magnified images is captured by a CCD camera, fed into a computer and processed digitally to yield a sound signal. In the image processing, each color image is first converted into a gray-level image, then transformed from the polar to Cartesian coordinate representations, processed for removing noises, and segmented into individual groove images. From the segmented groove images, sound signals are retrieved, which are connected mutually in the right sequence, processed for the trend removal and frequency filtering to yield finally a sound signal. 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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