A method for digital restoration of phonograph recordings contaminated by impulsive noise is proposed. Impulses are suppressed by applying median filtering on contaminated signal regions only, thus minimizing distortion of clean passages and loss of high musical frequencies. The algorithm can be implemented on a personal computer equipped with any inexpensive sound board, and thus it can be used for the restoration of damaged records in home collections. In experiments with old recordings the improvement in sound quality was dramatic. The restored audio signal can be archived in digital form on regular computer back-up tapes or on digital audio tapes, or it can be played through the sound board and stored onto an analog recording media such as high-quality cassette tapes.
Perceptual coding of digital audio
