New technics based on the wavelet transform for the restoration of old recordings

Abstract

Digital techniques used for the restoration of old recordings are presented in this paper. Three different flaws can be present in old recordings, these being, harmonic distortion, impulsive noise, and background noise. Only the cancellation of the impulsive noise and the reduction of the background noise are considered. In order to cancel the impulsive noise, the corrupted samples are replaced by interpolated samples. An interpolator that uses the information located near the impulsive noise must be achieved. In this paper, two different methods of interpalation are compared. For the reduction of the background noise, we have used a method worked out by Ephraim and Malah that dces riot crzate musical noise. In order to improve the filtering of transcients, a decomposition of the signal in several frequency channels is beforehand perf ormed.