Efficient DSP Implementation of Median Filtering for Real-Time Audio Noise Reduction

Stephan Herzog
DAFx-2013 - Maynooth
In this paper an efficient real-time implementation of a median filter on a DSP platform is described. The implementation is based on the usage of a doubly linked list, which allows effective handling of the operations needed for the running computation of a median value. The structure of a doubly linked list is mapped onto the DSP architecture exploiting its special features for an efficient implementation. As an application example, a real-time denoiser for vinyl record playback is presented. The application program consists of two main parts, namely a subsystem for click detection and a subsystem for click removal. Both parts can be implemented using median filters.