Applications of a nonlinear smoothing algorithm to speech processing

In this paper a nonlinear smoothing algorithm recently proposed by Tukey is described and evaluated for speech processing applications. Simple linear smoothing routines generally fail to provide adequate smoothing for data which exhibit both local roughness and sharp discontinuities. The proposed nonlinear smoothing algorithm can effectively smooth such data by using a combination of median smoothing routines and linear filtering. The concept of double smoothing is introduced as a refinement on the smoothing algorithm. Examples of the application of the nonlinear smoothing methods to typical speech parameters are included in this paper.