Implementation of a Speech Coding
Strategy for Auditory Implants

Lamia Bouafif, Kais Ouni, and Noureddine Ellouze
Signal Processing Laboratory, Engineering Faculty of Tunis, Tunisia

Abstract: In this paper we present the conception and the implementation of a speech processing interface for cochlea prosthesis. This ‎module is based on a numerical speech processing algorithm which modelizes the infected ear and generates the stimulus ‎signals for the cilia cells (brain).  This interface uses a gammachirp filter bank constituted of 16 band pass filters based on IIR ‎filters. The central frequencies and ERB bands are computed with Glasberg and Moore models; however stimulus signals are ‎selected after a spectral energy analysis of each channel. The energy and the amplitude of the selected BFG filter bank outputs ‎are quantized and transmitted to the cochlea electrodes.  To validate our work, we tested it on vowels, consonants then on ‎several words pronounced by different speakers. The results demonstrated a degree of discrimination and interferences ‎between different sounds especially in multi speaker environment.‎