Implementation of a speech coding strategy for auditory implants

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.