FPGA-implementation of a bio-inspired medical hearing aid based DWT-OLA

In this paper, we describe the implementation on Field Programmable Gate Array (FPGA) of generic platform for a Bio-Inspired Medical Hearing Aid (BIMHA). The rapid growth in the industrial technologies has participated in the development of several and performed hardware systems for digital signal processing applications. In spite of the fast emergence of the new micro and nanotechnologies, the most recent digital hearing aids do not still succeed in satisfying the hearing-impaired people. These hearing prosthesis use hardware as solution to correct the deficiency for impaired persons. But, for the same degree of hearing deficiency, the pathology of the hearing impaired persons could be different which explains the no satisfaction of deaf people using hearing prosthesis. It is in this perspective that the large number of studies and applications were oriented to the signal and speech processing rather than in purely hardware technological solutions. In order to contribute for the amelioration of intelligibility and the hearing comfort quality, we propose a new approach using Discrete Wavelet Transform and Over-Lap and Add technique (DWT-OLA). Our aim is to keep small device sizes and reduced power consumption in one side and in the other side, to enhance speech by denoising, echo-cancelling and frequency shifting. We conducted experiments on speech data taken from arctic corpus and evaluated the system performance using MSE and SNR for objective measurements and Mean Opinion Score (MOS) for subjective ones. We obtained a gain of intelligibility reaching 70%. Moreover, the proposed FPGA platform involves fewer resources, reduced memory-size and les power consumption as compared to some previous designs.