Microphone-array hearing aids with binaural output .I. Fixed-processing systems

Abstract

This work is aimed at developing a design for the use of a microphone array with binaural hearing aids. The goal of such a hearing aid is to provide both the spatial-filtering benefits of the array and the natural benefits to sound localization and speech intelligibility that accrue from binaural listening. The present study examines two types of designs for fixed-processing systems: one in which independent arrays provide outputs to the two ears, and another in which the binaural outputs are derived from a single array. For the latter, various methods are used to merge array processing with binaural listening. In one approach, filters are designed to satisfy a frequency-dependent trade between directionality and binaural cue fidelity. In another, the microphone signals are filtered into low-and high-frequency components with the lowpass signals providing binaural cues and the highpass signal being the single output of the array processor. Acoustic and behavioral measurements were made in an anechoic chamber and in a moderately reverberant room to evaluate example systems. Theoretical performance was calculated for model arrays mounted on an idealized spherical head. Results show that both single-and dual-array systems provided targetintelligibility enhancements (2-4 dB improvements in speech reception threshold) relative to binaural cardioid microphones. In addition, the binaural-output systems provided cues that assist in sound localization, with resulting performance depending directly upon the cue fidelity. Finally, the sphere-based calculations accurately reflected the major features of the actual head-mounted array results, both in terms of directional sensitivity and output binaural cues.

FPGA Prototype Implementation of Digital Hearing Aid from Software to Complete Hardware Design

“…It is obvious that the signal is located near 1200 Hz on the frequency scale. All of the digital hearing aids must contain some common basic blocks [1], [3]. It includes microphone, impedance matching network, preamplifiers, antialiasing filters, analog to digital converter, some kind of signal processing technique using custom hardware or an embedded processor, digital to analog converter, post amplifier, speaker.…”

Study of widely linear multichannel wiener filter for binaural noise reduction

“…A straightforward way of achieving binaural noise reduction is through the use of some monaural noise reduction techniques to produce two outputs while some constraints between the two outputs are applied to preserve the so-called sound spatial cues [3]- [5]. But this method requires good estimation of the spatial cues and preservation process is in general not optimal.…”

The Improved TS-BASE Approaches with Interference Compensation and Their Evaluations for Speech Enhancement

“…The generalized sidelobe canceller (GSC) was extended to binaural scenarios for hearing aids [2]. Campbell et al applied a sub-band GSC beamformer to binaural noise reduction for hearing aids [3].…”