Hearing aids using binaural processing principles

The performance of normal human hearing in noisy circumstances is helped considerably by its ability to focus on a specific sound source. This ability is derived from the binaural nature of hearing. In this paper we present signal-processing techniques that can partially replace the binaural hearing in situations where a monaural hearing aid is used (monaural deafness, cochlear implants). First, simple noise cancellation and beam forming solutions, which are applicable to speech, are presented. Then full adaptive filter versions and a successful combination of both are proposed. A key element to the success of all these algorithms is the use of a noise versus speech discrimination criterion on which basis selected parts of the adaptive filter structure are adapted at any given moment.