Abstract
The existing adaptive echo cancellation based howling (typically in hearing aids) removal methods have several drawbacks such as insufficient attenuation of the howling component, slow response and nonlinear distortion. To solve these problems, we propose a segmented notch filtering based scheme. Specifically, firstly, it is proved that the attenuation value can reach dB at any detected howling frequency; secondly, the filter coefficients can be readily calculated by a closed-form formula, yielding a fast response to the sudden howling accident; thirdly, the closed-form formula of this filter is theoretically an even function, indicating that this filter possesses a linear transfer characteristic. In combination with proper segmentation and precisely removing these transient samples arising from FIR (Finite Impulsive Response) filtering, nonlinear distortion can be entirely avoided. Experimental results show that our proposed scheme can not only accurately estimate the howling frequency, but can also completely remove it, which yields a high-quality output waveform with a recovery SNR of about 22 dB. Therefore, the proposed segmented notching based scheme possesses vast potential for hearing aid development and other relevant applications.
Highlights
Hearing, which acts as a crucial link of communication with the surroundings, is one of the most important senses of human beings
A hearing aid is mainly composed of microphone, amplifier, speaker, battery, various volume and tone control knobs and other components
On the basis of our previous work in [21], this paper proposes a closed-form FIR notch filter design, concurrently satisfying the above four conditions; Further, to ensure that howling suppression can work continuously while remaining the linear phase characteristic, we design a feasible segmentation based scheme consisting of an energy detector, spectrum corrector and a segmented notch filter; This paper develops a high-efficiency howling suppression mode, which can shorten the howling detection to an extent that a wearer can hardly recognize this accident, and readily removes the howling without incurring any phase distortions
Summary
Hearing, which acts as a crucial link of communication with the surroundings, is one of the most important senses of human beings. Global noise pollution and the aging of the world population have led to an increasing number of people with hearing loss [1]. Scientists are constantly adopting various methods to help hearing-impaired patients to improve hearing. Wearing hearing aids is one of the most commonly used methods to compensate patients for hearing loss. A hearing aid is mainly composed of microphone, amplifier, speaker, battery, various volume and tone control knobs and other components. The development of hearing aids has experienced the following five periods:
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call