Howling canceler using interaural level difference for binaural hearing assistant system

概要

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Howling cancelation is an important issue for realizing either monaural or binaural hearing assistant systems including hearing aids. Although binaural hearing assisting systems have become popular, most of them use two independent monaural howling cancelation systems without utilizing the advantage of binaural processing. In this paper, we propose a simple howling cancelation method for a binaural hearing assistant system using interaural level difference. The interaural level difference based on the observed signals is compared with a priori prepared interaural level difference database to distinguish whether howling occurs. Simulation is performed to verify the possibility of implementing the proposed method for a binaural hearing assistant system. Since the howling canceler works frame by frame because of its fast Fourier transform based processing, the performance of the howling canceler is measured with respect to a howling margin, which corresponds to how the frequency resolution depends on canceling performance. As a result, the proposed method showed the suppression of multiple oscillating frequency components simultaneously. In simulation for the effect of frequency resolution, the results showed that the maximum howling margin reaches up to 3.0 dB.