Criteria for estimating an FIR filter for cancelling the feedback path signal in hearing aid system

• Authors: Soudeh A. Khoubrouy;Issa M. S. Panahi
• Venue: Signal Processing
• Year: 2014

Many adaptive methods use a Finite Impulse Response (FIR) filter to estimate and cancel the effect of acoustic feedback from the loudspeaker to the microphone in a hearing aid system. In these methods the order of the filter is assumed to be fixed and known a priori, even if the feedback path characteristics change from one environment to another. Underestimation of the order of the filter and thus, the filter itself, results in inadequate feedback cancellation, while overestimation of the filter order increases computational complexity, delay, and power consumption without significantly improving cancellation of the feedback path effect. In this paper an adaptive method using short-duration noise injection with new criteria is proposed to recursively find the FIR filter of proper order for estimating the feedback path and cancelling its effect. The proposed method requires no a priori knowledge of the acoustic feedback path or its order. Using the speech and music signals as the desired signals at the input microphone, the performance of the proposed method is analyzed and compared with those based on the convergence of Misalignment (MISA) and Perceptual Evaluation of Speech Quality (PESQ) criteria.