A new adaptation mode controller for adaptive microphone arrays based on nested and symmetric leaky blocking matrices

An adaptation mode controller (AMC) based on an estimation of signal-to-interference ratio using multiple blocking matrices for adaptive microphone arrays is proposed. A new nested blocking matrix enhances detection of the interference power. A normalized cross-correlation between symmetric leaky blocking-matrix outputs improves directivity. The detection of hissing sounds in the target speech is enhanced by modifying the high frequency components of the fixed beamformer output. Evaluations are carried out using a four-microphone array in a real environment with reverberations for different signal-to-interference ratios, interference directions of arrival, and target distances from the array. They show that the proposed AMC contributes to an enhanced output quality as well as an increased speech recognition rate by as much as 31% compared to the conventional AMC.