Akihiro Hirano

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SUMMARY This paper proposes a new robust adaptive beamformer applicable to microphone arrays. The proposed beamformer is a generalized sidelobe canceller (GSC) with a variable blocking matrix using coefficient-constrained adaptive filters (CCAFs). The CCAFs, whose common input signal is the output of a fixed beamformer, minimize leakage of the target signal(More)
This paper proposes a stereo echo canceller with simultaneous input-sliding and sliding-period control. Periodic delays with different phases in two channels provide an additional condition for echo cancellation , leading to faster convergence. It also guarantees symmetrical shifts of a sound image around its original position for better subjective quality(More)
A robust adaptive microphone array (RAMA) using a new adaptation-mode control method (AMC) is proposed, and its evaluation results by hardware are presented. The adaptation of the RAMA is controlled based on an SNR (signal-to-noise) estimate using the output powers of the fixed beamformer and the adaptive blocking matrix. The RAMA is implemented on a(More)
In blind source separation, convergence and separation performance are highly dependent on a relation between a probability density function (pdf) of the output signals y and nonlinear functions f(y) used in updating coefficients of a separation block. This relation was analyzed based on kurtosis κ 4 of the output signals. The nonlinear functions, tanh(y)(More)
This paper presents convergence characteristics of stereo-phonic echo cancellers with pre-processing. The convergence analysis of the averaged tap-weights show that the convergence characteristics depends on the relation between the impulse response in the far-end room and the changes of the pre-processing filters. Examining the uniqueness of the solution(More)