Akihiro Hirano

Learn 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)
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)
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)
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)
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)