Yutaka Kamamoto

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We propose a novel principle based on Complex Spectrum Circle Centroid (CSCC) for restoring complex spectrum of the target signal from multiple microphone input signals in a noisy environment. If noise arrives at multiple microphones with different time delays relative to the target signal, the observed noisy signals lie on a circle in the complex spectrum(More)
This paper describes two low-complexity tools used for the new ITU-T recommendation G.711.0, the lossless coding of G.711 (A-law/μ-law logarithmic PCM) speech data. One is an algorithm for quantizing the PARCOR/reflection coefficients and the other is an estimation method for the optimal prediction order. Both tools are based on a criterion that minimizes(More)
We have devised a direct and simple scheme for linear conversion of line spectrum pairs (LSP) with low computational complexity aiming at weighting or inverse weighting spectral envelopes for noise control in speech and audio coders. Using optimally prepared coefficients, we can perform the conversion directly in the LSP domain, which ensures low(More)
We have devised a method for representing frequency spectral envelopes with warped frequency resolution based on sparse non-negative matrices aiming at its use for frequency domain audio coding. With optimally prepared matrices, we can selectively control the resolution of spectral envelopes and enhance the coding efficiency. We show that the devised method(More)