著者

Yoshiki Masuyama Tsubasa Kusano Kohei Yatabe Yasuhiro Oikawa

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.40, no.3, pp.186-197, 2019-05-01 (Released:2019-05-01)

参考文献数

29

被引用文献数

3

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For musical instrument sounds containing partials, which are referred to as modes, the decaying processes of the modes significantly affect the timbre of musical instruments and characterize the sounds. However, their accurate decomposition around the onset is not an easy task, especially when the sounds have sharp onsets and contain the non-modal percussive components such as the attack. This is because the sharp onsets of modes comprise peaky but broad spectra, which makes it difficult to get rid of the attack component. In this paper, an optimization-based method of modal decomposition is proposed to overcome it. The proposed method is formulated as a constrained optimization problem to enforce the perfect reconstruction property which is important for accurate decomposition and causality of modes. Three numerical simulations and application to the real piano sounds confirm the performance of the proposed method.

著者

Kohei Yatabe Yoshiki Masuyama Tsubasa Kusano Yasuhiro Oikawa

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.40, no.3, pp.170-177, 2019-05-01 (Released:2019-05-01)

参考文献数

48

被引用文献数

21

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As importance of the phase of complex spectrogram has been recognized widely, many techniques have been proposed for handling it. However, several definitions and terminologies for the same concept can be found in the literature, which has confused beginners. In this paper, two major definitions of the short-time Fourier transform and their phase conventions are summarized to alleviate such complication. A phase-aware signal-processing scheme based on phase conversion is also introduced with a set of executable MATLAB functions (https://doi.org/10/c3qb).

著者

Tsubasa Kusano Kohei Yatabe Yasuhiro Oikawa

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.39, no.3, pp.215-225, 2018-05-01 (Released:2018-05-01)

参考文献数

47

被引用文献数

2

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In marine seismic surveys to explore seafloor resources, the structure below the seafloor is estimated from the obtained sound waves, which are emitted by a marine seismic sound source and reflected or refracted between the layers below the seafloor. In order to estimate the structure below the seafloor from returned waves, information of the sound source position and the sound speed are needed. Marine seismic vibrators, which are one of the marine seismic sound sources, have some advantages such as high controllability of the frequency and phase of the sound, and oscillation at a high depth. However, when the sound source position is far from the sea surface, it becomes difficult to specify the exact position. In this paper, we propose a method to estimate the position of a marine seismic vibrator and the sound speed from obtained seismic data by formulating an optimization problem via hyperbolic Radon transform. Numerical simulations confirmed that the proposed method almost achieves theoretical lower bounds for the variances of the estimations.