Spherical near field acoustic holography with microphones on a rigid sphere

Jacobsen, Finn; Jø,; Hald, rgen; Fernández, E.; Moreno, Guillermo

doi:10.1121/1.2934035

Cited by 6 publications

(10 citation statements)

References 5 publications

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“…The existing reconstruction methods based on measurements with spherical arrays rely on expanding the measured sound field into spherical harmonics, and then make use of the radial functions to reconstruct the sound field elsewhere in free-space. [20][21][22][23][24] The measurement can be performed with an open sphere array 24 or with a rigid sphere array. [20][21][22] In the open sphere case, the array is assumed to be transparent, and the incident sound field is expanded using Bessel functions of the first kind as radial functions.…”

Section: A Existing Methodsmentioning

confidence: 99%

“…These studies have aimed at reconstructing either the total sound field 20,24 or only the incident waves on the array. [21][22][23] The present study proposes a sound-field reconstruction method based on an equivalent source model. It makes use of a combination of point sources to describe the sound field on the array.…”

Section: Introductionmentioning

confidence: 99%

“…10,11 Spherical microphone arrays are widely used for sound source localization, [12][13][14] sound field reproduction-to capture sound fields that can be reproduced with an array of loudspeakers, [15][16][17][18] and sound field analysis and reconstruction. [19][20][21][22][23][24][25][26] The use of rigid spherical microphone arrays for reconstructing sound fields has been the subject of several studies, [20][21][22][23][24] which employ a spherical harmonic expansion to provide a full representation of the sound field (sound pressure, particle velocity, and sound intensity). The expansion is used to extrapolate the sound field to a different radius than measured, thus reconstructing the sound field over a three-dimensional space about the array, i.e., predicting the sound field elsewhere than measured.…”

Section: Introductionmentioning

confidence: 99%

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Sound field reconstruction using a spherical microphone array

Fernández-Grande

2016

The Journal of the Acoustical Society of America

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A method is presented that makes it possible to reconstruct an arbitrary sound field based on measurements with a spherical microphone array. The proposed method (spherical equivalent source method) makes use of a point source expansion to describe the sound field on the rigid spherical array, from which it is possible to reconstruct the sound field over a three-dimensional domain, inferring all acoustic quantities: sound pressure, particle velocity, and sound intensity. The problem is formulated using a Neumann Green's function that accounts for the presence of the rigid sphere in the medium. One can reconstruct the total sound field, or only the incident part, i.e., the scattering introduced by the sphere can be removed, making the array virtually transparent. The method makes it possible to use sequential measurements: different measurement positions can be combined, providing an extended measurement area consisting of an array of spheres, and the sound field at any point of the source-free domain can be estimated, not being restricted to spherical surfaces. Because it is formulated as an elementary wave model, it allows for diverse solution strategies (least squares, ' 1 -norm minimization, etc.), revealing an interesting perspective for further work.

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Section: A Existing Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sound field reconstruction using a spherical microphone array

Fernández-Grande

2016

The Journal of the Acoustical Society of America

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“…xyplane) are captured by a UCA at the same plane. For the case of 3D plane, a spherical array [35] is often used, but is not considered here. The sound field in the 2D plane can be decomposed into a Fourier series in terms of the azimuth coordinate, ϑ.…”

Section: Stft ( ) W Ktmentioning

confidence: 99%

Indoor Multi-Speaker Localization Based on Bayesian Nonparametrics in the Circular Harmonic Domain

SongGong

Chen

Wang

2021

IEEE/ACM Trans. Audio Speech Lang. Process.

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Circular microphone arrays have been used for multi-speaker localization in computational auditory scene analysis, for their high flexibility in sound field analysis, including the generation of frequency-invariant eigenbeams for wideband acoustic sources. However, the localization performance of existing circular harmonic approaches, such as circular harmonics beamformer (CHB) depends strongly on the physical characteristics (such as shape) of sensor arrays, and the level of uncertainties presented in acoustic environments (such as background noise, room reverberation, and the number of sources). These uncertainties may limit the performance or practical application of the speaker localization algorithms. To address these issues, in this paper, we present a new indoor multi-speaker localization method in the circular harmonic domain based on the acoustic holography beamforming (AHB) technique and the Bayesian nonparametrics (BNP) method. More specifically, we use the AHB technique, which combines the delay-and-sum beamforming with acoustic-holography-based virtual sensing, to generate direction of arrival (DOA) measurements in the time-frequency (TF) domain, and then design a BNP algorithm based on the infinite Gaussian mixture model (IGMM) to estimate the DOAs of the individual sources without the prior knowledge about the number of sources. These estimates may degrade in the presence of room reverberation and background noise. To address this issue, we develop a robust TF bin selection and permutation method on the basis of mixture weights, using power, power ratio and local variance estimated at each TF bin. Experiments performed on both simulated and real-data show that our method gives significantly better performance, than four recent baseline methods, in a variety of noise and reverberation levels, in terms of the root-mean-square error (RMSE) of the DOA estimation and the source detecting success rate.

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“…Firstly introduced by Williams et al [2] and Maynard et al [3], this Fourier approach reconstructs the sound sources using a spatial 2D Fourier transform of the Helmholtz equation. Initially, NAH was developped to be used with a planar array of microphones but has been extended to cylindrical [4] or spherical geometries [5]. Many alternative methods, all based on NAH, can be found in the literature.…”

Section: Introductionmentioning

confidence: 99%

Sound fields separation and reconstruction of irregularly shaped sources

Totaro

Vigoureux

Leclère

et al. 2015

Journal of Sound and Vibration

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International audienceNowadays, the need of source identification methods is still growing and application cases are more and more complex. As a consequence, it is necessary to develop methods allowing us to reconstruct sound fields on irregularly shaped sources in reverberant or confined acoustic environment. The inverse Patch Transfer Functions (iPTF) method is suitable to achieve these objectives. Indeed, as the iPTF method is based on Green's identity and double measurements of pressure and particle velocity on a surface surrounding the source, it is independent of the acoustic environment. In addition, the finite element solver used to compute the patch transfer functions permits us to handle sources with 3D irregular shapes. In the present paper, two experimental applications on a flat plate and an oil pan have been carried out to show the performances of the method on real applications. As for all ill-posed problem, it is shown that the crucial point of this method is the choice of the parameter of the Tikhonov regularization, one of the most widely used in the literature. The classical L-curve strategy sometimes fails to choose the best solution. This issue is clearly explained and an adapted strategy combining L-curve and acoustic power conservation is proposed. The efficiency of this strategy is demonstrated on both applications and compared to results obtained with Generalized Cross Validation (GCV) technique

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Spherical near field acoustic holography with microphones on a rigid sphere

Cited by 6 publications

References 5 publications

Sound field reconstruction using a spherical microphone array

Sound field reconstruction using a spherical microphone array

Indoor Multi-Speaker Localization Based on Bayesian Nonparametrics in the Circular Harmonic Domain

Sound fields separation and reconstruction of irregularly shaped sources

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