scholarly journals Three-Dimensional Sound Field Reconstruction and Sound Power Estimation by Stereo Vision and Beamforming Technology

2020 ◽  
Vol 11 (1) ◽  
pp. 92
Author(s):  
Yetian Cai ◽  
Xiaoqin Liu ◽  
Yanjiao Xiong ◽  
Xing Wu
Keyword(s):  
Stereo Vision ◽  
Sound Source ◽  
Power Level ◽  
Three Dimensional ◽  
Sound Field ◽  
Sound Intensity ◽  
Depth Information ◽  
Sound Power ◽  
Field Reconstruction ◽  
Sound Field Reconstruction

The size of the sound field reconstruction area has an important influence on the beamforming sound source localization method and determines the speed of reconstruction. To reduce the sound field reconstruction area, stereo vision technology is introduced to continuously obtain the three-dimensional surface of the target and reconstruct the sound field on it. The fusion method can quickly locate the three-dimensional position of the sound source, and the computational complexity of this method is mathematically analyzed. The sound power level can be estimated dynamically by the sound intensity scaling method based on beamforming and the depth information of the sound source. Experimental results in a hemi-anechoic chamber show that this method can quickly identify the three-dimensional position of the moving source. When the depth of the moving sound source changes, the estimated sound power is more stable than the sound pressure on the microphone.

Ghost Image Suppression Based on Particle Swarm Optimization-MVDR in Sound Field Reconstruction

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Min Li ◽  
Long Wei ◽  
Qiang Fu ◽  
Debin Yang
Keyword(s):  
Sound Source ◽  
Sound Pressure ◽  
Microphone Array ◽  
Sound Field ◽  
Distribution Map ◽  
Swarm Optimization ◽  
Field Reconstruction ◽  
Grating Lobe ◽  
Sound Field Reconstruction ◽  
Ghost Images

In sound field reconstruction, spurious sources called ghost images always appear around the position of the real sound source in the sound pressure distribution map because of the grating and side lobes, thus resulting in an incorrect identification of the sound source. To solve this problem, a method for suppressing ghost images is proposed in this paper; such method is based on particle swarm optimization (PSO) and minimum variance distortionless response (MVDR) beamforming. In this method, the elements distribution of a microphone array is first optimized by the PSO algorithm to acquire the optimal design of an unequal spacing microphone array. With this array, the grating lobe is suppressed, and the increscent value of the inherent side lobe value is reduced. Second, MVDR algorithm is used to weaken the effect of the side lobes and to obtain a sound pressure distribution map in which the ghost images are suppressed. The advantage of this method is the combination of the unequal spacing array, which suppresses the grating lobe, and the MVDR algorithm, which has excellent performance in spatial filtering. Through this method, a microphone array with a few number of elements can achieve ghost image suppression. Experiments on sound field reconstruction in an anechoic chamber for a single-tone sound source are conducted to validate the proposed method. Moreover, some extra sound field reconstructions for a single-tone sound source and double sound sources with broadband in a normal room with different parameters such as the array shape and distance from the sources to the array are conducted to discuss their influences on the effectiveness of the proposed method.

Three-Dimensional Sound Directivity around a Helicopter Turboshaft Engine

2012 ◽  
Vol 57 (4) ◽  
pp. 1-10
Author(s):  
Helene Gounet ◽  
Serge Lewy
Keyword(s):  
Microphone Array ◽  
Power Level ◽  
Three Dimensional ◽  
Sound Field ◽  
Broadband Noise ◽  
Sound Power ◽  
The Novel ◽  
Sound Power Level ◽  
Directivity Patterns ◽  
Turboshaft Engine

Turboshaft engines can be the main source of noise due to a helicopter at takeoff. Some new silencing designs of the inlets and of the ejector were tested on a Turbomeca Arrius 2B2 engine in an open-air static facility. Intake and exhaust are not axisymmetric, and conventional directivity patterns of sound field on a horizontal arc of circle are insufficient. A special microphone array on a vertical half-circle translating axially was built. Data processing has been implemented to plot maps of sound pressure levels in third-octave bands and to compute sound power levels. Intake and exhaust radiations are separated thanks to mufflers on the other side. The lined fins in the secondary lateral inlet well reduce the compressor tone, which is largely dominant in intake radiation. Its sound power level is decreased by 7 dB. The novel ejector is also successful to reduce exhaust broadband noise above 1 kHz with a gain of 5 dB on sound power level. Finally, the benefit on the acoustic emission of the helicopter in flight is appraised.

scholarly journals Separation of the Sound Power Spectrum of Multiple Sources by Three-Dimensional Sound Intensity Decomposition

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 279
Author(s):  
Shiyi Chai ◽  
Xiaoqin Liu ◽  
Xing Wu ◽  
Yanjiao Xiong
Keyword(s):  
Power Spectrum ◽  
Sound Source ◽  
Three Dimensional ◽  
Sound Intensity ◽  
Point Sources ◽  
Mechanical Equipment ◽  
Sound Power ◽  
Test Bed ◽  
Multiple Sources ◽  
Noise Sources

The identification and separation of sources are the prerequisite of industrial noise control. Industrial machinery usually contains multiple noise sources sharing same-frequency components. There are usually multiple noise sources in mechanical equipment, and there are few effective methods available to separate the spectrum intensity of each sound source. This study tries to solve the problem by the radiation relationship between three-dimensional sound intensity vectors and the power of the sources. When the positions of the probe and the sound source are determined, the sound power of the sound source at each frequency can be solved by the particle swarm optimization algorithm. The solution results at each frequency are combined to obtain the sound power spectrum of each sound source. The proposed method is first verified by a simulation on two point sources. The experiment is carried out on a fault simulation test bed in an ordinary laboratory; we used three three-dimensional sound intensity probes to form a line array and conducted spectrum separation of the nine main noise sources. The sound intensity on the main frequency band of each sound source was close to the result of the near-field measurement of the one-dimensional sound intensity probe. The proposed spectral separation method of the sound power of multiple sound sources provides a new method for accurate noise identification in industrial environments.

Sound Power Measurements in the Near Field of Transformers

2012 ◽  
Author(s):  
Michael Ertl ◽  
Hermann Landes
Keyword(s):  
Sound Pressure ◽  
Power Level ◽  
Near Field ◽  
Sound Field ◽  
Sound Intensity ◽  
Sound Level ◽  
Numerical Analyses ◽  
Sound Power ◽  
3D Fem ◽  
Sound Power Level

The international standard for the determination of the sound power level of transformers allows both the sound pressure and the sound intensity measurement method. Since the sound measurements take place in the reactive near-field next to the vibrating transformer tank walls, local disturbances influence the sound field characteristics at the measurement positions. As a result, the measured mean sound power level differs commonly up to 6dB at comparative measurements with both methods. Beyond these near field effects, the influence of an industrial measurement environment (background sound sources, hard-reflecting floor, semi-reverberant walls, and standing waves) to the sound pressure and sound intensity field characteristics is investigated. Hereby, numerical analyses based on 3D-FEM with consideration of the fluid-structure-coupling are used. The measured sound level differences can be re-produced and clarified in numerical analyses.

Gaussian processes for sound field reconstruction

2021 ◽  
Vol 149 (2) ◽  
pp. 1107-1119
Author(s):  
Diego Caviedes-Nozal ◽  
Nicolai A. B. Riis ◽  
Franz M. Heuchel ◽  
Jonas Brunskog ◽  
Peter Gerstoft ◽  
...  
Keyword(s):  
Gaussian Processes ◽  
Sound Field ◽  
Field Reconstruction ◽  
Sound Field Reconstruction

Sound Radiation Characteristics of Lightweight Roof Constructions Excited by Rain

1994 ◽  
Vol 1 (4) ◽  
pp. 249-270 ◽  
Author(s):  
Hiromi Suga ◽  
Hideki Tachibana
Keyword(s):  
Transmission Loss ◽  
Power Level ◽  
Sound Radiation ◽  
Sound Intensity ◽  
Sound Power ◽  
Radiation Characteristics ◽  
Natural Rainfall ◽  
Artificial Rainfall ◽  
Sound Power Level ◽  
Measurement Results

In order to investigate the sound radiation characteristics of lightweight roof constructions when excited by rainfall, an artificial rainfall apparatus was constructed to simulate natural rainfall conditions. From the measurement results, it can be seen that the facility developed is practically applicable for the examination of the sound radiation characteristics of rain noise. It was therefore used in the measurement of sound power of 20 lightweight roofs. In addition, the relationship between sound power level and sound transmission loss measured by the sound intensity method was investigated statistically. As a result, it has been shown that a linear relationship exists between them and there is a possibility of estimating the sound power level from the transmission loss.

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