scholarly journals Acoustic Imaging of Sound Sources with a Student-Designed Acoustic Camera

2007 ◽  
Vol 6 (2) ◽  
Author(s):  
Joachim Sigl ◽  
René Scheucher
Keyword(s):  
Microphone Array ◽  
Visual Image ◽  
Sound Level ◽  
Sound Sources ◽  
Multiple Signal Classification ◽  
Visualization Software ◽  
Comprehensive Information ◽  
Sound Maps ◽  
Established Technique ◽  
Phase Differences

An acoustic camera consists of a microphone array, a data recorder and sound analysis- and -visualization software. It creates a color-coded sound map that displays the sound sources overlaid on the visual image of the recorded object. The sound maps are usually produced by analyzing the phase differences of the signals measured by the array microphones. Delay-and-sum beamformer and multiple signal classification (MUSIC) techniques are used in this work for the localization of sound sources. Beamformers are able to determine the amplitude of incident sound, but suffer from poor resolution and from ghost images. MUSIC, on the other hand, is an established technique for efficient and accurate noise source location, which can provide high-resolution source maps, but does not provide any information about the sound level. The combination of both methods gives comprehensive information about the acoustic emission of the system under investigation.

scholarly journals Soundscape approach integrating noise mapping techniques: a case study in Brighton, UK

Noise Mapping ◽  
2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Francesco Aletta ◽  
Jian Kang
Keyword(s):  
Road Traffic ◽  
Environmental Noise ◽  
Sound Level ◽  
Road Traffic Noise ◽  
Sound Sources ◽  
Noise Mapping ◽  
Acoustic Environment ◽  
Sound Environment ◽  
Sound Maps

AbstractIn the guidelines about the management of areas of good environmental noise quality recently published by the European Environment Agency (EEA) it is suggested to combine different methodologies, like noise mapping, sound level measurements and the soundscape approach. Such a recommendation has started to be recognised by a number of local authorities in Europe that are gradually integrating a holistic concept into their environmental noise policies. This research aimed to explore and demonstrate the possibility to integrate conventional noise mapping methods and soundscape methods in an actual urban redevelopment project. A case study was made using the Valley Gardens project in Brighton & Hove (UK). Different scenarios of sound-pressure level distributionswere simulated for both traffic sound sources (i.e. noise maps) and natural sound sources (i.e. sound maps). Additionally, individual responses about the sound environment of the place collected during an on-site question survey were used to implement soundscape maps.The overall picture revealed that the road traffic noise should be reduced, but also it is feasible that preferred sounds likewater features or birdsong could be introduced to make the sound environment more appropriate for the place. Generally, within the framework of this research, noise maps, sound maps and soundscape maps were used together to "triangulate" different layers of information related to the acoustic environment and the way it is perceived, providing a possible working procedure to consider for planners and policy-makers in the future.

Locating and tracking sound sources on a horizontal axis wind turbine using a compact microphone array based on beamforming

2019 ◽  
Vol 146 ◽  
pp. 295-309 ◽  
Author(s):  
Cui Qing Zhang ◽  
Zhi Ying Gao ◽  
Yong Yan Chen ◽  
Yuan Jun Dai ◽  
Jian Wen Wang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Microphone Array ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Sound Sources

NOISE SHIELDING BY SIMPLE BARRIERS: COMPARISON BETWEEN THE PERFORMANCE OF SPHERICAL AND LINE SOUND SOURCES

2000 ◽  
Vol 08 (03) ◽  
pp. 495-502 ◽  
Author(s):  
D. OUIS
Keyword(s):  
Sound Source ◽  
Insertion Loss ◽  
Line Source ◽  
Wave Reflection ◽  
Noise Source ◽  
Sound Level ◽  
Sound Sources ◽  
Noise Shielding ◽  
Noise Barrier ◽  
Wave Incidence

This study is concerned with the theoretical solution to the problem of sound screening by simple hard barriers on the ground with special emphasis given to the type of wave incidence, namely a comparison between the use of either a spherical or a cylindrical sound source. For a receiver at the shadow of the noise source, the field may be assumed to be due to the edge wave and for this, exact solutions are used. Regarding the wave reflection on an impedance ground, exact formulations are also used, and finally, some calculations are made on the performance of a hard noise barrier on a two-impedance ground. As a conclusion, it is found that although the sound level at the receiver may show some small differences depending on the frequency and on the geometry of the problem, the overall insertion loss of the thin hard barrier is almost the same for the spherical and the line source, and the differences are found to amount to less than 1 dB for geometries of practical occurrence.

A Real-Time Multiple Acoustic Sources Localization Method Using Widely Spaced Microphone Array

2013 ◽  
Vol 391 ◽  
pp. 580-583 ◽  
Author(s):  
Tian Yi Gu ◽  
Zhao Zhao ◽  
Ya Qi Wu ◽  
Zhi Yong Xu ◽  
Jing Yi Wang
Keyword(s):  
Real Time ◽  
Microphone Array ◽  
Localization Method ◽  
Cluster Process ◽  
Sound Detection ◽  
Acoustic Sources ◽  
Phase Differences

A real-time disambiguous localization method for multiple acoustic sources using widely spaced microphone array is proposed in this paper. The observation signals in each frame are firstly discriminated utilizing conventional energy-based sound detection measurement. Using inter-microphone phase differences (IPD), as well as an iterative cluster process, the DOAs of sources can be estimated while the phase wrapping ambiguity in conventional DUET is avoided.

Layout Optimization of Cooperative Distributed Microphone Arrays Based on Estimation of Source Separation Performance

2017 ◽  
Vol 29 (1) ◽  
pp. 83-93
Author(s):  
Kouhei Sekiguchi ◽  
◽  
Yoshiaki Bando ◽  
Katsutoshi Itoyama ◽  
Kazuyoshi Yoshii
Keyword(s):  
Mobile Robots ◽  
Microphone Array ◽  
Source Separation ◽  
Microphone Arrays ◽  
Separation Performance ◽  
Sound Sources ◽  
Multiple Mobile Robots ◽  
Position Information ◽  
Reconfigurable Array ◽  
Source Signals

[abstFig src='/00290001/08.jpg' width='300' text='Optimizing robot positions for source separation' ] The active audition method presented here improves source separation performance by moving multiple mobile robots to optimal positions. One advantage of using multiple mobile robots that each has a microphone array is that each robot can work independently or as part of a big reconfigurable array. To determine optimal layout of the robots, we must be able to predict source separation performance from source position information because actual source signals are unknown and actual separation performance cannot be calculated. Our method thus simulates delay-and-sum beamforming from a possible layout to calculate gain theoretically, i.e., the expected ratio of a target sound source to other sound sources in the corresponding separated signal. Robots are moved into the layout with the highest average gain over target sources. Experimental results showed that our method improved the harmonic mean of signal-to-distortion ratios (SDRs) by 5.5 dB in simulation and by 3.5 dB in a real environment.

Acoustical feature extraction of rotating machinery with combined wave superposition and blind source separation

2006 ◽  
Vol 220 (9) ◽  
pp. 1423-1431 ◽  
Author(s):  
W F Xue ◽  
J Chen ◽  
J Q Li ◽  
X F Liu
Keyword(s):  
Fault Diagnosis ◽  
Blind Source Separation ◽  
Acoustic Radiation ◽  
Microphone Array ◽  
Source Separation ◽  
Point Sources ◽  
Superposition Method ◽  
Sound Sources ◽  
Reconstruction Process ◽  
Wave Superposition

As the result of vibration emission in air, machine sound signal carries affluent information about the working condition of machine and it can be used to make mechanical fault diagnosis. The fundamental problems with fault diagnosis are the estimation of the number of sound sources and the localization of sound sources. The wave superposition can be employed to identify and locate sound sources, which is based on the idea that an acoustic radiator can be approximated and represented by the sum of the fields due to a finite number of interior point sources. But, in practice, a large number of measurements must be used in order to achieve a desired resolution, which makes the reconstruction process very time-consuming and expensive. In this paper, a combined wave superposition method has been developed reconstruct to acoustic radiation from machine acoustical signals. This method combines the advantages of both the wave superposition and Helmholtz equationleast squares methods, and it allows for reconstruction of the acoustic field from an arbitrary object with relatively few measurements, thus significantly enhancing the reconstruction efficiency. After sound source localization, the blind source separation (BSS) is proposed to extract acoustical feature from the mixed measuring sound signals. In a semi-anechoic chamber, a cross-planar microphone array, which consists of 29 microphones, was successfully applied to obtain the two-dimensional mapping of the sound sources. The location, the sound pressure, and the properties in frequency domain of the sound sources can be found through this method precisely. The experimental results demonstrate that the methods presented can potentially become an acoustical diagnosis tool.

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