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1

Microphone Based Acoustic Vector Sensor for Direction Finding with Bias Removal

Wajid Mohd, Kumar Arun, Bahl Rajendar

Archives of Acoustics

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2022

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Vol. 47, No. 2

151--167

EN

The acoustic vector sensor (AVS) is used to measure the acoustic intensity, which gives the direction-of-arrival (DOA) of an acoustic source. However, while estimating the DOA from the measured acoustic intensity the finite microphone separation (d) in a practical AVS causes angular bias. Also, in the presence of noise there exists a trade off between the bias (strictly increasing function of d) and variance (strictly decreasing function of d) of the DOA estimate. In this paper, we propose a novel method for mitigating the angular bias caused due to finite microphone separation in an AVS. We have reduced the variance by increasing the microphone separation and then removed the bias with the proposed bias model. Our approach employs the finite element method (FEM) and curves fitting to model the angular bias in terms of microphone separations and frequency of a narrowband signal. Further, the bias correction algorithm based on the intensity spectrum has been proposed to improve the DOA estimation accuracy of a broadband signal. Simulation results demonstrate that the proposed bias correction scheme significantly reduces the angular bias and improves the root mean square angular error (RMSAE) in the presence of noise. Experiments have been performed in an acoustic full anechoic room to corroborate the effect of microphone separation on DOA estimation and the efficacy of the bias correction method.

2

The Combination of Spectrum Subtraction and Cross-power Spectrum Phase Method for Time Delay Estimation

Bin Feng, Lei Xu

Archives of Acoustics

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2020

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Vol. 45, No. 3

453--458

EN

In order to solve the problem of large error of delay estimation in low SNR environment, a new delay estimation method based on cross power spectral frequency domain weighting and spectrum subtraction is proposed. Through theoretical analysis and MATLAB simulation, among the four common weighting functions, it is proved that the cross-power spectral phase weighting method has a good sharpening effect on the peak value of the cross-correlation function, and it is verified that the improved spectral subtraction method generally has a good noise reduction effect under different SNR environments. Finally, the joint simulation results of the whole algorithm show that the combination of spectrum subtraction and cross-power spectrum phase method can effectively sharpen the peak value of cross-correlation function and improve the accuracy of time delay estimation in the low SNR environment. The results of this paper can provide useful help for sound source localization in complex environments.

3

Akustyczny system rozpoznawania środowiska

Kornatowski E.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 5

257-259

PL

W artykule zaprezentowano system lokalizacji źródła dźwięku zbudowany z wykorzystaniem planarnej cztero – mikrofonowej matrycy mikrofonów. Rozwiązanie to może znaleźć zastosowanie w robotyce, w konstruowaniu samobieżnych robotów, jako jeden z elementów rozpoznawania otoczenia. Wyniki badań eksperymentalnych są niezwykle zachęcające. Błędy w lokalizacji źródła dźwięku wskazują na to, że proponowany system umożliwia lokalizację z precyzję niewiele gorszą niż ludzki słuch. Człowiek bowiem jest w stanie określić kąt azymutu akustycznego źródła z dokładnością ok. +/-6°.

EN

The paper offers a system for determination of sound source direction with a use of planar four - microphone matrix. This solution may be useful in design of robots, e.g. as one of the components for a recognition of surroundings. Obtained results of simulation tests are very encouraging. The errors shown in the paper prove that the system is able to localize the sound source direction as well as human ear. Based on sense of hearing, a human being is able to determine the azimuth within accuracy ca. +/-6°.

4

Objectivization of Audio-Visual Correlation Analysis

Kunka B., Kostek B.

Archives of Acoustics

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2012

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Vol. 37, No. 1

63-72

EN

Simultaneous perception of audio and visual stimuli often causes concealment or misrepresentation of information actually contained in these stimuli. Such effects are called the "image proximity effect" or the "ventriloquism effect" in the literature. Until recently, most research carried out to understand their nature was based on subjective assessments. The authors of this paper propose a methodology based on both subjective and objectively retrieved data. In this methodology, objective data reflect the screen areas that attract most attention. The data were collected and processed by an eye-gaze tracking system. To support the proposed methodology, two series of experiments were conducted – one with a commercial eye-gaze tracking system Tobii T60, and another with the Cyber-Eye system developed at the Multimedia Systems Department of the Gdańsk University of Technology. In most cases, the visual-auditory stimuli were presented using a 3D video. It was found that the eye-gaze tracking system did objectivize the results of experiments. Moreover, the tests revealed a strong correlation between the localization of a visual stimulus on which a participant’s gaze focused and the value of the "image proximity effect". It was also proved that gaze tracking may be useful in experiments which aim at evaluation of the proximity effect when presented visual stimuli are stereoscopic.

5

Dependence of the head-related transfer function on pinna flare angle

Plaskota P., Dobrucki A. B.

Elektronika : konstrukcje, technologie, zastosowania

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2009

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Vol. 50, nr 3

19-21

EN

Head Related Transfer-Function (HRTF) describes the modification of the spectrum of acoustic wave arriving to the ear. The HRTF influences sound source localization by auditory system. It has been proved that individual properties strongly influence HRTF. Application of HRTF which is different for each individual decreases the ability of sound source localization by the listener during headphones sound projection. The aim of the paper is the study of influence of pinna flare angle on the HRTF shape.

PL

Funkcja Transmitancji Odniesiona dp Głowy (HRTF) opisuje modyfikację widma fali akustycznej docierającej do ucha. HRTF wpływa na lokalizację źródła dżwięku przez system słuchowy. Zostało udowodnione, że cechy osobnicze silnie wpływają, na HRTF. Zastosowanie HRTF, które jest różne dla każdego słuchacza powoduje pogorszenie zdolności lokalizacji źródła dźwięku podczas odsłuchu przez słuchawki. Celem pracy jest zbadanie wpływu kąta odchylenia małżowiny usznej na przebieg HRTF.

6

Automatic measuring system for head-related transfer function measurement

Plaskota P.

Archives of Acoustics

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2008

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Vol. 33, No. 1

19-25

EN

In this paper the Head Related Transfer Function (HRTF) Automatic Measurement Equipment is presented. The system allows to measure HRTF with high spatial resolution within a considerably short time. The system employs many switched sound sources and a rotary chair. HRTF describes a transfer function of the human head and pinna and is unique for each human. Individual measurement of HRTF is necessary for applications where precise simulation of sound source localization is essential. An accurate determination of HRTF requires the position of sound source to be changed in the space surrounding test participants. It necessitates hundreds of measurements with high spatial resolution. The procedure becomes very time consuming and tiring for the participants.

7

Localization of areas of increased vibroactivity by means of the inverse method

Stryczniewicz L.

Archives of Acoustics

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2007

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Vol. 32, No. 2

377-386

EN

Increased possibilities of parallel acquiring data and transforming them effectively together with the improvement of calculation tools made the inverse methods more important. Some examples of research, carried out by the author, during, which the possibilities of localization of increased vibroactivity areas were studied using the multi-microphone method, are presented in the paper. The theoretical basis of the inversion method of sound sources localization and certain laboratory test results are also given.

8

Investigations on the angle of directional hearing acuity

Niewiarowicz M., Czajka J., Hojan E.

Archives of Acoustics

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2005

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Vol. 30, No. 2

147-157

EN

This article presents results of investigations of the angle of directional hearing acuity (ADHA) as a measure of the spatial hearing ability. A modified method proposed by Zakrzewski has been used -- ADHA values have been determined for azimuths in the horizontal plane at the height of the listener's head. Application of different acoustic signals - sinusoidal signals (pure tones), 1/3 octave noise, and amplitude modulated 1/3 octave noise, helped to reveal significant differences in ADHA values for individual signal types. A better localization of the sound source for noise type signals than those for sinusoidal signals has been found. Furthermore, smaller differences in the perception of noise signals compared with differences in the perception of sinusoidal signals were recorded for individual listeners. The best localization was stated for the azimuth 0° and the worst for the azimuth 90° and 270°.