Acoustic noise reduction for speech communication: (second-order gradient microphone)

Kang, G.; Heide, David A.

doi:10.1109/iscas.1999.780065

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…Recall the beam-pattern magnitude's diametric symmetry described in Eq. (6). Either both 6ðu c ; v c ; w c Þ are local maximum of the magnitude beam-pattern or neither is.…”

Section: Odd Kmentioning

confidence: 97%

Higher-order figure-8 microphones/hydrophones collocated as a perpendicular triad—Their “spatial-matched-filter” beam steering

Wong

Song

et al. 2022

The Journal of the Acoustical Society of America

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Directional sensors, if collocated but perpendicularly oriented among themselves, would facilitate signal processing to uncouple the azimuth-polar direction from the time-frequency dimension-in addition to the physical advantage of spatial compactness. One such acoustical sensing unit is the well-known "tri-axial velocity sensor" (also known as the "gradient sensor," the "velocity-sensor triad," the "acoustic vector sensor," and the "vector hydrophone"), which comprises three identical figure-8 sensors of the first directivity-order, collocated spatially but oriented perpendicularly of each other. The directivity of the figure-8 sensors is hypothetically raised to a higher order in this analytical investigation with an innocent hope to sharpen the overall triad's directionality and steerability. Against this wishful aspiration, this paper rigorously analyzes how the directivity-order would affect the triad's "spatial-matched-filter" beam's directional steering capability, revealing which directivity-order(s) would allow the beam-pattern of full maneuverability toward any azimuthal direction and which directivity-order(s) cannot. V

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“…Recall the beam-pattern magnitude's diametric symmetry described in Eq. (6). Either both 6ðu c ; v c ; w c Þ are local maximum of the magnitude beam-pattern or neither is.…”

Section: Odd Kmentioning

confidence: 97%

Higher-order figure-8 microphones/hydrophones collocated as a perpendicular triad—Their “spatial-matched-filter” beam steering

Wong

Song

et al. 2022

The Journal of the Acoustical Society of America

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show abstract

“…Indeed, the directivity and the beam-patterns of higher-order directional sensors have been investigated in [1]- [5], [8], [9], [11], [13]- [15], [18]. Moreover, [16] derives the Cramér-Rao bounds (in open form) for direction finding using such higher-order directional sensors.…”

Section: B Directional Acoustic Sensors That Measure a Higher-order mentioning

confidence: 99%

Closed-Form Direction Finding Using Collocated but Orthogonally Oriented Higher Order Acoustic Sensors

Song

Wong

2012

IEEE Sensors J.

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This paper introduces new closed-form formulas to estimate an incident source's azimuth-elevation angle-ofarrival, for various combinations of higher order directional acoustic sensors, that are orthogonally oriented in a collocated triad. Also identified are the validity regions for unambiguous estimation of the azimuth-elevation arrival-angle. These new direction-finding formulas may be used in the open literature's eigen-structure-based direction-finding algorithms, originally designed for (first-order) acoustic particle-velocity sensors.Index Terms-Acoustic interferometry, acoustic signal processing, acoustic velocity measurement, array signal processing, direction of arrival estimation, phased arrays, sonar arrays, underwater acoustic arrays.

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“…In 1999, we developed what-is-called the second-order gradient microphone that can reduce ambient noise as much as 20 to 30 dB [21]. The use of this microphone also solves the problem of reverberation because it effectively attenuates farfield sounds (i.e., late arriving multipath signals).…”

mentioning

confidence: 99%

Voice Biometrics for Information Assurance Applications

Kang¹,

Lee²

2002

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Standard Form 298 (Rev. 8-98)Prescribed by ANSI Std. Z39.18Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Approved for public release; distribution is unlimited. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S ACRONYM(S) 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S REPORT NUMBER(S)In 2000, the President of the United States established an organization within the DoD to develop and promulgate biometrics technologies to achieve security in information, information systems, weapons, and facilities. NRL has been tasked to study voice biometrics for applications in which other biometrics techniques are difficult to apply. The ultimate goal of voice biometrics is to enable the use of voice as a password.Voice biometrics are "man-in-the-loop" systems in which system performance is significantly dependent on human performance. This aspect has not been properly emphasized by previous researchers in this field. Accordingly, we let each speaker choose his (or her) own test phrase that can be uttered consistently. The speech waveform is then pre-processed (i.e., equalized and normalized) to reduce the effect of inconsistent speaking. Subsequently, we extract five different voice features from the speech waveform. Some of them have never been used for voice biometrics. Finally, individual feature errors are combined to indicate a confidence level of speaker verification.Initial laboratory testing under various conditions shows encouraging results. We will be prepared to fleet-test our voice biometrics system in FY03. UnclassifiedUnclassified Unclassified VOICE BIOMETRICS FOR INFORMATION ASSURANCE APPLICATIONS INTRODUCTIONThe Department of Defense (DoD) has a critical need to ensure security and integrity in all its information and information systems, weapons, and facilities. To meet this need, DoD is exploiting biometrics technology that uses measurable physical characteristics of an individual for identification or verification. LTG Peter Cuviello, Director of the DoD Biometrics Management Office (BMO), envisions that, "on the battlefield of the future, a soldier's voice will be his password."In support of DoD biometrics efforts, we at NRL are focusing on voice biometrics for applications where other biometrics techniques are difficult to apply. An example of voice biometrics is remote speaker verification over computer or communication links in which the user and the information source are not collocated. Another example is when the speaker wears a gas mask and gloves in a nuclear-biologicalchemical ...

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Acoustic noise reduction for speech communication: (second-order gradient microphone)

Cited by 6 publications

References 5 publications

Higher-order figure-8 microphones/hydrophones collocated as a perpendicular triad—Their “spatial-matched-filter” beam steering

Higher-order figure-8 microphones/hydrophones collocated as a perpendicular triad—Their “spatial-matched-filter” beam steering

Closed-Form Direction Finding Using Collocated but Orthogonally Oriented Higher Order Acoustic Sensors

Voice Biometrics for Information Assurance Applications

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