The Experts below are selected from a list of 28923 Experts worldwide ranked by ideXlab platform
Cha Zhang - One of the best experts on this subject based on the ideXlab platform.
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enhanced mvdr beamforming for arrays of directional Microphones
International Conference on Multimedia and Expo, 2007Co-Authors: Dinei Florencio, Cha ZhangAbstract:Microphone arrays based on the minimum variance distortionless response (MVDR) beamformer are among the most popular for speech enhancement applications. The original MVDR is excessively sensitive to source location and microphone gains. Previous research has made MVDR practical by successfully increasing the robustness of MVDR to source location, and MVDR-based microphone arrays are already commercially available. Nevertheless, MVDR performance is still weak in cases where microphone gain variations are too large, e.g., for circular arrays of directional Microphones. In this paper we propose an improved MVDR beamformer which takes into account the effect of sensors (e.g. Microphones) with arbitrary, potentially directional responses. Specifically, we form estimates of the relative magnitude responses of the sensors based on the data received at the array and include those in the original formulation of the MVDR beamforming problem. Experimental results on real-world audio data show an average 2.4 dB improvement over conventional MVDR beamforming, which does not account for the magnitude responses of the sensors.
Ruth A. Bentler - One of the best experts on this subject based on the ideXlab platform.
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predictive measures of directional benefit part 1 estimating the directivity index on a manikin
Ear and Hearing, 2007Co-Authors: Andrew Dittberner, Ruth A. BentlerAbstract:OBJECTIVE: In this investigation, a method for computing a directivity index (DI) on a manikin for directional Microphones in hearing aids was proposed and evaluated comparatively to other conventional methods. DESIGN: Test devices included first- and second-order directional Microphones. Signal presentation, implemented in an anechoic chamber, involved a single noise source rotated completely around the directional microphone in a hearing aid, in free field and on a manikin, at a defined radius. The area covered was equivalent to the approximate surface area of a sphere. It was anticipated that an equal angular resolution of 10 degrees (elevation and azimuth) would effectively estimate the DI of first-, second-, and higher-order directional microphone systems located in a hearing aid on a manikin. A total of 450 spatially varied presentation points were analyzed, each weighted in reference to direction of arrival on the directional microphone. RESULTS: Empiric differences between the DI derived from the 3D-DI method proposed in this investigation and the conventionally derived 2D-DI method DI on a manikin were as large as 3.8 dB in the higher frequencies, depending on the device under test. CONCLUSIONS: The magnitude of these differences was dependent on the device under test microphone location. The further the microphone was placed into the ear of the manikin, the larger the empiric differences.
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evaluation of a second order directional microphone hearing aid i speech perception outcomes
Journal of The American Academy of Audiology, 2006Co-Authors: Ruth A. Bentler, Catherine V Palmer, Gustav H MuellerAbstract:This clinical trial was undertaken to evaluate the benefit obtained from hearing aids employing second-order adaptive directional microphone technology, used in conjunction with digital noise reduction. Data were collected for 49 subjects across two sites. New and experienced hearing aid users were fit bilaterally with behind-the-ear hearing aids using the National Acoustics Laboratory—Nonlinear version 1 (NAL-NL1) prescriptive method with manufacturer default settings for various parameters of signal processing (e.g., noise reduction, compression, etc.). Laboratory results indicated that (1) for the stationary noise environment, directional Microphones provided better speech perception than omnidirectional Microphones, regardless of the number of Microphones; and (2) for the moving noise environment, the three-microphone option (whether in adaptive or fixed mode) and the two-microphone option in its adaptive mode resulted in better performance than the two-microphone fixed mode, or the omnidirectional modes.
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method for calculating directivity index of a directional microphone in a hearing aid on a manikin
Journal of the Acoustical Society of America, 2005Co-Authors: Andrew Dittberner, Ruth A. BentlerAbstract:A method for computing a directivity index (DI) on a manikin for directional Microphones in hearing aids is proposed and investigated. Test devices included first‐ and second‐order directional Microphones in hearing aids. Signal presentation involved a single noise source rotated completely around the directional microphone, in free field and on a manikin, at a defined radius. The area covered was equivalent to the approximate surface area of a sphere. It was anticipated that an equal angular resolution of 10 deg (elevation and azimuth) would effectively estimate the DI of first‐, second‐, and higher‐order directional microphone systems located in a hearing aid on a manikin. A total of 450 spatially varied presentation points was analyzed, each weighted in reference to direction of arrival on the directional microphone. The absolute difference between the Directivity Index derived from the modified method proposed in this investigation and the conventionally derived Directivity Index on a manikin were as ...
Hiroshi Kawaguchi - One of the best experts on this subject based on the ideXlab platform.
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microphone array network for ubiquitous sound acquisition
International Conference on Acoustics Speech and Signal Processing, 2010Co-Authors: Tomoya Takagi, Hiroki Noguchi, Koji Kugata, Masahiko Yoshimoto, Hiroshi KawaguchiAbstract:We propose a microphone array network that realizes ubiquitous sound acquisition. Nodes with 16 Microphones are connected to form a huge sound acquisition system that carries out VAD, sound source localization and separation. The three operations are distributed among nodes. The VAD is implemented to manage power consumption. Consequently, the system consumes little power when speech is not active. The VAD module uses only 2.1 mW. The system can improve an SNR by 7.75 dB using 112 Microphones.
Paris Smaragdis - One of the best experts on this subject based on the ideXlab platform.
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communication cost aware microphone selection for neural speech enhancement with ad hoc microphone arrays
International Conference on Acoustics Speech and Signal Processing, 2021Co-Authors: Jonah Casebeer, Jamshed Kaikaus, Paris SmaragdisAbstract:In this paper, we present a method for jointly-learning a microphone selection mechanism and a speech enhancement network for multi-channel speech enhancement with an ad-hoc microphone array. The attention-based microphone selection mechanism is trained to reduce communication-costs through a penalty term which represents a task-performance/ communication-cost trade-off. While working within the trade-off, our method can intelligently stream from more Microphones in lower SNR scenes and fewer Microphones in higher SNR scenes. We evaluate the model in complex echoic acoustic scenes with moving sources and show that it matches the performance of models that stream from a fixed number of Microphones while reducing communication costs.
Dinei Florencio - One of the best experts on this subject based on the ideXlab platform.
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enhanced mvdr beamforming for arrays of directional Microphones
International Conference on Multimedia and Expo, 2007Co-Authors: Dinei Florencio, Cha ZhangAbstract:Microphone arrays based on the minimum variance distortionless response (MVDR) beamformer are among the most popular for speech enhancement applications. The original MVDR is excessively sensitive to source location and microphone gains. Previous research has made MVDR practical by successfully increasing the robustness of MVDR to source location, and MVDR-based microphone arrays are already commercially available. Nevertheless, MVDR performance is still weak in cases where microphone gain variations are too large, e.g., for circular arrays of directional Microphones. In this paper we propose an improved MVDR beamformer which takes into account the effect of sensors (e.g. Microphones) with arbitrary, potentially directional responses. Specifically, we form estimates of the relative magnitude responses of the sensors based on the data received at the array and include those in the original formulation of the MVDR beamforming problem. Experimental results on real-world audio data show an average 2.4 dB improvement over conventional MVDR beamforming, which does not account for the magnitude responses of the sensors.
