Comparing Binaural Pre-processing Strategies I

Baumgärtel, Regina M.; Krawczyk-Becker, Martin; Marquardt, Daniel; Völker, Christoph; Hu, Hongmei; Herzke, Tobias; Coleman, Graham; Adiloğlu, Kamil; Ernst, Stephan; Gerkmann, Timo; Doclo, Simon; Kollmeier, Birger; Hohmann, Volker; Dietz, Mathias

doi:10.1177/2331216515617916

Cited by 40 publications

(56 citation statements)

References 42 publications

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“…In this study, we examine performance using a beamforming microphone array that combines signals from 16 microphones mounted on a headband. The intelligibility-weighted directivity index of this array is around 9 dB, similar to values reported in the literature for other beamformers (e.g., Baumgärtel et al., 2015 ; Desloge et al., 1997 ; Kates & Weiss, 1996 ; Soede, Bilsen, & Berkhout, 1993 ; Stadler & Rabinowitz, 1993 ). Previous studies from our laboratory have demonstrated that this type of beamformer can enhance speech intelligibility (relative to natural binaural listening) for fixed-location, frontal speech targets amidst spatially separated maskers ( Kidd, 2017 ; Kidd, Favrot, Desloge, Streeter, & Mason, 2013 ; Kidd, Mason, Best, & Swaminathan, 2015 ).…”

Section: Introductionsupporting

confidence: 86%

The Benefit of a Visually Guided Beamformer in a Dynamic Speech Task

et al. 2017

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The aim of this study was to evaluate the performance of a visually guided hearing aid (VGHA) under conditions designed to capture some aspects of “real-world” communication settings. The VGHA uses eye gaze to steer the acoustic look direction of a highly directional beamforming microphone array. Although the VGHA has been shown to enhance speech intelligibility for fixed-location, frontal targets, it is currently not known whether these benefits persist in the face of frequent changes in location of the target talker that are typical of conversational turn-taking. Participants were 14 young adults, 7 with normal hearing and 7 with bilateral sensorineural hearing impairment. Target stimuli were sequences of 12 question–answer pairs that were embedded in a mixture of competing conversations. The participant’s task was to respond via a key press after each answer indicating whether it was correct or not. Spatialization of the stimuli and microphone array processing were done offline using recorded impulse responses, before presentation over headphones. The look direction of the array was steered according to the eye movements of the participant as they followed a visual cue presented on a widescreen monitor. Performance was compared for a “dynamic” condition in which the target stimulus moved between three locations, and a “fixed” condition with a single target location. The benefits of the VGHA over natural binaural listening observed in the fixed condition were reduced in the dynamic condition, largely because visual fixation was less accurate.

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Section: Introductionsupporting

confidence: 86%

The Benefit of a Visually Guided Beamformer in a Dynamic Speech Task

et al. 2017

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“…To achieve binaural noise reduction with binaural cue preservation, two main concepts have been developed. In the first concept, a common real-valued spectro-temporal gain is applied to the reference microphone signals in the left and the right hearing device [4][5][6][7][8][9][10], ensuring perfect preservation of the instantaneous binaural cues but inevitably introducing speech distortion. The second concept, which is considered in this paper, is to apply a complex-valued filter to all available microphone signals on the left and the right hearing device using binaural extensions of spatial filtering techniques [11][12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Optimal Binaural LCMV Beamforming in Complex Acoustic Scenarios: Theoretical and Practical Insights

Gobling

Marquardt

Merks

et al. 2018

2018 16th International Workshop on Acoustic Signal Enhancement (IWAENC)

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Binaural beamforming algorithms for head-mounted assistive listening devices are crucial to improve speech quality and speech intelligibility in noisy environments, while maintaining the spatial impression of the acoustic scene. While the well-known BMVDR beamformer is able to preserve the binaural cues of one desired source, the BLCMV beamformer uses additional constraints to also preserve the binaural cues of interfering sources. In this paper, we provide theoretical and practical insights on how to optimally set the interference scaling parameters in the BLCMV beamformer for an arbitrary number of interfering sources. In addition, since in practice only a limited temporal observation interval is available to estimate all required beamformer quantities, we provide an experimental evaluation in a complex acoustic scenario using measured impulse responses from hearing aids in a cafeteria for different observation intervals. The results show that even rather short observation intervals are sufficient to achieve a decent noise reduction performance and that a proposed threshold on the optimal interference scaling parameters leads to smaller binaural cue errors in practice.

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“…The algorithms have been described and instrumentally evaluated in depth in an accompanying study ( Baumgärtel et al., 2015 ). In a second accompanying article ( Völker, Warzybok, & Ernst, 2015 ), the same algorithms were tested in the same noise scenarios with acoustically stimulated hearing-impaired (HI) and normal-hearing (NH) listeners.…”

Section: Introductionmentioning

confidence: 99%

Comparing Binaural Pre-processing Strategies II

Baumgärtel

Krawczyk-Becker

et al. 2015

Trends in Hearing

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Several binaural audio signal enhancement algorithms were evaluated with respect to their potential to improve speech intelligibility in noise for users of bilateral cochlear implants (CIs). 50% speech reception thresholds (SRT50) were assessed using an adaptive procedure in three distinct, realistic noise scenarios. All scenarios were highly nonstationary, complex, and included a significant amount of reverberation. Other aspects, such as the perfectly frontal target position, were idealized laboratory settings, allowing the algorithms to perform better than in corresponding real-world conditions. Eight bilaterally implanted CI users, wearing devices from three manufacturers, participated in the study. In all noise conditions, a substantial improvement in SRT50 compared to the unprocessed signal was observed for most of the algorithms tested, with the largest improvements generally provided by binaural minimum variance distortionless response (MVDR) beamforming algorithms. The largest overall improvement in speech intelligibility was achieved by an adaptive binaural MVDR in a spatially separated, single competing talker noise scenario. A no-pre-processing condition and adaptive differential microphones without a binaural link served as the two baseline conditions. SRT50 improvements provided by the binaural MVDR beamformers surpassed the performance of the adaptive differential microphones in most cases. Speech intelligibility improvements predicted by instrumental measures were shown to account for some but not all aspects of the perceptually obtained SRT50 improvements measured in bilaterally implanted CI users.

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Comparing Binaural Pre-processing Strategies I

Cited by 40 publications

References 42 publications

The Benefit of a Visually Guided Beamformer in a Dynamic Speech Task

The Benefit of a Visually Guided Beamformer in a Dynamic Speech Task

Optimal Binaural LCMV Beamforming in Complex Acoustic Scenarios: Theoretical and Practical Insights

Comparing Binaural Pre-processing Strategies II

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