Multimicrophone adaptive beamforming for interference reduction in hearing aids.
Multimicrophone adaptive beamforming for interference reduction in hearing aids.
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发表时间：
1987
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通讯作者：
P. Peterson;N. Durlach;W. M. Rabinowitz;P. Zurek
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作者：
P. Peterson;N. Durlach;W. M. Rabinowitz;P. Zurek
为了减少来自与目标源空间分离的声源的单耳助听器的干扰，我们正在研究用于组合来自多个麦克风的信息的方法。在本文中，我们描述了一种自适应波束形成方法，其功能是保持从麦克风阵列的直线前方到达的目标信号，同时最小化来自离轴干扰源的输出功率。在一个双麦克风系统的初步评估，句子清晰度测试进行了管理正常听力科目使用处理和未处理的材料从模拟环境中的目标是在轴上，干扰（语音串音）是45度离轴，和混响模仿的客厅，会议室，和消声空间。与通过单个麦克风收听相比，双麦克风波束形成器在消声、起居室和会议室条件下分别将实现50%关键词可懂度所需的目标干扰比降低了30、14和0 dB。双耳听力（每只耳朵一个麦克风）的相应改善分别为24、9和0 dB。在起居室环境中使用相同的波束形成系统但滤波器脉冲响应缩短四倍（这将使自适应时间减少四倍）的进一步测试使改善减少了5dB。这些结果足以令人鼓舞，以保证进一步的测试，涉及更现实的混响条件，多个干扰源，和时变的声学环境。
To reduce interference in monaural hearing aids from sound sources that are spatially separated from a target source, we are investigating methods for combining information from multiple microphones. In this paper, we describe an adaptive beamforming method that functions to preserve target signals arriving from straight-ahead of a microphone array while minimizing output power from off-axis interference sources. In a preliminary evaluation of a two-microphone system, sentence intelligibility tests were administered to normal-hearing subjects using processed and unprocessed materials from simulated environments in which the target was on-axis, the interference (speech babble) was 45 degrees off-axis, and the reverberation mimicked that of a living room, a conference room, and anechoic space. Compared to listening through a single microphone, the two-microphone beamformer reduced the target-to-interference ratio required to achieve 50 percent keyword intelligibility by 30, 14, and 0 dB in the anechoic, living-room, and conference-room conditions, respectively. The corresponding improvements over binaural listening (one microphone to each ear) were 24, 9, and 0 dB. Further tests in the living-room environment using the same beam-forming system but with filter impulse responses shortened by a factor of four (which would decrease the adaptation time by a factor of four) decreased the improvement by 5 dB. These results are sufficiently encouraging to warrant further tests involving more realistic reverberant conditions, multiple sources of interference, and time-varying acoustic environments.