Department of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer-Sheva, 84105 Israel.
J Acoust Soc Am. 2012 Sep;132(3):1473-81. doi: 10.1121/1.4742698.
Reverberation and noise have a significant effect on the intelligibility of speech in rooms. The detection of clear speech in highly reverberant and noisy enclosures is an extremely difficult task. Recently, spherical microphone arrays have been studied for processing of sound fields in three-dimensions, with applications ranging from acoustic analysis to speech enhancement. This paper presents the derivation of a model that facilitates the prediction of spherical array configurations that guarantee an acceptable level of speech intelligibility in reverberant and noisy environments. A spherical microphone array is employed to generate a spatial filter that maximizes speech intelligibility according to an objective measure that combines the effects of both reverberation and noise. The spherical array beamformer is designed to enhance the speech signal while minimizing noise power and maintaining robustness over a wide frequency range. The paper includes simulation and experimental studies with a comparison to speech transmission index based analysis to provide initial validation of the model. Examples are presented in which the minimum number of microphones in a spherical array can be determined from environment conditions such as reverberation time, noise level, and distance of the array to the speech source.
混响和噪声对室内语音的可懂度有很大影响。在高度混响和嘈杂的封闭环境中检测清晰语音是一项极其困难的任务。最近，球形麦克风阵列已被研究用于三维声场处理，其应用范围从声学分析到语音增强。本文提出了一种模型的推导，该模型有助于预测球形阵列配置，以保证在混响和噪声环境中具有可接受的语音可懂度水平。采用球形麦克风阵列生成空间滤波器，根据综合考虑混响和噪声影响的客观度量来最大化语音可懂度。球形阵列波束形成器的设计旨在增强语音信号，同时最小化噪声功率，并在宽频率范围内保持鲁棒性。本文包括仿真和实验研究，并与基于语音传输指数的分析进行比较，为模型提供初步验证。本文还给出了一些示例，可根据环境条件（如混响时间、噪声水平和阵列到语音源的距离）确定球形阵列中最小的麦克风数量。
