School of Information Technology and Engineering, University of Ottawa, 800 King Edward, Ottawa, Ontario K1N 6N5, Canada.
J Acoust Soc Am. 2011 Apr;129(4):2042-51. doi: 10.1121/1.3557055.
Beamforming is done with an array of sensors to achieve a directional or spatially-specific response by using a model of the arriving wavefront. Conventionally, a plane wave or point source model is used and this can cause decreased array gain or even total breakdown of beamforming when the source is directional. To avoid this, the authors proposed in recent work an alternative beamforming method which defines a set of "sub-beamformers," each designed to respond to a different spatial mode of the source. The outputs of the individual sub-beamformers are combined in a weighted sum to give an overall output of better quality than that of a monopole beamformer. This paper extends the previous work by introducing an additional estimator for the weighted sum and by presenting simulation results to demonstrate the relative performance of the proposed method and the different estimators for a directional source in the presence of diffuse noise, reverberation, and an interfering source. Gain optimization subject to a constraint on the white-noise gain with the proposed beamforming method is also introduced. Generally, when beamforming on directional sources, the proposed method outperforms beamforming with a point source model when the input signal-to-noise ratio (SNR) is 0 dB or higher.
波束形成是通过使用到达波前的模型，用传感器的阵列来实现定向或空间特定的响应。传统上，使用平面波或点源模型，当源是定向时，这可能会导致阵列增益降低，甚至波束形成完全失效。为了避免这种情况，作者在最近的工作中提出了一种替代的波束形成方法，该方法定义了一组“子波束形成器”，每个子波束形成器设计用于响应源的不同空间模式。各个子波束形成器的输出在加权和中组合，以提供比单极子波束形成器更好的整体输出质量。本文通过引入加权和的附加估计器并呈现模拟结果来扩展以前的工作，以证明在存在扩散噪声、混响和干扰源的情况下，所提出的方法和不同的定向源估计器的相对性能。还介绍了针对具有所提出的波束形成方法的白噪声增益的约束的增益优化。通常，在对定向源进行波束形成时，当输入信噪比 (SNR) 为 0 dB 或更高时，所提出的方法优于使用点源模型的波束形成。
