自适应麦克风波束形成

应用背景频率不变波束形成(Frequency-invariant beamforming, FIB)在麦克风阵列语音信号的无失真采集和处理中具有重要的应用。经典的FIB设计方法通常是在远场平面波的模型下提出的，本文根据麦克风阵列近场球面波模型，将空间响应变化函数(spatial response variation, SRV)运用到近场线性约束方差(Linear Constrained Minimum Variance, LCMV)宽带波束形成中，把空间响应函数作为优化条件，然后根据拉格朗日乘子法计算得到闭式解，从而得到频率不变的权向量。但是该方法受到环境干扰和噪声影响，权值分配值需要较大的浮动。因此本文采取了自适应加权频率不变波速形成，能够根据环境自适应的选择加权值的大小。仿真实例证明了所提方法的有效性和理论分析的正确性。关键技术The frequency invariant beamforming (FIB) has important applications in the microphone array speech signal acquisition and processing. Conventional FIB design methods are usually proposed in the far-field plane wave model, this paper according to microphone array in the near field spherical wave model , the response variation spatial (SRV) is applied to the formation of broadband beamforming in the near field linear Constrained Minimum (Variance LCMV), spatial response function as the optimal conditions, then according to the Lagrange multiplier method computing a closed