Patent ID: 7269263

Claim:
A beamformer for correcting the beam pattern and beamwidth of a microphone array embedded in an obstacle whose shape is not axi-symmetric, comprising: a multiplier for multiplying a signal d of a sound source from a directivity angle θ to each respective microphone of said array by a respective weighting vector w to generate a product that enhances the signal d while minimising noise n, where n is not correlated to the signal d, and where n and d are both dependant upon frequency ω; and an adder for summing each respective product to generate an output signal such that w opt H d=1; wherein optimised weighting vector w opt is a solution of Min w ⁢ 1 2 ⁢ w H ⁢ R nn ⁢ w where R nn is a normalised noise correlation matrix, and wherein said solution is constrained by introducing symmetric vectors d 0+0 i and d 0−0 i on either side of d where θ i >0, with i={1, . . . , N θ } is a set of directions belonging to directivity angle θ for increasing beamwidth of said array, and at least one further vector to correct for beam pattern asymmetry resulting from said obstacle having a shape that is non-axisymmetric.