Microphone array system and a method for sound acquisition

摘要

A microphone array system for sound acquisition from multiple sound sources in a reception space surrounding a microphone array that is interfaced with a beamformer module is disclosed. The microphone array includes microphone transducers that are arranged relative to each other in N-fold rotationally symmetry, and the beamformer includes beamformer weights that are associated with one of a plurality of spatial reception sectors corresponding to the N-fold rotational symmetry of the microphone array. Microphone indexes of the microphone transducers are arithmetically displaceable angularly about the vertical axis during a process cycle, so that a same set of beamformer weights is used selectively for calculating a beamformer output signal associated with any one of the spatial reception sectors. A sound source location module is also disclosed that includes a modified steered power response sound source location method. A post filter module for a microphone array system is also disclosed.

主权项

1. A method for processing output audio signals, the method including the steps of:
sampling the audio signals in a series of processing cycles to form discrete time domain signals; in each processing cycle:
transforming the time domain signals into discrete frequency domain signals that each have a set of defined frequency bins;defining a pre-filter mask vector for each discrete frequency domain signal for population with entries corresponding with respective frequency bins;populating the pre-filter mask vector such that each entry has a defined high value if a value of the corresponding frequency bin is a highest value amongst associated frequency bins of the respective discrete frequency domain signals, otherwise each entry having a defined low value;calculating an indicator value for each discrete frequency domain signal using the entries populating the pre-filter mask vector;defining a post-filter mask vector for each discrete frequency domain signal with entries corresponding to the entries of the pre-filter mask vector;populating the post-filter mask vector such that entries of the post-filter mask vector corresponding with entries in the pre-filter mask vector that are said high values are the indicator value and the remaining entries of the post-filter mask vector are prior values from a previous processing cycle scaled with an attenuating factor for decaying the prior value; andforming discrete filtered frequency domain signals by applying the post-filter mask vector to the frequency domain signals such that the audio signals associated with the indicator value are emphasised and the remaining audio signals are de-emphasised.