Noise suppression in beam-steered microphone array
A system for suppressing unwanted signals in steerable microphone arrays. The lobes of a steerable microphone array are monitored, to identify lobes having large speech content and low noise content. One of the identified lobes is then used to deliver speech to a speech recognition system, as at a self-service kiosk.
1. Apparatus comprising:
a) a self-service kiosk which dispenses articles, currency, or communication services; and
b) within the kiosk,
i) a steerable beam microphone array, having multiple lobes;
ii) means for sampling lobes, and
A) distinguishing the difference between speech content and noise content from sound signals received by each lobe,
B) identifying lobes having a relatively high speech content,
C) identifying lobes having a relatively low noise content, and
D) actuating a lobe having both a relatively high speech content and relatively low noise content.
2. Apparatus according to claim 1 , and further comprising:
c) speech recognition means for recognizing speech contained in the lobe actuated.
3. A method, comprising the following steps:
a) maintaining a self-service kiosk which dispenses articles, currency, or communication services;
b) maintaining a beam-steerable microphone array at the self-service kiosk;
c) measuring noise content and speech content of several lobes of the array; and
d) selecting a lobe which carries
i) larger speech signals than other lobes and
ii) smaller noise signals than other lobes.
4. Method according to claim 3 , and further comprising the step of:
e) receiving signals from the lobe selected, and performing speech recognition on the data.