SPEECH ENHANCEMENT SYSTEM AND METHOD

摘要

The invention relates to a system for speech enhancement in a room (10), comprising a directional lapel microphone arrangement for capturing an audio signal from a speaker's voice; audio signal processing means (32, 34, 38, 38', 56, 70) for generating a processed audio signal from the captured audio signal, comprising an adaptive beam former unit (32) for imparting a directivity to the microphone arrangement, wherein the maximum sensitivity is towards the speaker's mouth (21) and the minimum sensitivity is towards noise sources as identified by the beam former unit, a unit (38, 38') for shifting the frequency of components of the audio signal above a frequency threshold value only, a feedback cancelling unit (56) comprising an adaptive filter and a selection unit (68) adapted to automatically switch between a first mode in which the audio signal by-passes the adaptive filter when the total acoustic gain or the feedback is below a critical value and a second mode in which the audio signal is filtered by the adaptive filter when the total acoustic gain or the feedback is above said critical value: a loudspeaker arrangement (24) to be located in the room for generating sound according to the processed audio signal and comprising a plurality of loudspeakers (25) arranged to form a directional loudspeaker array.