Patent ID: 8351618

Claim:
A dereverberation and noise reduction method, adapted for a single input multiple output (SIMO) microphone array, wherein the SIMO microphone array comprises a plurality of microphones, and each of the microphones respectively receives one of a plurality of audio signals from an audio source, wherein each of the audio signals respectively experiences a gain of a system response between the audio source and the SIMO microphone array, the system response is obtained by a measurement in advance and expressed as a system response matrix H, and the gain respectively experienced by each of the audio signals is not substantially completely identical, the dereverberation and noise reduction method comprising: applying a beamforming processing on the audio signals received by the microphone array, and generating a first audio signal, wherein the beamforming processing allows a main-lobe portion of the audio signals pass through and reduces a plurality of side-lobe portions of the audio signals, and the beamforming processing executes a computation of an inverse filter matrix C, wherein a relationship between the inverse filter matrix C and the system response matrix H is expressed as the following equation (1): C T =αH H equation (1), wherein, α is a real number and greater than zero, C T is a transpose matrix of the inverse filter matrix C, and H H is a Hermitian matrix of the system response matrix H; applying a suppression processing on the audio signals received by the microphone array, and generating a suppression audio vector, wherein the suppression processing allows the side-lobe portions of the audio signals pass through and reduces the main-lobe portion of the audio signals, and the suppression processing executes a computation of a blocking matrix B, wherein the blocking matrix B is expressed as the following equation (2): h H B= 0 equation (2), wherein, h H is a Hermitian matrix of a frequency response matrix h between the audio source and each of the microphones; applying an adaptive filtering processing on the suppression audio vector, and generating a second audio signal and subtracting the second audio signal from the first audio signal to acquire an audio output signal, wherein a plurality of parameters of the adaptive filtering processing are adjusted according to a feedback of the audio output signal.