Patent ID: 7930175

Claim:
A method for reducing background noise in an audio signal, comprising: converting sound into an analog signal; digitizing the analog signal to obtain a discrete output signal; detecting structure-borne noise by an acoustic emission sensor to obtain an acoustic noise reference signal; digitizing the acoustic noise reference signal to obtain a discrete acoustic noise reference signal; and detecting noise to obtain a reference noise signal; digitizing the reference noise signal to obtain a discrete reference noise signal; calculating a correlation between the discrete output signal and the discrete acoustic noise reference signal to obtain a first correlation value; calculating a correlation between the discrete output signal and the discrete reference noise signal to obtain a second correlation value; adaptively filtering the discrete acoustic noise reference signal to obtain a noise estimate signal, if the first correlation value is greater than the second correlation value; adaptively filtering the discrete reference noise signal to obtain the noise estimate signal, if the first correlation value is not greater than the second correlation value; and subtracting the noise estimate signal from the discrete output signal to obtain a noise compensated digital audio signal.