Method and apparatus for canceling acoustic echo, and method for updating adaptive filter coefficient by the apparatus

A method for canceling an acoustic echo signal caused by a far-end talker signal by an acoustic echo canceller, the method comprising:

• estimating a variance of a first audio signal of a near-end talker signal and a variance of a first noise signal of the near-end talker signal;
• determining a step size by using the variance of the first audio signal and the variance of the first noise signal;
• updating an adaptive filter coefficient of an adaptive filter by using the step size;
• generating an estimated acoustic echo signal corresponding to the acoustic echo signal by using the adaptive filter coefficient;
• and
• canceling the acoustic echo signal from a microphone input signal by using the estimated acoustic echo signal,
• wherein the step size is determined such that a first residual signal is equal to the near-end talker signal, and the first residual signal is a signal obtained by subtracting the estimated acoustic echo signal from the microphone input signal,
• wherein the estimated acoustic echo signal is a signal obtained by using the updated adaptive filter coefficient, and
• wherein the variance of the first noise signal and the variance of the first audio signal are estimated by using a probability that a second audio signal will exist in the far-end talker signal.

An apparatus for canceling an acoustic echo signal caused by a far-end talker signal, the apparatus comprising:

• a variance estimating unit configured to estimate a variance of a first audio signal of a near-end talker signal and a variance of a first noise signal of the near-end talker signal;
• a step size determining unit configured to determine a step size by using the variance of the first audio signal and the variance of the first noise signal;
• an adaptive filter coefficient updating unit configured to update an adaptive filter coefficient of an adaptive filter by using the step size;
• and
• an acoustic echo canceling unit configured to generate an estimated acoustic echo signal corresponding to the acoustic echo signal by using the adaptive filter coefficient, and cancel the acoustic echo signal from a microphone input signal by using the estimated acoustic echo signal,
• wherein the step size determining unit determines the step size such that a first residual signal is equal to the near-end talker signal, the first residual signal being a signal obtained by subtracting the estimated acoustic echo signal from the microphone input signal,
• wherein the estimated acoustic echo signal is a signal obtained by using the updated adaptive filter coefficient, and
• wherein the variance estimating unit estimates the variance of the first noise signal and the variance of the first audio signal by using a probability of presence of the acoustic echo signal.