Patent ID: 7035398

Claim:
An echo cancellation processing system in a full duplex telephony system comprising: a microphone array; a loudspeaker converting a speech signal transmitted from a telephony system on a communication partner side to a speech; an echo cancellation processing part comprising: an estimated wraparound speech signal generating part estimating a speech signal that is outputted from the loudspeaker and wraps around to the microphone array, using a time difference or a level difference between input speech signals of a plurality of channels of the microphone array, and generate an estimated wraparound speech signal in accordance with an estimated result based on an output speech signal supplied to the loudspeaker, comprising: an adaptive filter, and a coefficient updating part updating a coefficient of the adaptive filter at a predetermined timing, wherein the coefficient updating part determines the estimated result and a coefficient update amount of the adaptive filter based on a level of a wraparound speech signal remaining in an echo cancellation result obtained by the echo cancellation processing part, and the adaptive filter conducts the adaptation based on an output speech signal supplied to the loudspeaker and generates the estimated wraparound speech signal, a subtracter subtracting the estimated wraparound speech signal from an input speech signal inputted to the microphone array; and a loudspeaker output speech signal power calculating part calculating a power of an output speech signal supplied to the loudspeaker, wherein in a case where a power with a predetermined value or more is not detected by the loudspeaker output speech signal power calculating part, a coefficient update of the adaptive filter by the coefficient updating part of the estimated wraparound speech signal generating part is made slow or suspended.