ECHO SUPPRESSION GAIN ESTIMATION METHOD, ECHO ELIMINATION APPARATUS USING THE SAME, AND PROGRAM

PROBLEM TO BE SOLVED: To prevent a tone quality degradation attributable to a residual echo component and suppress musical noise generation.SOLUTION: An echo suppression gain estimation method includes: an echo power correction factor calculation step of calculating, as an echo power correction factor estimate, the quotient of an absolute value || of an inner product value of a reproduction signal spectrum Xand a pickup signal spectrum Ydivided by the product of a squared norm value ||X||of the reproduction signal spectrum Xmultiplied by a square root |H^| of an acoustic coupling estimate; and an echo suppression gain calculation step of calculating a gain factor for echo suppression that decreases as the echo power correction factor estimate increases from the input of the pickup signal spectrum, the echo power correction factor estimate and an echo power estimate. The echo power correction factor estimate, whose value is in the range of zero to infinity, is operative to reduce a defect in a near end talker signal.