Patent ID: 7542577

Claim:
An input sound processor for estimation of the total power of an input sound received by a microphone, comprising: first frequency analysis means for dividing an input sound signal sent to a loudspeaker into a plurality of frequency components; first power calculating means for determining the sound power at each of the frequency components; square amplitude calculating means for determining a square amplitude of a filter coefficient at each of the frequency components, the filter coefficient comprising a filter characteristic corresponding to a transfer characteristic of an acoustic space located between the loudspeaker and the microphone; power comparing means for comparing the sound power at each of the frequency components with a reference value; multiplication point setting means for setting multiplication points indicating frequency components at which the total power of the input sound is to be determined based upon a comparison result produced by the power comparing means; and product-sum operation means for performing a product-sum operation at the multiplication points using the sound power at each of the frequency components and the square amplitude of the filter coefficient at each of the frequency components.