Patent ID: 8401844

Claim:
A gain control system that adjusts a sound pressure of an input signal and produces the adjusted signal, comprising: an input signal acquisition unit, of a computer, that acquires a speech signal supplied from an input device and extracts the speech signal for each unit time; a feature conversion unit, of the computer, that calculates a feature and the sound pressure from the input signal extracted for the each unit time; a speech model storage unit that stores therein a speech model having a feature and sound pressure information for each plural phonemes or for each of clusters into which a speech is divided; a distance calculation unit, of the computer, that calculates a distance between the feature of the input signal extracted for the each unit time and the feature of the speech model stored in the speech model storage unit; a sound pressure comparison unit, of the computer, that calculates a ratio between the sound pressure of the input signal extracted for the each unit time and a sound pressure of the speech model stored in the speech model storage unit; a gain value calculation unit, of the computer, that calculates a gain, based on the distance and the sound pressure ratio calculated for the speech model; and a sound pressure compensation unit, of the computer, that compensates for the sound pressure of the input signal extracted for the each unit time, using the gain calculated by the gain value calculation unit, wherein the speech model storage unit further stores and bolds occurrence frequency information on the speech model; and the gain value calculation unit performs gain calculation based on the distance and the sound pressure ratio calculated for the speech model and a frequency of occurrence of the speech model stored in the speech model storage unit.