Patent ID: 8498862

Claim:
A speech signal processing apparatus comprising: a control signal output unit configured to receive as an input signal either one of a first speech signal corresponding to a sound uttered by a user and a second speech signal corresponding to a sound output from an eardrum of the user when the user utters a sound, and output a control signal corresponding to a noise level of the input signal; and a speech signal output unit configured to output either one of the first speech signal and the second speech signal according to the control signal, wherein the control signal output unit includes: a noise-level calculation unit configured to calculate a noise level of the input signal; and a control signal generation unit configured to generate the control signal for allowing the speech signal output unit to output the second speech signal when the noise level is higher than a predetermined level, and generate the control signal for allowing the speech signal output unit to output the first speech signal when the noise level is lower than the predetermined level, and wherein the control signal generation unit includes: a comparison unit configured to output a comparison signal corresponding to a comparison result each time the noise level and a predetermined level are compared; and a generation unit configured to generate the control signal for allowing the speech signal output unit to output the second speech signal when the comparison unit outputs, a predetermined number or more on a consecutive basis, the comparison signal indicating that the noise level is higher than the predetermined level, and generate the control signal for allowing the speech signal output unit to output the first speech signal when the comparison unit does not output, the predetermined number or more on the consecutive basis, the comparison signal indicating that the noise level is higher than the predetermined level.