Noise reduction device and noise reduction method

A noise reduction method, comprising:

• generating a reference signal based on an estimation value,
• wherein the reference signal represents a waveform of noise, wherein the waveform of noise corresponds to a reduction control target, and
• wherein the estimation value indicates estimation of an acoustic characteristic in a route from at least one speaker to at least one microphone,
• measuring an error corresponding to each of a sound wave and a waveform of a synthetic wave,
• wherein the synthetic wave is based on synthesis of the noise;
• outputting the sound wave from the at least one speaker to cancel the noise;
• obtaining an amplitude-frequency characteristic from the acoustic characteristic;
• processing an error signal based on the amplitude-frequency characteristic,
• wherein the error signal includes a waveform of the error;
• calculating a filter coefficient with which the error signal becomes zero under adaptive algorithm with reference to the reference signal;
• filtering the reference signal based on the filter coefficient to obtain a control signal;
• and
• supplying the control signal to the at least one speaker.

A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by a processor, cause a computer to execute operations, the operations comprising:

• generating a reference signal based on an estimation value,
• wherein the reference signal represents a waveform of noise, wherein the waveform of noise corresponds to a reduction control target, and
• wherein the estimation value indicates estimation of an acoustic characteristic in a route from at least one speaker to at least one microphone;
• measuring an error corresponding to each of a sound wave and a waveform of a synthetic wave,
• wherein the synthetic wave is based on synthesis of the noise;
• outputting the sound wave is from the at least one speaker to cancel the noise;
• obtaining an amplitude-frequency characteristic from the acoustic characteristic;
• processing an error signal based on the amplitude-frequency characteristic,
• wherein the error signal includes a waveform of the error;
• calculating a filter coefficient with which the error signal becomes zero under adaptive algorithm with reference to the reference signal;
• filtering the reference signal based on the filter coefficient to obtain a control signal;
• and
• supplying the control signal to the at least one speaker.