Noise reduction device, mobile body device, and noise reduction method

1. A noise reduction device that reduces noise in a sound reception location, the noise reduction device comprising:

a first input terminal that inputs a noise reference signal correlated with the noise;

a standard signal generator that generates a standard signal having a frequency specified based on the input noise reference signal;

an adaptive filter unit that generates an output signal to be used to output a cancellation sound for reducing the noise, by applying a filter coefficient to the generated standard signal;

an output terminal that outputs the generated output signal;

a first corrector that generates a corrected standard signal by correcting the generated standard signal based on a transfer characteristic of a transmission route of the generated output signal;

a second input terminal that inputs an error signal based on a first residual sound occurring in a sound collection location different from the sound reception location due to interference between the cancellation sound and the noise;

a second corrector that generates a correction signal by correcting the generated output signal or the generated standard signal by a predetermined parameter and adds the generated correction signal to the error signal, to generate a corrected error signal approximating the error signal, which is based on the first residual sound occurring in the sound collection location, to an approximated error signal indicating a second residual sound occurring in the sound reception location; and

a filter coefficient update unit that sequentially updates the filter coefficient based on the generated corrected error signal and the generated corrected standard signal.

2. The noise reduction device according to claim 1 , wherein the second corrector generates the correction signal by correcting the generated output signal by the predetermined parameter.

3. The noise reduction device according to claim 1 , wherein the second corrector generates the correction signal by correcting the generated standard signal by the predetermined parameter, and applying the filter coefficient to the corrected standard signal.

4. The noise reduction device according to claim 1 further comprising a storage unit that stores a plurality of predetermined parameters, wherein the predetermined parameter is one of the plurality of the predetermined parameters and

the second corrector

further acquires a moving state signal correlated with a moving state of a mobile body device using the noise reduction device,

selects one of the plurality of predetermined parameters stored in the storage unit according to the acquired moving state signal, and

generates the correction signal by correcting the generated output signal or the generated standard signal by the selected one of the plurality of the predetermined parameters.

5. A mobile body device comprising:

the noise reduction device according to claim 1 ;

a sound output device that outputs the cancellation sound by use of the generated output signal; and

a sound collection device that is arranged in the sound collection location and outputs the error signal to the second input terminal.

6. A noise reduction method of reducing noise in a sound reception location, the noise reduction method comprising:

generating a standard signal having a frequency specified based on a noise reference signal correlated with the noise;

generating an output signal to be used to output a cancellation sound for reducing the noise, by applying a filter coefficient to the generated standard signal;

generating a corrected standard signal by correcting the generated standard signal based on a transfer characteristic of a transmission route of the generated output signal;

generating a correction signal by correcting the generated output signal or the generated standard signal by a predetermined parameter;

adding the generated correction signal to an error signal based on a first residual sound occurring in a sound collection location different from the sound reception location due to interference between the cancellation sound and the noise, to generate a corrected error signal approximating the error signal, which is based on the first residual sound occurring in the sound collection location, to an approximated error signal indicating a second residual sound occurring in the sound reception location; and

sequentially updating the filter coefficient based on the generated corrected error signal and the generated corrected standard signal.