Noise reduction device, vehicle, noise reduction system, and noise reduction method

1. A noise reduction device using a speaker and a microphone corresponding to each seat in a vehicle to reduce a noise in each seat, the noise reduction device comprising:

a memory; and

a processor coupled to the memory and configured to:

generate a canceling sound that reduces a noise at an ear of an occupant in a predetermined seat by using an auxiliary filter;

disable operations of a speaker and a microphone corresponding to each empty seat in the vehicle; and

change a setting value of the auxiliary filter to generate the canceling sound in accordance with a number of occupants in seats other than the predetermined seat, the seats affecting the noise in the predetermined seat,

wherein when the occupant rides in the predetermined seat, the processor sets a setting value of the auxiliary filter to generate the canceling sound in accordance with the number of occupants in the seats other than the predetermined seat, and the processor enables an operation of a speaker corresponding to the predetermined seat and, after the processor has enabled the operation of the speaker or when the processor enables the operation of the speaker, the processor enables an operation of a microphone corresponding to the predetermined seat.

2. The noise reduction device as claimed in claim 1 , wherein the processor sets a setting value of the auxiliary filter to the auxiliary filter used to generate the canceling sound when the occupant is present in each of the seats other than the predetermined seat, the setting value of the auxiliary filter being learned while operations of a speaker and a microphone corresponding to each of the seats other than the predetermined seat are enabled.

3. The noise reduction device as claimed in claim 2 , wherein the processor sets a setting value of the auxiliary filter to the auxiliary filter to generate the canceling sound when the occupant is present in either of the seats other than the predetermined seat, the setting value of the auxiliary filter being learned while, among the seats other than the predetermined seat, operations of a speaker and a microphone corresponding to one seat are enabled and operations of a speaker and a microphone corresponding to another seat are disabled.

4. The noise reduction device as claimed in claim 1 ,

wherein the predetermined seat includes a first speaker and a first microphone provided near a left ear of the occupant, and a second speaker and a second microphone provided near a right ear of the occupant, and

wherein the processor generates a first canceling sound that reduces a noise at the left ear of the occupant and a second canceling sound that reduces a noise at the right ear of the occupant.

5. The noise reduction device as claimed in claim 1 ,

wherein the predetermined seat is a driver seat or a passenger seat in the vehicle, and

wherein the seats other than the predetermined seat are rear seats in the vehicle.

6. The noise reduction device as claimed in claim 1 ,

wherein the predetermined seat is one of rear seats in the vehicle, and

wherein the seats other than the predetermined seat are a driver seat and a passenger seat in the vehicle.

7. A vehicle to which the noise reduction device as claimed in claim 1 is mounted.

8. A noise reduction system using a speaker and a microphone corresponding to each seat in a vehicle to reduce a noise in each seat, the noise reduction system comprising:

a memory; and

a processor coupled to the memory and configured to:

generate a canceling sound that reduces a noise at an ear of an occupant in a predetermined seat by using an auxiliary filter;

disable operations of a speaker and a microphone corresponding to each empty seat in the vehicle; and

change a setting value of the auxiliary filter to generate the canceling sound in accordance with a number of occupants in seats other than the predetermined seat, the seats affecting the noise in the predetermined seat

wherein when the occupant rides in the predetermined seat, the processor sets a setting value of the auxiliary filter to generate the canceling sound in accordance with the number of occupants in the seats other than the predetermined seat, and the processor enables an operation of a speaker corresponding to the predetermined seat and, after the processor has enabled the operation of the speaker or when the processor enables the operation of the speaker, the processor enables an operation of a microphone corresponding to the predetermined seat.

9. A noise reduction method performed by a noise reduction system using a speaker and a microphone corresponding to each seat in a vehicle to reduce a noise in each seat, the noise reduction method comprising:

generating a canceling sound that reduces a noise at an ear of an occupant in a predetermined seat by using an auxiliary filter;

disabling operations of a speaker and a microphone corresponding to each empty seat in the vehicle;

changing a setting value of the auxiliary filter to generate the canceling sound in accordance with a number of occupants in seats other than the predetermined seat, the seats affecting the noise in the predetermined seat; and

setting, when the occupant rides in the predetermined seat, a setting value of the auxiliary filter to generate the canceling sound in accordance with the number of occupants in the seats other than the predetermined seat, and enabling an operation of a speaker corresponding to the predetermined seat and, after the operation of the speaker is enabled or when the operation of the speaker is enabled, enabling an operation of a microphone corresponding to the predetermined seat.