ACTIVE NOISE REDUCTION DEVICE, ACTIVE NOISE REDUCTION SYSTEM AND ACTIVE NOISE REDUCTION METHOD
An active noise reduction device includes a signal processor that generates a cancelling signal for outputting a cancelling sound for reducing noise in an interior of a vehicle and a communicator that receives a change request for changing a parameter set related to generation of the cancelling signal to a user-designated parameter set that is designated by a user, and the signal processor generates the cancelling signal by using the user-designated parameter set based on the change request received.
1 . An active noise reduction device comprising:
a signal processor that generates a cancelling signal for outputting a cancelling sound for reducing noise in an interior of a moving body device, by applying an adaptive filter to a reference signal having a correlation with the noise, the adaptive filter having a coefficient that is updated based on an error signal indicating a state of the noise when the cancelling sound is being outputted; and
a communicator that receives a change request for changing a parameter set related to generation of the cancelling signal to a user-designated parameter set that is designated by a user, wherein
the signal processor generates the cancelling signal by using the user-designated parameter set based on the change request received.
2 . The active noise reduction device according to claim 1 , wherein
the parameter set includes at least one of a gain coefficient by which the reference signal is multiplied, a gain coefficient by which the error signal is multiplied, or a step-size parameter for determining an update amount of the coefficient of the adaptive filter.
3 . The active noise reduction device according to claim 1 , wherein
the parameter set includes a characteristic of a band pass filter (BPF) that is applied to the reference signal and a characteristic of a BPF that is applied to the error signal.
4 . The active noise reduction device according to claim 1 , wherein
the signal processor further includes an anomaly determiner that determines whether an anomaly is present or absent based on at least one of the coefficient of the adaptive filter, an update amount of the coefficient of the adaptive filter, or a signal level of the cancelling signal, and
the anomaly determiner outputs information indicating a determination result when the anomaly determiner determines that an anomaly is present.
5 . The active noise reduction device according to claim 4 , wherein
the anomaly determiner performs a fail-safe process when the anomaly determiner determines that the anomaly is present, and
the fail-safe process includes at least one of a process for stopping output of the cancelling sound or a process for resetting the coefficient of the adaptive filter.
6 . The active noise reduction device according to claim 4 , wherein
while the cancelling signal is generated by using the user-designated parameter set, the anomaly determiner changes a determination criterion for determining whether an anomaly is present or absent to increase a likelihood of determining that an anomaly is present.
7 . The active noise reduction device according to claim 4 , wherein
while the cancelling signal is generated by using the user-designated parameter set, the anomaly determiner changes a determination criterion for determining whether an anomaly is present or absent to decrease a likelihood of determining that an anomaly is present.
8 . The active noise reduction device according to claim 5 , wherein
while the cancelling signal is generated by using the user-designated parameter set, the anomaly determiner extends a period of time from when the anomaly is determined to be present to when the fail-safe process is performed.
9 . The active noise reduction device according to claim 1 , wherein
the signal processor includes an effect calculator that calculates a noise reduction effect of the cancelling sound, and
the effect calculator outputs information indicating the noise reduction effect calculated.
10 . The active noise reduction device according to claim 1 , wherein
the communicator receives the change request outputted by a user interface device based on an operation performed, by the user, on the user interface device.
11 . An active noise reduction system comprising:
the active noise reduction device according to claim 1 ;
a server device; and
a user interface device, wherein
the server device includes:
a storage that stores a plurality of user-designated parameter sets created by a plurality of users other than the user; and
a parameter provider that provides one of the plurality of user-designated parameter sets to the signal processor based on a selection operation performed, by the user, on the user interface device.
12 . The active noise reduction system according to claim 11 , wherein
the plurality of user-designated parameter sets are displayed in a ranking format on the user interface device.
13 . An active noise reduction method that is executed by a computer, the active noise reduction method comprising:
generating a cancelling signal for outputting a cancelling sound for reducing noise in an interior of a moving body device, by applying an adaptive filter to a reference signal having a correlation with the noise, the adaptive filter having a coefficient that is updated based on an error signal indicating a state of the noise when the cancelling sound is being outputted;
receiving a change request for changing a parameter set related to generation of the cancelling signal to a user-designated parameter set that is designated by a user; and
generating the cancelling signal by using the user-designated parameter set based on the change request received.