Interference sound suppressing device, interference sound suppressing method, and non-transitory computer readable recording medium storing interference sound suppressing program

1 . An interference sound suppressing device comprising:

an input signal acquiring part that acquires an input signal obtained from a microphone;

a reference signal acquiring part that acquires a reference signal;

a data inserting part that increases an amount of data of the input signal to be larger than an amount of data of the reference signal by inserting a plurality of zeros into the input signal acquired;

an interference sound suppressing part that suppresses an interference sound component included in the input signal by using the input signal having the amount of data increased and the reference signal acquired;

a data deleting part that restores the amount of data of the input signal to an original amount by deleting the plurality of zeros inserted from the input signal in which the interference sound component is suppressed; and

an output part that outputs the input signal having the amount of data restored.

2 . The interference sound suppressing device according to claim 1 , wherein the data inserting part increases number of samples of the input signal to twice or more number of samples of the reference signal.

3 . The interference sound suppressing device according to claim 1 , wherein the reference signal is a reproduction signal output to a loudspeaker.

4 . The interference sound suppressing device according to claim 1 , wherein the reference signal is a noise signal obtained from another microphone different from the microphone.

5 . The interference sound suppressing device according to claim 1 , wherein the reference signal is a noise signal from a predetermined direction obtained from the microphone.

6 . The interference sound suppressing device according to claim 1 , wherein

the input signal acquiring part acquires the input signal in a time domain,

the reference signal acquiring part acquires the reference signal in a time domain, and

the interference sound suppressing part includes:

a first frequency domain conversion part that converts the input signal in the time domain having the amount of data increased into an input signal in a frequency domain;

a second frequency domain conversion part that converts the reference signal in the time domain acquired into a reference signal in a frequency domain;

a sample number reduction part that reduces number of samples of the input signal in the frequency domain converted to same number of samples as the reference signal;

a coefficient calculation part that calculates a suppression coefficient for suppressing the interference sound component based on the input signal in the frequency domain with the number of samples reduced and the reference signal in the frequency domain converted;

a sample number increasing part that increases number of samples of the suppression coefficient calculated to same number of samples as the input signal having the amount of data increased;

a multiplication part that multiplies the input signal in the frequency domain converted by the suppression coefficient obtained by increasing the number of samples; and

a time domain conversion part that converts the input signal in the frequency domain multiplied by the suppression coefficient into an input signal in the time domain.

7 . The interference sound suppressing device according to claim 1 , wherein

the reference signal acquiring part acquires a plurality of reference signals, and

the interference sound suppressing part suppresses the interference sound component included in the input signal by using the input signal having the amount of data increased and the plurality of reference signals acquired.

8 . An interference sound suppressing method in a computer, the interference sound suppressing method comprising:

acquiring an input signal obtained from a microphone;

acquiring a reference signal;

increasing an amount of data of the input signal to be larger than an amount of data of the reference signal by inserting a plurality of zeros into the input signal acquired;

suppressing an interference sound component included in the input signal by using the input signal having the amount of data increased and the reference signal acquired;

restoring the amount of data of the input signal to an original amount by deleting the plurality of zeros inserted from the input signal in which the interference sound component is suppressed; and

outputting the input signal having the amount of data restored.

9 . A non-transitory computer readable recording medium storing an interference sound suppressing program that causes a computer to function as:

an input signal acquiring part that acquires an input signal obtained from a microphone;

a reference signal acquiring part that acquires a reference signal;

a data inserting part that increases an amount of data of the input signal to be larger than an amount of data of the reference signal by inserting a plurality of zeros into the input signal acquired;

an interference sound suppressing part that suppresses an interference sound component included in the input signal by using the input signal having the amount of data increased and the reference signal acquired;

a data deleting part that restores the amount of data of the input signal to an original amount by deleting the plurality of zeros inserted from the input signal in which the interference sound component is suppressed; and

an output part that outputs the input signal having the amount of data restored.