Audio signal processing device and remote control system

Abstract

To provide an audio signal processing device and a remote control system that remove a noise component in an audio signal with a simple configuration.SOLUTION: In the audio signal processing device, an IFFT outputs, to an adaptive filter, a reference sound generated by performing an inverse fast Fourier transform on a Fourier coefficient stored in noise element sound data. A subtractor 234 subtracts a noise cancel sound output from the adaptive filter from an input audio signal S for output as an output signal S' to a speaker. The adaptive filter subjects the reference sound as input to filter processing for output, and performs an adaptive operation of a filter coefficient using an output signal S' as an error. A Fourier coefficient is stored in the noise element sound data, the Fourier coefficient representing information about a frequency domain of a synthetic sound of simple tones of a plurality of frequencies extracted at every predetermined frequency interval from within a removal target frequency band which is a frequency band not including a main frequency band of a listening target sound component included in the audio signal S and including a frequency band of an assumed noise component.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a technique for reducing the level of unknown noise components contained in an audio signal. [Background technology]

[0002] Known techniques for reducing the level of unknown noise components contained in an audio signal include a technique for removing unknown noise components contained in an audio signal using blind source separation, which separates individual sound source signals from a mixed signal in which multiple sound source signals are mixed, by taking advantage of the independence of each sound source signal (e.g., Patent Documents 1 and 2).

[0003] With this technology, sound to be heard in a noisy environment is picked up by multiple microphones in a space in which the sound is generated, and the correlation between the audio signals output by each microphone is evaluated to extract only the sound components to be heard. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6966750 [Patent Document 2] Patent No. 4616529 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology for removing unknown noise components using the above-mentioned blind source separation requires the placement of many microphones, and therefore cannot be applied when it is not possible to secure the placement locations for many microphones in the space in which the sounds to be listened to are generated. Even when it is possible to secure the placement locations for many microphones, the placement of many microphones requires cumbersome work and increases costs.

[0006] Therefore, an object of the present invention is to reduce the level of unknown noise components contained in an audio signal using a relatively simple configuration. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an audio signal processing device that suppresses noise components of an input signal containing audible sound components and noise components and outputs the result as an output signal, the audio signal processing device comprising: synthetic sound output means for outputting a synthetic sound signal; an adaptive filter to which the synthetic sound signal output by the synthetic sound output means is input; and subtraction means for subtracting the output signal of the adaptive filter from the input sound signal and outputting the result as the output sound signal. Here, the adaptive filter performs an adaptive operation using the output sound signal output by the subtraction means as an error. Also, the synthetic sound output means outputs, as the synthetic sound signal, a signal of a synthetic sound of pure tones of multiple frequencies extracted from a removal target frequency band, which is the frequency band of the noise components to be suppressed in the audio signal processing device.

[0008] Here, in this audio signal processing device, the synthetic sound output means may output, as the synthetic sound signal, a signal of a synthetic sound of pure tones of a plurality of frequencies extracted at regular frequency intervals from within the target frequency band for elimination. Here, the synthetic sound output means of this audio signal processing device may be configured with an information storage means for storing information on the frequency domain of the synthetic sound signal to be output, and a conversion means for converting the information stored in the information storage means into the synthetic sound signal. In this case, in this audio signal processing apparatus, information in the frequency domain of the synthetic sound signal may be used as a Fourier coefficient, and the conversion means may perform conversion to the synthetic sound signal by inverse fast Fourier transform. Alternatively, in this case, in this audio signal processing device, information in the frequency domain of the synthetic sound signal may be used as a wavelet transform coefficient, and the transform means may perform the transform to the synthetic sound signal by inverse wavelet transform. In order to achieve the above object, the present invention provides an audio signal processing device that suppresses a noise component of an input signal containing a target sound component and a noise component and outputs the result as an output signal, the audio signal processing device comprising: a first conversion means that converts the input sound signal into first information that is information in the frequency domain of the input sound signal; information storage means that stores a signal of a synthetic sound of pure tones of multiple frequencies extracted from a target frequency band for elimination that is the frequency band of the noise component to be suppressed in the audio signal processing device as a synthetic sound signal and information in the frequency domain of the synthetic sound signal as second information; an adaptive filter that receives as input the second information stored in the information storage means and outputs third information that is information in the frequency domain of a noise-canceled sound; and subtraction means that outputs frequency domain information obtained by subtracting the third information from the first information as fourth information. and second conversion means for converting the fourth information into a sound signal and outputting the sound signal as the output sound signal. Here, the adaptive filter performs an adaptive operation using the fourth information as an error.

[0009] Here, in such an audio signal processing apparatus, the synthetic sound signal may be a synthetic sound signal of pure tones of a plurality of frequencies extracted at regular frequency intervals from within the target frequency band for elimination. In addition, in such an audio signal processing device, the frequency domain information may be a Fourier coefficient, and the first conversion means may perform a fast Fourier transform to convert the input sound signal into the first information, and the second conversion means may perform an inverse fast Fourier transform to convert the fourth information into the output sound signal.

[0010] Alternatively, in such an audio signal processing device, the frequency domain information may be a wavelet transform coefficient, the first transform means may perform a wavelet transform to convert the input sound signal into the first information, and the second transform means may perform an inverse wavelet transform to convert the fourth information into the output sound signal.

[0011] The present invention also provides a remote control system including the audio signal processing device. The remote control system includes a vehicle-side system mounted in a vehicle and a control-side system that remotely controls the vehicle, the vehicle-side system including a microphone that picks up a mixture of the target sound and the noise and outputs the mixture as a monitoring sound signal, and a transmission means that transmits the monitoring sound signal output by the microphone to the control-side system. The control-side system includes a reception means that receives the monitoring sound signal from the vehicle-side system, a speaker, and the audio signal processing device, the monitoring sound signal received by the reception means is input to the audio signal processing device as the input sound signal, and the audio signal processing device outputs the output sound signal to the speaker.

[0012] According to the audio signal processing device as described above, with a simple configuration that does not require multiple microphones, it is possible to reduce the level of unknown noise components contained in an input sound signal and output the reduced noise components as an output sound signal. Effect of the Invention

[0013] As described above, according to the present invention, it is possible to reduce the level of unknown noise components contained in an audio signal with a relatively simple configuration. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a configuration of a remote control system according to a first embodiment of the present invention. [Diagram 2] 1 is a block diagram showing a configuration of an audio signal processing device according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram illustrating reference sound data according to the first embodiment of the present invention. [Figure 4] 4A to 4C are diagrams illustrating examples of noise cancellation sounds according to the first embodiment of the present invention. [Diagram 5] FIG. 11 is a block diagram showing another example of the configuration of the audio signal processing device according to the second embodiment of the present invention. [Figure 6] FIG. 11 is a block diagram showing another example of the configuration of the audio signal processing device according to the third embodiment of the present invention. [Figure 7] FIG. 13 is a block diagram showing another example of the configuration of the audio signal processing device according to the fourth embodiment of the present invention. [Figure 8] 13 is a block diagram showing another configuration example of an audio signal processing device according to the fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described taking as an example an application to a remote control system. First, the first embodiment will be described. FIG. 1 shows the configuration of a remote control system according to the first embodiment. The remote control system is a system for remotely controlling a construction vehicle such as heavy machinery, and includes a vehicle system 1 mounted on the construction vehicle, and a remote control room system 2 installed in a remote control room. The vehicle system 1 is equipped with an actuator 11 that controls the operation of the construction vehicle, a camera 12 that captures images of the surroundings and the interior of the vehicle, a sensor 13 that detects the condition of the construction vehicle and its surroundings, a microphone 14 that picks up a mixture of sounds to be heard, such as operation sounds and warning sounds, and noises such as engine noise, and a control device 15.

[0016] The control device 15 then transmits the images captured by the camera 12, the conditions detected by the sensor 13, and the audio signals picked up by the microphone 14 to the remote control room system 2 via the network 3, and drives the actuator 11 in accordance with the control signals received from the remote control room system 2 to operate the construction vehicle.

[0017] On the other hand, the remote control room system 2 includes a controller 21 , a monitor 22 , an audio signal processing device 23 , a speaker 24 , and a remote control device 2 . The remote control device 25 controls the operation of the construction vehicle by transmitting a control signal according to the operator's operation received by the controller 21 to the vehicle system 1 via the network 3. The remote control device 25 also displays on the monitor 22 the video and status received from the vehicle system 1 via the network 3, and outputs the audio signal received from the vehicle system 1 via the network 3 to the audio signal processing device 23.

[0018] Then, the audio signal processing device 23 performs signal processing on the audio signal output from the remote control device 25 to suppress noise components, and outputs the resulting signal to the speaker 24 . The audio signal processing device 23 will now be described. FIG. 2 shows the configuration of the audio signal processing device 23. As shown in the figure, the audio signal processing device 23 includes noise element sound data 231, an IFFT 232 that performs an inverse fast Fourier transform, an adaptive filter 233, and a subtractor 234 that subtracts the output of the adaptive filter 233 from an audio signal S input from the remote control device 25 and outputs the result as an output signal S' to the speaker 24.

[0019] The noise element sound data 231 stores Fourier coefficients, and the IFFT 232 performs inverse fast Fourier transform on the Fourier coefficients to generate a reference sound, which is output to the adaptive filter 233 . The adaptive filter 233 performs filtering on the input reference sound and outputs the result as a noise-canceled sound to the subtractor 234. Furthermore, the adaptive filter 233 uses the output signal S' output by the subtractor 234 as an error, and adapts the filter coefficients (transfer function, tap coefficients) of the filtering performed on the reference sound using an adaptive algorithm such as LMS or NLMS so as to minimize the error.

[0020] Now, the Fourier coefficients stored in the noise element sound data 231 represent, in frequency domain information, a synthesized sound of pure tones of multiple frequencies extracted at predetermined frequency intervals from within a predetermined frequency band to be removed. In other words, the Fourier coefficients stored in the noise element sound data 231 are determined so that the reference sound obtained by inverse fast Fourier transform in IFFT 23 becomes a composite sound of pure tones of multiple frequencies extracted at predetermined frequency intervals from within the frequency band to be removed. Therefore, the noise element sound data 231 and the IFFT 232 function as a sound source device that outputs a synthesized sound of the above pure tones. Moreover, the Fourier coefficients stored in the noise element sound data 231 are equivalent to F(ω) calculated by the following equation 1, where f(t) is the synthetic sound. Moreover, the sound f(t) obtained by performing inverse fast Fourier transform on the Fourier coefficient F(ω) stored in the noise element sound data 231 using, for example, equation 2, becomes the reference sound.

[0021]

number

[0022] The Fourier coefficients of the frequencies of the pure tones, that is, the magnitudes (amplitude and power) of the pure tones of the multiple frequencies to be synthesized into the synthetic sound, are all set to the same magnitude, although the magnitudes may be varied for each frequency. The frequency band to be removed is set so as not to include the main frequency band of the target sound component contained in the audio signal S, but to include the frequency band of expected noise components. For example, if the expected noise component is engine noise, as shown by the frequency spectrum of the synthetic sound in Figure 3a, the frequency band to be removed is set to 20 Hz to 800 Hz, taking into consideration low-order harmonics, and the frequency interval of the pure tones is set to 5 Hz. The frequency band to be removed does not necessarily have to be 20 Hz-800 Hz, but may be another frequency band range, such as 20 Hz-1 kHz. Also, as shown in FIG. 3b where two frequency bands are set as an example, a plurality of frequency bands may be set as the elimination target bands. According to such an audio signal processing device 23, the noise-canceled sound output by the adaptive filter 233 and the audio signal S are similar in magnitude to each other for each frequency within the frequency band to be removed by adapting the filter coefficients. Therefore, as shown in FIG. 4 where the band of 20 Hz-1 kHz is the frequency band to be removed, the noise cancellation sound is approximate to the components of the frequency band to be removed that are contained in the audio signal S, and as a result, the output signal S' output by the subtractor 234 to the speaker 24 has the level of the noise components of the audio signal S reduced.

[0023] On the other hand, since there is no significant effect on frequency bands outside the frequency band to be removed from the audio signal S, the target sound components of the audio signal S are included in the output signal S' with almost no attenuation, and the operator can clearly hear the target sound from the output sound of the speaker 24.

[0024] The first embodiment of the present invention has been described above. Next, a second embodiment of the present invention will be described. In the second embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the first embodiment is performed in the frequency domain, and only the configuration of the audio signal processing device 23 is different. FIG. 5 shows a configuration of an audio signal processing device 23 according to the second embodiment. As shown in the figure, the audio signal processing device 23 according to the second embodiment includes noise element sound data 531, a frequency domain adaptive filter 532, an FFT 533, a subtractor 534, and an IFFT 535. The noise element sound data 531 stores the same Fourier coefficients as the noise element sound data 231 of the first embodiment. The FFT 533 performs a fast Fourier transform on the audio signal S input from the remote control device 25 , and outputs a Fourier coefficient, which is information on the audio signal S in the frequency domain, to the subtractor 534 . The subtractor 534 subtracts the Fourier coefficient output by the frequency domain adaptive filter 532 from the Fourier coefficient input by the FFT 533 for each frequency, and outputs the result to the frequency domain adaptive filter 532 and the IFFT 535 . The IFFT 535 performs an inverse fast Fourier transform on the Fourier coefficients output by the subtractor 534 and outputs the result to the speaker 24 as an output signal S′. The frequency domain adaptive filter 532 performs filtering on the Fourier coefficients stored in the noise element sound data 531 and outputs the result to the subtractor 534 . In addition, the frequency domain adaptive filter 532 uses the Fourier coefficients output by the subtractor 534 as errors and adapts the filter coefficients of the filtering process applied to the Fourier coefficients stored in the noise element sound data 531 using an adaptive algorithm such as LMS or NLMS so as to minimize the error.

[0025] According to the second embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the first embodiment can be performed in the frequency domain, and, similar to the first embodiment, an audio signal in which only the noise components have been reduced in level from the audio signal S can be generated as an output signal S' and output from the speaker 24.

[0026] Next, a third embodiment of the present invention will be described. In the third embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the first embodiment is performed using wavelet transform instead of Fourier transform, and only the configuration of the audio signal processing device 23 is different. FIG. 6 shows a configuration of an audio signal processing device 23 according to the third embodiment. As shown in the figure, the audio signal processing device 23 includes noise element sound data 631, an inverse wavelet transform unit 632 that performs an inverse wavelet transform, an adaptive filter 633, and a subtractor 634 that subtracts the output of the adaptive filter 633 from the audio signal S input from the remote control device 25 and outputs the result as an output signal S' to the speaker 24.

[0027] The noise element sound data 631 stores wavelet transform coefficients, and an inverse wavelet transform unit 632 performs inverse wavelet transform on the wavelet transform coefficients to generate a reference sound, which is output to an adaptive filter 633 . The adaptive filter 633 performs filtering on the input reference sound and outputs the result to the subtractor 634. The adaptive filter 633 also uses the output signal S' output by the subtractor 634 as an error and adapts the filter coefficient of the filtering performed on the reference sound using an adaptive algorithm such as LMS or NLMS so as to minimize the error.

[0028] Now, the wavelet transform coefficients stored in the noise element sound data 631, as in the first embodiment, represent, as frequency domain information, a synthesized sound of pure tones of multiple frequencies extracted at predetermined frequency intervals from within the frequency band to be removed. In other words, the wavelet transform coefficients stored in the noise element sound data 631 are determined so that the inverse wavelet transformed reference sound becomes a composite sound of pure tones of multiple frequencies extracted at predetermined frequency intervals from within the predetermined frequency band to be removed. Therefore, the noise element sound data 631 and the inverse wavelet transform unit 632 function as a sound source device that outputs the above-mentioned synthesized sound of pure tones. Here, while the wavelet transform can obtain information in the frequency domain and information in the time domain, the wavelet transform coefficients stored in the noise element sound data 631 in this third embodiment do not represent temporal fluctuations, and therefore the magnitude of the pure tone components of each frequency contained in the reference sound does not change over time.

[0029] Furthermore, the wavelet transform coefficients stored in the noise element sound data 631 are equivalent to T(a, b) calculated by the following equation 3, for example, where f(t) is the synthetic sound. where a is the scale parameter, b is the shift parameter, and Ψ a、b is a wavelet with scale a and shift b, and * denotes the complex conjugate. In addition, the reference sound is a sound f(t) obtained by performing an inverse wavelet transform on the wavelet transform coefficients T(a, b) stored in the noise element sound data 631 using, for example, the formula 4. Ψ is a constant determined for the type of mother wavelet.

[0030]

number

[0031] According to the third embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the first embodiment can be performed using wavelet transform instead of Fourier transform, and similarly to the first embodiment, an audio signal in which only the level of the noise component is roughly reduced from the audio signal S can be generated as an output signal S' and output from the speaker 24.

[0032] Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the third embodiment is performed in the wavelet transform coefficient domain, and only the configuration of the audio signal processing device 23 is different. FIG. 7 shows a configuration of an audio signal processing device 23 according to the fourth embodiment. As shown in the figure, the audio signal processing device 23 according to the second embodiment includes noise element sound data 731, a wavelet transform coefficient domain adaptive filter 732, a wavelet transform section 733, a subtractor 734, and an inverse wavelet transform section 735. The noise element sound data 731 stores the same wavelet transform coefficients as those of the noise element sound data 631 of the third embodiment. The wavelet transform section 733 performs wavelet transform on the audio signal S input from the remote control device 25 , and outputs to the subtractor 734 a wavelet transform coefficient that represents the audio signal S as information in the frequency domain. For each wavelet, the subtractor 734 subtracts the wavelet transform coefficient output by the wavelet transform coefficient domain adaptive filter 732 from the wavelet transform coefficient input from the wavelet transform unit 733 , and outputs the result to the wavelet transform coefficient domain adaptive filter 732 and the inverse wavelet transform unit 735 .

[0033] The inverse wavelet transform unit 735 performs an inverse wavelet transform on the wavelet transform coefficients output by the subtractor 734 and outputs the result to the speaker 24 as an output signal S′. The wavelet transform coefficient domain adaptive filter 732 performs filtering on the wavelet transform coefficients stored in the noise element sound data 731 and outputs the result to a subtractor 734 . The wavelet transform coefficient domain adaptive filter 732 uses the wavelet transform coefficients output by the subtractor 734 as errors and adapts the filter coefficients of the filtering process applied to the wavelet transform coefficients stored in the noise element sound data 731 by an adaptive algorithm such as LMS or NLMS so as to minimize the error.

[0034] According to the fourth embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the third embodiment can be performed in the wavelet transform coefficient domain, and, similar to the third embodiment, an audio signal in which only the level of the noise component has been reduced from the audio signal S can be generated as an output signal S' and output from the speaker 24.

[0035] Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the first embodiment is performed without using Fourier transform, and only the configuration of the audio signal processing device 23 is different. FIG. 8 shows a configuration of an audio signal processing device 23 according to the fifth embodiment. As shown in the figure, the audio signal processing device 23 includes a sound source device 831 that sets audio data for the above-mentioned synthetic sound of pure tones, which is a synthetic sound of pure tones of a plurality of frequencies extracted at predetermined frequency intervals from within the frequency band to be removed, an adaptive filter 832, and a subtractor 733 that subtracts the output of the adaptive filter 832 from the audio signal S input from the remote control device 25 and outputs the result as an output signal S' to the speaker 24.

[0036] The sound source device 831 reproduces the set audio data and outputs it to the adaptive filter 832 as a reference sound. The adaptive filter 832 performs filtering on the input reference sound and outputs the result to the subtractor 833. Furthermore, the adaptive filter 832 uses the output signal S' output by the subtractor 833 as an error, and adapts the filter coefficients of the filtering performed on the reference sound using an adaptive algorithm such as LMS or NLMS so as to minimize the error.

[0037] According to the fifth embodiment, signal processing equivalent to the operation of the audio signal processing device 23 of the first embodiment can be performed without using a Fourier transform, and similarly to the third embodiment, an audio signal in which only the level of the noise component is reduced from the audio signal S can be generated as an output signal S' and output from the speaker 24.

[0038] The embodiment of the present invention has been described above. As described above, according to each embodiment, unknown noise components contained in an audio signal S can be suppressed and output as an output signal S' using a simple configuration that does not require multiple microphones. While the above embodiments have been described with reference to an application to a remote control system, they can be used in any system to reduce the level of noise components in a mixture of a target sound picked up by the microphone 14 and noise. For example, by applying each of the above embodiments to an online conference system, it becomes possible to reduce the noise level of received sounds from participants participating in an online conference using mobile terminals from inside a vehicle and output the sounds to the speakers 24 of the terminals of other participants, without relying on the noise cancellation function of the mobile terminal. [Explanation of symbols]

[0039] 1...vehicle system, 2...remote control room system, 3...network, 11...actuator, 12...camera, 13...sensor, 14...microphone, 15...control device, 21...controller, 22...monitor, 23...audio signal processing device, 24...speaker, 25...remote control device, 231...noise element sound data, 232...IFFT, 233...adaptive filter, 234...subtractor, 531...noise element sound data, 532...frequency domain Adaptive filter, 533...FFT, 534...subtractor, 535...IFFT, 631...noise element sound data, 632...inverse wavelet transform unit, 633...adaptive filter, 634...subtractor, 731...noise element sound data, 732...wavelet transform coefficient domain adaptive filter, 733...wavelet transform unit, 734...subtractor, 735...inverse wavelet transform unit, 831...sound source device, 832...adaptive filter, 833...subtractor.

Claims

1. 1. An audio signal processing device that suppresses a noise component of an input signal including a target sound component and a noise component and outputs the result as an output signal, A synthetic sound output means for outputting a synthetic sound signal; an adaptive filter to which the synthetic sound signal output by the synthetic sound output means is input; a subtraction means for subtracting an output signal of the adaptive filter from the input sound signal and outputting the result as the output sound signal, the adaptive filter performs an adaptive operation using the output sound signal output by the subtraction means as an error; The audio signal processing device is characterized in that the synthetic sound output means outputs, as the synthetic sound signal, a signal of a synthetic sound of pure tones of a plurality of frequencies extracted from a removal target frequency band, which is a frequency band of noise components to be suppressed in the audio signal processing device.

2. 2. The audio signal processing apparatus according to claim 1, The audio signal processing apparatus according to claim 1, wherein the synthetic sound output means outputs, as the synthetic sound signal, a signal of a synthetic sound of pure tones of a plurality of frequencies extracted at regular frequency intervals from within the target frequency band for elimination.

3. 2. The audio signal processing apparatus according to claim 1, The synthetic sound output means includes information storage means for storing information on the frequency domain of the synthetic sound signal to be output; a conversion means for converting the information stored in said information storage means into said synthetic sound signal,

4. 4. The audio signal processing apparatus according to claim 3, the frequency domain information of the synthetic sound signal is a Fourier coefficient; 2. The audio signal processing apparatus according to claim 1, wherein said conversion means converts said synthetic sound signal into said synthetic sound signal by inverse fast Fourier transform.

5. 4. The audio signal processing apparatus according to claim 3, the frequency domain information of the synthetic sound signal is a wavelet transform coefficient; 2. The audio signal processing apparatus according to claim 1, wherein said transforming means performs transformation into said synthetic sound signal by inverse wavelet transform.

6. 1. An audio signal processing device that suppresses a noise component of an input signal including a target sound component and a noise component and outputs the result as an output signal, a first conversion means for converting the input sound signal into first information which is information in a frequency domain of the input sound signal; an information storage means for storing, as a synthetic sound signal, a signal of a synthetic sound of pure tones of a plurality of frequencies extracted from a removal target frequency band, which is a frequency band of a noise component to be suppressed in the audio signal processing device, and storing, as second information, information of a frequency domain of the synthetic sound signal; an adaptive filter that receives the second information stored in the information storage means and outputs third information that is information in the frequency domain of the noise cancellation sound; a subtraction means for outputting frequency domain information obtained by subtracting the third information from the first information as fourth information; a second conversion means for converting the fourth information into a sound signal and outputting the sound signal as the output sound signal; The audio signal processing apparatus according to claim 1, wherein the adaptive filter performs an adaptive operation using the fourth information as an error.

7. 7. An audio signal processing apparatus according to claim 6, 13. An audio signal processing apparatus, comprising: a signal representing a synthetic sound of pure tones of a plurality of frequencies extracted at regular frequency intervals from within the target frequency band for elimination;

8. 7. An audio signal processing apparatus according to claim 6, the frequency domain information being Fourier coefficients; The first conversion means converts an input sound signal into the first information by performing a fast Fourier transform; 2. The audio signal processing apparatus according to claim 1, wherein the second conversion means converts the fourth information into the output sound signal by performing an inverse fast Fourier transform.

9. 7. An audio signal processing apparatus according to claim 6, the frequency domain information being wavelet transform coefficients; The first conversion means converts an input sound signal into the first information by performing a wavelet transform; The audio signal processing apparatus according to claim 1, wherein the second transforming means performs an inverse wavelet transform to transform the fourth information into the output sound signal.

10. A remote control system comprising the audio signal processing device according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, A vehicle-side system installed in a vehicle; a control side system that remotely controls the vehicle, The vehicle-side system includes: a microphone that picks up a mixture of the target sound and the noise and outputs it as a monitoring sound signal; a transmitting means for transmitting a monitoring sound signal outputted from the microphone to the control side system, the control-side system includes a receiving means for receiving the monitoring sound signal from the vehicle-side system; A speaker and The audio signal processing device includes: A remote control system characterized in that the monitoring sound signal received by the receiving means is input to the audio signal processing device as the input sound signal, and the output sound signal is output from the audio signal processing device to the speaker.

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