WO2022017424A1 - Procédé et appareil de commande de bruit active, et dispositif de lecture audio - Google Patents

Procédé et appareil de commande de bruit active, et dispositif de lecture audio Download PDF

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Publication number
WO2022017424A1
WO2022017424A1 PCT/CN2021/107685 CN2021107685W WO2022017424A1 WO 2022017424 A1 WO2022017424 A1 WO 2022017424A1 CN 2021107685 W CN2021107685 W CN 2021107685W WO 2022017424 A1 WO2022017424 A1 WO 2022017424A1
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Prior art keywords
signal
target
output signal
noise reduction
error
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PCT/CN2021/107685
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English (en)
Chinese (zh)
Inventor
张立斌
袁庭球
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华为技术有限公司
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Publication of WO2022017424A1 publication Critical patent/WO2022017424A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones
    • H04R1/1083—Reduction of ambient noise
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
    • G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
    • G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
    • G10L21/0208—Noise filtering
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones

Definitions

  • the present application relates to the field of active noise reduction technology, in particular to the active noise reduction technology for earphones. And more particularly, it relates to an active noise reduction method and device and an audio playback device in the field of active noise reduction technology.
  • Active noise control is a noise reduction technology and one of the methods used in earphone noise reduction.
  • the active noise reduction function refers to the generation of reverse sound waves equal to the external noise through the noise reduction system to neutralize the noise, thereby achieving the effect of noise reduction.
  • the basic principle of active noise reduction is to calculate the reverse phase sound wave of the reference signal at the fastest speed based on the reference signal collected by the reference microphone set outside the headset and/or the error signal collected by the error microphone set inside the headset. , and then control the speaker to play the reverse sound wave to achieve the effect of active noise reduction. Therefore, it is calculated that the lower the time delay of the anti-phase sound wave is, the better the effect of active noise reduction is, otherwise it is easy to have an adverse effect.
  • the time required to calculate the inverse sound waves is also different.
  • the higher the audio frequency the shorter the time required to calculate the reverse sound wave, even in the sub-millisecond level. Therefore, the existing active noise reduction system has poor noise reduction effect on high frequency noise.
  • the active noise reduction method and device and the audio playback device provided by the embodiments of the present application can improve the noise reduction effect on high frequency noise.
  • inventions of the present application provide a composite active noise reduction system.
  • the system can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system may include a reference sensor (eg, a reference microphone), an error sensor (eg, an error microphone), a speaker, and an active noise reduction device, wherein the active noise reduction device includes a first pre-emphasis module, a second pre-emphasis module, a control module, and De-emphasis module.
  • the reference sensor is connected to the first input terminal of the control module through the first pre-emphasis module
  • the error sensor is connected to the second input terminal of the control module through the second pre-emphasis module
  • the speaker is connected to the control module through the de-emphasis module.
  • the output of the control module is connected.
  • the reference sensor is used to collect ambient noise outside the earphone to obtain a first reference signal x(n); and send the first reference signal x(n) to the first pre-emphasis module.
  • the first pre-emphasis module is configured to receive the first reference signal x(n) from the reference sensor; perform pre-emphasis processing on the first reference signal x(n) to obtain the target reference signal x 1 (n);
  • the first input terminal of the control module sends the target reference signal x 1 (n).
  • the frequency energy of the high frequency part of the pre-emphasized signal is higher than the frequency energy of the high frequency part of the original signal, that is to say, the resolution of the high frequency part of the pre-emphasized signal higher than the resolution of the high frequency portion of the original signal. Therefore, the high-frequency resolution of the signal processed by the control module can be improved, thereby improving the noise reduction effect of high-frequency noise.
  • the high frequency part can be understood as the first frequency band whose starting frequency is greater than or equal to the preset frequency threshold, and correspondingly, the low frequency part can be understood as the first frequency band whose cutoff frequency is less than the frequency threshold. two frequency bands.
  • the first frequency threshold may be 4000 Hz
  • the part of the signal whose frequency is greater than or equal to 4000 Hz is called the high frequency part
  • the part whose frequency is less than 4000 Hz is called the low frequency part.
  • the function implemented by the first pre-emphasis module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the first pre-emphasis module may include a first pre-emphasis circuit, and the first pre-emphasis circuit is configured to implement the function of the first pre-emphasis module.
  • the error sensor is used to collect residual noise inside the earphone to obtain a first error signal e(n); and send the first error signal e(n) to the second pre-emphasis module.
  • the second pre-emphasis module is configured to receive the first error signal e(n) from the error sensor; perform pre-emphasis processing on the first error signal e(n) to obtain the target error signal e 1 (n); A second input of the control module sends the target error signal e 1 (n).
  • the control module is configured to receive the target reference signal x 1 (n) from the first pre-emphasis module and the target error signal e 1 (n) from the second pre-emphasis module; according to the target error signal e 1 ( n), perform adaptive filtering processing on the target reference signal x 1 (n) to obtain a first output signal y(n); send the first output signal y(n) to the de-emphasis module.
  • control module may include an adaptive filter.
  • the adaptive filter means in accordance with changes in the environment, adaptive filter parameters and algorithms to alter the structure of the filter.
  • the structure of the adaptive filter is not changed.
  • the coefficients of the adaptive filter is updated by an adaptive algorithm for time varying coefficients. That is, its coefficients are automatically and continuously adapted to a given signal to obtain the desired response.
  • the most important feature of an adaptive filter is that it can work effectively in an unknown environment and can track the time-varying characteristics of the input signal.
  • control module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • control module may include a control circuit, and the control circuit is used to implement the function of the control module.
  • the adaptive filter may adopt a variety of adaptive filtering algorithms, which is not limited in this embodiment of the present application.
  • the adaptive filter may use a minimum mean square error algorithm.
  • the de-emphasis module is used to receive the first output signal y(n) from the control module; perform de-emphasis processing on the first output signal y(n) to obtain the target output signal y 1 (n); send it to the speaker The target output signal y 1 (n).
  • the function implemented by the de-emphasis module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the de-emphasis module may include a de-emphasis circuit, and the de-emphasis circuit is used to implement the function of the de-emphasis module.
  • the speaker is used for receiving the target output signal y 1 (n) from the de-emphasis module; playing the target output signal y 1 (n).
  • the resolution of the first reference signal and the high frequency part of the first error signal is improved by the pre-emphasis module, and then input to the control module for adaptive filtering, and the control module is restored by the de-emphasis module Output the resolution of the high frequency part of the first output signal, and control the speaker to play. That is to say, in the active noise reduction system provided by the embodiments of the present application, the pre-emphasis module and the de-emphasis module improve the high-frequency resolution of the signal processed by the control module, thereby improving the noise reduction effect on high-frequency noise.
  • the embodiments of the present application further provide a feedforward active noise reduction system.
  • the system can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system may include a reference sensor (eg, a reference microphone), a speaker, and an active noise reduction device, wherein the active noise reduction device includes a first pre-emphasis module control module and a de-emphasis module.
  • the reference sensor is connected to the first input end of the control module through the first pre-emphasis module, and the speaker is connected to the output end of the control module through the de-emphasis module.
  • the reference sensor is used to collect ambient noise outside the earphone to obtain a first reference signal x(n); and send the first reference signal x(n) to the first pre-emphasis module.
  • the first pre-emphasis module is configured to receive the first reference signal x(n) from the reference sensor; perform pre-emphasis processing on the first reference signal x(n) to obtain the target reference signal x 1 (n);
  • the first input terminal of the control module sends the target reference signal x 1 (n).
  • the control module is configured to receive the target reference signal x 1 (n) from the first pre-emphasis module; perform adaptive filtering processing on the target reference signal x 1 (n) to obtain a first output signal y(n); The first output signal y(n) is sent to the de-emphasis module.
  • the de-emphasis module is used to receive the first output signal y(n) from the control module; perform de-emphasis processing on the first output signal y(n) to obtain the target output signal y 1 (n); send it to the speaker The target output signal y 1 (n).
  • the speaker is used for receiving the target output signal y 1 (n) from the de-emphasis module; playing the target output signal y 1 (n).
  • the embodiments of the present application further provide a feedback active noise reduction system.
  • the system can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system may include an error sensor (eg, an error microphone), a speaker, and an active noise reduction device, wherein the active noise reduction device includes a second pre-emphasis module, a control module, and a de-emphasis module.
  • the error sensor is connected to the second input end of the control module through the second pre-emphasis module, and the speaker is connected to the output end of the control module through the de-emphasis module.
  • the error sensor is used to collect residual noise inside the earphone to obtain a first error signal e(n); and send the first error signal e(n) to the second pre-emphasis module.
  • the second pre-emphasis module is configured to receive the first error signal e(n) from the error sensor; perform pre-emphasis processing on the first error signal e(n) to obtain the target error signal e 1 (n); A second input of the control module sends the target error signal e 1 (n).
  • the control module is configured to receive the target error signal e 1 (n) from the second pre-emphasis module; perform adaptive filtering processing according to the target error signal e 1 (n) to obtain a first output signal y(n); The first output signal y(n) is sent to the de-emphasis module.
  • the de-emphasis module is used to receive the first output signal y(n) from the control module; perform de-emphasis processing on the first output signal y(n) to obtain the target output signal y 1 (n); send it to the speaker The target output signal y 1 (n).
  • the speaker is used for receiving the target output signal y 1 (n) from the de-emphasis module; playing the target output signal y 1 (n).
  • inventions of the present application provide a composite active noise reduction system.
  • the system can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system may include a reference sensor (eg, a reference microphone), an error sensor (eg, an error microphone), a speaker, and an active noise reduction device, wherein the active noise reduction device includes a first low-pass filtering module, a second low-pass filtering module, a control modules and bandwidth extension modules.
  • the reference sensor is connected to the first input end of the control module through the first low-pass filter module, the error sensor is connected to the second input end of the control module through the second low-pass filter module, and the speaker is connected to the second input end of the control module through the second low-pass filter module.
  • the output terminals of the control module are connected.
  • the reference sensor is used for collecting ambient noise outside the earphone to obtain a first reference signal x(n); and sending the first reference signal x(n) to the first low-pass filtering module.
  • the first low-pass filtering module is configured to receive a first reference signal x(n) from the reference sensor; perform low-pass filtering processing on the first reference signal x(n) to obtain a target reference signal x 1 (n);
  • the target reference signal x 1 (n) is sent to the first input of the control module.
  • the low-pass filtering signal has filtered out the high-frequency part in the original signal, and only contains the low-frequency part with higher stability. Therefore, the high-frequency stability and robustness of the signal processed by the control module can be improved, thereby improving the noise reduction effect of high-frequency noise.
  • the high frequency part can be understood as the first frequency band whose starting frequency is greater than or equal to the preset frequency threshold, and correspondingly, the low frequency part can be understood as the first frequency band whose cutoff frequency is less than the frequency threshold. two frequency bands.
  • the first frequency threshold may be 4000 Hz
  • the part of the signal whose frequency is greater than or equal to 4000 Hz is called the high frequency part
  • the part whose frequency is less than 4000 Hz is called the low frequency part.
  • the first low-pass filtering module is specifically configured to downsample the first reference signal x(n) to obtain the target reference signal x 1 (n).
  • the first low-pass filtering module is specifically used to extract an audio sampling point for every four audio sampling points to obtain the down-sampled x 1 (n), whose frequency width is is 1kHz bandwidth.
  • the function implemented by the first low-pass filtering module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the first low-pass filtering module may include a first low-pass filtering circuit, and the first low-pass filtering circuit is configured to implement the function of the first low-pass filtering module.
  • the error sensor is used for collecting residual noise inside the earphone to obtain a first error signal e(n); and sending the first error signal e(n) to the second low-pass filtering module.
  • the second low-pass filtering module is configured to receive the first error signal e(n) from the error sensor; perform low-pass filtering processing on the first error signal e(n) to obtain the target error signal e 1 (n); The target error signal e 1 (n) is sent to a second input of the control module.
  • the function implemented by the second low-pass filtering module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the second low-pass filtering module may include a second low-pass filtering circuit, and the second low-pass filtering circuit is configured to implement the function of the second low-pass filtering module.
  • the control module is configured to receive the target reference signal x 1 (n) from the first low-pass filtering module and the target error signal e 1 (n) from the second low-pass filtering module; according to the target error signal e 1 (n), perform adaptive filtering processing on the target reference signal x 1 (n) to obtain a first output signal y(n); send the first output signal y(n) to the target reference signal y(n).
  • control module may include an adaptive filter.
  • the adaptive filter means in accordance with changes in the environment, adaptive filter parameters and algorithms to alter the structure of the filter.
  • the structure of the adaptive filter is not changed.
  • the coefficients of the adaptive filter is updated by an adaptive algorithm for time varying coefficients. That is, its coefficients are automatically and continuously adapted to a given signal to obtain the desired response.
  • the most important feature of an adaptive filter is that it can work effectively in an unknown environment and can track the time-varying characteristics of the input signal.
  • control module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • control module may include a control circuit, and the control circuit is used to implement the function of the control module.
  • the adaptive filter may adopt a variety of adaptive filtering algorithms, which is not limited in this embodiment of the present application.
  • the adaptive filter may use a minimum mean square error algorithm.
  • the bandwidth expansion module is used for receiving the first output signal y(n) from the control module; performing bandwidth expansion processing on the first output signal y(n) to obtain the target output signal y 1 (n); sending it to the speaker The target output signal y 1 (n).
  • the bandwidth expansion module may perform bandwidth expansion processing on the first output signal in various manners to obtain the target output signal, which is not limited in this embodiment of the present application.
  • the bandwidth expansion module may perform bandwidth expansion processing on the first output signal through a blind high-frequency reconstruction method to obtain the target output signal.
  • the blind high-frequency reconstruction method may include: linear extrapolation (LE), efficient high-frequency bandwidth extension (EHBE), hybrid signal extrapolation (HSE) and nonlinear prediction.
  • L linear extrapolation
  • EHBE efficient high-frequency bandwidth extension
  • HSE hybrid signal extrapolation
  • the linear extrapolation method means that the logarithmic amplitude spectral envelope of the audio signal is in an approximately linearly decreasing relationship to perform high-frequency reconstruction, wherein the high-frequency reconstruction includes the frequency domain envelope of the high-frequency part and the spectral details of the high-frequency part. two parts. Among them, the high spectral envelope can be obtained by the linear relationship of the amplitude spectrum, and the high spectral details can be obtained by replicating the harmonic structure of the low frequency band.
  • the bandwidth expansion module is specifically used to perform time-frequency transformation on the low-frequency signal y(n) to obtain its spectral envelope; use the linear least squares method to fit the envelope into a logarithmic domain straight line to obtain the best slope and intercept of the straight line; copy the spectral information of the low-frequency part to obtain the spectral details of the high-frequency part; use the slope of the fitted straight line to perform envelope attenuation on the high-frequency spectral details to complete the reconstruction of the high-frequency part , so as to obtain a complete signal y 1 (n) including high frequency part and low frequency part.
  • the function implemented by the bandwidth expansion module may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the bandwidth extension module may include a bandwidth extension circuit, and the bandwidth extension circuit is configured to implement the function of the bandwidth extension module.
  • the speaker is used for receiving the target output signal y 1 (n) from the bandwidth expansion module; playing the target output signal y 1 (n).
  • the first low-pass filtering module filters out the high-frequency part with poor stability in the first reference signal and/or the second low-pass filtering module filters out the first error signal.
  • the control module for adaptive filtering, and the first reference signal output by the control module is reconstructed through the bandwidth expansion module.
  • a high-frequency part of an output signal obtain a target output signal with a complete bandwidth (including both high-frequency part and low-frequency part), and control the speaker to play. That is, the stability and robustness of the high-frequency part of the signal processed by the control module are improved through the low-pass filtering module and the bandwidth expansion module, thereby improving the noise reduction effect of high-frequency noise.
  • the embodiments of the present application further provide a feedforward active noise reduction system.
  • the system can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system may include a reference sensor (eg, a reference microphone), a speaker, and an active noise reduction device, wherein the active noise reduction device includes a first low-pass filtering module, a control module, and a bandwidth expansion module.
  • the reference sensor is connected to the first input end of the control module through the first low-pass filter module, and the speaker is connected to the output end of the control module through this.
  • the reference sensor is used for collecting ambient noise outside the earphone to obtain a first reference signal x(n); and sending the first reference signal x(n) to the first low-pass filtering module.
  • the first low-pass filtering module is configured to receive a first reference signal x(n) from the reference sensor; perform low-pass filtering processing on the first reference signal x(n) to obtain a target reference signal x 1 (n);
  • the target reference signal x 1 (n) is sent to the first input of the control module.
  • the control module is configured to receive the target reference signal x 1 (n) from the first low-pass filtering module; perform adaptive filtering processing on the target reference signal x 1 (n) to obtain a first output signal y(n) ; send the first output signal y(n) to this.
  • the bandwidth expansion module is used for receiving the first output signal y(n) from the control module; performing bandwidth expansion processing on the first output signal y(n) to obtain the target output signal y 1 (n); sending it to the speaker The target output signal y 1 (n).
  • the speaker is used for receiving the target output signal y 1 (n) from the bandwidth expansion module; playing the target output signal y 1 (n).
  • an embodiment of the present application provides a feedback active noise reduction system.
  • the system can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system may include an error sensor (eg, an error microphone), a speaker, and an active noise reduction device, wherein the active noise reduction device includes a second low-pass filter module, a control module, and a bandwidth expansion module.
  • the error sensor is connected to the second input end of the control module through the second low-pass filter module, and the speaker is connected to the output end of the control module through the second low-pass filter module.
  • the error sensor is used for collecting residual noise inside the earphone to obtain a first error signal e(n); and sending the first error signal e(n) to the second low-pass filtering module.
  • the second low-pass filtering module is configured to receive the first error signal e(n) from the error sensor; perform low-pass filtering processing on the first error signal e(n) to obtain the target error signal e 1 (n); The target error signal e 1 (n) is sent to a second input of the control module.
  • the control module is configured to receive the target error signal e 1 (n) from the second low-pass filtering module; perform adaptive filtering processing according to the target error signal e 1 (n) to obtain a first output signal y(n) ; send the first output signal y(n) to this.
  • the bandwidth expansion module is used for receiving the first output signal y(n) from the control module; performing bandwidth expansion processing on the first output signal y(n) to obtain the target output signal y 1 (n); sending it to the speaker The target output signal y 1 (n).
  • the speaker is used for receiving the target output signal y 1 (n) from the bandwidth expansion module; playing the target output signal y 1 (n).
  • the embodiments of the present application further provide an active noise reduction method, and the method may include the methods performed by the active noise reduction apparatus in the above aspects or various possible implementation manners thereof.
  • an embodiment of the present application further provides an active noise reduction device, the device includes: a memory, at least one processor, a transceiver, and instructions stored on the memory and executable on the processor. Further, the memory, the processor and the communication interface communicate with each other through an internal connection path. Execution of the instructions by the at least one processor causes the apparatus to implement the method performed by the active noise reduction apparatus in the aspects or any possible implementations thereof.
  • the present application further provides a computer-readable storage medium for storing a computer program, the computer program including a method for implementing the above-mentioned first aspect or any possible implementation manners thereof and executed by an active noise reduction apparatus.
  • the present application also provides a computer program product comprising instructions, which, when run on a computer, enable the computer to implement the method performed by the active noise reduction device in each of the above aspects or any possible implementations thereof.
  • the present application further provides a chip device, including: an input interface, an output interface, and at least one processor.
  • the chip device further includes a memory.
  • the at least one processor is configured to execute the code in the memory, and when the at least one processor executes the code, the chip device implements the method performed by the active noise reduction apparatus in the above-mentioned various aspects or any possible implementation manners thereof.
  • FIG. 1 is a schematic diagram of an active noise reduction principle provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a scene of a feedforward active noise reduction system provided by an embodiment of the present application
  • FIG. 3 is a schematic diagram of the principle of a feedforward active noise reduction system provided by an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a scene of a feedback active noise reduction system provided by an embodiment of the present application.
  • FIG. 5 is a schematic diagram of the principle of a feedback active noise reduction system provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a scene of a composite active noise reduction system provided by an embodiment of the present application.
  • FIG. 7 is a schematic diagram of the principle of a composite active noise reduction system provided by an embodiment of the present application.
  • FIG. 8 is a schematic diagram of an application scenario provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of another application scenario provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of another application scenario provided by an embodiment of the present application.
  • FIG. 11 is a schematic diagram of another application scenario provided by an embodiment of the present application.
  • FIG. 12 is a schematic diagram of another application scenario provided by an embodiment of the present application.
  • FIG. 13 is a schematic diagram of another application scenario provided by an embodiment of the present application.
  • FIG. 14 is a schematic block diagram of an active noise reduction system 500 provided by an embodiment of the present application.
  • 15 is a schematic diagram of a spectrum of pre-emphasis processing provided by an embodiment of the present application.
  • FIG. 16 is a schematic block diagram of another active noise reduction system 500 provided by an embodiment of the present application.
  • FIG. 17 is a schematic block diagram of another active noise reduction system 500 provided by an embodiment of the present application.
  • FIG. 18 is a schematic block diagram of an active noise reduction system 600 provided by an embodiment of the present application.
  • 19 is a schematic diagram of a spectrum of low-pass filtering processing provided by an embodiment of the present application.
  • FIG. 20 is a schematic block diagram of another active noise reduction system 600 provided by an embodiment of the present application.
  • FIG. 21 is a schematic block diagram of another active noise reduction system 600 provided by an embodiment of the present application.
  • FIG. 22 is a schematic flowchart of an active noise reduction method 700 provided by an embodiment of the present application.
  • FIG. 23 is a schematic flowchart of another active noise reduction method 800 provided by an embodiment of the present application.
  • FIG. 24 is a schematic block diagram of an active noise reduction apparatus 900 provided by an embodiment of the present application.
  • FIG. 25 is a schematic block diagram of an active noise reduction apparatus 1000 provided by an embodiment of the present application.
  • FIG. 26 is a schematic block diagram of a chip 1100 provided by an embodiment of the present application.
  • Active noise reduction is a noise control technique that attenuates initial noise by referencing sound waves from a secondary sound source that have the same amplitude and opposite phase as the primary sound source, and the output of the secondary sound source is used to interfere with the primary sound source. (noise source), as shown in Figure 1.
  • control circuit classification it can include: analog and digital.
  • control structure classification it can include: feed forward, feedback and compound.
  • the feedforward active noise cancellation system may include a reference sensor (such as a reference microphone) deployed outside the earphone, a controller deployed inside the earphone, and speaker.
  • a reference sensor such as a reference microphone
  • controller deployed inside the earphone
  • speaker The connection relationship among the controller, the reference sensor and the speaker is shown in FIG. 3 .
  • the reference sensor is used to collect ambient noise outside the earphone (such as the primary noise or noise source in Figure 1), to obtain a reference signal x(n), and input the x(n) to the controller, and the controller is used for the x(n) (n) Invert the phase to obtain the output signal y(n) (the secondary noise in Figure 1), the output signal y(n) is opposite to the phase of the noise source, and the speaker is used to play the output signal y(n) ) to achieve noise reduction of the noise source.
  • the outside of the earphone described in the embodiments of the present application can be understood as the side of the earphone that is far away from the human ear, and the inside of the earphone can be understood as the side of the earphone that is close to the human ear.
  • the feedback active noise cancellation system may include an error sensor (eg, an error microphone), a controller, and a speaker deployed inside the headset.
  • an error sensor eg, an error microphone
  • controller e.g., a controller
  • speaker deployed inside the headset.
  • FIG. 5 The connection relationship among the controller, the error sensor and the speaker is shown in FIG. 5 .
  • the error sensor is used to collect the residual noise inside the earphone (such as the residual noise in Figure 1) to obtain the error signal e(n), and the e(n) is input to the controller, and the controller is used for according to the e(n) Perform adaptive filtering to obtain an output signal y(n) (secondary noise in Figure 1), the output signal y(n) is opposite to the phase of the noise source, and the speaker is used to play the output signal y(n), It is a closed-loop process to minimize e(n) obtained after y(n) is superimposed with the noise source.
  • the feedback active noise reduction system may include a reference sensor (such as a reference microphone) deployed outside the earphone, an error sensor (such as a reference microphone) deployed inside the earphone such as error microphones), controllers and speakers.
  • a reference sensor such as a reference microphone
  • an error sensor such as a reference microphone deployed inside the earphone such as error microphones
  • controllers and speakers.
  • the connection relationship among the controller, the reference sensor, the error sensor and the speaker is shown in FIG. 7 .
  • the reference sensor is used to collect the ambient noise outside the earphone (such as the primary noise or noise source in Figure 1), and the obtained reference signal x(n) is input to the controller, and the error microphone collects the inside of the earphone.
  • the residual noise (residual noise in Figure 1) is obtained, the error signal e(n) is obtained, the e(n) is input to the controller, the controller according to the e(n), the x(n) is automatically Adaptive filtering to obtain an output signal y(n) (secondary noise in Figure 1), the output signal y(n) is opposite to the phase of the noise source, and the output signal y(n) is played through the speaker so that y(n ) and the noise source are superimposed to obtain the smallest e(n).
  • the active noise reduction method provided by the embodiment of the present application can be applied to an audio playback device.
  • the audio playback device described in this embodiment of the present application refers to an audio playback device worn on or near the ear by the user, which may include earphones, wearable smart devices, and the like, which are not limited in this embodiment of the present application.
  • the audio playback device when it is an earphone, it may include an in-ear earphone, a headphone, etc. according to the wearing method; and may include: wired earphones, wireless earphones, such as Bluetooth earphones, etc. according to the connection method.
  • the wearable smart device may include augmented reality (AR)/virtual reality (VR) devices, such as AR/VR helmets, AR/VR VR masks, AR/VR glasses, etc.
  • AR augmented reality
  • VR virtual reality
  • the audio playback device may implement the audio playback function without relying on an intelligent terminal (such as a smart phone), or may need to be used in conjunction with an intelligent terminal (such as a smart phone) to implement the audio playback function, which is not limited in this embodiment of the present application.
  • the active noise reduction system provided in the embodiment of the present application may be applicable to various scenarios that require the noise reduction function of an audio playback device, such as: an active noise reduction scenario of answering a phone call, video call, playing audio or video, etc., This embodiment of the present application does not limit this.
  • the audio playback device as an earphone as an example to introduce the applicable scene of the active noise reduction method provided by the embodiment of the present application, but the embodiment of the present application is not limited thereto.
  • the audio playback device is a wearable device
  • the applicable scene of the active noise reduction method is similar to that of an earphone, and in order to avoid repetition, details are not repeated here.
  • a trigger condition for triggering the active noise reduction instruction may be set on the earphone, and when the user wants to enable the active noise reduction function, the earphone can be operated to trigger the active noise reduction instruction of the earphone.
  • the trigger condition for triggering the active noise reduction instruction may be set in various ways, which is not limited in this embodiment of the present application.
  • a physical button or the like that triggers active noise reduction may be provided on the earphone or the wire control of the earphone.
  • the gesture recognition instruction can be triggered.
  • the in-ear headphone 100 may include a physical button 101 , and the physical button 101 is a noise reduction button.
  • the user can press the physical button 101 with a finger to trigger an active noise reduction instruction and enable the active noise reduction function.
  • the in-ear headphone 100 shown in FIG. 8 may also be the headphone 100 shown in FIG. 9 or the Bluetooth wireless headphone 100 shown in FIG. 10 , which is not limited in this embodiment of the present application.
  • the in-ear wire-controlled headset 200 may include an earphone 210 and a wire-controlled device 220, and the wire-controlled device may include a physical button 221 and a physical button 222, where the physical button 221 is a volume button, and the physical button 222 is for answering /hang up key.
  • the user needs to use the noise reduction function of the headset, press the first side and the second side of the volume key with two fingers at the same time to trigger the active noise reduction command and enable the active noise reduction function.
  • the headset when the headset relies on a terminal connected to it and capable of performing playback control to implement the active noise reduction function, the terminal may be provided with a virtual key for triggering active noise reduction.
  • the active noise reduction instruction can be triggered, and the headset can be controlled to realize the active noise reduction function.
  • the foregoing headset and the terminal may be connected in a wired or wireless manner, which is not limited in this embodiment of the present application.
  • the terminal described in the embodiments of the present application may be able to cooperate with the audio playback device to use a mobile phone, a tablet computer, a wearable device, a vehicle-mounted device, a smart TV, a notebook computer, a super mobile personal computer ( Ultra-mobile personal computer, UMPC), netbook, personal digital assistant (personal digital assistant, PDA) and other devices, the embodiment of the present application does not impose any restrictions on the specific type of the terminal.
  • Ultra-mobile personal computer, UMPC Ultra-mobile personal computer
  • PDA personal digital assistant
  • the setting options of the mobile phone 300 may include an “ANC” option 301.
  • the display will display In the interface shown in (b) of FIG. 12 , the “ON” option 302 is used to enable the ANC function, and the “OFF” option 303 is used to disable the ANC function, then when the user selects the “ON” option 302 , the mobile phone 300 can control the headset connected to it to activate the corresponding active noise reduction function to play audio.
  • the terminal may set the association between certain applications and the active noise reduction command.
  • the active noise cancellation command is automatically triggered, and the headset is controlled to implement the active noise cancellation function.
  • the user can set the association between the audio software and the active noise reduction instruction on the mobile phone.
  • the terminal 400 displays that the default song list of the audio software includes A song 401 and B song 402 .
  • the user clicks the B song 402 starts the audio software to play the B song 402, and the B song 402 automatically triggers the active noise reduction command when the audio software starts, and the mobile phone 400 can control the headset connected to it to start the corresponding active noise reduction function for audio playback.
  • FIG. 14 is a schematic block diagram of an active noise reduction system 500 provided by an embodiment of the present application.
  • the system 500 can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system 500 may include a reference sensor 510 (eg, a reference microphone), an error sensor 520 (eg, an error microphone), a speaker 530 and an active noise reduction device 540 , wherein the active noise reduction device 540 includes a first A pre-emphasis module 541 , a second pre-emphasis module 542 , a control module 543 and a de-emphasis module 544 .
  • the reference sensor 510 is connected to the first input end of the control module 543 through the first pre-emphasis module 541 , the error sensor 520 is connected to the second input end of the control module 543 through the second pre-emphasis module 542 , the speaker 530 is connected to the output end of the control module 543 through the de-emphasis module 544 .
  • the reference sensor 510 the error sensor 520 , the speaker 530 and the active noise reduction device 540 .
  • the reference sensor 510 is used to collect ambient noise outside the earphone to obtain a first reference signal x(n); and send the first reference signal x(n) to the first pre-emphasis module 541 .
  • the first pre-emphasis module 541 is configured to receive the first reference signal x(n) from the reference sensor 510; perform pre-emphasis processing on the first reference signal x(n) to obtain the target reference signal x 1 (n);
  • the target reference signal x 1 (n) is sent to the first input of the control module 543 .
  • FIG. 15 shows a schematic diagram of the spectrum of the pre-emphasis process. It can be seen from FIG. 15 that the frequency point energy of the high-frequency part of the pre-emphasized signal is higher than that of the original signal. Part of the frequency bin energy, that is, the resolution of the high-frequency part of the pre-emphasized signal is higher than the resolution of the high-frequency part of the original signal. Therefore, the high-frequency resolution of the signal processed by the control module 543 can be improved, thereby improving the noise reduction effect of high-frequency noise.
  • the high frequency part described in the embodiments of the present application can be understood as the first frequency band whose starting frequency is greater than or equal to the preset frequency threshold, and correspondingly, the low frequency part can be understood as the cutoff frequency less than the frequency threshold. second frequency band.
  • the first frequency threshold may be 4000 Hz
  • the part of the signal whose frequency is greater than or equal to 4000 Hz is called the high frequency part
  • the part whose frequency is less than 4000 Hz is called the low frequency part.
  • the first pre-emphasis module 541 may perform pre-emphasis processing on the first reference noise reduction signal x(n) according to the following formula 1 to obtain the target reference noise reduction signal x 1 (n).
  • x(n) represents the sampled value at the nth time
  • x(n-1) represents the sampled value at the n-1th time
  • x 1 (n) represents the pre-emphasized sampled value at the nth time
  • a represents The weighting factor is 0.9 ⁇ a ⁇ 1.
  • the function implemented by the first pre-emphasis module 541 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the first pre-emphasis module 541 may include a first pre-emphasis circuit, and the first pre-emphasis circuit is used to implement the function of the first pre-emphasis module 541 .
  • the error sensor 520 is used for collecting residual noise inside the earphone to obtain a first error signal e(n); and sending the first error signal e(n) to the second pre-emphasis module 542 .
  • the second pre-emphasis module 542 is configured to receive the first error signal e(n) from the error sensor 520; perform pre-emphasis processing on the first error signal e(n) to obtain the target error signal e 1 (n); The target error signal e 1 (n) is sent to the second input of the control module 543 .
  • the second pre-emphasis module 542 may perform pre-emphasis processing on the first error noise reduction signal e(n) according to the following formula 2 to obtain the target error noise reduction signal e 1 (n).
  • e(n) represents the sampled value at the nth time
  • e(n-1) represents the sampled value at the n-1th time
  • e 1 (n) represents the pre-emphasized sampled value at the nth time
  • b represents The weighting factor is 0.9 ⁇ b ⁇ 1.
  • the function implemented by the second pre-emphasis module 542 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the second pre-emphasis module 542 may include a second pre-emphasis circuit, and the second pre-emphasis circuit is configured to implement the function of the second pre-emphasis module 542 .
  • the control module 543 is configured to receive the target reference signal x 1 (n) from the first pre-emphasis module 541 and the target error signal e 1 (n) from the second pre-emphasis module 542; according to the target error signal e 1 (n), perform adaptive filtering processing on the target reference signal x 1 (n) to obtain a first output signal y(n); send the first output signal y(n) to the de-emphasis module 544 .
  • control module 543 can perform adaptive filtering processing on the target reference signal x 1 (n) according to the target error signal e 1 (n) through the following formulas 3 to 5, to obtain The first output signal y(n).
  • y 1 (n) represents the de-emphasized sample value at the nth time
  • x 1 (n) represents the pre-emphasis sample value at the nth time
  • e 1 (n) represents the pre-emphasis at the nth time.
  • the sampled value after emphasis, d(n) represents the external noise signal (ie noise source) of the earphone
  • w(n+1) represents the filter coefficient at the n+1th time
  • w(n) represents the filter at the nth time coefficient
  • c represents the convergence factor.
  • control module 543 may include an adaptive filter.
  • the adaptive filter means in accordance with changes in the environment, adaptive filter parameters and algorithms to alter the structure of the filter.
  • the structure of the adaptive filter is not changed.
  • the coefficients of the adaptive filter is updated by an adaptive algorithm for time varying coefficients. That is, its coefficients are automatically and continuously adapted to a given signal to obtain the desired response.
  • the most important feature of an adaptive filter is that it can work effectively in an unknown environment and can track the time-varying characteristics of the input signal.
  • control module 543 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • control module 543 may include a control circuit, and the control circuit is used to implement the function of the control module 543 .
  • the adaptive filter may adopt a variety of adaptive filtering algorithms, which is not limited in this embodiment of the present application.
  • the adaptive filter may use a minimum mean square error algorithm.
  • the de-emphasis module 544 is configured to receive the first output signal y(n) from the control module 543; perform de-emphasis processing on the first output signal y(n) to obtain the target output signal y 1 (n); The speaker sends the target output signal y 1 (n).
  • the de-emphasis module 544 may perform de-emphasis processing on the first output signal y(n) according to the following formula 6 to obtain the target output signal y 1 (n).
  • y(n) represents the sampled value at the nth time
  • y(n-1) represents the sampled value at the n-1th time
  • y 1 (n) represents the de-emphasized sampled value at the nth time
  • d represents the The aggravation factor, and 0.9 ⁇ d ⁇ 1.
  • the function implemented by the de-emphasis module 544 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the de-emphasis module 544 may include a de-emphasis circuit, and the de-emphasis circuit is used to implement the function of the de-emphasis module 544 .
  • the speaker 530 is used for receiving the target output signal y 1 (n) from the de-emphasis module 544; and playing the target output signal y 1 (n).
  • the resolution of the first reference signal and the high-frequency part of the first error signal is improved through the pre-emphasis module, and then input to the control module for adaptive filtering, and the de-emphasis module restores the control module Output the resolution of the high frequency part of the first output signal, and control the speaker to play. That is to say, in the active noise reduction system provided by the embodiments of the present application, the pre-emphasis module and the de-emphasis module improve the high-frequency resolution of the signal processed by the control module, thereby improving the noise reduction effect on high-frequency noise.
  • FIG. 14 only exemplifies the introduction of the active noise reduction system provided by the embodiment of the present application as a composite active noise reduction system, and the active noise reduction system may also be a feedforward type as shown in FIG. 16 .
  • the active noise reduction system, or the feedback active noise reduction system as shown in FIG. 17 is not limited in this embodiment of the present application.
  • the processing process of the active noise reduction system may refer to the composite active noise reduction described in FIG. 14 above.
  • the processing process of the corresponding module in the noise system is not repeated here in order to avoid repetition.
  • FIG. 18 is a schematic block diagram of an active noise reduction system 600 provided by an embodiment of the present application.
  • the system 600 can be applied to audio playback devices, such as headphones, and can be applied to active noise reduction scenarios of audio playback devices.
  • the system 500 may include a reference sensor 610 (eg, a reference microphone), an error sensor 620 (eg, an error microphone), a speaker 630 and an active noise reduction device 640 , wherein the active noise reduction device 640 includes a first A low-pass filtering module 641 , a second low-pass filtering module 642 , a control module 643 and a bandwidth expansion module 644 .
  • the reference sensor 610 is connected to the first input terminal of the control module 643 through the first low-pass filter module 641 , the error sensor 620 is connected to the second input terminal of the control module 643 through the second low-pass filter module 642 ,
  • the speaker 630 is connected to the output end of the control module 643 through the 644 .
  • FIG. 6 For the arrangement positions and connection relationships of the reference sensor 610 , the error sensor 620 , the speaker 630 and the active noise reduction device 640 , reference may be made to FIG. 6 .
  • the reference sensor 610 is used to collect ambient noise outside the earphone to obtain a first reference signal x(n); and send the first reference signal x(n) to the first low-pass filtering module 641 .
  • the first low-pass filtering module 641 is configured to receive the first reference signal x(n) from the reference sensor 610; perform low-pass filtering on the first reference signal x(n) to obtain the target reference signal x 1 (n ); send the target reference signal x 1 (n) to the first input terminal of the control module 643 .
  • FIG. 19 shows a schematic diagram of the frequency spectrum of the low-pass filtering process. It can be seen from FIG. 19 that the low-pass filtering signal has filtered out the high-frequency part in the original signal, and only contains stable The higher frequency low frequency part. Therefore, the high-frequency stability and robustness of the signal processed by the control module 543 can be improved, thereby improving the noise reduction effect of high-frequency noise.
  • the high frequency part described in the embodiments of the present application can be understood as the first frequency band whose starting frequency is greater than or equal to the preset frequency threshold, and correspondingly, the low frequency part can be understood as the cutoff frequency less than the frequency threshold. second frequency band.
  • the first frequency threshold may be 4000 Hz
  • the part of the signal whose frequency is greater than or equal to 4000 Hz is called the high frequency part
  • the part whose frequency is less than 4000 Hz is called the low frequency part.
  • the first low-pass filtering module 641 is specifically configured to downsample the first reference signal x(n) to obtain the target reference signal x 1 (n).
  • the first low-pass filtering module 641 is specifically used to extract an audio sampling point for every four audio sampling points to obtain the down-sampled x 1 (n), whose frequency The width is 1kHz bandwidth.
  • the function implemented by the first low-pass filtering module 641 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the first low-pass filtering module 641 may include a first low-pass filtering circuit, and the first low-pass filtering circuit is used to implement the function of the first low-pass filtering module 641 .
  • the error sensor 620 is used for collecting residual noise inside the earphone to obtain a first error signal e(n); and sending the first error signal e(n) to the second low-pass filtering module 642 .
  • the second low-pass filtering module 642 is configured to receive the first error signal e(n) from the error sensor 620; perform low-pass filtering on the first error signal e(n) to obtain the target error signal e 1 (n ); send the target error signal e 1 (n) to the second input terminal of the control module 643 .
  • the function implemented by the second low-pass filtering module 642 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the second low-pass filtering module 642 may include a second low-pass filtering circuit, and the second low-pass filtering circuit is used to implement the function of the second low-pass filtering module 642 .
  • the control module 643 is configured to receive the target reference signal x 1 (n) from the first low-pass filtering module 641 and the target error signal e 1 (n) from the second low-pass filtering module 642; according to the target The error signal e 1 (n) is subjected to adaptive filtering processing on the target reference signal x 1 (n) to obtain the first output signal y(n); the first output signal y(n) is sent to the 644 .
  • control module 643 may include an adaptive filter.
  • the adaptive filter means in accordance with changes in the environment, adaptive filter parameters and algorithms to alter the structure of the filter.
  • the structure of the adaptive filter is not changed.
  • the coefficients of the adaptive filter is updated by an adaptive algorithm for time varying coefficients. That is, its coefficients are automatically and continuously adapted to a given signal to obtain the desired response.
  • the most important feature of an adaptive filter is that it can work effectively in an unknown environment and can track the time-varying characteristics of the input signal.
  • control module 643 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • control module 643 may include a control circuit, and the control circuit is used to realize the function of the control module 643 .
  • the adaptive filter may adopt a variety of adaptive filtering algorithms, which is not limited in this embodiment of the present application.
  • the adaptive filter may use a minimum mean square error algorithm.
  • the bandwidth expansion module 644 is configured to receive the first output signal y(n) from the control module 643; perform bandwidth expansion processing on the first output signal y(n) to obtain the target output signal y 1 (n); The speaker sends the target output signal y 1 (n).
  • the bandwidth expansion module 644 may perform bandwidth expansion processing on the first output signal in various manners to obtain a target output signal, which is not limited in this embodiment of the present application.
  • the bandwidth expansion module 644 may perform bandwidth expansion processing on the first output signal through a blind high-frequency reconstruction method to obtain the target output signal.
  • the blind high-frequency reconstruction method may include: linear extrapolation (LE), efficient high-frequency bandwidth extension (EHBE), hybrid signal extrapolation (HSE) and nonlinear prediction.
  • L linear extrapolation
  • EHBE efficient high-frequency bandwidth extension
  • HSE hybrid signal extrapolation
  • the linear extrapolation method means that the logarithmic amplitude spectral envelope of the audio signal is in an approximately linearly decreasing relationship to perform high-frequency reconstruction, wherein the high-frequency reconstruction includes the frequency domain envelope of the high-frequency part and the spectral details of the high-frequency part. two parts. Among them, the high spectral envelope can be obtained by the linear relationship of the amplitude spectrum, and the high spectral details can be obtained by replicating the harmonic structure of the low frequency band.
  • the bandwidth expansion module 644 is specifically configured to perform time-frequency transformation on the low-frequency signal y(n) to obtain its spectral envelope; use the linear least squares method to fit the envelope in the logarithmic domain as A straight line is used to obtain the best slope and intercept of the straight line; the spectral information of the low-frequency part is copied to obtain the spectral details of the high-frequency part; the envelope attenuation of the high-frequency spectral details is performed by the slope of the fitted straight line to complete the high-frequency part. Reconstruction to obtain a complete signal y 1 (n) including high frequency part and low frequency part.
  • the function implemented by the bandwidth expansion module 644 may be implemented by hardware or software, which is not limited in this embodiment of the present application.
  • the bandwidth extension module 644 may include a bandwidth extension circuit, and the bandwidth extension circuit is used to implement the function of the bandwidth extension module 644 .
  • the speaker 630 is used for receiving the target output signal y 1 (n) from the bandwidth expansion module 644; and playing the target output signal y 1 (n).
  • the first low-pass filtering module filters out the high-frequency part with poor stability in the first reference signal and/or the second low-pass filtering module filters out the first error signal.
  • the control module for adaptive filtering, and the first reference signal output by the control module is reconstructed through the bandwidth expansion module.
  • a high-frequency part of an output signal obtain a target output signal with a complete bandwidth (including both high-frequency part and low-frequency part), and control the speaker to play. That is, the stability and robustness of the high-frequency part of the signal processed by the control module are improved through the low-pass filtering module and the bandwidth expansion module, thereby improving the noise reduction effect of high-frequency noise.
  • FIG. 18 only exemplifies the introduction of the active noise reduction system provided by the embodiment of the present application as a composite active noise reduction system.
  • the active noise reduction system may also be a feedforward type as shown in FIG. 20 .
  • the active noise reduction system, or the feedback active noise reduction system as shown in FIG. 21 is not limited in this embodiment of the present application.
  • the processing process of the active noise reduction system may refer to the composite active noise reduction described in FIG. 18 above.
  • the processing process of the corresponding module in the noise system is not repeated here in order to avoid repetition.
  • FIG. 22 shows a schematic flowchart of an active noise reduction method 700 provided by an embodiment of the present application.
  • the method 700 can be applied to the composite active noise reduction system 500 as shown in FIG. 14 and executed by the active noise reduction device 540 in the system 500 .
  • the method 700 may include the following S701-S707.
  • S701 Acquire a first reference signal collected by a reference sensor, where the first reference signal is used to represent ambient noise outside the audio playback device.
  • S702 Perform pre-emphasis processing on the first reference signal to obtain a target reference signal.
  • S703 Acquire a first error signal collected by an error sensor, where the first error signal is used to represent residual noise inside the audio playback device.
  • S705 Perform filtering processing on the target reference signal according to the target error signal to obtain a first output signal for noise reduction, where the phase of the first output signal is opposite to that of the target reference signal.
  • the method 700 can also be applied to the feedforward active noise reduction system 500 shown in FIG. 16 , and executed by the active noise reduction device 540 in the system 500 .
  • the method 700 includes the above-mentioned S701-S702 and S705-S707.
  • S705 includes: filtering the target reference signal to obtain the first output signal.
  • the method 700 can also be applied to the feedback active noise reduction system 500 as shown in FIG. 17 and executed by the active noise reduction device 540 in the system 500 .
  • the method 700 includes the above-mentioned S703-S707.
  • S705 includes: performing filtering processing according to the target error signal to obtain the first output signal.
  • FIG. 23 shows a schematic flowchart of an active noise reduction method 800 provided by an embodiment of the present application.
  • the method 800 can be applied to the composite active noise reduction system 600 as shown in FIG. 18 and executed by the active noise reduction device 640 in the system 600 .
  • the method 800 may include the following S801-S807.
  • S801 Acquire a first reference signal collected by a reference sensor, where the first reference signal is used to represent ambient noise outside the audio playback device.
  • S802 Perform low-pass filtering on the first reference signal to obtain a target reference signal.
  • S803 Acquire a first error signal collected by an error sensor, where the first error signal is used to represent residual noise inside the audio playback device.
  • S804 Perform low-pass filtering on the first error signal to obtain a target error signal.
  • the method 800 can also be applied to the feedforward active noise reduction system 600 as shown in FIG. 16 and executed by the active noise reduction device 640 in the system 600 .
  • the method 800 includes the above-mentioned S801-S802 and S805-S807.
  • S805 includes: filtering the target reference signal to obtain the first output signal.
  • the method 800 can also be applied to the feedback active noise reduction system 600 as shown in FIG. 18 and executed by the active noise reduction device 640 in the system 600 .
  • the method 800 includes the above-mentioned S803-S807.
  • S805 includes: performing filtering processing according to the target error signal to obtain the first output signal.
  • the active noise reduction method provided by the embodiments of the present application is described above with reference to FIGS. 22 and 23 , and the active noise reduction device 900 provided by the embodiments of the present application will be described below with reference to FIGS. 24 to 25 .
  • apparatus 900 may be the active noise reduction apparatus described in the foregoing system 500 embodiment and the method 700 embodiment, or may be the active noise reduction apparatus described in the foregoing system 600 embodiment and method 800 embodiment. noise device, which is not limited in this embodiment of the present application.
  • the apparatus 900 includes corresponding hardware and/or software modules for executing each function.
  • the present application can be implemented in hardware or a combination of hardware and computer software in conjunction with the algorithm steps of the examples described in conjunction with the embodiments disclosed herein. Whether a function is performed by hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functionality for each particular application in conjunction with the embodiments, but such implementations should not be considered beyond the scope of this application.
  • the apparatus 900 may be divided into functional modules according to the foregoing method examples.
  • each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.
  • the above-mentioned integrated modules can be implemented in the form of hardware. It should be noted that, the division of modules in this embodiment is schematic, and is only a logical function division, and there may be other division manners in actual implementation.
  • FIG. 24 shows a possible schematic diagram of the composition of the active noise reduction device involved in the above embodiments.
  • the device 900 may include: unit 910 and processing unit 920.
  • processing unit 920 may control the transceiver unit 910 to implement the method described in the foregoing method 700 embodiment or 800, and/or other processes for the techniques described herein.
  • the apparatus 900 provided in this embodiment is used to execute the above-mentioned method 700 and/or the method 800, and thus can achieve the same effect as the above-mentioned implementation method.
  • the apparatus 900 is an active noise reduction apparatus, and correspondingly, the processing unit 910 may include a first pre-emphasis module 541 and/or a second pre-emphasis module 542, a control module 543 and a de-emphasis module 544; Alternatively, the processing unit 310 may have a first low-pass filtering module 641 and/or a second low-pass filtering module 642 , a control module 643 and a bandwidth expansion module 644 .
  • the apparatus 900 may include a processing unit, a storage unit, and a communication unit.
  • the processing unit may be used to control and manage the actions of the apparatus 900, for example, may be used to support the apparatus 900 to perform the steps performed by the above-mentioned units.
  • the storage unit may be used to support the execution of the apparatus 900 to store program codes, data, and the like.
  • the communication unit may be used to support the communication of the apparatus 900 with other devices.
  • the processing unit may be a processor or a controller. It may implement or execute the various exemplary logical blocks, modules and circuits described in connection with this disclosure.
  • the processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, and the like.
  • the storage unit may be a memory.
  • the communication unit may specifically be a device that interacts with other electronic devices, such as a radio frequency circuit, a Bluetooth chip, and a Wi-Fi chip.
  • the apparatus 900 involved in this embodiment may be an active noise reduction apparatus 1000 having the structure shown in FIG. 25
  • the apparatus 1000 includes a processor 1010 and a transceiver 1020
  • the processor 1010 and the transceiver The devices 1020 communicate with each other through internal connection paths.
  • the related functions implemented by the processing unit 920 in FIG. 25 can be implemented by the processor 1010
  • the related functions implemented by the transceiver unit 910 can be implemented by the processor 1010 controlling the transceiver 1020 .
  • the apparatus 1000 may further include a memory 1030, and the processor 1010, the transceiver 1020 and the memory 1030 communicate with each other through an internal connection path.
  • the related functions implemented by the storage unit described in FIG. 24 may be implemented by the memory 1030 .
  • This embodiment also provides a computer storage medium, where computer instructions are stored in the computer storage medium, and when the computer instructions are executed on the electronic device, the electronic device executes the above-mentioned relevant method steps to realize the active noise reduction method in the above-mentioned embodiment. .
  • This embodiment also provides a computer program product, which when the computer program product runs on the computer, causes the computer to execute the above-mentioned relevant steps, so as to realize the active noise reduction method in the above-mentioned embodiment.
  • the embodiments of the present application also provide an apparatus, which may specifically be a chip, a component or a module, and the apparatus may include a connected processor and a memory; wherein, the memory is used to store computer execution instructions, and when the apparatus is running, The processor can execute the computer-executable instructions stored in the memory, so that the chip executes the active noise reduction method in the foregoing method embodiments.
  • FIG. 26 shows a schematic structural diagram of a chip 1100 .
  • Chip 1100 includes one or more processors 1110 and interface circuits 1120 .
  • the chip 1100 may further include a bus 1130 . in:
  • the processor 1110 may be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above-mentioned method can be completed by an integrated logic circuit of hardware in the processor 1110 or an instruction in the form of software.
  • the aforementioned processor 1110 may be a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware components. Various methods and steps disclosed in the embodiments of this application can be implemented or executed.
  • a general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the interface circuit 1120 can be used for transmitting or receiving radar signals.
  • the processor 1110 can process the radar signals received by the interface circuit 1120 , and can send the processing completion information through the interface circuit 1120 .
  • the chip further includes a memory, which may include a read-only memory and a random access memory, and provides operation instructions and data to the processor.
  • a portion of the memory may also include non-volatile random access memory (NVRAM).
  • NVRAM non-volatile random access memory
  • the memory stores executable software modules or data structures
  • the processor may execute corresponding operations by calling operation instructions stored in the memory (the operation instructions may be stored in the operating system).
  • the chip may be used in the active noise reduction system involved in the embodiments of the present application.
  • the interface circuit 1120 may be used to output the execution result of the processor 1110 .
  • processor 1110 and the interface circuit 1120 can be implemented by hardware design, software design, or a combination of software and hardware, which is not limited here.
  • the active noise reduction device, computer storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved may refer to the above provided. The beneficial effects in the corresponding method will not be repeated here.
  • the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.
  • the disclosed system, apparatus and method may be implemented in other manners.
  • the apparatus embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.
  • the functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium.
  • the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution, and the computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .

Abstract

La présente demande concerne un procédé et un appareil de commande de bruit active, et un dispositif de lecture audio, capables d'améliorer l'effet de commande de bruit de bruit haute fréquence. Ledit procédé consiste à : acquérir un premier signal de référence acquis par un capteur de référence, le premier signal de référence étant utilisé pour caractériser un bruit ambiant à l'extérieur d'un dispositif de lecture audio, et le capteur de référence étant disposé à l'extérieur du dispositif de lecture audio ; effectuer un traitement de préaccentuation sur le premier signal de référence, pour obtenir un signal de référence cible ; effectuer un traitement de filtrage sur le signal de référence cible, pour obtenir un premier signal de sortie pour une commande de bruit, la phase du premier signal de sortie étant opposée à celle du signal de référence cible ; effectuer un traitement de désaccentuation sur le premier signal de sortie, pour obtenir un signal de sortie cible ; et commander un haut-parleur pour lire le signal de sortie cible.
PCT/CN2021/107685 2020-07-24 2021-07-21 Procédé et appareil de commande de bruit active, et dispositif de lecture audio WO2022017424A1 (fr)

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WO2019056301A1 (fr) * 2017-09-22 2019-03-28 深圳传音通讯有限公司 Casque audio à suppression de bruit
CN110708625A (zh) * 2019-09-25 2020-01-17 华东师范大学 基于智能终端的环境声抑制与增强可调节耳机系统与方法
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US20120170766A1 (en) * 2011-01-05 2012-07-05 Cambridge Silicon Radio Limited ANC For BT Headphones
US20140126734A1 (en) * 2012-11-02 2014-05-08 Bose Corporation Providing Ambient Naturalness in ANR Headphones
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WO2019056301A1 (fr) * 2017-09-22 2019-03-28 深圳传音通讯有限公司 Casque audio à suppression de bruit
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