Active noise reduction method and active noise reduction audio equipment

Abstract

The invention relates to the field of audio noise reduction, in particular to an active noise reduction method and active noise reduction audio equipment, and the method comprises the steps: collecting and obtaining feedforward sound signal frequency spectrums from different directions through employing a plurality of feedforward microphones, and collecting and obtaining feedback sound signal frequency spectrums in the active noise reduction audio equipment through employing a feedback microphone; dynamically updating the parameters of the filter of the feed-forward channel at the current moment according to the parameters of the filter of the feed-forward channel between each feed-forward microphone and the feedback microphone at the previous moment, and filtering the frequency spectrum of the feed-forward sound signal in the feed-forward channel through the filter; according to the correlation between each feed-forward microphone and the feedback microphone at the current moment, calculating a weight value corresponding to each feed-forward microphone at the current moment; and according to the weight value corresponding to each feed-forward microphone, mixing each filtered feed-forward sound signal frequency spectrum to obtain a noise-reduced sound signal. The stability and accuracy of the noise reduction effect can be remarkably improved, and the noise reduction experience is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of audio noise reduction, and in particular to an active noise reduction method and an active noise reduction audio device. Background Art

[0002] Noise reduction technology, especially active noise cancellation (ANC) technology, plays an important role in people's daily life and work. It is widely used in various devices, such as headphones, hearing aids, industrial equipment, etc., to reduce environmental noise and improve audio quality, so that people can better listen to audio content in noisy environments. Noise reduction technology can not only provide people with a more comfortable listening environment and reduce the potential damage of noise to hearing, but also has a positive impact on work efficiency, mental health and other aspects.

[0003] At present, the industry generally adopts an adaptive ANC algorithm based on a feedforward microphone to achieve noise reduction. In this solution, after the headset turns on noise reduction, the feedforward microphone and the feedback microphone will collect sound signals, and then run the adaptive ANC algorithm based on these signals. This algorithm calculates a set of filter parameters and sets these parameters to the hardware filter. In this way, the noise reduction effect is achieved in the current wearing state, thereby providing a better noise reduction experience. However, this method may have poor noise reduction effects when facing rapid changes in environmental noise or complex noise characteristics. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an active noise reduction method and an active noise reduction audio device.

[0005] A first aspect of the present invention discloses an active noise reduction method, which is applied to an active noise reduction audio device, wherein the active noise reduction audio device includes a plurality of feedforward microphones, a feedback microphone and an audio output port, and the method includes:

[0006] Using the plurality of the feedforward microphones to collect and obtain the frequency spectrum of the feedforward sound signal from different directions, and using the feedback microphone to collect and obtain the frequency spectrum of the feedback sound signal inside the active noise reduction audio device;

[0007] Dynamically updating the parameters of the filter of the feedforward channel at the current moment according to the parameters of the filter of each feedforward microphone and the feedback microphone at the previous moment, and filtering the spectrum of the feedforward sound signal in the feedforward channel through the filter;

[0008] Calculate a weight value corresponding to each of the feedforward microphones at the current moment according to the correlation between each of the feedforward microphones and the feedback microphone at the current moment;

[0009] According to the weight value corresponding to each of the feedforward microphones, the frequency spectra of the filtered feedforward sound signals are mixed to obtain a noise-reduced sound signal.

[0010] Furthermore, the step of using the plurality of feedforward microphones to collect and obtain the feedforward sound signal spectrum from different directions, and using the feedback microphone to collect and obtain the feedback sound signal spectrum inside the active noise reduction audio device includes:

[0011] Collecting multiple feedforward time-domain sound signals at the current moment through the multiple feedforward microphones;

[0012] Collecting the feedback time-domain sound signal at the current moment through the feedback microphone;

[0013] The feedback time-domain sound signal and the plurality of feedforward time-domain sound signals are subjected to frequency-domain conversion to obtain and save corresponding frequency spectra of the feedback sound signal and the plurality of frequency spectra of the feedforward sound signals.

[0014] Furthermore, the step of dynamically updating the parameters of the filter of the feedforward channel between each of the feedforward microphones and the feedback microphone at the previous moment includes:

[0015] The parameters of the filter are adaptively updated according to a feedback frequency response function, the feedback sound signal spectrum at a previous moment, and the feedforward sound signal spectrum at a previous moment; wherein the feedback frequency response function represents a frequency response function between the feedback microphone and the audio output port.

[0016] Furthermore, the feedback frequency response function is obtained in advance according to the following calculation steps:

[0017] Calculating a feedforward frequency response function corresponding to each of the feedforward microphones, wherein the feedforward frequency response function represents a frequency response function from the feedforward microphone to the feedback microphone;

[0018] Based on all the feedforward frequency response functions, the feedback frequency response function S is calculated:

[0019] S=

[0020] [fb req (T1)-mean(ff1 req (T1)×P1,ff2 req (T1)×P2,…,ffN req (T1)×P N)] / ref req ;

[0021] Among them, fb req (T1) represents the feedback sound signal spectrum corresponding to the T1th frame, mean() represents the mean operation, N represents the number of the feedforward microphones, ref req represents the reference signal, ffN req (T1) represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone at the T1th frame, P N represents the feedforward frequency response function corresponding to the Nth feedforward microphone.

[0022] Furthermore, the step of calculating the feedforward frequency response function corresponding to each of the feedforward microphones includes:

[0023] For each of the feed-forward microphones:

[0024] When the active noise reduction function is turned off, a ratio of the feedback sound signal spectrum of the feedback microphone to the feedforward sound signal spectrum of the feedforward microphone is calculated as a feedforward frequency response function of the feedforward microphone.

[0025] Furthermore, the reference signal is an output signal of the audio output port.

[0026] Furthermore, the step of calculating the weight value corresponding to each of the feedforward microphones at the current moment according to the correlation between each of the feedforward microphones and the feedback microphone at the current moment includes:

[0027] Calculating the correlation between each of the feedforward microphones and the feedback microphone at the current moment as the signal propagation correlation of each of the feedforward microphones at the current moment;

[0028] Sum the signal propagation correlations of all feedforward microphones at the current moment to obtain the system signal propagation correlation at the current moment;

[0029] The weight value of each feedforward microphone is obtained according to the signal propagation correlation of each feedforward microphone and the system signal propagation correlation at the current moment.

[0030] Furthermore, the step of obtaining the weight value of each feedforward microphone according to the signal propagation correlation of each feedforward microphone and the system signal propagation correlation at the current moment includes:

[0031] For each feed-forward microphone:

[0032] The ratio of the signal propagation correlation of the feedforward microphone to the system signal propagation correlation at the current moment is calculated as the weight value of the feedforward microphone.

[0033] Furthermore, the step of mixing the filtered feedforward sound signal spectra according to the weight value corresponding to each feedforward microphone to obtain the noise-reduced sound signal includes:

[0034] The filtered feedforward sound signal spectra of each feedforward channel are mixed according to the weight value corresponding to each feedforward microphone to obtain a mixed output frequency domain signal:

[0035] output(T3)=scale1(T3)×ff1 req (T3)*ω1(T3)+…+scaleN(T3)×ffN req (T3)*ωN(T3);

[0036] Wherein, output(T3) represents the output frequency domain signal corresponding to the T3th frame, scaleN(T3) represents the weight value corresponding to the Nth feedforward microphone at the T3th frame, and ffN req (T3) represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone at the T3th frame, ωN(T3) represents the parameters of the filter corresponding to the Nth feedforward microphone at the T3th frame, and * represents convolution calculation;

[0037] The output frequency domain signal is subjected to inverse Fourier transform to obtain a noise-reduced sound signal.

[0038] A second aspect of the present invention discloses an active noise reduction audio device, which includes multiple feedforward microphones, a feedback microphone and an audio output port, and can execute any active noise reduction method disclosed in the first aspect of the present invention.

[0039] The present invention calculates the correlation between the signals of multiple feedforward microphones and uses these correlation values ​​as weights to mix the feedforward signals, thereby obtaining a comprehensive and accurate noise signal; and the present invention also adopts an adaptive filter algorithm, which can adjust the parameters of the filter in real time to adapt to the real-time changes in the noise environment. Therefore, the present invention can significantly improve the stability and accuracy of the noise reduction effect, enhance the noise reduction experience, and has obvious advantages, especially when facing complex and changing noise environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a flow chart of an active noise reduction method disclosed in an embodiment of the present invention;

[0042] Figure 2 It is a schematic diagram of the principle of an active noise reduction method disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, device, or product end including a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units inherent to these processes, methods, products, or ends.

[0045] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] Embodiment 1

[0047] See also Figure 1 As shown, Figure 1 It is a flowchart of an active noise reduction method disclosed in an embodiment of the present invention. The active noise reduction method is applied to an active noise reduction audio device, and the active noise reduction audio device includes multiple feedforward microphones, a feedback microphone and an audio output port. The active noise reduction audio device can be various devices that require active noise reduction function, such as headphones, speakers, home theaters, etc., and the present invention does not limit it. The present invention can be applied in smart homes, industrial production, health care, environmental monitoring and other fields, and the present invention does not limit it. Figure 1 As shown, the active noise reduction method may include the following operations:

[0048] S100, using the plurality of feedforward microphones to collect and obtain feedforward sound signal spectra from different directions, and using the feedback microphone to collect and obtain feedback sound signal spectra inside the active noise reduction audio device;

[0049] A single feedforward microphone is limited to its single position and angle, and can often only effectively capture and suppress noise from a specific direction. However, in actual applications, noise sources may come from multiple different directions, and the nature and intensity of these noise sources may also change over time. This embodiment uses the data of multiple feedforward microphones in different positions to capture noise signals in the environment in all directions and at multiple angles. When faced with scenes with noise sources from different directions, the introduction of multiple feedforward microphones in different positions can show a more excellent noise reduction effect, ensuring that users can enjoy a clearer and quieter listening experience in different environments.

[0050] In an optional embodiment, the feedforward microphones are arranged at different positions or directions in the active noise reduction audio device to capture ambient sounds from different directions. The number, position and pointing direction of the microphones can be determined according to the shape of the device and the use environment. The feedback microphone is arranged inside the active noise reduction audio device, close to the audio output port, to monitor the output of the audio device.

[0051] For example, multiple feedforward microphones can be used to collect feedforward sound signal spectra from different directions based on directional microphone array technology, which can improve the active noise reduction system's ability to perceive sounds in complex environments, positioning accuracy, and noise reduction effects, thereby providing users with a better audio experience.

[0052] S200, dynamically updating the parameters of the filter of the feedforward channel at the current moment according to the parameters of the filter of each feedforward microphone and the feedback microphone at the previous moment, and filtering the spectrum of the feedforward sound signal in the feedforward channel through the filter;

[0053] In this embodiment, the filter can be a FIR filter or an IIR filter. Since the FIR filter has advantages such as good stability, easy design, and the ability to achieve linear phase characteristics, the FIR filter is preferred.

[0054] S300, calculating a weight value corresponding to each of the feedforward microphones at the current moment according to the correlation between each of the feedforward microphones and the feedback microphone at the current moment;

[0055] S400 , according to the weight value corresponding to each of the feedforward microphones, mixing the frequency spectra of the filtered feedforward sound signals to obtain a noise-reduced sound signal.

[0056] The present invention calculates the correlation between the signals of multiple feedforward microphones and uses these correlation values ​​as weights to mix the feedforward signals, thereby obtaining a comprehensive and accurate noise signal; and the present invention also adopts an adaptive filter algorithm, which can adjust the parameters of the filter in real time to adapt to the real-time changes in the noise environment. Therefore, the present invention can significantly improve the stability and accuracy of the noise reduction effect, enhance the noise reduction experience, and has obvious advantages, especially when facing complex and changing noise environments.

[0057] In an optional embodiment, the specific steps of using a plurality of the feedforward microphones to collect and obtain the feedforward sound signal spectrum from different directions, and using the feedback microphone to collect and obtain the feedback sound signal spectrum inside the active noise reduction audio device may include:

[0058] Collecting multiple feedforward time-domain sound signals at the current moment through the multiple feedforward microphones;

[0059] Collecting the feedback time-domain sound signal at the current moment through the feedback microphone;

[0060] The feedback time-domain sound signal and the plurality of feedforward time-domain sound signals are subjected to frequency-domain conversion to obtain and save corresponding frequency spectra of the feedback sound signal and the plurality of frequency spectra of the feedforward sound signals.

[0061] This can be achieved by installing a dedicated sound collection module on each feedforward microphone, for example, using a high-precision analog-to-digital converter to collect sound signals, and using a digital signal processor to perform preliminary processing on the collected sound signals.

[0062] After frequency domain conversion, the feedback sound signal spectrum and multiple feedforward sound signal spectrums can be optimized using filtering, equalization, compression and other techniques.

[0063] In this optional embodiment, frequency domain conversion refers to performing Fourier transform on the time domain sound signal to obtain a frequency domain signal.

[0064] In an optional embodiment, the step of dynamically updating the filter parameters of the feedforward channel between each of the feedforward microphones and the feedback microphone at the previous moment includes:

[0065] The parameters of the filter are adaptively updated according to a feedback frequency response function, the feedback sound signal spectrum at a previous moment, and the feedforward sound signal spectrum at a previous moment; wherein the feedback frequency response function represents a frequency response function between the feedback microphone and the audio output port.

[0066] In this optional embodiment, taking the filter parameters of the feedforward channel corresponding to the first feedforward microphone as an example, the filter parameter w1(T+1) at frame T+1 is:

[0067] w1(T+1)=w1(T)+μ×ff1 req (T+1)×S×fb req (T+1);

[0068] Among them, μ represents the update step size, ff1 req (T+1) represents the feedforward sound signal spectrum of the first feedforward microphone at the T+1 frame, S represents the feedback frequency response function, fb req (T+1) represents the frequency spectrum of the feedback sound signal at the T+1th frame.

[0069] In this optional embodiment, further optionally, the feedback frequency response function is obtained in advance according to the following calculation steps:

[0070] Calculating a feedforward frequency response function corresponding to each of the feedforward microphones, wherein the feedforward frequency response function represents a frequency response function from the feedforward microphone to the feedback microphone;

[0071] Based on all the feedforward frequency response functions, the feedback frequency response function S is calculated:

[0072] S=

[0073] [fb req (T1)-mean(ff1 req (T1)×P1,ff2 req (T1)×P2,…,ffN req (T1)×P N )] / refr req ;

[0074] Among them, fb req (T1) represents the feedback sound signal spectrum corresponding to the T1th frame, mean() represents the mean operation, N represents the number of the feedforward microphones, ref req represents the reference signal, ffN req (T1) represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone at the T1th frame, P N represents the feedforward frequency response function corresponding to the Nth feedforward microphone.

[0075] Further optionally, the reference signal can be a pre-recorded noise sample or a noise signal in a real-time environment. In this embodiment, the reference signal is an output signal of an audio output port. Using the output signal of an audio output port as a reference signal can achieve real-time monitoring and adjustment of the output sound quality, thereby improving the sound quality of the audio device.

[0076] Further optionally, the step of calculating the feedforward frequency response function corresponding to each of the feedforward microphones includes:

[0077] For each of the feed-forward microphones:

[0078] When the active noise reduction function is turned off, the ratio of the feedback sound signal spectrum of the feedback microphone to the feedforward sound signal spectrum of the feedforward microphone is calculated as the feedforward frequency response function of the feedforward microphone. This ratio can be understood as the propagation loss of the noise signal between the feedforward microphone and the feedback microphone, and can be used to estimate the feedforward frequency response function of each feedforward microphone.

[0079] In this optional embodiment, take the feedforward frequency response function P1 corresponding to the first feedforward microphone as an example:

[0080] P1=fb req (T2) / ff1 req (T2);

[0081] Among them, fb req (T2) represents the feedback sound signal spectrum corresponding to the T2 frame, ff1 req (T2) represents the feedforward sound signal spectrum corresponding to the first feedforward microphone at the T2th frame.

[0082] By calculating the ratio of the feedback sound signal spectrum to the feedforward sound signal spectrum when the active noise reduction function is turned off, the feedforward frequency response function of each feedforward microphone can be obtained more accurately, thereby improving the active noise reduction effect.

[0083] In an optional embodiment, according to the correlation between each of the feedforward microphones and the feedback microphone at the current moment, the step of calculating the weight value corresponding to each of the feedforward microphones at the current moment may include:

[0084] Calculating the correlation between each of the feedforward microphones and the feedback microphone at the current moment as the signal propagation correlation of each of the feedforward microphones at the current moment;

[0085] Sum the signal propagation correlations of all feedforward microphones at the current moment to obtain the system signal propagation correlation at the current moment;

[0086] The weight value of each feedforward microphone is obtained according to the signal propagation correlation of each feedforward microphone and the system signal propagation correlation at the current moment.

[0087] By calculating the correlation between the feedforward microphone and the feedback microphone to determine the weight value of each feedforward microphone, sound signals from all directions can be captured more accurately, thereby improving the active noise reduction effect.

[0088] In a further optional embodiment, the step of obtaining the weight value of each feedforward microphone according to the signal propagation correlation of each feedforward microphone and the system signal propagation correlation at the current moment comprises:

[0089] For each feed-forward microphone:

[0090] The ratio of the signal propagation correlation of the feedforward microphone to the system signal propagation correlation at the current moment is calculated as the weight value of the feedforward microphone.

[0091] In this optional embodiment, the weight value scale1 corresponding to the first feedforward microphone at the current moment is:

[0092] scale1=cor1 / (cor1+cor2+,,,+corN);

[0093] Where corN represents the signal propagation correlation of the Nth feedforward microphone.

[0094] In this optional embodiment, the correlation between the feedforward microphone and the feedback microphone is calculated by calculating the cross-correlation function of the feedforward time-domain sound signal and the feedback time-domain sound signal of the feedforward microphone to obtain the correlation. The correlation between the feedforward time-domain sound signal and the feedback time-domain sound signal can also be calculated by a covariance function, an information theory method, etc.

[0095] By calculating the ratio of the signal propagation correlation to the system signal propagation correlation to obtain the weight value of the feedforward microphone, the importance of each feedforward microphone in the active noise reduction system of the active noise reduction audio device can be more accurately reflected, thereby improving the active noise reduction effect.

[0096] In an optional embodiment, the step of mixing the filtered feedforward sound signal spectra according to the weight value corresponding to each of the feedforward microphones to obtain the noise-reduced sound signal may include:

[0097] The filtered feedforward sound signal spectra of each feedforward channel are mixed according to the weight value corresponding to each feedforward microphone to obtain a mixed output frequency domain signal:

[0098] output(T3)=scale1(T3)×ff1 req (T3)*ω1(T3)+…+scaleN(T3)×

[0099] FWf req (T3)*ωN(T3);

[0100] Wherein, output(T3) represents the output frequency domain signal corresponding to the T3th frame, scaleN(T3) represents the weight value corresponding to the Nth feedforward microphone at the T3th frame, and ffN req (T3) represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone at the T3th frame, ωN(T3) represents the parameters of the filter corresponding to the Nth feedforward microphone at the T3th frame, and * represents convolution calculation;

[0101] The output frequency domain signal is subjected to inverse Fourier transform to obtain a noise-reduced sound signal.

[0102] Traditional single feedforward ANC algorithms may encounter challenges when dealing with multiple noise sources, because noise signals from different directions may interfere with each other in a single channel, affecting the noise reduction effect. The present invention uses a multi-feedforward path data fusion algorithm to effectively integrate the noise signals captured by each feedforward microphone and accurately calculate the reverse noise signal required for each channel. After optimization, these reverse noise signals can not only accurately offset their corresponding noise sources, but also coordinate with each other in time and space to produce a positive superposition effect, thereby further improving the overall noise reduction performance.

[0103] Figure 2 The schematic diagram of the active noise reduction method of this embodiment is shown. In the figure, FxLMS represents the Filtered-x Least Mean Squares filtering algorithm. FxLMS adjusts the weight of the filter by comparing with the reference signal to minimize the mean square error of the error signal, which can help the system effectively remove noise and improve signal quality. NLMS stands for the Normalized Least Mean Squares filtering algorithm, which adjusts the weight of the filter according to the error signal between the input signal and the estimated output. It has strong adaptability and can quickly adapt to changes in the signal to improve the noise reduction effect.

[0104] FF1 represents the feedforward sound signal spectrum corresponding to the first feedforward microphone, FF2 represents the feedforward sound signal spectrum corresponding to the second feedforward microphone, FFN represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone, P1 represents the feedforward frequency response function corresponding to the first feedforward microphone, P2 represents the feedforward frequency response function corresponding to the second feedforward microphone, W1 represents the parameters of the filter of the feedforward channel corresponding to the first feedforward microphone, W2 represents the parameters of the filter of the feedforward channel corresponding to the second feedforward microphone, FB represents the feedback sound signal spectrum, and S represents the feedback frequency response function.

[0105] Embodiment 2

[0106] The present invention provides an active noise reduction audio device, which includes multiple feedforward microphones, a feedback microphone and an audio output port, and can perform the active noise reduction method in any one of the embodiments in Embodiment 1. The active noise reduction audio device can be various devices that require active noise reduction functions, such as headphones, speakers, home theaters, etc., and the present invention does not limit this.

[0107] In summary, the active noise reduction method and active noise reduction audio device disclosed in the present invention can significantly improve the stability and accuracy of the noise reduction effect, enhance the noise reduction experience, and have obvious advantages especially when facing complex and changing noise environments. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0108] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An active noise reduction method, characterized in that: The active noise reduction method is applied to an active noise reduction audio device, the active noise reduction audio device includes a plurality of feedforward microphones, a feedback microphone and an audio output port, and the method includes: Using the plurality of the feedforward microphones to collect and obtain the frequency spectrum of the feedforward sound signal from different directions, and using the feedback microphone to collect and obtain the frequency spectrum of the feedback sound signal inside the active noise reduction audio device; Dynamically updating the parameters of the filter of the feedforward channel at the current moment according to the parameters of the filter of each feedforward microphone and the feedback microphone at the previous moment, and filtering the spectrum of the feedforward sound signal in the feedforward channel through the filter; Calculate a weight value corresponding to each of the feedforward microphones at the current moment according to the correlation between each of the feedforward microphones and the feedback microphone at the current moment; According to the weight value corresponding to each of the feedforward microphones, the frequency spectra of the filtered feedforward sound signals are mixed to obtain a noise-reduced sound signal.

2. An active noise reduction method according to claim 1, characterized in that: The steps of using the plurality of feedforward microphones to collect and obtain the frequency spectrum of the feedforward sound signal from different directions, and using the feedback microphone to collect and obtain the frequency spectrum of the feedback sound signal inside the active noise reduction audio device include: Collecting multiple feedforward time-domain sound signals at the current moment through the multiple feedforward microphones; Collecting the feedback time-domain sound signal at the current moment through the feedback microphone; The feedback time-domain sound signal and the plurality of feedforward time-domain sound signals are subjected to frequency domain conversion to obtain and save corresponding frequency spectra of the feedback sound signal and the plurality of frequency spectra of the feedforward sound signals.

3. The active noise reduction method according to claim 2, characterized in that: The step of dynamically updating the filter parameters of the feedforward channel between each of the feedforward microphones and the feedback microphone at the previous moment according to the filter parameters of the feedforward channel between each of the feedforward microphones and the feedback microphone at the previous moment comprises: The parameters of the filter are adaptively updated according to a feedback frequency response function, the feedback sound signal spectrum at a previous moment, and the feedforward sound signal spectrum at a previous moment; wherein the feedback frequency response function represents a frequency response function between the feedback microphone and the audio output port.

4. The active noise reduction method according to claim 3, characterized in that: The feedback frequency response function is obtained in advance according to the following calculation steps: Calculating a feedforward frequency response function corresponding to each of the feedforward microphones, wherein the feedforward frequency response function represents a frequency response function from the feedforward microphone to the feedback microphone; Based on all the feedforward frequency response functions, the feedback frequency response function S is calculated: S＝ [fb req (T1)-mean(ff1 req (T1)×P1, ff2 req (T1)×P2,...,ffN req (T1)×P N )] / ref req ; Among them, fb req (T1) represents the feedback sound signal spectrum corresponding to the T1th frame, mean() represents the mean operation, N represents the number of the feedforward microphones, ref reg represents the reference signal, ffN reg (T1) represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone at the T1th frame, P N represents the feedforward frequency response function corresponding to the Nth feedforward microphone.

5. The active noise reduction method according to claim 4, characterized in that: The step of calculating the feedforward frequency response function corresponding to each feedforward microphone comprises: For each of the feed-forward microphones: When the active noise reduction function is turned off, a ratio of the feedback sound signal spectrum of the feedback microphone to the feedforward sound signal spectrum of the feedforward microphone is calculated as a feedforward frequency response function of the feedforward microphone.

6. The active noise reduction method according to claim 4, characterized in that: The reference signal is an output signal of the audio output port.

7. The active noise reduction method according to claim 1, characterized in that: The step of calculating the weight value corresponding to each of the feedforward microphones at the current moment according to the correlation between each of the feedforward microphones and the feedback microphone at the current moment comprises: Calculating the correlation between each of the feedforward microphones and the feedback microphone at the current moment as the signal propagation correlation of each of the feedforward microphones at the current moment; Sum the signal propagation correlations of all feedforward microphones at the current moment to obtain the system signal propagation correlation at the current moment; The weight value of each feedforward microphone is obtained according to the signal propagation correlation of each feedforward microphone and the system signal propagation correlation at the current moment.

8. An active noise reduction method according to claim 7, characterized in that: The step of obtaining the weight value of each feedforward microphone according to the signal propagation correlation of each feedforward microphone and the system signal propagation correlation at the current moment comprises: For each feed-forward microphone: The ratio of the signal propagation correlation of the feedforward microphone to the system signal propagation correlation at the current moment is calculated as the weight value of the feedforward microphone.

9. The active noise reduction method according to claim 2, characterized in that: The step of mixing the filtered feedforward sound signal spectra according to the weight value corresponding to each feedforward microphone to obtain the noise-reduced sound signal comprises: The filtered feedforward sound signal spectra of each feedforward channel are mixed according to the weight value corresponding to each feedforward microphone to obtain a mixed output frequency domain signal: <h2 style=";text-align:left;direction:ltr">output(T3) = scale1(T3)×ff1<h2 style=";text-align:left;direction:ltr"> req <h2 style=";text-align:left;direction:ltr"> (T3)*ω1(T3)+…+scaleN(T3)×ffN<h2 style=";text-align:left;direction:ltr"> req <h2 style=";text-align:left;direction:ltr"> (T3)*ωN(T3); Wherein, output(T3) represents the output frequency domain signal corresponding to the T3th frame, scaleN(T3) represents the weight value corresponding to the Nth feedforward microphone at the T3th frame, and ffN req (T3) represents the feedforward sound signal spectrum corresponding to the Nth feedforward microphone at the T3th frame, ωN(T3) represents the parameters of the filter corresponding to the Nth feedforward microphone at the T3th frame, and * represents convolution calculation; The output frequency domain signal is subjected to inverse Fourier transform to obtain a noise-reduced sound signal.

10. An active noise reduction audio device, comprising a plurality of feedforward microphones, a feedback microphone and an audio output port, and capable of executing the active noise reduction method according to any one of claims 1 to 9.

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