Active noise reduction automatic adjustment method and device, earphone and program product

Abstract

The invention provides an active noise reduction automatic adjustment method and device, an earphone and a program product, and the method comprises the steps: controlling a loudspeaker of the earphone to give out a prompt tone under the condition that it is determined that the active noise reduction function of the earphone is enabled; obtaining an audio signal of a prompt tone collected by a feedback microphone of the earphone; performing spectral analysis on the audio signal of the prompt tone to obtain a first spectrum; determining a deviation between the first spectrum and an ideal spectrum; and adjusting a filter coefficient of a noise reduction filter of the earphone according to the deviation. According to the invention, the filtering coefficient of the noise reduction filter is adjusted according to the deviation, so that the noise reduction filter can better adapt to the acoustic environment changed due to the wearing position difference. According to the invention, noise reduction effect differences caused by wearing position differences when different people wear earphones can be effectively compensated, the noise reduction performance and stability of the earphones under various wearing conditions are improved, more consistent and high-quality noise reduction experience is provided for users, manual intervention of the users is not needed, and the use is more convenient.

Description

Technical Field

[0001] This application belongs to the technical field of headphone noise reduction, and particularly relates to an active noise reduction automatic adjustment method, device, headphone, and program product. Background Art

[0002] Since in-ear and semi-in-ear headphones are uncomfortable to wear for a long time, in recent years, open headphones have become popular in the market due to their wearing comfort and safety. However, open headphones lack passive noise reduction compared to other types of headphones and cannot clearly hear music and call voices in some noisy scenarios. Therefore, active noise reduction for open headphones is necessary.

[0003] When in-ear and semi-in-ear headphones are worn, they fit closely to the human ear, and the wearing state is relatively stable. While open headphones do not fit closely to the human ear and have a certain distance, which leads to a large difference in the relative position between the human ear and different wearers. The wearing difference may cause changes in the acoustic coupling conditions, resulting in a deterioration of the noise reduction effect when different people wear open headphones due to different wearing positions. Summary of the Invention

[0004] Embodiments of this application provide an active noise reduction automatic adjustment method, device, headphone, and program product to solve the problem of the deterioration of the noise reduction effect when different people wear open headphones due to different wearing positions.

[0005] In a first aspect, embodiments of this application provide an active noise reduction automatic adjustment method, including:

[0006] When it is determined that the active noise reduction function of the headphone is turned on, control the speaker of the headphone to emit a prompt sound;

[0007] Obtain the audio signal of the prompt sound collected by the feedback microphone of the headphone;

[0008] Perform spectral analysis on the audio signal of the prompt sound to obtain a first spectrum;

[0009] Determine the deviation between the first spectrum and the ideal spectrum;

[0010] Adjust the filter coefficient of the noise reduction filter of the headphone according to the deviation.

[0011] In the embodiment of the present application, when the active noise reduction function of the earphone is turned on, a prompt tone can be automatically emitted and an audio signal can be collected, the deviation between the first spectrum and the ideal spectrum can be analyzed, and then the filtering coefficient of the noise reduction filter can be adjusted, so that the noise reduction filter can better adapt to the acoustic environment changed due to the difference in wearing positions. This method can effectively compensate for the difference in noise reduction effects caused by the difference in wearing positions when different people wear earphones, improve the noise reduction performance and stability of the earphone in various wearing situations, provide users with a more consistent and high-quality noise reduction experience, and is more convenient to use without manual intervention by the user.

[0012] In an optional implementation manner of the first aspect, determining the deviation between the first spectrum and the ideal spectrum includes:

[0013] Extracting the first amplitude of the target frequency point in the first spectrum and the first bandwidth at which the first amplitude drops by a set decibel; the target frequency point is any one of multiple frequency points in the prompt tone;

[0014] Determining the amplitude deviation of the target frequency point according to the first amplitude of the target frequency point and the ideal amplitude of the target frequency point;

[0015] Determining the bandwidth deviation corresponding to the target frequency point according to the first bandwidth corresponding to the target frequency point and the ideal bandwidth corresponding to the target frequency point.

[0016] In this embodiment, by separately extracting the amplitude and bandwidth of the target frequency point and calculating the deviation from the ideal value, the influence of the position difference on the acoustic characteristics when different people wear earphones can be quantified more accurately. Since both the amplitude and bandwidth deviations are considered, the influence of the wearing position change on the sound propagation can be reflected more comprehensively. In addition, calculating the amplitude and bandwidth deviations for multiple frequency points in the prompt tone respectively can adapt to the change situations of different frequency components at different wearing positions, making the active noise reduction automatic adjustment method have stronger adaptability and flexibility.

[0017] In an optional implementation manner of the first aspect, adjusting the filtering coefficient of the noise reduction filter of the earphone according to the deviation includes:

[0018] Adjusting the gain of the target frequency point in the noise reduction filter according to the amplitude deviation of the target frequency point;

[0019] Adjusting the quality factor of the target frequency point in the noise reduction filter according to the bandwidth deviation corresponding to the target frequency point.

[0020] Adjustment of the gain helps to compensate for the amplitude changes caused by wearing differences, while adjustment of the quality factor can precisely control the bandwidth characteristics of the filter. Thus, this embodiment can adjust the gain and quality factor of the filter according to the actual wearing state of the wearer. By combining the amplitude deviation and the bandwidth deviation, the working effect of the noise reduction filter can be optimized specifically, so that the noise reduction performance can reach an ideal level under different wearing conditions.

[0021] In an alternative embodiment of the first aspect, the method further includes:

[0022] When the earphone is in the wearing state or a switching signal for switching the earphone to the active noise reduction mode is received, it is determined to turn on the active noise reduction function of the earphone.

[0023] This embodiment can determine whether the earphone is in the wearing state and whether it is switched to the active noise reduction mode in various ways, which simplifies the operation of the user and improves the user experience.

[0024] In an alternative embodiment of the first aspect, the prompt tone has a first feature:

[0025] The first feature includes one or more of the following:

[0026] The frequency points of the prompt tone cover the mid-frequency point of the noise reduction filter;

[0027] The prompt tone is formed by superimposing sine wave audio signals of multiple frequency points, and there is a phase difference between the initial phases of adjacent frequency points among the multiple frequency points;

[0028] The duration of the prompt tone is a preset duration.

[0029] By specifically designing the prompt tone in this embodiment, phase interference of different frequency components in the prompt tone can be avoided, so that the prompt tone signal has clear separability in both the frequency domain and the time domain.

[0030] In an alternative embodiment of the first aspect, the prompt tone also undergoes envelope smoothing signal processing to smooth the start and end of the prompt tone.

[0031] In this embodiment, the start and end are smoothed by performing envelope smoothing processing on the prompt tone to avoid abrupt start and end effects, so that the change of the prompt tone is smoother and more natural.

[0032] In an alternative embodiment of the first aspect, the noise reduction filter includes a feedforward filter on the feedforward noise reduction path of the earphone and / or a feedback filter on the feedback noise reduction path;

[0033] Both the feedforward filter and the feedback filter include a plurality of second-order IIR filters, and the center frequencies of the plurality of second-order IIR filters correspond one-to-one to the multiple frequencies of the prompt sound.

[0034] In this embodiment, by making the center frequencies of the plurality of second-order IIR filters correspond one-to-one to the multiple frequencies of the prompt sound, the noise reduction filter can be accurately adjusted for sounds of different frequencies. Compared with the traditional unified processing method, this targeted processing can better adapt to the changes of sounds of each frequency in different wearing positions, improve the accuracy and adaptability of noise reduction, and further optimize the user's auditory experience.

[0035] In a second aspect, an embodiment of the present application provides an active noise reduction automatic adjustment device, including:

[0036] A control module, configured to control the speaker of the earphone to emit a prompt sound when it is determined that the active noise reduction function of the earphone is turned on;

[0037] An acquisition module, configured to acquire the audio signal of the prompt sound collected by the feedback microphone of the earphone;

[0038] A spectrum analysis module, configured to perform spectrum analysis on the audio signal of the prompt sound to obtain a first spectrum;

[0039] A determination module, configured to determine the deviation between the first spectrum and the ideal spectrum;

[0040] An adjustment module, configured to adjust the filtering coefficient of the noise reduction filter of the earphone according to the deviation.

[0041] In a third aspect, an embodiment of the present application provides an earphone, which has an active noise reduction function. The earphone includes: a speaker, a feedback microphone, a noise reduction filter, and a processor;

[0042] The processor is configured to execute the active noise reduction automatic adjustment method as described in any item of the first aspect.

[0043] In a fourth aspect, an embodiment of the present application provides a computer program product, which, when running on an earphone, enables the earphone to execute the method as described in any item of the first aspect.

[0044] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the method as described in any item of the first aspect is implemented.

[0045] It can be understood that the beneficial effects of the above second aspect to the fifth aspect can refer to the relevant descriptions in the first aspect above, and will not be repeated here.

[0046] The beneficial effects of the embodiments of the present application are as follows: When the active noise reduction function of the earphone is turned on, the embodiments of the present application can automatically emit a prompt sound and collect an audio signal, analyze the deviation between the first spectrum and the ideal spectrum, and then adjust the filtering coefficient of the noise reduction filter, so that the noise reduction filter can better adapt to the acoustic environment changed due to the difference in wearing positions. This method can effectively compensate for the difference in noise reduction effects caused by the difference in wearing positions when different people wear the earphone, improve the noise reduction performance and stability of the earphone in various wearing situations, provide a more consistent and high-quality noise reduction experience for users, and is more convenient to use without manual intervention by the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0048] Figure 1 is a schematic structural diagram of an earphone provided by an embodiment of the present application;

[0049] Figure 2 is a schematic flowchart of an active noise reduction automatic adjustment method provided by an embodiment of the present application Figure 1 ;

[0050] Figure 3 is a schematic flowchart of an active noise reduction automatic adjustment method provided by an embodiment of the present application Figure 2 ;

[0051] Figure 4 is a schematic flowchart of an active noise reduction automatic adjustment method provided by an embodiment of the present application Figure 3 ;

[0052] Figure 5 is a schematic structural diagram of an active noise reduction automatic adjustment device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0054] It should be understood that, as used in the specification of this application and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their combinations.

[0055] It should also be understood that the term "and / or" as used in the specification of this application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0056] As used in the specification of this application and the appended claims, the term "if" can be interpreted as "when" or "once" or "in response to determining" or "in response to detecting" according to the context. Similarly, the phrases "if determined" or "if [the described condition or event] is detected" can be interpreted as meaning "once determined" or "in response to determining" or "once [the described condition or event] is detected" or "in response to detecting [the described condition or event]" according to the context.

[0057] In addition, in the description of the specification of this application and the appended claims, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0058] Reference to "one embodiment" or "some embodiments" or the like described in the specification of this application means that a specific feature, structure or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0059] Currently, in-ear and semi-in-ear headphones fit well with the human ear when worn, and the wearing state is relatively stable. However, open headphones do not fit well with the human ear and have a certain distance, which results in a relatively large difference in the relative position between different people's wearings and the human ear. The wearing difference may cause changes in the acoustic coupling conditions, so that the noise reduction effect of open headphones worn by different people becomes worse due to different wearing positions. To solve this problem, Figure 1 A schematic structural diagram of a headphone according to an embodiment of this application is shown, including: a speaker 1, a feedback microphone 2, a noise reduction filter, and a processor.

[0060] See Figure 1, the feedback microphone 2 is installed on one side of the earphone near the speaker 1, and is used to collect the audio signal after the prompt sound emitted by the speaker 1 is reflected by the ear canal. By analyzing the audio signal of the prompt sound, it can be determined whether the earphone is in the ideal wearing position.

[0061] Specifically, the noise reduction filter includes a feedforward filter on the feedforward noise reduction path of the earphone and / or a feedback filter on the feedback noise reduction path.

[0062] The feedforward filter is located on the feedforward noise reduction path and is used to filter the external environmental noise to generate an inverted noise signal to cancel the external noise.

[0063] The feedback filter is located on the feedback noise reduction path and is used to filter the noise inside the earphone to generate an inverted noise signal to cancel the noise inside the earphone.

[0064] Specifically, the processor is configured to:

[0065] When it is determined that the active noise reduction function of the earphone is turned on, control the speaker to emit a prompt sound; obtain the audio signal of the prompt sound collected by the feedback microphone; perform spectral analysis on the audio signal of the prompt sound to obtain the first spectrum; determine the deviation between the first spectrum and the ideal spectrum; adjust the filtering coefficient of the noise reduction filter according to the deviation.

[0066] Specifically, when the earphone is in the wearing state or receives a switching signal for the earphone to switch to the active noise reduction mode, it is determined to turn on the active noise reduction function of the earphone.

[0067] Whether the earphone is in the wearing state can be known in various ways.

[0068] Exemplarily, an infrared sensor or a distance sensor can be set inside the earphone. The infrared sensor or the distance sensor can sense whether an object is approaching. When an object is approaching, the external sensor or the distance sensor emits a sensing signal. The processor receives and responds to the sensing signal emitted by the infrared sensor or the distance sensor, and determines that the earphone is in the wearing state; then the processor controls the speaker to emit a prompt sound.

[0069] Specifically, whether the earphone switches to the active noise reduction mode can be obtained in various forms.

[0070] Exemplarily, a touch sensor can be set on the earphone. When the user switches the active noise reduction mode through the touch sensor, the processor receives the switching signal and then controls the speaker to emit a prompt sound.

[0071] Exemplarily, a physical button can also be set on the earphone for switching the active noise reduction mode. When the user presses the button to switch to the active noise reduction mode, the processor receives the switching signal and then controls the speaker to emit a prompt sound.

[0072] Exemplarily, the active noise cancellation mode of the earphone can also be controlled by a mobile phone, a smart watch / band. When the earphone receives a switching signal sent by the mobile phone or the smart watch / band, the processor of the earphone controls the speaker to emit a prompt tone.

[0073] Optionally, the prompt tone includes multiple frequency points, the feedforward filter and the feedback filter include multiple second-order IIR filters, and the center frequency points of the multiple second-order IIR filters correspond one-to-one with the multiple frequency points of the prompt tone. By analyzing the audio signal of the prompt tone, a first spectrum can be obtained. By comparing it with the ideal spectrum, it can be known which specific frequency points are too high and which are too low, and then the filter coefficients of the second-order IIR filters can be adjusted accordingly. This targeted adjustment can better adapt to the changes in sounds of different frequencies under different wearing positions, improve the accuracy and adaptability of noise cancellation, and further optimize the user's auditory experience.

[0074] The earphone of this embodiment can be applicable to earphone types with relatively unstable wearing states, such as open earphones, over-ear headphones, etc. It is easy to understand that for in-ear and semi-in-ear headphones, due to individual wearing habits and auricle differences, for example, some people like to wear them tightly and some people like to wear them loosely, there will also be situations where the earphones are not worn in an ideal state. Therefore, the earphone of this embodiment can also be applicable to in-ear and semi-in-ear headphones, and this embodiment does not limit this.

[0075] Taking the open earphone as an example in this embodiment, when different people wear open earphones, due to large differences in wearing positions, the acoustic coupling conditions will change. The change in the acoustic coupling conditions will directly affect the acoustic environment around the earphone, and further cause a deviation between the prompt tone audio signal collected by the feedback microphone and the ideal state. Spectrum analysis can display the characteristics of the audio signal in the form of a spectrum. By comparing the first spectrum (the spectrum of the prompt tone audio signal actually collected) with the ideal spectrum, the deviation between the two can be determined, and this deviation actually reflects the change in the acoustic environment caused by the difference in wearing positions. The filter coefficient of the noise cancellation filter determines its processing method and degree for sounds of different frequencies. When adjusting the filter coefficient of the noise cancellation filter according to the above deviation, it is equivalent to adjusting the noise cancellation processing strategy of the earphone. By changing the filter coefficient, the noise cancellation filter can better adapt to the acoustic environment changed due to the difference in wearing positions, process different frequencies of noise more precisely, so as to effectively compensate for the difference in noise cancellation effect caused by the difference in wearing positions, and improve the noise cancellation performance and stability of the earphone in various wearing situations.

[0076] Figure 2 The schematic flowchart of the active noise cancellation automatic adjustment method provided by the embodiment of the present application is shown, including steps S110-S150:

[0077] S110: When it is determined that the active noise cancellation function of the earphone is turned on, control the speaker of the earphone to emit a prompt tone.

[0078] Specifically, when it is determined that the active noise cancellation function of the earphone is turned on, the processor of the earphone controls the speaker to emit a characteristic prompt tone as an audio signal source to start the noise cancellation adjustment process.

[0079] The design of the prompt tone has specific spectral characteristics, thus providing necessary information for the subsequent adjustment of the noise cancellation filter.

[0080] Exemplarily, the design of the prompt tone is as follows:

[0081] (1) Prompt tone frequency selection:

[0082] When selecting the frequency of the prompt tone, the frequency point f of the prompt tone i covers the center frequency point f of the noise cancellation filter ANC ={f1, f2,..., f n}}. The noise cancellation filter includes multiple second-order IIR filters, each second-order IIR filter has a center frequency point, and the center frequency points of the multiple second-order IIR filters correspond one-to-one with the multiple frequency points f of the prompt tone i .

[0083] (2) Prompt tone synthesis:

[0084] The prompt tone is generated by superimposing multi-frequency sine waves:

[0085] A i : frequency point amplitude; φ i : initial phase, the initial phases of adjacent two frequency points are set to complementary values or have a phase difference to avoid interference.

[0086] The initial phases of adjacent two frequency points φ i are set to complementary values or have a phase difference to avoid phase interference of different frequency components in the prompt tone, so that the prompt tone signal has clear separability in the frequency domain and time domain.

[0087] Complementary phase: It means that the phase difference of the initial phases of two signals relative to each other is 180°. By reasonably distributing the initial phases, the superposition of these signals is evenly distributed in the time domain to avoid excessive energy peaks at certain time points.

[0088] The initial phase can adopt the following design method:

[0089] 1), Linear phase distribution: φ i is evenly distributed in the interval [0, 2π].

[0090]

[0091] n: The total number of frequency components included in the prompt tone.

[0092] The phases of each frequency are evenly spaced, so that the signal energy is evenly distributed.

[0093] 2), Orthogonal phase distribution: The phase difference of the initial phases of adjacent frequency components is π / 2 or π, ensuring the orthogonality of different frequency components.

[0094]

[0095] (3) Prompt tone time:

[0096] The total duration T = 500 ms. Add the envelope smoothing signal w(t) to smooth the start and end, and obtain the final prompt tone: s final (t) = w(t) · s(t).

[0097] Envelope smoothing refers to smoothing the envelope of the prompt tone to reduce sudden changes or noise in the signal, so that the change of the prompt tone is smoother and more natural. Among them, the envelope is a curve describing the change of signal intensity over time, which is used to analyze the dynamic characteristics of the audio signal.

[0098] Smoothing the start and end means performing smoothing processing at the start and end parts of the prompt tone to avoid abrupt start and end effects.

[0099] Specifically, smoothing the start and end includes:

[0100] Start smoothing: At the start part of the prompt tone, use a gradual change method to increase the volume instead of suddenly changing from silence to full volume. This can be achieved by applying a fade-in technique, so that the audio signal gradually increases to the target volume at the start.

[0101] End smoothing: At the end part of the prompt tone, similarly, use a gradual change method to reduce the volume instead of suddenly stopping. This can be achieved by applying a fade-out technique, so that the audio signal gradually decreases to silence at the end.

[0102] By smoothing the start and end parts of the prompt tone, the listening experience of the prompt tone can be improved, making the playback of the prompt tone more natural and avoiding the discomfort caused by abrupt start and end.

[0103] S120: Control the feedback microphone of the earphone to collect the audio signal of the prompt tone.

[0104] Specifically, the processor of the earphone sends a collection instruction to the feedback microphone to control the feedback microphone to collect the audio signal x(t) of the prompt tone emitted by the speaker.

[0105] S130: Perform spectral analysis on the audio signal of the prompt tone to obtain a first spectrum.

[0106] Specifically, the processor of the earphone performs spectral analysis on the audio signal collected by the feedback microphone, thereby converting the prompt tone from the time domain to the frequency domain.

[0107] Optionally, perform a Fast Fourier Transform (FFT) on the audio signal x(t) of the prompt tone to obtain a first spectrum:

[0108] In addition to the Fast Fourier Transform (FFT), this embodiment can also use a variety of spectral analyses to convert the prompt tone from the time domain to the frequency domain. For example: Discrete Fourier Transform (DFT), Short-Time Fourier Transform (STFT), Wavelet Transform (WT), Hilbert Transform (HT), etc.

[0109] S140: Determine the deviation between the first spectrum and the ideal spectrum.

[0110] Specifically, the processor of the earphone compares the first spectrum with the ideal spectrum to determine the deviation between the two. Among them, the ideal spectrum is measured under the reference wearing conditions during design. Under the reference wearing conditions, active noise reduction can achieve the best effect. The first spectrum is the actual spectrum measured when the user actually wears the earphone. Due to different habits or different auricle structures of different people, etc., there is a certain difference between the actual wearing and the reference wearing conditions, and this difference causes a deviation between the first spectrum and the ideal spectrum.

[0111] S150: Adjust the filtering coefficient of the noise reduction filter of the earphone according to the deviation.

[0112] According to the deviation between the first spectrum and the ideal spectrum, the processor adjusts by controlling the filtering coefficient of the noise reduction filter. In this way, the processor can adjust the parameters of the noise reduction filter according to the difference in the wearing position, optimize the noise reduction effect, and thus achieve better noise suppression.

[0113] When it is determined in the embodiment of the present application that the active noise reduction function of the earphone is turned on, a prompt tone is automatically emitted and an audio signal is collected, the deviation between the first spectrum and the ideal spectrum is analyzed, and then the filtering coefficient of the noise reduction filter is adjusted, so that the noise reduction filter can better adapt to the acoustic environment changed due to the difference in wearing positions. This method can effectively compensate for the difference in noise reduction effect caused by the difference in wearing positions when different people wear the earphone, improve the noise reduction performance and stability of the earphone in various wearing situations, provide a more consistent and high-quality noise reduction experience for users, and is more convenient to use without manual intervention by the user.

[0114] As an optional implementation manner, the active noise reduction automatic adjustment method further includes: S160: When the earphone is in a worn state or a switching signal for the earphone to switch to the active noise reduction mode is received, determine to turn on the active noise reduction function of the earphone.

[0115] In this embodiment, the earphone can be known whether it is in a worn state and whether it is switched to the active noise reduction mode through various methods. The above embodiments have been introduced and will not be elaborated in this embodiment.

[0116] As an optional implementation manner, refer to Figure 3 , S140: Determine the deviation between the first spectrum and the ideal spectrum, specifically including S141 - S143:

[0117] S141: Extract the first amplitude and the first bandwidth at which the first amplitude drops by a set decibel of the target frequency point in the first spectrum; the target frequency point is any one of multiple frequency points in the prompt tone.

[0118] The amplitude and bandwidth are important characteristics of the spectrum. Different wearing positions will cause changes in the amplitude and bandwidth of the target frequency point. Extracting these parameters provides a specific data basis for subsequent determination of the deviation.

[0119] After obtaining the first spectrum through spectral analysis of the prompt tone audio signal, for any target frequency point among multiple frequency points in the prompt tone, extract the first amplitude of the target frequency point from the first spectrum. At the same time, determine the frequency range corresponding to when the first amplitude drops by a set decibel (for example, -3 dB), and define this frequency range as the first bandwidth.

[0120] Specifically, for the target frequency point f i Extract the first amplitude |X(f i )| and the first bandwidth BW measured .

[0121] A) First amplitude extraction: Extract the first amplitude |X(f i )| of the target frequency point in the first spectrum: G measured (f i ) = 20log 10(|X(f i )|);

[0122] Among them, G measured (f i ) represents the first amplitude value after unit conversion.

[0123] B) Determine the first bandwidth: Define the first bandwidth BW measured as the frequency range of -3dB of the target frequency point f i in the first spectrum as the first bandwidth of the target frequency point.

[0124] Calculate the first bandwidth BW measured : BW measured = f H - f L ;

[0125] Among them, f H , f L represent: the high-frequency point (the frequency point to the right of the target frequency point in the frequency response curve) and the low-frequency point (the frequency point to the left of the target frequency point in the frequency response curve) where the target frequency point reaches -3dB.

[0126] S142: Determine the amplitude deviation of the target frequency point according to the first amplitude of the target frequency point and the ideal amplitude of the target frequency point.

[0127] The ideal amplitude of the target frequency point is measured under the reference wearing conditions during design and stored in the memory of the earphone. Compare the first amplitude of the extracted target frequency point with the ideal amplitude of the target frequency point, and determine the amplitude deviation of the target frequency point by calculating the difference between the two.

[0128] The change in amplitude reflects the influence of the wearing position on the energy attenuation during the sound propagation process. By calculating the amplitude deviation, the influence degree of the wearing position difference on the energy of the target frequency point can be understood.

[0129] Specifically, the amplitude deviation: ΔG(f i ) = G ideal (f i ) - G measured (f i );

[0130] Among them, G ideal (f i ) is the ideal amplitude of the target frequency point.

[0131] S143: Determine the bandwidth deviation corresponding to the target frequency point according to the first bandwidth corresponding to the target frequency point and the ideal bandwidth corresponding to the target frequency point.

[0132] Similarly, the ideal bandwidth corresponding to the target frequency point is also measured under the reference wearing conditions during design and stored in the memory of the earphone. The first bandwidth corresponding to the target frequency point is compared with the ideal bandwidth corresponding to the target frequency point, and the difference between the two is calculated to determine the bandwidth deviation corresponding to the target frequency point.

[0133] The change in bandwidth reflects the influence of the wearing position on the sound frequency distribution. By calculating the bandwidth deviation, the degree of influence of the wearing position difference on the frequency characteristics of the target frequency point can be understood.

[0134] Specifically, the bandwidth deviation: ΔBW(f i ) = BW ideal - BW measured ;

[0135] where BW ideal is the ideal bandwidth.

[0136] In this embodiment, by separately extracting the amplitude and bandwidth of the target frequency point and calculating the deviation from the ideal value, the influence of the position difference when different people wear the earphone on the acoustic characteristics can be quantified more accurately. Since both the amplitude and bandwidth deviations are considered simultaneously, the influence of the wearing position change on the sound propagation can be reflected more comprehensively. In addition, by calculating the amplitude and bandwidth deviations for multiple frequency points in the prompt sound respectively, the changes of different frequency components under different wearing positions can be adapted, making the active noise reduction automatic adjustment method more adaptable and flexible.

[0137] As an optional implementation manner, refer to Figure 4 , S150: Adjust the filter coefficient of the noise reduction filter of the earphone according to the deviation, including S151 - S152:

[0138] S151: Adjust the gain of the target frequency point in the noise reduction filter according to the amplitude deviation of the target frequency point.

[0139] After obtaining the amplitude deviation of the target frequency point, it is necessary to adjust the gain of the target frequency point in the noise reduction filter according to this deviation.

[0140] Exemplarily, first, establish a mapping relationship between the amplitude deviation and the gain adjustment amount. This mapping relationship can be obtained through experiments or theoretical calculations and stored in the memory of the earphone. For example, when the amplitude deviation is positive, it means the first amplitude is greater than the ideal amplitude, and at this time, it is necessary to appropriately reduce the gain of the target frequency point; when the amplitude deviation is negative, it means the first amplitude is less than the ideal amplitude, and it is necessary to appropriately increase the gain of the target frequency point. According to the amplitude deviation and the mapping relationship, the gain adjustment amount can be calculated, and then the gain of the target frequency point in the noise reduction filter is adjusted.

[0141] By adjusting the gain of the target frequency points in the noise reduction filter, the amplitude change of the target frequency points caused by different wearing positions can be compensated. Specifically, due to the position differences of different people wearing open headphones, the energy attenuation of sound during propagation is different, resulting in a deviation between the amplitude of the target frequency points and the ideal amplitude. By adjusting the gain, the processing of the target frequency points by the noise reduction filter can be made more in line with the ideal state, improving the noise reduction effect.

[0142] S152: Adjust the quality factor of the target frequency points in the noise reduction filter according to the bandwidth deviation corresponding to the target frequency points.

[0143] Exemplarily, for the bandwidth deviation corresponding to the target frequency points, a mapping relationship between the bandwidth deviation and the quality factor adjustment amount also needs to be established.

[0144] The quality factor Q is closely related to the bandwidth. The narrower the bandwidth, the higher the quality factor; the wider the bandwidth, the lower the quality factor. When the bandwidth deviation is positive, that is, the first bandwidth is greater than the ideal bandwidth, the quality factor needs to be increased to narrow the bandwidth of the noise reduction filter; when the bandwidth deviation is negative, that is, the first bandwidth is less than the ideal bandwidth, the quality factor needs to be decreased to widen the bandwidth of the noise reduction filter. According to the bandwidth deviation and the mapping relationship, the quality factor adjustment amount can be calculated, and then the quality factor of the target frequency points in the noise reduction filter is adjusted.

[0145] By adjusting the quality factor of the target frequency points in the noise reduction filter, the bandwidth change of the target frequency points caused by different wearing positions can be compensated. Specifically, the difference in wearing positions affects the frequency distribution of sound, resulting in a discrepancy between the bandwidth of the target frequency points and the ideal bandwidth. By adjusting the quality factor, the bandwidth characteristics of the noise reduction filter can be adjusted to make the noise reduction filter better adapt to the actual acoustic environment and further optimize the noise reduction effect.

[0146] Exemplarily, the noise reduction filter coefficients are adjusted in the following manner:

[0147] 1) Filter coefficient mapping:

[0148] Map the measured deviations ΔG(f i ) and ΔBW(f i ) to the center frequency point f ANC of the noise reduction filter, and adjust the filter coefficients point by point.

[0149] 2) Adjustment of the gain G:

[0150] Adjust the gain G of each center frequency point: G new (f i ) = G old (f i ) + η·ΔG(f i );

[0151] η: Compensation ratio coefficient, used for smooth adjustment, 0 < η ≤ 1.

[0152] 3) Adjustment of quality factor Q:

[0153] Indirectly adjust the quality factor Q through the bandwidth deviation, and calculate the new first bandwidth: BW new = BW old + η·ΔBW(f i );

[0154] where BW old is the first bandwidth before adjustment.

[0155] Update the quality factor Q:

[0156] The adjustment of gain helps to compensate for the amplitude changes caused by wearing differences, while the adjustment of the quality factor can precisely control the bandwidth characteristics of the filter. Therefore, this embodiment can adjust the gain and quality factor of the filter according to the actual wearing state of the wearer. By combining the amplitude deviation and the bandwidth deviation, the working effect of the noise reduction filter can be optimized specifically, so that the noise reduction performance can reach an ideal level under different wearing conditions.

[0157] As an alternative embodiment, the noise reduction filter includes a feedforward filter located on the feedforward noise reduction path of the earphone and / or a feedback filter located on the feedback noise reduction path; both the feedforward filter and the feedback filter include a plurality of second-order IIR filters, and the center frequencies of the plurality of second-order IIR filters correspond one-to-one to the multiple frequency points of the prompt sound.

[0158] The center frequency of the noise reduction filter refers to the center point of the specific frequency range targeted by each second-order IIR filter in its design. That is to say, the center frequency of each second-order IIR filter corresponds to a specific frequency component, which enables the filter to effectively enhance or suppress the signal near that frequency.

[0159] The feedforward noise reduction path mainly collects the environmental noise signal in advance through the feedforward microphone outside the earphone and processes it before the sound reaches the human ear; the feedback noise reduction path uses the feedback microphone near the human ear inside the earphone to collect the sound signal that has already entered the earphone and processes the residual noise.

[0160] The feedforward filter processes the environmental noise signal before it affects the human ear. By collecting the noise signal in advance, the feedforward filter can generate a corresponding anti-phase signal according to the characteristics of the noise, thereby offsetting the environmental noise to a certain extent and reducing the interference of the noise on the user's hearing.

[0161] The feedback filter is used to process the residual noise that has entered the earphone. Since the feedforward filter may not be able to completely eliminate all noise, the feedback filter can further process this residual noise to improve the overall noise reduction effect.

[0162] The combined use of the feedforward filter and the feedback filter can process environmental noise more comprehensively, give full play to the advantages of feedforward and feedback noise reduction, and improve the overall noise reduction performance. The feedforward filter processes noise in advance, and the feedback filter corrects the residual noise. The two work together to more effectively reduce environmental noise and provide a quieter listening environment for users.

[0163] Both the feedforward filter and the feedback filter include multiple second-order infinite impulse response (IIR) filters. The second-order IIR filter has the advantages of simple structure, high computational efficiency, and can better achieve various frequency response characteristics. The center frequencies of these second-order IIR filters correspond one-to-one to the multiple frequencies of the prompt tone. For example, if the prompt tone contains 10 different frequencies, then there will be 10 second-order IIR filters in the feedforward filter and the feedback filter respectively, and the center frequency of each second-order IIR filter corresponds to one frequency of the prompt tone.

[0164] Corresponding the center frequencies of multiple second-order IIR filters one-to-one to the multiple frequencies of the prompt tone is to be able to precisely process different frequency components of the prompt tone. Different wearing positions may have different degrees of influence on sounds of different frequencies. Through this correspondence, each second-order IIR filter can specifically process the prompt tone frequency point corresponding to its center frequency, so as to more accurately adjust the noise reduction effect to adapt to the changes in acoustic characteristics under different wearing positions.

[0165] In this embodiment, the center frequencies of multiple second-order IIR filters are corresponded one-to-one to the multiple frequencies of the prompt tone, so that the noise reduction filter can precisely adjust for sounds of different frequencies. Compared with the traditional unified processing method, this targeted processing can better adapt to the changes in sounds of each frequency under different wearing positions, improve the accuracy and adaptability of noise reduction, and further optimize the user's auditory experience.

[0166] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0167] Corresponding to the active noise reduction automatic adjustment method described in the above embodiments, Figure 5 The structural block diagram of the active noise reduction automatic adjustment device provided by the embodiment of the present application is shown. For the sake of convenience of description, only the parts related to the embodiment of the present application are shown.

[0168] Refer toFigure 5 , the device includes:

[0169] A control module 210, configured to control a speaker of the earphone to emit a prompt tone when it is determined that the active noise reduction function of the earphone is turned on;

[0170] An acquisition module 220, configured to acquire an audio signal of the prompt tone collected by a feedback microphone of the earphone;

[0171] A spectrum analysis module 230, configured to perform spectrum analysis on the audio signal of the prompt tone to obtain a first spectrum;

[0172] A determination module 240, configured to determine a deviation between the first spectrum and an ideal spectrum;

[0173] An adjustment module 250, configured to adjust a filtering coefficient of a noise reduction filter of the earphone according to the deviation.

[0174] As an optional implementation manner, the determination module 240 further includes:

[0175] An extraction module 241, configured to extract a first amplitude of a target frequency point in the first spectrum and a first bandwidth at which the first amplitude drops by a set decibel; the target frequency point is any one of a plurality of frequency points in the prompt tone;

[0176] A first determination sub-module, configured to determine an amplitude deviation of the target frequency point according to the first amplitude of the target frequency point and an ideal amplitude of the target frequency point;

[0177] A second determination sub-module, configured to determine a bandwidth deviation corresponding to the target frequency point according to the first bandwidth corresponding to the target frequency point and an ideal bandwidth corresponding to the target frequency point.

[0178] As an optional implementation manner, the adjustment module 250 further includes:

[0179] A first adjustment sub-module 251, configured to adjust a gain of the target frequency point in the noise reduction filter according to the amplitude deviation of the target frequency point;

[0180] A second adjustment sub-module 252, configured to adjust a quality factor of the target frequency point in the noise reduction filter according to the bandwidth deviation corresponding to the target frequency point.

[0181] As an optional implementation manner, the active noise reduction automatic adjustment device further includes:

[0182] A determination module, configured to determine to turn on the active noise reduction function of the earphone when the earphone is in a worn state or a switching signal for the earphone to switch to the active noise reduction mode is received.

[0183] It should be noted that for the content such as information interaction and execution process among the above-mentioned devices / units, since it is based on the same concept as the method embodiments of the present application, for its specific functions and the resulting technical effects, reference may be specifically made to the method embodiment part, and details will not be elaborated here.

[0184] Those skilled in the art can clearly understand that, for the convenience and conciseness of description, only the above-mentioned division of each functional unit and module is used as an example for illustration. In practical applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated here.

[0185] The embodiments of the present application further provide a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0186] The embodiments of the present application provide a computer program product. When the computer program product runs on the earphone, the earphone can implement the steps in the above-mentioned method embodiments when executed.

[0187] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of this application, a computer program can be used to instruct the relevant hardware to complete. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can at least include: any entity or device that can carry the computer program code to the earphone, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium. For example, USB flash drive, mobile hard disk, magnetic disk, or optical disc, etc. In some jurisdictions, according to legislation and patent practice, the computer-readable medium cannot be electrical carrier signals and telecommunication signals.

[0188] The program code contained on the computer-readable medium can be transmitted by any suitable medium, including but not limited to wireless, wire, optical fiber, RF, etc., or any suitable combination of the above.

[0189] The computer program code for performing the operations of the embodiments of this application can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Python, Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed completely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0190] In the above embodiments, the descriptions of each embodiment have their own emphases. For parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0191] Those of ordinary skill in the art will realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. A professional technician can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0192] In the embodiments provided in this application, it should be understood that the disclosed device / headphone and method can be implemented in other ways. For example, the device / headphone embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0193] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0194] The above-described embodiments are only used to illustrate the technical solutions of this application, rather than to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included in the protection scope of this application.

Claims

1. An active noise reduction automatic adjustment method, characterized in that, Including: When it is determined that the active noise cancellation function of the earphone is turned on, controlling the speaker of the earphone to emit a prompt sound; Obtaining the audio signal of the prompt sound collected by the feedback microphone of the earphone; Performing spectrum analysis on the audio signal of the prompt sound to obtain a first spectrum; Determining the deviation between the first spectrum and the ideal spectrum; Adjusting the filtering coefficient of the noise cancellation filter of the earphone according to the deviation.

2. The active noise reduction automatic adjustment method according to claim 1, wherein The determining the deviation between the first spectrum and the ideal spectrum includes: Extracting the first amplitude of the target frequency point in the first spectrum and the first bandwidth where the first amplitude drops by a set decibel; the target frequency point is any one of multiple frequency points in the prompt sound; Determining the amplitude deviation of the target frequency point according to the first amplitude of the target frequency point and the ideal amplitude of the target frequency point; Determining the bandwidth deviation corresponding to the target frequency point according to the first bandwidth corresponding to the target frequency point and the ideal bandwidth corresponding to the target frequency point.

3. The active noise reduction automatic adjustment method according to claim 2, characterized in that, The adjusting the filtering coefficient of the noise cancellation filter of the earphone according to the deviation includes: Adjusting the gain of the target frequency point in the noise cancellation filter according to the amplitude deviation of the target frequency point; Adjusting the quality factor of the target frequency point in the noise cancellation filter according to the bandwidth deviation corresponding to the target frequency point.

4. The active noise reduction automatic adjustment method according to any one of claims 1-3, characterized in that The method further includes: When the earphone is in a worn state or when a switching signal for the earphone to switch to the active noise cancellation mode is received, determining to turn on the active noise cancellation function of the earphone.

5. The active noise reduction automatic adjustment method according to any one of claims 1 to 3, characterized in that The prompt sound has a first feature: The first feature includes one or more of the following: The frequency points of the prompt sound cover the midpoint frequency point of the noise cancellation filter; The prompt sound is formed by superimposing sine wave audio signals of multiple frequency points, and there is a phase difference between the initial phases of adjacent frequency points among the multiple frequency points; The duration of the prompt sound is a preset duration.

6. The active noise reduction automatic adjustment method according to claim 5, characterized in that The prompt sound also undergoes envelope smoothing signal processing to smooth the prompt sound.

7. The active noise reduction automatic adjustment method according to claim 5, characterized in that, The noise cancellation filter includes a feedforward filter on the feedforward noise cancellation path of the earphone and / or a feedback filter on the feedback noise cancellation path; Both the feedforward filter and the feedback filter include a plurality of second-order IIR filters, and the center frequency points of the plurality of second-order IIR filters correspond one-to-one to the multiple frequency points of the prompt sound.

8. An active noise reduction automatic adjustment device, characterized in that, Including: A control module, configured to control the speaker of the earphone to emit a prompt sound when it is determined that the active noise cancellation function of the earphone is turned on; An acquisition module, configured to acquire the audio signal of the prompt sound collected by the feedback microphone of the earphone; A spectrum analysis module, configured to perform spectrum analysis on the audio signal of the prompt sound to obtain a first spectrum; A determination module, configured to determine the deviation between the first spectrum and the ideal spectrum; An adjustment module, configured to adjust the filtering coefficient of the noise cancellation filter of the earphone according to the deviation.

9. A headset, characterized in that, The earphone has an active noise cancellation function, and the earphone includes: a speaker, a feedback microphone, a noise cancellation filter, and a processor; The processor is configured to execute the active noise cancellation automatic adjustment method according to any one of claims 1-7.

10. A computer program product, characterized in that, When the computer program product runs on the earphone, the earphone is caused to execute the method according to any one of claims 1 to 7.

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