CN115379354A - Filter coefficient setting method and device and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a filter coefficient setting method and device and electronic equipment. The method comprises the following steps: acquiring a first transfer function between a sound source and a microphone, a second transfer function between the sound source and the microphone wearing an earphone, and a third transfer function between a loudspeaker and the microphone, wherein the microphone is arranged in an artificial ear, and the loudspeaker is arranged in the earphone; determining a filter transfer function of each sub-filter in a pass-through filter, the pass-through filter being disposed in the earpiece; and determining the coefficients of the pass-through filter according to the first transfer function, the second transfer function, the third transfer function and the filter transfer function of each sub-filter. The accuracy of setting the filter coefficients is improved.

Description

Filter coefficient setting method, device and electronic equipment

technical field

The embodiments of the present application relate to the technical field of signal processing, and in particular to a filter coefficient setting method, device, and electronic equipment.

Background technique

Users can use earphones with pass-through function to obtain ambient sounds similar to those without earphones. A pass-through filter can be set in the headset so that the headset has a pass-through function.

In order to make the external ambient sound heard by the user when wearing the earphone be as consistent as possible with the external ambient sound when not wearing the earphone, it is necessary to adjust the coefficient of the transparent transmission filter. In related technologies, the coefficients of the transparent transmission filter may be adjusted in the following manner: manually adjusting the parameters of each sub-filter to determine the frequency response of the adjusted transparent transmission filter. When the frequency response of the transparent filter is close to the frequency response of the ideal transparent filter, the adjustment is completed. According to the parameters of each sub-filter after the adjustment is completed, the parameters of the transparent transmission filter are determined. In the above process, since it is necessary to manually adjust the parameters of each sub-filter to obtain the coefficients of the pass-through filter, the accuracy of setting the filter coefficients is low.

Contents of the invention

Embodiments of the present application provide a filter coefficient setting method, device, and electronic equipment to solve the problem of low accuracy in setting filter coefficients.

In the first aspect, the embodiment of the present application provides a filter coefficient setting method, including:

Obtaining a first transfer function between a sound source and a microphone, a second transfer function between a sound source and the microphone wearing an earphone, and a third transfer function between a loudspeaker and the microphone, the microphone being set in an artificial In the ear, the loudspeaker is arranged in the earphone;

Determining the filter transfer function of each sub-filter in the transparent filter, the transparent filter is set in the earphone;

Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function and the filter transfer functions of the sub-filters.

In a possible implementation manner, the coefficients of the transparent transmission filter are determined according to the first transfer function, the second transfer function, the third transfer function and the filter transfer functions of each sub-filter ,include:

determining the product of the filter transfer functions of the respective sub-filters as a fourth transfer function;

Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function.

In a possible implementation manner, determining coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function includes:

determining a sensitivity function based on the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function;

According to the sensitivity function, the coefficients of the transparent transmission filter are determined.

In a possible implementation manner, determining a sensitivity function according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function includes:

obtaining a product function of the third transfer function and the fourth transfer function;

Determining the difference between the first transfer function minus the second transfer function and the product function as an error signal;

A ratio of the error signal to the first transfer function is determined as the sensitivity function.

In a possible implementation manner, determining the coefficients of the transparent transmission filter according to the sensitivity function includes:

determining an objective function corresponding to the sensitivity function;

Adjusting the values of the filter parameters of the sub-filters until the minimum value of the objective function is obtained;

According to the value of the filter parameter of each sub-filter when the objective function takes the minimum value, it is determined as the coefficient of the transparent transmission filter.

In a possible implementation manner, according to the value of the filter parameter of each sub-filter when the objective function takes the minimum value, it is determined as the coefficient of the transparent transmission filter, including:

Determining the value of each sub-filter parameter as a coefficient of each sub-filter;

The coefficients of the sub-filters are cascaded to obtain the coefficients of the transparent transmission filter.

In a possible implementation manner, the sub-filter is a biquad filter.

In a second aspect, an embodiment of the present application provides a device for setting filter coefficients, the device comprising:

An acquisition module, configured to acquire a first transfer function between a sound source and a microphone, a second transfer function between a sound source and the microphone wearing an earphone, and a third transfer function between a speaker and the microphone, the The microphone is set in the artificial ear, and the speaker is set in the earphone;

The first determining module is used to determine the filter transfer function of each sub-filter in the transparent filter, and the transparent filter is set in the earphone;

The second determining module is configured to determine the coefficients of the transparent filter according to the first transfer function, the second transfer function, the third transfer function and the filter transfer functions of the sub-filters.

In a possible implementation manner, the second determining module is specifically configured to:

determining the product of the filter transfer functions of the respective sub-filters as a fourth transfer function;

Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function.

In a possible implementation manner, the second determining module is specifically configured to:

determining a sensitivity function based on the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function;

According to the sensitivity function, the coefficients of the transparent transmission filter are determined.

In a possible implementation manner, the second determining module is specifically configured to:

obtaining a product function of the third transfer function and the fourth transfer function;

Determining the difference between the first transfer function minus the second transfer function and the product function as an error signal;

A ratio of the error signal to the first transfer function is determined as the sensitivity function.

In a possible implementation manner, the second determining module is specifically configured to:

determining an objective function corresponding to the sensitivity function;

Adjusting the values of the filter parameters of the sub-filters until the minimum value of the objective function is obtained;

According to the value of the filter parameter of each sub-filter when the objective function takes the minimum value, it is determined as the coefficient of the transparent transmission filter.

In a possible implementation manner, the second determining module is specifically configured to:

Determining the value of each sub-filter parameter as a coefficient of each sub-filter;

The coefficients of the sub-filters are cascaded to obtain the coefficients of the transparent transmission filter.

In a possible implementation manner, the sub-filter is a biquad filter.

In a third aspect, the present application provides a chip, on which a computer program is stored, and when the computer program is executed by the chip, the method according to any one of the first aspect is realized.

In a fourth aspect, the present application provides a chip module, where a computer program is stored on the chip module, and when the computer program is executed by the chip module, the method according to any one of the first aspect is realized.

In a fifth aspect, the embodiment of the present application provides an electronic device, including:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor, so that the at least one processor can execute the method according to any one of the first aspect.

In a sixth aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to execute the method according to any one of the first aspect.

In a seventh aspect, an embodiment of the present application provides a computer program product, including a computer program, which implements the method according to any one of the first aspect when the computer program is executed by a processor.

The filter coefficient setting method, device and electronic equipment provided in the embodiments of the present application can obtain transfer functions of sound sources under different conditions, and determine the filter transfer functions of each sub-filter in the transparent transmission filter. According to the transfer function of the sound source under different conditions and the transfer function of each sub-filter, the coefficients of the transparent filter are automatically determined. There is no need for manual adjustment, which improves the accuracy of setting filter coefficients.

Description of drawings

FIG. 1 is a schematic diagram of an application scenario provided by an embodiment of the present application;

FIG. 2 is a schematic flowchart of a method for setting filter coefficients provided in an embodiment of the present application;

FIG. 3A is a schematic diagram of a process of obtaining a transfer function provided by an embodiment of the present application;

FIG. 3B is a schematic diagram of another process of obtaining a transfer function provided by the embodiment of the present application;

FIG. 4 is a schematic flowchart of another method for setting filter coefficients provided in an embodiment of the present application;

Fig. 5 is a schematic diagram of the process of determining f _k provided by the embodiment of the present application;

FIG. 6 is a schematic diagram of the design of the transparent transmission filter provided by the embodiment of the present application;

FIG. 7 is a schematic structural diagram of a filter coefficient setting device provided in an embodiment of the present application;

FIG. 8 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Detailed ways

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with aspects of the present application as recited in the appended claims.

It should be noted that, in this document, the term "comprising", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising that element.

FIG. 1 is a schematic diagram of an application scenario provided by an embodiment of the present application. Referring to FIG. 1 , a transparent filter 101 is set in the earphone. When the user wears the earphone, when the user needs to hear the external ambient sound, the earphone can transparently transmit the external environmental sound through the transparent transmission filter 101, so that the external environmental sound heard by the user while wearing the earphone is It is as close as possible to the external ambient sound heard by the user without headphones.

In the related art, since it is necessary to manually adjust the coefficients of the transparent transmission filter, the accuracy of setting the filter coefficients is low.

In the embodiment of the present application, the transfer function of the sound source under different conditions can be obtained, and the filter transfer function of each sub-filter in the transparent filter can be determined. According to the transfer function of the sound source under different conditions and the transfer function of each sub-filter, the coefficients of the transparent filter are automatically determined. There is no need for manual adjustment, which improves the accuracy of setting filter coefficients.

In the following, the method shown in this application will be described through specific examples. It should be noted that the following embodiments may exist independently or be combined with each other, and the same or similar content will not be repeatedly described in different embodiments.

FIG. 2 is a schematic flowchart of a method for setting filter coefficients provided in an embodiment of the present application. See Figure 2, the method can include:

S201. Acquire a first transfer function between a sound source and a microphone, a second transfer function between a sound source and a microphone wearing an earphone, and a third transfer function between a speaker and the microphone.

The executor of the embodiment of the present application may be an electronic device, or may be a chip, a chip module, or a filter coefficient setting device installed in the electronic device. The device for setting filter coefficients can be implemented by software, or by a combination of software and hardware. The electronic device may be a computer.

The microphone is set in the artificial ear, and the speaker is set in the earphone.

The first transfer function, the second transfer function and the third transfer function can be obtained through experimental testing.

Next, the process of obtaining the first transfer function, the second transfer function and the third transfer function will be described with reference to FIGS. 3A-3B .

FIG. 3A is a schematic diagram of a process of obtaining a transfer function provided by an embodiment of the present application. Please refer to FIG. 3A , which includes a playback device 301 and a model 302 . The playback device 301 may be a high-fidelity speaker, and the model 302 is provided with an artificial ear, and a microphone is provided in the artificial ear (the microphone is not shown in the figure). The playback device 301 is used to play the frequency sweep signal, and the microphone in the model 302 is used to collect the frequency sweep signal played by the playback device 301 . This process is used to simulate the external ambient sound heard by the human ear when the earphone is not worn. The frequency sweep signal can be a sine wave signal with a linear increase from 20Hz to 20kHz.

The first transfer function may be obtained in the following manner: when the model 302 plays the frequency sweep signal on the playback device 301 , the microphone of the model 302 collects the frequency sweep signal played by the playback device 301 . Fourier transform is performed on the frequency sweep signal played by the playback device 302 and the frequency sweep signal collected by the model 302 to change the time domain signal into a frequency domain signal. According to changes in the amplitude frequency and phase frequency of the frequency domain signal, a first transfer function between the sound source played by the playback device 301 and the microphone is determined.

FIG. 3B is a schematic diagram of another process of obtaining a transfer function provided by the embodiment of the present application. Please refer to FIG. 3B , which includes a playback device 301 , a model 302 and earphones 303 . The playback device 301 can be a high-fidelity speaker, the model 302 is provided with an artificial ear (artificial ear is not shown in the figure), a microphone is provided in the artificial ear, and an earphone 303 is worn on the artificial ear of the model 302 .

The playback device 301 is used to play the frequency sweep signal, and the microphone in the model 302 is used to collect the frequency sweep signal played by the playback device 301 when the earphone 303 is worn. This process is used to simulate the external environment sound heard by the human ear when wearing earphones.

The second transfer function can be acquired in the following manner: when the playback device 301 plays the frequency sweep signal, and the model 302 wears the earphone 303 , the artificial ear microphone of the model 302 collects the frequency sweep signal played by the playback device 301 . Fourier transform is performed on the frequency sweep signal played by the playback device 302 and the frequency sweep signal collected by the model 302 to change the time domain signal into a frequency domain signal. A second transfer function between the sound source and the microphone wearing the earphone is determined according to the amplitude-frequency and phase-frequency changes of the frequency domain signal.

When the model 302 is wearing the earphone 303, the earphone 303 is used to directly play the sweeping signal, so as to simulate the sound source played by the earphone when a person uses the earphone.

The third transfer function can be obtained in the following manner: when the model 302 wears the earphone 303 , the speaker of the earphone 303 plays a frequency sweep signal, and the artificial ear microphone of the model 302 collects and plays the frequency sweep signal played by the speaker of the earphone 303 . Fourier transform is performed on the frequency sweep signal played by the speaker of the earphone 303 and the frequency sweep signal collected by the model 302, and the time domain signal is changed into a frequency domain signal. A third transfer function between the loudspeaker and the microphone is determined according to the amplitude-frequency and phase-frequency changes of the frequency domain signal.

S202. Determine the filter transfer function of each sub-filter in the pass-through filter.

The pass-through filter is set in the earphone. A pass-through filter can include one or more sub-filters. Wherein, multiple sub-filters are cascaded to form a pass-through filter. The sub-filters may be biquad filters. The filter transfer function of the sub-filter may be determined according to the type of the sub-filter.

For example, if the transparent filter includes a peak filter, then the sub-filter in the transparent filter is a peak filter. The filter transfer function of the peak filter can be shown in Equation 1:

Wherein, H ₀ (z) is the filter transfer function of the peak filter. The parameters in Formula 1 can be determined by Formula 2, Formula 3, and Formula 4.

Formula 2: A = 10 ^g/40

Formula 3:

Formula 4:

Among them, g is the single-section gain; f is the center frequency; f _s is the sampling frequency; Q is the quality factor.

S203. Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function, and the filter transfer functions of the sub-filters.

The coefficients of the transparent filter can be determined in the following manner: the product of the filter transfer functions of each sub-filter is determined as the fourth transfer function; according to the first transfer function, the second transfer function, the third transfer function and the fourth Transfer function, which determines the coefficients of the pass-through filter.

For example, the transparent transmission filter includes two sub-filters, which are sub-filter 1 and sub-filter 2 respectively. The filter transfer function of the sub-filter 1 is H ₀ (z), and the filter transfer function of the sub-filter 2 is H ₁ (z). Then it can be determined that the fourth transfer function is H ₀ (z)×H ₁ (z).

A sensitivity function is determined based on the first transfer function, the second transfer function, the third transfer function and the fourth transfer function. According to the sensitivity function, the coefficients of the pass-through filter are determined.

In order to make the external ambient sound heard by the user when wearing the earphone be as consistent as possible with the external ambient sound when not wearing the earphone, it is necessary to make the sensitivity function close to 0. When the sensitivity function is close to 0, the frequency response of the transparent filter is close to the frequency response of the ideal transparent filter. At this time, the coefficient of the transparent filter is the coefficient of the transparent filter set in the earphone.

The filter coefficient setting method provided in the embodiment of the present application obtains the first transfer function between the sound source and the microphone, the second transfer function between the sound source and the microphone wearing the earphone, and the third transfer function between the speaker and the microphone function; determine the filter transfer function of each sub-filter in the transparent filter; determine the filter transfer function of the transparent filter according to the first transfer function, the second transfer function, the third transfer function and the filter transfer function of each sub-filter coefficient. In the above process, the coefficients of the transparent filter are determined according to the first transfer function, the second transfer function, the third transfer function and the filter transfer functions of each sub-filter instead of manual adjustment. Improved accuracy of setting filter coefficients.

FIG. 4 is a schematic flowchart of another method for setting filter coefficients provided in an embodiment of the present application.

See Figure 4, the method can include:

S401. Acquire a first transfer function, a second transfer function, and a third transfer function.

It should be noted that, for the execution process of S401, refer to S201, which will not be repeated here.

S402. Determine the filter transfer function of each sub-filter in the pass-through filter.

The pass-through filter is set in the earphone. A type of sub-filter corresponds to a transfer function of the same form.

For example, assuming the sub-filter is a shelving filter, its transfer function can be shown in Equation 5:

Wherein, H ₁ (z) is the filter transfer function of the shelf filter. See above for explanation of other parameters. The parameters in Formula 5 can be determined by Formula 2, Formula 3, and Formula 4.

S403. Determine the product of the filter transfer functions of the sub-filters as a fourth transfer function.

For example, a pass-through filter includes three sub-filters, namely sub-filter 1, sub-filter 2 and sub-filter 3. The filter transfer function of the sub-filter 1 is H ₀ (z), the filter transfer function of the sub-filter 2 is H ₁ (z), and the filter transfer function of the sub-filter 2 is H ₂ (z). Then it can be determined that the fourth transfer function is H ₀ (z)×H ₁ (z)×H ₂ (z).

S404. Determine a sensitivity function according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function.

The sensitivity function can be determined in the following manner: obtain the product function of the third transfer function and the fourth transfer function; subtract the difference between the first transfer function and the second transfer function and the product function, and determine it as an error signal; combine the difference function with The ratio of the first transfer function is determined as the sensitivity function.

The sensitivity function can be determined by the following formula 5:

Among them, E(z) is the z transformation of the error signal; T(z) is the first transfer function; P(z) is the second transfer function; S(z) is the third transfer function; A(z) is the fourth Transfer Function.

The error signal is a difference signal between the ambient sound source signal acquired when the earphone is not worn and the ambient sound source signal acquired when the earphone is worn.

For example, r(n) is the ambient sound source signal acquired when the earphone is not worn, and d(n) is the difference signal of the ambient sound source signal acquired when the earphone is worn. Then the error signal is e(n)=r(n)-d(n).

S405. Determine an objective function corresponding to the sensitivity function.

The objective function can be determined by the following formula 6:

Among them, E ^obj is the objective function corresponding to the sensitivity function; f _k is any frequency point within the frequency range of the transparent filter; f _stop is the cut-off frequency of the transparent filter; w(f _k ) is the fitting frequency weight factor. Other related parameters are explained above.

After putting on the earphones, the corresponding frequency range when the external environment sound can be heard is determined as the frequency band of the transparent transmission filter. For example, the frequency band of the transparent transmission filter is 20Hz-4000Hz. Then the value of f _k can be any frequency within 20Hz-4000Hz.

When determining the value of f _k , the value of k at each sampling point can be determined according to a preset relationship. According to the k value, f _k corresponding to each k value is determined. Next, with reference to FIG. 5 , the process of determining f _k will be described.

FIG. 5 is a schematic diagram of a process of determining f _k provided by an embodiment of the present application. See Figure 5, including two processes. Please refer to process 1, the curve in process 1 is the relationship curve between sampling points and k value. Wherein, sampling points=1, 2, 3, ... n. According to the relationship curve between the sampling point and the k value, determine the k value corresponding to each sampling point. Please refer to process 2, the curve in process 2 is the relationship curve between k and f _k . According to the relationship curve between k and f _k , determine f _k corresponding to each value of k. According to the k value corresponding to the sampling point in process 1, determine the f _k corresponding to each sampling point. The f _k corresponding to each sampling point can be specifically shown in Table 1:

Table 1

Sampling point k f_k 1 k₁ f₁ 2 k₂ f₂ 3 k₃ f₃ 4 k₄ f₄ 5 k₅ f₅

It should be noted that if f _k is greater than f _stop , the sampling is stopped.

The weight coefficient w(f _k ) of the fitting frequency can be adjusted according to the frequency band on which the transparent transmission filter acts.

When determining the coefficients of the transparent transmission filter, the value of the filter parameter of each sub-filter may be adjusted through a preset algorithm, so as to minimize the value of the objective function E ^obj . The smaller the value of the objective function E ^obj , the better the external ambient sound heard by the user when wearing the earphone is as consistent as possible with the external ambient sound when not wearing the earphone. Initially, the values of the filter parameters of each sub-filter can be randomly selected.

The preset algorithm may be a global optimization algorithm. For example, the preset algorithm may be a genetic algorithm, a particle swarm algorithm, and a differential evolution algorithm.

The value of the objective function can be determined in the following manner: determine the value of the filter parameters of each sub-filter; determine the transfer function of each sub-filter according to the value of the parameter of each sub-filter; The product of the transfer function of the device, determine the corresponding fourth transfer function under this condition; determine the error signal according to the first transfer function, the second transfer function, the third transfer function and the fourth transfer function; according to the error signal and the first transfer function function to determine the sensitivity function; according to the sensitivity function, determine the value of the objective function under this condition.

For example, a pass-through filter includes 2 sub-filters. When determining the value of the objective function, the values of the filter parameters of the two sub-filters are determined according to a preset algorithm. The values of the filter parameters of the sub-filter 1 are f ₁ , Q ₁ , g ₁ , and the values of the filter parameters of the sub-filter 2 are f ₂ , Q ₂ , g ₂ . According to the values f ₁ , Q ₁ , and g ₁ of the parameters of the sub-filter 1, the transfer function of the sub-filter 1 is determined to be H ₁ (z). According to the values f ₂ , Q ₂ , and g ₂ of the filter parameters of the sub-filter 2, the transfer function of the sub-filter 2 is determined to be H ₂ (z). At this time, it can be determined that the corresponding fourth transfer function under this condition is H ₁ (z)×H ₂ (z). According to the first transfer function, the second transfer function, the third transfer function and the corresponding fourth transfer function under this condition, the error signal is determined as E ₁ (z). From the error signal E ₁ (z) and the first transfer function, a sensitivity function is determined. According to the sensitivity function, determine the value of the objective function under this condition

S406. Determine whether the objective function is to obtain a minimum value.

If yes, execute S408.

If not, execute S407.

S407. Adjust the value of the filter parameter of each sub-filter, so as to update the transfer function of each sub-filter.

The parameters of the sub-filter include: single section gain g, center frequency f and quality factor Q.

For example, a pass-through filter includes 2 sub-filters. Wherein, the center frequency corresponding to the sub-filter 1 is f ₁ , the quality factor is Q ₁ , and the single-section gain is g ₁ . The center frequency corresponding to the sub-filter 2 is f ₂ , the quality factor is Q ₂ , and the single-section gain is g ₂ . Then it can be determined that the values of the filter parameters of the sub-filter 1 are f ₁ , Q ₁ , and g ₁ . Determine the values of the filter parameters of the sub-filter 2 as f ₂ , Q ₂ , and g ₂ .

The transfer function of each sub-filter can be updated in the following manner: the value of the filter parameter of each sub-filter is determined as the adjusted coefficient of each sub-filter; according to the adjusted coefficient of each sub-filter, each sub-filter is updated. The transfer function of the filter.

此时，若确定

并不是灵敏度函数对应的目标函数的最小值。则调整2个子滤波器的滤波器参数的取值。调整后子滤波器1的系数x₁′＝[f₁′，Q₁′，g₁′]，子滤波器2的系数x₂’＝[f₂′，Q₂′，g₂′]。根据调整后子滤波器1的系数，更新子滤波器1的传递函数为H₁′(z)。根据调整后子滤波器2的系数，更新子滤波器2的传递函数为H₂′(z)。For example, a pass-through filter includes 2 sub-filters. Wherein, the coefficient x ₁ of the sub-filter 1 =[f ₁ , Q ₁ , g ₁ ], and the coefficient x ₂ of the sub-filter 2 =[f ₂ , Q ₂ , g ₂ ]. According to the coefficient x ₁ of the sub-filter 1, the transfer function of the sub-filter 1 is determined as H ₁ (z). According to the filter coefficient x ₂ of the sub-filter 2, the transfer function of the sub-filter 2 is determined as H ₂ (z). When minimizing the objective function corresponding to the sensitivity function, the objective function corresponding to the sensitivity function is obtained as

At this point, if determined

is not the minimum value of the objective function corresponding to the sensitivity function. Then adjust the values of the filter parameters of the two sub-filters. After adjustment, the coefficient x ₁ ′ of the sub-filter 1=[f ₁ ′, Q ₁ ′, g ₁ ′], and the coefficient x _{2 ′} of the sub-filter 2=[f ₂ ′, Q ₂ ′, g ₂ ′]. According to the adjusted coefficients of the sub-filter 1, the transfer function of the sub-filter 1 is updated as H ₁ ′(z). According to the adjusted coefficients of the sub-filter 2, the transfer function of the sub-filter 2 is updated as H ₂ ′(z).

After S407, execute S403.

S408. Determine coefficients of the transparent transmission filter according to values of filter parameters of each sub-filter.

The coefficients of the transparent filter can be determined in the following manner: determining the value of each sub-filter parameter as the coefficient of each sub-filter; cascading the coefficients of the sub-filters to obtain the coefficients of the transparent filter.

For example, suppose a pass-through filter can be composed of a peak filter and a shelving filter. Wherein, the center frequency corresponding to the peak filter is f ₁ , the quality factor is Q ₁ , and the single-section gain is g ₁ . The center frequency corresponding to the shelf filter is f ₂ , the quality factor is Q ₂ , and the single-section gain is g ₂ . Then the coefficient x ₁ =[f ₁ , Q ₁ , g ₁ ] of the peak filter can be determined. The coefficients x ₂ =[f ₂ , Q ₂ , g ₂ ] of the shelving filter are determined. The coefficients of the two sub-filters are cascaded to obtain the coefficients X=[x ₁ , x ₂ , G] of the transparent filter. Among them, G is the global gain.

The filter parameter setting method provided by the embodiment of the present application obtains the first transfer function, the second transfer function and the third transfer function; determines the fourth transfer function; according to the first transfer function, the second transfer function, the third transfer function and The fourth transfer function is to determine the sensitivity function; the objective function corresponding to the sensitivity function is minimized through a preset algorithm, and the value of the filter parameter of each sub-filter is adjusted. According to the value of the filter parameter of each sub-filter, the coefficient of the transparent transmission filter is determined. In the above process, since the objective function corresponding to the sensitivity function is minimized through a preset algorithm, the filter parameters of each sub-filter are adjusted. According to the filter parameters of each sub-filter, the coefficients of the transparent transmission filter are determined. Instead of manual adjustment, the accuracy of setting filter coefficients is improved.

On the basis of any one of the above embodiments, the process of setting filter parameters will be illustrated below with reference to FIG. 6 . FIG. 6 is a design schematic diagram of a transparent transmission filter provided by an embodiment of the present application. Please refer to FIG. 6 , T(z) is the first transfer function; P(z) is the second transfer function; S(z) is the third transfer function; A(z) is the fourth transfer function. After the input signal x(n), x(n) becomes r(n) through the first transfer function T(z), x(n) becomes d(n) through the second transfer function P(z), and x( n) becomes y(n) through the fourth transfer function A(z). S(z) becomes y'(n) through the third transfer function. e(n) is an error signal, and e(n) is E(z) after z transformation.

It is assumed that the transparent transmission filter includes 2 sub-filters. Initially, the coefficient x ₁ of the sub-filter 1 =[f ₁ , Q ₁ , g ₁ ], and the coefficient x ₂ of the sub-filter 2 =[f ₂ , Q ₂ , g ₂ ]. According to the coefficient x ₁ of the sub-filter 1, the transfer function of the sub-filter 1 is determined as H ₁ (z). According to the coefficient x ₂ of the sub-filter 2, the transfer function of the sub-filter 2 is determined as H ₂ (z). At this time, the fourth transfer function A ₁ (z)=H ₁ (z)×H ₂ (z). The error signal e ₁ (n) obtained after the input signal x ₁ (n) is transformed by z to obtain E ₁ (z).

Sensitivity function 1 can be determined by Equation 5:

According to formula 6, the objective function corresponding to the sensitivity function 1 is determined.

是否为最小值。若是，则对每个子滤波器的系数进行级联处理，得到透传滤波器的系数X＝[x₁，x₂，G]。其中，G为全局增益。According to the preset algorithm, the judgment

Is it the minimum value. If yes, the coefficients of each sub-filter are cascaded to obtain the coefficient X=[x ₁ , x ₂ , G] of the transparent filter. Among them, G is the global gain.

If not, the values of the filter parameters of each sub-filter are adjusted. After adjustment, the coefficient x ₁ ′ of the sub-filter 1=[f ₁ ′, Q ₁ ′, g ₁ ′], and the coefficient x ₂ ′ of the sub-filter 2=[f ₂ ′, Q ₂ ′, g ₂ ′]. According to the coefficients of the adjusted sub-filter 1, it is determined that the transfer function of the adjusted sub-filter 1 is H ₁ ′(z). According to the coefficients of the adjusted sub-filter 2, it is determined that the transfer function of the adjusted sub-filter 2 is H ₂ ′(z). Then it can be determined that the adjusted fourth transfer function is A ₂ (z)=H ₁ ′(z)×H ₂ ′(z). At this time, the error signal e ₂ (n) obtained after the input signal x ₂ (n) is transformed by z to obtain E ₂ (z).

Sensitivity function 2 can be determined by Equation 5:

According to formula 6, the objective function corresponding to the sensitivity function 2 is determined.

是否为最小值。若是，则对每个子滤波器的系数进行级联处理，得到透传滤波器的系数X＝[x₁′，x₂′，G]。According to the preset algorithm, the judgment

Is it the minimum value. If yes, the coefficients of each sub-filter are cascaded to obtain the coefficients X=[x ₁ ′, x ₂ ′, G] of the transparent filter.

If not, adjust the values of the filter parameters of each sub-filter, and repeat the above steps until the objective function E ^obj corresponding to the sensitivity function is the minimum value. At this time, cascade processing is performed on the coefficients of each sub-filter to obtain the coefficients of the transparent transmission filter.

The coefficients of the obtained transparent filter are set after the transparent filter, and the transparent filter is configured into the earphone. At this time, the headset has the transparent transmission function.

The example of the process of setting filter parameters provided by the embodiment of the present application obtains the first transfer function, the second transfer function and the third transfer function; according to the values of the filter parameters of each sub-filter, determine the fourth transfer function ; Determine the sensitivity function according to the first transfer function, the second transfer function, the third transfer function and the fourth transfer function; minimize the target function corresponding to the sensitivity function through a preset algorithm, and adjust the filter parameters of each sub-filter value. The values of the filter parameters of each sub-filter determine the coefficients of each sub-filter. According to the coefficients of each sub-filter, the coefficients of the transparent transmission filter are determined. In the above process, since the objective function corresponding to the sensitivity function is minimized through a preset algorithm, the coefficients of each sub-filter are adjusted. According to the coefficients of each sub-filter, the coefficients of the transparent transmission filter are determined. Instead of manual adjustment, the accuracy of setting filter coefficients is improved.

FIG. 7 is a schematic structural diagram of an apparatus for setting filter coefficients provided by an embodiment of the present application. The filter coefficient setting device can be a chip or a chip module. Referring to Fig. 7, the filter coefficient setting device 10 may include:

An acquisition module 11, configured to acquire a first transfer function between a sound source and a microphone, a second transfer function between a sound source and the microphone wearing an earphone, and a third transfer function between a speaker and the microphone, The microphone is arranged in the artificial ear, and the speaker is arranged in the earphone;

The first determination module 12 is used to determine the filter transfer function of each sub-filter in the transparent filter, the transparent filter is arranged in the earphone;

The second determination module 13 is configured to determine coefficients of the transparent filter according to the first transfer function, the second transfer function, the third transfer function and filter transfer functions of each sub-filter.

The device for setting filter coefficients provided in the embodiments of the present application can implement the technical solutions shown in the above method embodiments, and its implementation principles and beneficial effects are similar, and will not be repeated here.

In a possible implementation manner, the second determination module 13 is specifically configured to:

determining the product of the filter transfer functions of the respective sub-filters as a fourth transfer function;

Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function.

In a possible implementation manner, the second determination module 13 is specifically configured to:

determining a sensitivity function based on the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function;

According to the sensitivity function, the coefficients of the transparent transmission filter are determined.

In a possible implementation manner, the second determining module 13 is specifically configured to:

obtaining a product function of the third transfer function and the fourth transfer function;

Determining the difference between the first transfer function minus the second transfer function and the product function as an error signal;

A ratio of the error signal to the first transfer function is determined as the sensitivity function.

In a possible implementation manner, the second determining module 13 is specifically configured to:

determining an objective function corresponding to the sensitivity function;

Adjusting the values of the filter parameters of the sub-filters until the minimum value of the objective function is obtained;

According to the value of the filter parameter of each sub-filter when the objective function takes the minimum value, it is determined as the coefficient of the transparent transmission filter.

In a possible implementation manner, the second determination module 13 is specifically configured to:

Determining the value of each sub-filter parameter as a coefficient of each sub-filter;

The coefficients of the sub-filters are cascaded to obtain the coefficients of the transparent transmission filter.

In a possible implementation manner, the sub-filter is a biquad filter.

The device for setting filter coefficients provided in the embodiments of the present application can implement the technical solutions shown in the above method embodiments, and its implementation principles and beneficial effects are similar, and will not be repeated here.

FIG. 8 is a schematic structural diagram of an electronic device provided by an embodiment of the present application. Referring to FIG. 8 , the electronic device 20 may include: a memory 21 and a processor 22 . Exemplarily, the memory 21 and the processor 22 are connected to each other through a bus 23 .

The memory 21 is used to store program instructions;

The processor 22 is configured to execute the program instructions stored in the memory, so as to make the electronic device 20 execute the methods shown in the above method embodiments.

The electronic device provided by the embodiment of the present application can implement the technical solutions shown in the above method embodiments, and its implementation principles and beneficial effects are similar, and will not be repeated here.

An embodiment of the present application provides a computer-readable storage medium, where computer-executable instructions are stored in the computer-readable storage medium, and the computer-executable instructions are used to implement the foregoing method when executed by a processor.

The embodiment of the present application may further provide a computer program product, including a computer program, and when the computer program is executed by a processor, the foregoing method may be implemented.

All or part of the steps for implementing the above method embodiments can be completed by program instructions and related hardware. The aforementioned program can be stored in a readable memory. When the program is executed, it executes the steps comprising the above-mentioned method embodiments; and the aforementioned memory (storage medium) includes: read-only memory (English: read-only memory, abbreviated: ROM), random access memory (English: Random Access Memor, abbreviation: RAM), flash memory, hard disk, solid state disk, magnetic tape (English: magnetic tape), floppy disk (English: floppy disk), optical disc (English: optical disc) and any combination thereof.

Embodiments of the present application are described with reference to flowcharts and/or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processing unit of other programmable data processing equipment to produce a machine such that the instructions executed by the processing unit of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

Apparently, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. In this way, if the modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and equivalent technologies, the present application also intends to include these modifications and variations.

In this application, the term "include" and its variants may mean non-limiting inclusion; the term "or" and its variants may mean "and/or". The terms "first", "second", etc. in this application are used to distinguish similar objects, and not necessarily used to describe a specific order or sequence. In the present application, "plurality" means two or more. "And/or" describes the association relationship of associated objects, indicating that there may be three types of relationships, for example, A and/or B may indicate: A exists alone, A and B exist simultaneously, and B exists independently. The character "/" generally indicates that the contextual objects are an "or" relationship.

Claims (11)

1. A filter coefficient setting method, characterized in that, comprising: Obtaining a first transfer function between a sound source and a microphone, a second transfer function between a sound source and the microphone wearing an earphone, and a third transfer function between a loudspeaker and the microphone, the microphone being set in an artificial In the ear, the loudspeaker is arranged in the earphone; Determining the filter transfer function of each sub-filter in the transparent filter, the transparent filter is set in the earphone; Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function and the filter transfer functions of the sub-filters. 2. The method according to claim 1, characterized in that, according to the filter transfer function of the first transfer function, the second transfer function, the third transfer function and each sub-filter, determine the The coefficients of the pass-through filter, including: determining the product of the filter transfer functions of the respective sub-filters as a fourth transfer function; Determine coefficients of the transparent transmission filter according to the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function. 3. The method according to claim 2, wherein, according to the first transfer function, the second transfer function, the third transfer function and the fourth transfer function, the transparent transmission filter is determined Coefficients of the device, including: determining a sensitivity function based on the first transfer function, the second transfer function, the third transfer function, and the fourth transfer function; According to the sensitivity function, the coefficients of the transparent transmission filter are determined. 4. The method according to claim 3, wherein, according to the first transfer function, the second transfer function, the third transfer function and the fourth transfer function, determining a sensitivity function comprises: obtaining a product function of the third transfer function and the fourth transfer function; Determining the difference between the first transfer function minus the second transfer function and the product function as an error signal; A ratio of the error signal to the first transfer function is determined as the sensitivity function. 5. The method according to claim 3 or 4, wherein, according to the sensitivity function, determining the coefficient of the transparent transmission filter comprises: determining an objective function corresponding to the sensitivity function; Adjusting the values of the filter parameters of the sub-filters until the minimum value of the objective function is obtained; According to the value of the filter parameter of each sub-filter when the objective function takes the minimum value, it is determined as the coefficient of the transparent transmission filter. 6. method according to claim 5, it is characterized in that, according to the value of the filter parameter of each sub-filter when getting described minimum value according to described objective function, be determined as the coefficient of described pass-through filter, comprise : Determining the value of each sub-filter parameter as a coefficient of each sub-filter; The coefficients of the sub-filters are cascaded to obtain the coefficients of the transparent transmission filter. 7. The method according to any one of claims 1-6, wherein the sub-filter is a biquad filter. 8. A filter coefficient setting device, characterized in that the device comprises: An acquisition module, configured to acquire a first transfer function between a sound source and a microphone, a second transfer function between a sound source and the microphone wearing an earphone, and a third transfer function between a speaker and the microphone, the The microphone is set in the artificial ear, and the speaker is set in the earphone; The first determining module is used to determine the filter transfer function of each sub-filter in the transparent filter, and the transparent filter is set in the earphone; The second determining module is configured to determine the coefficients of the transparent filter according to the first transfer function, the second transfer function, the third transfer function and the filter transfer functions of the sub-filters. 9. An electronic device, characterized in that it comprises: at least one processor; and a memory communicatively coupled to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, the instructions are executed by the at least one processor, so that the at least one processor can perform any one of claims 1 to 7 Methods. 10. A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to make the computer execute the method according to any one of claims 1-7. 11. A computer program product, comprising a computer program, characterized in that, when the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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