Method and equipment for determining amplitude gain of sub-band filter in graphic equalizer

Abstract

The invention provides a method and equipment for determining amplitude gains of sub-band filters in a graphic equalizer, and the method comprises the steps: determining the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer, and inputting an initial signal into all sub-band filters, obtaining a sub-band response signal which is output by each sub-band filter and corresponds to each center frequency and bandwidth, obtaining a difference value between each sub-band response signal and a preset target response signal, taking the difference value as an element to obtain a mutual influence matrix, and correcting the initial amplitude gain of each sub-band filter by an inverse matrix of the mutual influence matrix to obtain a sub-band response signal; according to the scheme of the invention, the method can eliminate the mutual influence between different sub-band filters through the change of the amplitude gain of each sub-band filter, and a final filtering result is higher in precision.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to a method and device for determining the amplitude gain of a sub-band filter in a graphic equalizer. Background Art

[0002] The graphic equalizer is an equalizer that uses equalization filtering to achieve filtering performance. It includes multiple cascaded sub-band filters. After the signal to be filtered is input into the graphic equalizer, each sub-band filter filters the signal with its center frequency and bandwidth. After the signal passes through different sub-band filters, the response signals of different center frequencies may overlap to varying degrees. This results in that when the signal enters the sub-band filter corresponding to one of the center frequencies, in addition to the response signal output by the sub-band filter itself, it may also carry the overlapping part of the response signal output by other sub-band filters of the center frequency. The overlapping part changes the amplitude of the response signal, making the actual amplitude gain of the sub-band filter inconsistent with the pre-designed target gain response, resulting in reduced accuracy of the filtering result. Summary of the invention

[0003] The technical problem to be solved by the present application is that the actual amplitude gain of each sub-band filter in the equalization filtering method in the prior art does not conform to the target gain, resulting in low accuracy of the filtering result. To this end, the present application proposes a method and device for determining the amplitude gain of a sub-band filter in a graphic equalizer.

[0004] In a first aspect, the technical solution of the present application provides a method for determining the amplitude gain of a sub-band filter in a graphic equalizer, comprising:

[0005] Determine the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer;

[0006] Inputting the initial signal to all the sub-band filters, and obtaining a sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths;

[0007] Obtaining a difference value between each of the sub-band response signals and a preset target response signal, and using the difference value as an element to obtain a mutual influence matrix;

[0008] The initial amplitude gain of each of the sub-band filters is corrected by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each of the sub-band filters.

[0009] In some embodiments, the method for determining the amplitude gain of a sub-band filter in a graphic equalizer, wherein the initial amplitude gain of each sub-band filter is corrected by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each sub-band filter, comprises:

[0010] Multiplying the inverse matrix of the mutual influence matrix by the initial amplitude gain matrix of each sub-band filter to determine the initial target amplitude gain of each sub-band filter;

[0011] The initial target amplitude gain of each of the sub-band filters is used as the target amplitude gain of each of the sub-band filters.

[0012] In some embodiments, the method for determining the amplitude gain of a sub-band filter in a graphic equalizer, wherein the initial amplitude gain of each sub-band filter is corrected by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each sub-band filter, comprises:

[0013] Multiplying the inverse matrix of the mutual influence matrix by the initial amplitude gain matrix of each sub-band filter to determine the initial target amplitude gain of each sub-band filter;

[0014] Updating the initial amplitude gain of each of the sub-band filters using the initial target amplitude gain of the sub-band filter;

[0015] inputting the initial signal to all the sub-band filters again, and obtaining a secondary sub-band response signal output by each sub-band filter corresponding to each center frequency and the bandwidth;

[0016] Obtaining the difference between each of the secondary sub-band response signals and the preset target response signal to obtain a secondary interaction matrix;

[0017] The inverse matrix of the quadratic interaction matrix is ​​multiplied by the initial target amplitude gain matrix of each sub-band filter to determine the target amplitude gain of each sub-band filter.

[0018] The method for determining the amplitude gain of a sub-band filter in a graphic equalizer in some embodiments, wherein the initial signal is input to all the sub-band filters, and a sub-band response signal corresponding to each of the center frequencies and the bandwidth output by each of the sub-band filters is obtained, further comprising:

[0019] Inserting an interpolation center frequency point between the center frequencies of every two adjacent sub-band response signals;

[0020] Obtaining a corresponding relationship between a center frequency of each sub-band response signal and an amplitude of the sub-band response signal;

[0021] Substituting each of the interpolation center frequencies into the corresponding relationship to obtain a response signal amplitude corresponding to each of the interpolation center frequencies;

[0022] The response signal amplitude corresponding to each of the interpolation center frequencies is merged into the sub-band response signal as the updated sub-band response signal.

[0023] Method for determining amplitude gain of sub-band filter in a graphic equalizer described in some schemes:

[0024] The interpolation center frequency point is an average value of center frequencies of two adjacent sub-band response signals, or the interpolation center frequency point is a square root value obtained by multiplying center frequencies of two adjacent sub-band response signals.

[0025] In some embodiments, the method for determining the amplitude gain of a sub-band filter in a graphic equalizer, if the graphic equalizer is a graphic equalizer filter suitable for sound signals applied to a vehicle, then determining the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer includes:

[0026] The center frequency value of the human ear audible range is used as the center frequency, and the bandwidth of the human ear audible range is used as the bandwidth; wherein the center frequency of the latter sub-band filter in the two adjacent sub-band filters is twice the center frequency of the previous sub-band filter.

[0027] In a second aspect, the technical solution of the present application provides an equalization filter, comprising:

[0028] An information acquisition module configured to determine the number of sub-band filters in the graphic equalizer and the center frequency, bandwidth and initial amplitude gain of each of the sub-band filters;

[0029] a response signal acquisition module, configured to input an initial signal into all the sub-band filters, and acquire a sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths;

[0030] An influence relationship acquisition module is configured to obtain a difference value between each of the sub-band response signals and a preset target response signal, and obtain a mutual influence matrix using the difference value as an element;

[0031] The gain determination module is configured to modify the initial amplitude gain of each of the sub-band filters by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each of the sub-band filters.

[0032] In a third aspect, the technical solution of the present application provides a computer-readable storage medium, in which program information is stored. After a computer reads the program information, it executes the filter amplitude gain determination method described in any one of the first aspects.

[0033] In a fourth aspect, the technical solution of the present application provides an electronic device, comprising at least one processor and at least one memory, wherein at least one of the memories stores program information, and after reading the program information, at least one of the processors executes the filter amplitude gain determination method described in any one of the first aspects.

[0034] In a fifth aspect, the technical solution of the present application provides a vehicle, wherein the vehicle is equipped with the equalizing filter described in the second aspect, the computer-readable storage medium described in the third aspect, or the electronic device described in the fourth aspect.

[0035] The above technical solution has the following beneficial effects:

[0036] The present application provides a method and device for determining the amplitude gain of a sub-band filter in a graphic equalizer. After determining the center frequency and bandwidth of each sub-band filter in the graphic equalizer, the initial signal is passed through all the sub-band filters, so that each sub-band filter can obtain a sub-band response signal corresponding to each center frequency and bandwidth, obtain the difference value between each sub-band response signal and a preset target response signal, and obtain a mutual influence matrix with the difference value as an element. The mutual influence matrix can be used to determine the influence of each sub-band filter on the amplitude response of other sub-band filters. On this basis, the initial amplitude gain of each sub-band filter is corrected by the inverse matrix of the mutual influence matrix, and the target amplitude gain of each sub-band filter is determined. Then, the change of the amplitude gain of each sub-band filter can be used to eliminate the influence of each sub-band filter on other sub-band filters. Since the target amplitude gain of each sub-band filter can eliminate the influence of different sub-band signals, the final filtering result of the graphic equalizer has higher accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of a method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to an embodiment of the present application;

[0038] Figure 2a A schematic diagram of the amplitude gain results of each sub-band filter of an existing graphic equalizer;

[0039] Figure 2b This is a schematic diagram of the amplitude gain result of the sub-band filter in the graphic equalizer according to an embodiment of the present application;

[0040] Figure 3 This is a flow chart of a method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to another embodiment of the present application;

[0041] Figure 4 A schematic diagram of the amplitude gain result of the sub-band filter in the graphic equalizer according to another embodiment of the present application;

[0042] Figure 5a This is a schematic diagram of the amplitude gain result of the sub-band filter in the graphic equalizer according to another embodiment of the present application;

[0043] Figure 5b for Figure 5a A magnified schematic diagram of the middle part of the curve;

[0044] Figure 6 This is a structural block diagram of a graphic equalizer according to an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the hardware connection relationship of an electronic device described in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The specific implementation of the present application is further described below with reference to the accompanying drawings.

[0047] It is easy to understand that according to the technical solution of the present application, without changing the essential spirit of the present application, a variety of structural modes and implementation modes that can be replaced by those skilled in the art can be replaced with each other. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present application, and should not be regarded as the entirety of the present application or as a limitation or restriction on the technical solution of the application.

[0048] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to different positions and different usage conditions. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0049] The embodiment of the present application provides a method for determining the amplitude gain of a sub-band filter in a graphic equalizer, which is applied to a controller module. The controller module may be an on-board controller in a vehicle, for example Figure 1 As shown, the method includes:

[0050] S10: Determine the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer.

[0051] The graphic equalizer includes a plurality of cascaded sub-band filters, and the number of sub-band filters and the center frequency, bandwidth and initial amplitude gain of each sub-band filter are pre-designed parameters. If there is a communication connection between the controller module performing this step and the graphic equalizer, the above information can be directly requested and obtained.

[0052] For example, suppose that the graphic equalizer includes 10 sub-band filters, and the center frequency of each sub-band filter is 31.25Hz, 62.5Hz, 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz, 4000Hz, 8000Hz, and 16000Hz, and the bandwidth of each sub-band filter also increases in multiples, such as the bandwidth of the first sub-band filter is 62.5Hz, the bandwidth of the second sub-band filter is 125Hz, and so on.

[0053] S20: Inputting the initial signal to all the sub-band filters, and acquiring a sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths.

[0054] The initial signal can be any signal without limitation.

[0055] According to step S10, the number of sub-band filters is 10, and the sub-band response signals in this step include 10×10, and the center frequency of each sub-band response signal is 31.25 Hz, 62.5 Hz, 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz, and 16000 Hz, respectively, and the bandwidth of each sub-band response signal also corresponds to the bandwidth of each sub-band filter. In this step, the signal will be input to all sub-band filters, and each sub-band filter will receive and process the signal. Because the filtering results of sub-band filters with different center frequencies will affect each other, the sub-band response signal output by each sub-band filter will include the response signal corresponding to its center frequency and the signal generated by the influence of other center frequency sub-band filters. Therefore, if the initial signal passes through the sub-band filter of the first center frequency, it will actually output ten center frequency response signals, but the response signal corresponding to the current sub-band filter has the largest intensity, so the initial signal will obtain ten sub-band response signals after passing through each sub-band filter. Therefore, when the initial signal passes through 10 sub-band filters, 10×10 sub-band response signals are obtained. In this step, the sub-band response signal can be a frequency domain signal. In specific implementation, the frequency response of each sub-band filter can be solved as a sub-band response signal by methods such as convolution; or the frequency domain analysis can be performed according to the system function of each sub-band filter to solve the frequency response of each sub-band filter as a sub-band response signal.

[0056] S30: Obtaining the difference between each of the sub-band response signals and a preset target response signal, and using the difference as an element to obtain a mutual influence matrix.

[0057] Because the initial amplitude gain of each sub-band filter is predetermined, the target response signal corresponding to each sub-band filter can be calculated and determined. The sub-band response signal is an actual amplitude response. If the actual amplitude response is different from the target response signal, it means that the actual amplitude response is affected by other sub-band filters. At this time, the difference between the actual amplitude response and the target response signal can be used to determine the degree of influence. Generally, the difference value can be determined by a ratio. In the above steps, 10×10 sub-band response signals are obtained. The ratio between all sub-band response signals and the target response signal can also be used as an element to obtain a 10×10 mutual influence matrix. The mutual influence matrix includes multiple rows and columns of signal values, wherein the serial number of the sub-band filter is the row subscript and the serial number of the sub-band response signal is the column subscript (it can also be the other way around). It can be understood that the ratio is a way of implementation, and other methods can also be selected to determine the difference value and obtain the mutual influence matrix during the application process.

[0058] S40: Correcting the initial amplitude gain of each of the sub-band filters by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each of the sub-band filters.

[0059] For a cascade filter with multiple sub-band filters, the initial amplitude gain matrix of each sub-band filter can be multiplied by the mutual influence matrix to obtain the final output. The expected amplitude gain of each sub-band filter can form a vector, and the correction value of the initial amplitude gain of each sub-band filter can be obtained by directly multiplying the inverse matrix of the mutual influence matrix with the vector. Since the final output is obtained by multiplying the initial amplitude gain of each sub-band filter by the interaction matrix, due to the mutual influence of each sub-band filter, the final output is inconsistent with the expected output of each frequency band. By inverting the interaction matrix and multiplying it with the expected amplitude gain of each sub-band filter, the amplitude gain that should be set for each sub-band filter is inversely solved, that is, the first correction of the initial amplitude gain of each sub-band filter is completed.

[0060] The above scheme of the present application, after determining the center frequency and bandwidth of each sub-band filter in the graphic equalizer, divides the initial signal into multiple sub-band signals corresponding to the center frequency and bandwidth of each sub-band filter, passes the signal through all sub-band filters, then each sub-band filter can obtain a sub-band response signal corresponding to the signal, obtains the difference between each sub-band response signal and the preset target response signal, and uses the difference as an element to obtain a mutual influence matrix, through which the influence of the signal on the amplitude response of other sub-band signals can be determined, and on this basis, the initial amplitude gain of each sub-band filter is corrected by the inverse matrix of the mutual influence matrix, and the target amplitude gain of each sub-band filter is determined, so that the change of the amplitude gain of each sub-band filter can be used to eliminate the influence of each sub-band filter on other sub-band filters, and since the target amplitude gain of each sub-band filter can eliminate the influence of different sub-band filters, the final filtering result of the graphic equalizer has a higher accuracy. After verification and comparison, such as Figure 2a This is a schematic diagram of the filtering result waveform of a conventional graphic equalizer. Figure 2b Schematic diagram of the waveform of the filtering result of the present application scheme, where Figure 2b The amplitude gain result is closer to the actual target response signal.

[0061] In the above solution, step S40 may include the following steps:

[0062] S401: Multiplying the inverse matrix of the mutual influence matrix by the target amplitude gain matrix of each sub-band filter to obtain the actual set amplitude gain of each sub-band filter.

[0063] S402: Using the initial target amplitude gain of each of the sub-band filters as the target amplitude gain of each of the sub-band filters.

[0064] As another approach, the step S40 may include:

[0065] S40A: Multiplying the inverse matrix of the mutual influence matrix by the target amplitude gain matrix of each sub-band filter to obtain the actual set amplitude gain of each sub-band filter.

[0066] S40B: Update the initial amplitude gain of each of the sub-band filters using the actual set amplitude gain of the sub-band filter.

[0067] That is, the actually set amplitude gain is used as the updated initial amplitude gain of each sub-band filter.

[0068] S40C: Inputting the initial signal to all the sub-band filters again, and obtaining a secondary sub-band response signal output by each sub-band filter corresponding to each center frequency and the bandwidth.

[0069] That is, the process of step S20 is repeated, and at this time, the initial amplitude gain of each sub-band filter is already the updated amplitude gain.

[0070] S40D: Obtain the difference between each of the secondary sub-band response signals and the preset target response signal to obtain a secondary interaction matrix.

[0071] That is, the process of step S30 is repeated.

[0072] S40E: Multiplying the inverse matrix of the quadratic interaction matrix by the expected target amplitude gain matrix of each sub-band filter to determine the actual set amplitude gain of each sub-band filter.

[0073] That is, the steps S20 and S30 are performed again, thereby further improving the accuracy of the target amplitude gain result. With this solution, the initial amplitude gain of each sub-band filter is corrected twice, thereby eliminating the mutual influence between different sub-band filters twice, and improving the accuracy of the filtering results of each sub-band filter.

[0074] In some preferred embodiments, Figure 3 As shown, the following steps may also be included between step S20 and step S30:

[0075] S21: inserting an interpolation center frequency point between the center frequencies of every two adjacent sub-band response signals.

[0076] Specifically, a new center frequency point can be interpolated between the center frequencies of each adjacent sub-band response signal. Assuming that there are N sub-band response signals, that is, signals of N frequency bands, (N-1) interpolation center frequency points are interpolated using the intermediate values ​​of the center frequencies of adjacent frequency bands, and the corresponding interpolation center frequency points are f i1 ,f i2 ,…,f iN-1 , that is, the average value of two adjacent center frequency points is taken as the center frequency point of the intermediate interpolation. Another method can be selected. (k=1, 2, ..., N-1). In specific applications, it can be selected according to the application scenario.

[0077] S22: Obtaining the corresponding relationship between the center frequency of each sub-band response signal and the amplitude of the sub-band response signal.

[0078] As described in the above steps, there are N sub-band filters. After adding the original center frequency plus the interpolated center frequency point, there are a total of (2N-1) center frequencies. Assuming that there is a functional relationship between the center frequency and the initial amplitude gain, the functional relationship can be obtained by using the fitting relationship between the original N center frequencies and the sub-band response signal amplitude.

[0079] S23: Substituting each of the interpolation center frequencies into the corresponding relationship to obtain a response signal amplitude corresponding to each of the interpolation center frequencies.

[0080] Substituting the newly inserted interpolation center frequency point into the above functional relationship can determine the initial interpolation amplitude gain corresponding to each interpolation center frequency.

[0081] S24: Merging the response signal amplitude corresponding to each of the interpolation center frequencies into the sub-band response signal as the updated sub-band response signal.

[0082] In this way, (2N-1) center frequencies and (2N-1) sub-band response signals corresponding to the (2N-1) center frequencies are obtained.

[0083] By interpolating the central frequency points, the amount of data is increased, and more accurate results can be obtained during the calculation process, such as Figure 4 As shown, the amplitude of the response signal obtained by interpolation is closer to the target gain amplitude than the amplitude of the response signal obtained without interpolation.

[0084] In the above embodiments of the present application, the graphic equalizer may be a graphic equalizer filter suitable for sound signals used in vehicles. Then, in step S10: the center frequency value of the human ear audible range is used as the center frequency, and the bandwidth of the human ear audible range is used as the bandwidth; wherein the center frequency of the latter sub-band filter of the two adjacent sub-band filters is twice the center frequency of the former sub-band filter. Specifically, the graphic equalizer includes N sub-band filters, and the center frequency of each sub-band filter is determined to be f c1 ,f c2 ,…,f cN Since the human ear audible range can be divided into about 10 octave bands, taking N=10 as an example, the center frequencies of each band are 31.25, 62.5, 125, 250, 500, 1000, 2000, 4000, 8000, and 16000 Hz, respectively, that is, the center frequencies of each sub-band filter are the above frequency points.

[0085] After determining the frequency band of each sub-band filter, determine the initial amplitude gain at the center frequency of each sub-band filter. Assuming that the sub-band filter uses a Peak filter (peak filter) and adopts a biquad IIR filter structure, the system function of the Peak filter is expressed as:

[0086]

[0087] Peak filter coefficients:

[0088]

[0089] b 1 =-2cos(ω c );

[0090]

[0091]

[0092] a 1 =-2cos(ω c );

[0093]

[0094] B: bandwidth;

[0095] f c Center frequency, f s Sampling rate;

[0096] G: gain value in decibels at the center frequency;

[0097] G B : Gain value in decibels corresponding to the bandwidth.

[0098] At each center frequency point, each sub-band filter is pre-set with an initial amplitude gain as the filter gain. In order to avoid mutual influence between different sub-band filters, the bandwidth of each sub-band filter can be reduced, but the fluctuation of the amplitude response between each center frequency point will be increased. Therefore, in this application, the gain of the sub-band filter is set to be different from the above initial amplitude gain to improve the accuracy of the amplitude response of each sub-band filter. Since the amplitude response of the Peak filter has a self-similar property on the decibel scale:

[0099] alog|H(ω;G)|≈log|H(ω;aG)|;

[0100] That is, the amplitude response of the filter when the gain is aG (dB) is approximately proportional to the amplitude response of the filter when the gain is G (dB), and the proportional factor is a. After the amplitude response of the Peak filter at different gains is normalized, the shape of the waveform is approximate. In the above scheme of the present application, the mutual influence matrix B actually represents the normalized amplitude response (decibel value) of each sub-band filter of the graphic equalizer at each center frequency, where B is a matrix of (2N-1) rows (2N-1 center frequencies, N columns (N sub-band filters). The N-row and column vectors G represent the amplitude gain (decibel value) of each filter. Due to the self-similar characteristics of the sub-band filters, the total amplitude response at all center frequencies of the graphic equalizer can be expressed as: B×G. Using the mutual influence matrix B, the target amplitude gain G of each sub-band filter is solved. opt =B -1 t, t is the target amplitude gain vector. When the target amplitude gain vector t is given, it is expected that the total amplitude response B×G at all center frequencies of the graphic equalizer is consistent with the target amplitude gain vector t, that is, B×G=t. At this time, the target amplitude gain G of each sub-band filter is opt It can be obtained by solving the equation, that is, G opt =B -1 t, the above process can improve the accuracy of the filtering result. In order to further improve the accuracy of the filtering result, the filter gain G can also be used. opt , re-solve the interaction matrix B 1 , using the interaction matrix B 1 , iteratively solve the filter gain G of each subband opt1 =B 1 -1 t, combined with the improvement of the interpolation center frequency point, the filtering result can be basically consistent with the amplitude of the expected response signal. Figure 5a and Figure 5b As shown, assuming that the target gains of the 10 frequency bands are 10,-10,-10,-10,-10,-10,-10,-10,-10,-10,-10 dB, the amplitude responses obtained by the two methods are closer to the target gains by the quadratic correction method.

[0101] The present application also provides an equalization filter. Figure 6 As shown, including:

[0102] The information acquisition module 10 is configured to determine the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer; the graphic equalizer includes a plurality of cascaded sub-band filters, and the number of sub-band filters and the center frequency, bandwidth and initial amplitude gain of each sub-band filter are pre-designed parameters. If there is a communication connection between the controller module performing this step and the graphic equalizer, the above information can be directly requested and obtained.

[0103] The response signal acquisition module 20 is configured to input the initial signal to all the sub-band filters, and obtain the sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths; the initial signal can be any signal without limitation.

[0104] The influence relationship acquisition module 30 is configured to obtain the difference between each of the sub-band response signals and the preset target response signal, and use the difference as an element to obtain a mutual influence matrix; because the initial amplitude gain of each sub-band filter is predetermined, the target response signal corresponding to each sub-band filter can be calculated and determined. The sub-band response signal is an actual amplitude response. If the actual amplitude response is different from the target response signal, it means that the actual amplitude response is affected by other sub-band filters. At this time, the difference between the actual amplitude response and the target response signal can be used to determine the degree of influence. Generally, the difference value can be determined in the form of a ratio. The ratio between all sub-band response signals and the target response signal is arranged in the form of a matrix to obtain a mutual influence matrix, which includes multiple rows and columns of signal values, wherein the serial number of the sub-band filter is the row subscript and the serial number of the sub-band response signal is the column subscript (it can also be the opposite). It can be understood that the ratio is a way of implementation, and other ways can also be selected in the application process to determine the difference value and then obtain the mutual influence matrix.

[0105] The gain determination module 40 corrects the initial amplitude gain of each of the sub-band filters by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each of the sub-band filters.

[0106] For a cascade filter with multiple sub-band filters, the initial amplitude gain matrix of each sub-band filter can be multiplied by the mutual influence matrix to obtain the final output. The initial amplitude gain of each sub-band filter can form a vector, and the correction value of the initial amplitude gain of each sub-band filter can be obtained by directly multiplying the inverse matrix of the mutual influence matrix with the vector. In fact, the operation of this step is equivalent to: the initial amplitude gain of the sub-band filter is multiplied by the corresponding difference value calculated in step S30. If the difference value is target response signal / sub-band response signal=(signal×target amplitude gain) / (signal×initial amplitude gain), it can be seen that the difference value should be the ratio between the target amplitude gain and the initial amplitude gain. After determining the difference value, the target amplitude gain can be obtained by multiplying the initial amplitude gain by the difference value.

[0107] It can be understood that in the above scheme, the result of the calculation is based on the case where the difference value is equal to the target response signal / sub-band response signal. In actual application, if the difference value is calculated using other methods, the final target amplitude gain can also be determined using other reversible calculation methods.

[0108] In the above scheme of the present application, after determining the center frequency and bandwidth of each sub-band filter in the graphic equalizer, the initial signal is divided into a plurality of sub-band signals corresponding to the center frequency and bandwidth of each sub-band filter, and the signal is passed through all the sub-band filters, so that each sub-band filter can obtain a sub-band response signal corresponding to the signal, and the difference between each sub-band response signal and a preset target response signal is obtained, and the difference is used as an element to obtain a mutual influence matrix, and the influence of the signal on the amplitude response of other sub-band signals can be determined through the mutual influence matrix, and on this basis, the initial amplitude gain of each sub-band filter is corrected by the inverse matrix of the mutual influence matrix, and the target amplitude gain of each sub-band filter is determined, so that the change of the amplitude gain of each sub-band filter can be used to eliminate the influence of each sub-band filter on other sub-band filters, and since the target amplitude gain of each sub-band filter can eliminate the influence of different sub-band filters, the final filtering result of the graphic equalizer has higher accuracy.

[0109] In the above scheme, the gain determination module 40 is also used to multiply the inverse matrix of the mutual influence matrix with the initial amplitude gain matrix of each sub-band filter to determine the initial target amplitude gain of each sub-band filter. The initial target amplitude gain of each sub-band filter is used as the target amplitude gain of each sub-band filter. That is, the initial target amplitude gain is directly determined by using the reversible calculation method, using the initial amplitude gain of each sub-band filter and the difference value corresponding to each row and column in the mutual influence matrix. The initial target amplitude gain is used as the target amplitude gain of the final draft. By adopting the method in this scheme, the initial amplitude gain of each sub-band filter can be corrected according to the difference value between the target response signal of each sub-band filter and the actual sub-band response signal, thereby eliminating the mutual influence between different sub-band signals and improving the accuracy of the filtering results of each sub-band filter.

[0110] As another method, the gain determination module 40 is further used to multiply the inverse matrix of the mutual influence matrix with the initial amplitude gain matrix of each sub-band filter to determine the initial target amplitude gain of each sub-band filter. The initial amplitude gain of each sub-band filter is updated using the initial target amplitude gain of the sub-band filter. The initial signal is input to all the sub-band filters again to obtain the secondary sub-band response signal corresponding to each center frequency and the bandwidth output by each sub-band filter. The difference between each secondary sub-band response signal and the preset target response signal is obtained to obtain the secondary mutual influence matrix. The inverse matrix of the secondary mutual influence matrix is ​​multiplied with the initial target amplitude gain matrix of each sub-band filter to determine the target amplitude gain of each sub-band filter. That is, the initial target amplitude gain is determined by directly using the reversible calculation method, using the initial amplitude gain of each sub-band filter and the difference value corresponding to each row and column in the mutual influence matrix, and the initial target amplitude gain is used as the updated initial amplitude gain of each sub-band filter. That is, the initial amplitude gain of each sub-band filter is corrected twice, thereby eliminating the mutual influence between different sub-band filters twice, and further improving the accuracy of the filtering results of each sub-band filter.

[0111] In some preferred schemes, an interpolation module is also included, which is used to insert an interpolation center frequency point between the center frequencies of every two adjacent sub-band response signals. The corresponding relationship between the center frequency of each sub-band response signal and the sub-band response signal amplitude is obtained. Each interpolation center frequency is substituted into the corresponding relationship to obtain the response signal amplitude corresponding to each interpolation center frequency. The response signal amplitude corresponding to each interpolation center frequency is merged into the sub-band response signal as the updated sub-band response signal. Specifically, a new center frequency point can be interpolated between the center frequencies of each adjacent sub-band response signal. Assuming that there are N sub-band response signals in total, that is, signals with N frequency bands in total, (N-1) interpolation center frequency points are interpolated using the intermediate values ​​of the center frequencies of adjacent frequency bands, and the corresponding interpolation center frequency points are f respectively. i1 ,f i2 ,…,f iN-1 , that is, the average value of two adjacent center frequency points is taken as the center frequency point of the intermediate interpolation. Another method can be selected. (k=1, 2, ..., N-1). In specific applications, it can be selected according to the application scenario. There are N sub-band filters. After adding the original center frequency and the interpolated center frequency point, there are a total of (2N-1) center frequencies. Assuming that there is a functional relationship between the center frequency and the initial amplitude gain, the functional relationship can be obtained by using the fitting relationship between the original N center frequencies and the sub-band response signal amplitude. Substituting the newly inserted interpolation center frequency point into the above functional relationship can determine the initial interpolation amplitude gain corresponding to each of the interpolation center frequencies. In this way, (2N-1) center frequencies and (2N-1) initial target amplitude gains corresponding to the (2N-1) center frequencies are obtained. The amount of data is increased by interpolating the center frequency points, and more accurate results can be obtained during the calculation process.

[0112] In the above embodiments of the present application, the graphic equalizer may be a graphic equalizer filter suitable for sound signals used in vehicles, and in the information acquisition module 10: the center frequency value of the human ear audible range is used as the center frequency, and the bandwidth of the human ear audible range is used as the bandwidth; wherein the center frequency of the latter sub-band filter of the two adjacent sub-band filters is twice the center frequency of the former sub-band filter. Specifically, the graphic equalizer includes N sub-band filters, and the center frequency of each sub-band filter is determined to be f c1 ,f c2 ,…,f cNSince the human ear audible range can be divided into about 10 octave bands, taking N=10 as an example, the center frequencies of each band are 31.25, 62.5, 125, 250, 500, 1000, 2000, 4000, 8000, and 16000 Hz, respectively, that is, the center frequencies of each sub-band filter are the above frequency points.

[0113] The technical solution of the present application provides a computer-readable storage medium, in which program information is stored. After a computer reads the program information, it executes the filter amplitude gain determination method described in any one of the first aspects.

[0114] The present application also provides an electronic device, such as Figure 7 As shown, the electronic device includes at least one processor 71 and at least one memory 72, at least one of the memories 72 stores program information, and at least one of the processors 71 reads the program information and executes the method for determining the amplitude gain of the sub-band filter in the graphic equalizer described in any one of the above method embodiments. The device may also include: an input device 73 and an output device 77. The processor 71, the memory 72, the input device 73 and the output device 77 may be communicatively connected. The memory 72, as a non-volatile computer-readable storage medium, may be used to store non-volatile software programs, non-volatile computer executable programs and modules. The processor 71 executes various functional applications and data processing by running the non-volatile software programs, instructions and modules stored in the memory 72, that is, the method for determining the amplitude gain of the sub-band filter in the graphic equalizer provided in any one of the above schemes is implemented. The memory 72 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required by at least one function; the data storage area may store data created according to the use of the method for determining the amplitude gain of the sub-band filter in the graphic equalizer, etc. In addition, the memory 72 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices. In some embodiments, the memory 72 may optionally include a memory remotely arranged relative to the processor 71, and these remote memories may be connected to a device for executing the method for determining the amplitude gain of a sub-band filter in a graphic equalizer through a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The input device 73 may receive input user clicks, and generate signal inputs related to user settings and function controls of the method for determining the amplitude gain of a sub-band filter in a graphic equalizer. The output device 77 may include a display device such as a display screen. When the one or more modules are stored in the memory 72, when they are run by the one or more processors 71, the method for determining the amplitude gain of a sub-band filter in a graphic equalizer in any of the above-mentioned method embodiments is executed.

[0115] The technical solution of the present application provides a vehicle, in which the equalizing filter described in the above embodiments or the computer-readable storage medium or electronic device is configured.

[0116] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0117] The above are only the principles and preferred embodiments of the present application. It should be noted that, for ordinary technicians in this field, on the basis of the principles of the present application, several other modifications can be made, which should also be considered as the protection scope of the present application.

Claims

1. A method for determining the amplitude gain of a sub-band filter in a graphic equalizer, characterized in that: include: Determine the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer; Inputting the initial signal to all the sub-band filters, and obtaining a sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths; Obtaining a difference value between each of the sub-band response signals and a preset target response signal, and using the difference value as an element to obtain a mutual influence matrix; The initial amplitude gain of each of the sub-band filters is corrected by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each of the sub-band filters.

2. The method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to claim 1, characterized in that: The step of correcting the initial amplitude gain of each sub-band filter by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each sub-band filter comprises: Multiplying the inverse matrix of the mutual influence matrix by the initial amplitude gain matrix of each sub-band filter to determine the initial target amplitude gain of each sub-band filter; The initial target amplitude gain of each of the sub-band filters is used as the target amplitude gain of each of the sub-band filters.

3. The method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to claim 1, characterized in that: The step of correcting the initial amplitude gain of each sub-band filter by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each sub-band filter comprises: Multiplying the inverse matrix of the mutual influence matrix by the initial amplitude gain matrix of each sub-band filter to determine the initial target amplitude gain of each sub-band filter; Updating the initial amplitude gain of each of the sub-band filters using the initial target amplitude gain of the sub-band filter; inputting the initial signal to all the sub-band filters again, and obtaining a secondary sub-band response signal output by each sub-band filter corresponding to each center frequency and the bandwidth; Obtaining the difference between each of the secondary sub-band response signals and the preset target response signal to obtain a secondary interaction matrix; The inverse matrix of the quadratic interaction matrix is ​​multiplied by the initial target amplitude gain matrix of each sub-band filter to determine the target amplitude gain of each sub-band filter.

4. The method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to claim 1, characterized in that: The step of inputting the initial signal to all the sub-band filters and obtaining the sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths further includes: Inserting an interpolation center frequency point between the center frequencies of every two adjacent sub-band response signals; Obtaining a corresponding relationship between a center frequency of each sub-band response signal and an amplitude of the sub-band response signal; Substituting each of the interpolation center frequencies into the corresponding relationship to obtain a response signal amplitude corresponding to each of the interpolation center frequencies; The response signal amplitude corresponding to each of the interpolation center frequencies is merged into the sub-band response signal as the updated sub-band response signal.

5. The method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to claim 4, characterized in that: The interpolation center frequency point is an average value of center frequencies of two adjacent sub-band response signals, or the interpolation center frequency point is a square root value obtained by multiplying center frequencies of two adjacent sub-band response signals.

6. The method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to any one of claims 1 to 5, characterized in that: If the graphic equalizer is a graphic equalizer filter suitable for sound signals applied in a vehicle, the step of determining the center frequency, bandwidth and initial amplitude gain of each sub-band filter in the graphic equalizer includes: The center frequency value of the human ear audible range is used as the center frequency, and the frequency bandwidth of the human ear audible range is used as the bandwidth; wherein the center frequency of the latter sub-band filter of the two adjacent sub-band filters is twice the center frequency of the former sub-band filter.

7. An equalization filter, characterized in that: include: An information acquisition module configured to determine the number of sub-band filters in the graphic equalizer and the center frequency, bandwidth and initial amplitude gain of each of the sub-band filters; a response signal acquisition module, configured to input an initial signal into all the sub-band filters, and acquire a sub-band response signal output by each of the sub-band filters corresponding to each of the center frequencies and the bandwidths; An influence relationship acquisition module is configured to obtain a difference value between each of the sub-band response signals and a preset target response signal, and obtain a mutual influence matrix using the difference value as an element; The gain determination module is configured to modify the initial amplitude gain of each of the sub-band filters by using the inverse matrix of the mutual influence matrix to determine the target amplitude gain of each of the sub-band filters.

8. A computer-readable storage medium, characterized in that: The storage medium stores program information, and after the computer reads the program information, it executes the method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to any one of claims 1 to 6.

9. An electronic device, characterized in that: The electronic device includes at least one processor and at least one memory, at least one of the memories stores program information, and at least one of the processors reads the program information and executes the method for determining the amplitude gain of a sub-band filter in a graphic equalizer according to any one of claims 1 to 6.

10. A vehicle, characterized in that: The vehicle is equipped with the equalizing filter according to claim 7, the computer-readable storage medium according to claim 8, or the electronic device according to claim 9.

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