Intelligent dynamic guiding noise-reducing earphone noise reduction performance test method and system

Abstract

The application relates to the technical field of intelligent sensors, in particular to a method and system for testing the noise reduction performance of intelligent dynamic flow guiding noise reduction earphones, which comprises the following steps: respectively using static noise and dynamic noise to test the performance of the noise reduction earphones, collecting the environmental noise entering the earphones at each moment and the residual noise after noise reduction by the earphones; in the process of static noise testing, dividing the environmental noise into signal intervals, determining the standard interval under the corresponding frequency of each signal interval; obtaining the matching residual noise of the environmental noise at each moment in the standard interval; analyzing the difference between the environmental noise at each moment in the standard interval and the matching residual noise, fusing the corresponding degree, and obtaining the static noise reduction performance factor of the earphones; in the process of dynamic noise testing, determining the dynamic noise reduction performance factor of the earphones, fusing the static noise reduction performance factor, and evaluating the noise reduction performance of the earphones. Therefore, the accuracy of the noise reduction performance test of the noise reduction earphones is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent sensor, in particular to a method and system for testing noise reduction performance of intelligent dynamic guiding noise reduction earphone. BACKGROUND

[0002] With the rapid development of active noise reduction (ANC) technology, intelligent earphones with dynamic guiding and adaptive noise reduction functions have become the mainstream in the market. Such earphones not only need to maintain excellent noise reduction effect in a steady noise environment, but also need to achieve rapid response and continuous effective noise suppression in dynamic scenes where the type and intensity of noise change instantaneously. Therefore, how to comprehensively and accurately evaluate the comprehensive noise reduction performance has become a key challenge in the industry testing field.

[0003] Existing earphone noise reduction performance testing methods are mostly based on a steady noise environment. For example, in an anechoic chamber or a simulated ear canal, an artificial head clamp is used to collect the original environmental noise through a reference microphone and the residual noise after noise reduction through an in-ear microphone, and then the sound pressure level difference or transfer function is calculated to evaluate the noise reduction amount. However, the existing technology has obvious limitations. When testing non-steady excitation such as sweep signal, since the signal frequency changes continuously, directly intercepting the signal interval for analysis will introduce interference of the frequency transient process, resulting in the inability to accurately extract the real noise reduction performance of the earphone at a specific steady frequency. Moreover, there is an inherent system transmission delay and acoustic path difference between the reference microphone and the in-ear microphone, so that the two-way sound signals are not strictly synchronized in time domain. Directly comparing the signals recorded by the synchronous time of the acquisition card ignores the time lag effect, resulting in distorted noise reduction amount and limited evaluation accuracy. In addition, the traditional testing scheme mainly targets static or slowly changing noise scenes, lacks effective evaluation means for earphone noise reduction performance under dynamic noise, and cannot objectively reflect the real performance of intelligent earphones in actual use environment. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a method and system for testing noise reduction performance of intelligent dynamic guiding noise reduction earphone, and the technical solutions adopted are as follows:

[0005] In the first aspect, the embodiments of the present application provide a method for testing noise reduction performance of intelligent dynamic guiding noise reduction earphone, which comprises the following steps:

[0006] Respectively use static noise and dynamic noise to test the performance of the noise reduction earphone, and collect the environmental noise entering the earphone at each time and the residual noise after noise reduction by the earphone;

[0007] In the static noise test process, the environmental noise is divided into signal intervals based on the frequency of the environmental noise; the symmetry of the environmental noise in each signal interval and the similarity of the environmental noise with adjacent signal intervals are analyzed to determine the standard degree of the noise in each signal interval, so as to determine the standard interval corresponding to the frequency of each signal interval;

[0008] The correspondence between the environmental noise and the residual noise is obtained through the difference between the environmental noise and the residual noise in the standard interval, so as to determine the matching residual noise of the maximum point noise in the standard interval; the time consistency is constructed by using the time interval between the maximum point of the standard interval and the matching residual noise, and the matching residual noise of the environmental noise at each time in the standard interval is obtained in combination with the correspondence;

[0009] The difference between the environmental noise at each time in the standard interval and the matching residual noise is analyzed, and the static noise reduction performance factor of the earphone is obtained by fusing the correspondence;

[0010] In the dynamic noise test process, correspondingly, the dynamic noise reduction performance factor of the earphone is determined for the switching process of the dynamic noise, and the noise reduction performance of the earphone is evaluated by fusing the static noise reduction performance factor.

[0011] In one embodiment, the environmental noise is divided into signal intervals based on the frequency of the environmental noise, including:

[0012] Identifying each minimum point of the environmental noise, and taking the environmental noise between adjacent minimum points as each signal interval.

[0013] In one embodiment, the standard degree of the noise in each signal interval is determined, including:

[0014] Identifying the maximum point of the environmental noise in each signal interval, calculating the distance difference between the maximum point and the left and right boundary points of the signal interval, calculating the proportion of the distance difference in the total length of the signal interval, and taking the difference between the natural number 1 and the proportion as the symmetry of each signal interval.

[0015] The frequency difference between each signal interval and its adjacent signal interval, and the correlation coefficient of the environmental noise between each signal interval and its adjacent signal interval are determined, and the noise similarity between each signal interval and its adjacent signal interval is determined in combination with the frequency difference and the correlation coefficient, wherein the noise similarity is positively correlated with the correlation coefficient and negatively correlated with the frequency difference.

[0016] The symmetry of each signal interval and the noise similarity between each signal interval and all its adjacent signal intervals are fused to obtain the standard degree of the noise in each signal interval.

[0017] In one embodiment, the standard interval corresponding to the frequency of each signal interval is determined, including:

[0018] For any signal interval, obtain each adjacent signal interval of the any signal interval, and take the signal interval with the maximum standard degree among all adjacent signal intervals as the standard interval under the corresponding frequency of the any signal interval.

[0019] In one embodiment, the obtaining of the correspondence between the environmental noise and the residual noise comprises:

[0020] For the environmental noise at the a-th moment and the residual noise at the b-th moment, obtain the environmental noise at a preset number of adjacent moments of the environmental noise at the a-th moment, arrange them according to the numerical value, and obtain a first noise sequence; correspondingly, obtain the residual noise at a same number of adjacent moments of the residual noise at the b-th moment, and obtain a second noise sequence;

[0021] Count the number of equal elements at the same positions in the first noise sequence and the second noise sequence, calculate the difference between the environmental noise at the a-th moment and the residual noise at the b-th moment, denoted as a first difference, and take the ratio of the first difference to the environmental noise at the a-th moment as the noise attenuation amplitude between the a-th moment and the b-th moment.

[0022] Based on the number and the noise attenuation amplitude, calculate the correspondence H between the environmental noise at the a-th moment and the residual noise at the b-th moment, expressed as:

[0023] ; h is the number, M is the preset number, the equal elements at the same positions in the first noise sequence and the second noise sequence are denoted as each adjacent point pair, is the noise attenuation amplitude between the m-th adjacent point pair at the a-th moment and the b-th moment, is a preset value greater than 0, wherein the b-th moment is after the a-th moment.

[0024] In one embodiment, the determining of the matching residual noise of the maximum value point noise in the standard interval comprises:

[0025] Obtain the residual noise at each moment within a preset time interval after the moment corresponding to the maximum value point noise in the standard interval, calculate the correspondence between the moment corresponding to the maximum value point noise and the residual noise at each moment, and take the residual noise corresponding to the maximum value of the correspondence as the matching residual noise of the maximum value point noise.

[0026] In one embodiment, the obtaining of the matching residual noise of each moment environmental noise in the standard interval comprises:

[0027] ​determine a time interval between the maximum point noise and the matching residual noise in each standard interval, count the occurrence frequency of each time interval, calculate the difference of the time interval corresponding to the maximum value of the occurrence frequency, denoted as a second difference, and take the ratio of the maximum value of the occurrence frequency to the sum of the second differences corresponding to all standard intervals as the time consistency;

[0028] calculate the subtraction result of the natural number 1 and the normalized value of the time consistency, obtain the time interval between the maximum point noise and the matching residual noise in the standard interval to which the environmental noise at the a-th moment in the standard interval belongs, and multiply the subtraction result to obtain a first product; and expand the time length corresponding to the first product to both sides with the a-th moment as the center to obtain a time interval of the a-th moment.

[0029] calculate the correspondence between the environmental noise at the a-th moment and the residual noise at all moments in the time interval of the a-th moment, and take the residual noise corresponding to the maximum value of the correspondence as the matching residual noise of the environmental noise at the a-th moment.

[0030] In one embodiment, the method further includes obtaining a static noise reduction performance factor of the earphone, including:

[0031] calculate the difference between the environmental noise at each moment in each standard interval and the matching residual noise, denoted as a third difference, determine the product of the third difference and the correspondence between the environmental noise at each moment and the matching residual noise, denoted as a second product, and take the cumulative sum of the second product at all moments in all standard intervals as the static noise reduction performance factor of the earphone.

[0032] In one embodiment, the method further includes determining a dynamic noise reduction performance factor of the earphone, including:

[0033] for each switching process of the dynamic noise, calculate the addition result of the second product of the environmental noise at all moments in the switching process, calculate the ratio of the addition result to the switching time length of each switching process, denoted as a first ratio, and take the sum of the first ratios of all switching processes as the dynamic noise reduction performance factor of the earphone.

[0034] The method further includes evaluating the noise reduction performance of the earphone, including calculating the product of the dynamic noise reduction performance factor and the static noise reduction performance factor of the earphone as an evaluation index of the noise reduction performance of the earphone.

[0035] In a second aspect, the embodiments of the present application also provide an intelligent dynamic flow guiding noise reduction earphone noise reduction performance testing system, including a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the method described in any one of the above embodiments when executing the computer program.

[0036] The application has at least the following beneficial effects:

[0037] The application determines the standard interval of the noise signal by analyzing the sinusoidal distribution characteristics of the time domain ambient noise, and constructs the standard degree of the noise of each signal interval by using the symmetry of the signal interval and the similarity with the adjacent signal interval, which can automatically select the signal interval with stable frequency and best representing the steady-state performance at this frequency for analysis, effectively eliminating the non-steady-state interference in the frequency change process. Further, the correspondence between the reference noise signal points and the residual noise signal points is calculated, and the noise signal search range is adaptively determined by using time consistency, realizing high-precision and adaptive alignment of the signals of the reference microphone and the noise microphone in the time domain. The problem of misalignment caused by system delay in directly comparing the noise signals is fundamentally overcome, so that the finally calculated static noise reduction performance factor can more truly and accurately reflect the noise reduction ability of the earphone in the steady-state environment.

[0038] Meanwhile, in a dynamic noise environment, the application applies the time interval obtained in the static noise test analysis to the alignment of the dynamic noise signal by identifying the switching process after the noise switching, solving the problem of complex time domain signal and difficult direct alignment in dynamic noise test. By calculating the comprehensive index of the noise reduction effect in the switching process and the switching time, i.e. the dynamic noise reduction performance factor, the noise reduction effect of the earphone under transient noise is quantified, and the response speed of the noise reduction system is also evaluated, so as to comprehensively and objectively measure the dynamic noise reduction performance of the earphone.

[0039] Finally, the product of the static noise reduction performance factor and the dynamic noise reduction performance factor is taken as the comprehensive performance evaluation index, which significantly improves the accuracy and reliability of the noise reduction performance test result. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0041] Figure 1 A step flow chart of an intelligent dynamic noise reduction performance test method of a noise reduction earphone is provided for an embodiment of the application. DETAILED DESCRIPTION

[0042] In order to further illustrate the technical means and effects taken by the present application to achieve the predetermined object, the specific implementation, structure, features and effects of the intelligent dynamic flow guiding noise reduction earphone noise reduction performance test method and system according to the present application are described in detail as follows. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0044] The specific scheme of the intelligent dynamic flow guiding noise reduction earphone noise reduction performance test method and system provided by the present application is described in detail below with reference to the accompanying drawings.

[0045] Please refer to Figure 1 which shows the step flowchart of the intelligent dynamic flow guiding noise reduction earphone noise reduction performance test method provided by one embodiment of the present application, which includes the following steps:

[0046] S1, respectively using static noise and dynamic noise to test the performance of the noise reduction earphone, collecting the environmental noise entering the earphone at each time and the residual noise after noise reduction by the earphone.

[0047] In the intelligent dynamic flow guiding noise reduction earphone, the microphone as the basic acoustic sensor undertakes the function of "auditory nerve ending" and is responsible for collecting the original environmental noise and the residual noise signal in the ear canal. In this embodiment, a reference microphone is placed outside the ear canal of the artificial head near the outside of the intelligent dynamic flow guiding noise reduction earphone, which is used to collect the original environmental noise about to enter the intelligent dynamic flow guiding noise reduction earphone, which is recorded as reference noise. A microphone is placed in the simulated ear canal of the artificial head, which is recorded as noise microphone, which is used to collect the residual noise after noise reduction by the intelligent dynamic flow guiding noise reduction earphone and finally transmitted to the ear. During the test, the host computer of the test system sends simulated noise signals, and the noise is collected by the reference microphone outside the intelligent dynamic flow guiding noise reduction earphone and the noise microphone in the simulated ear canal in turn after propagation, and the corresponding noise signal sequence is obtained.

[0048] In the intelligent dynamic guide noise reduction earphone noise reduction performance test, the embodiment is divided into static noise reduction performance test and dynamic noise reduction performance test. First, for the static noise reduction performance test, the test system controls the speaker to play the noise signal, which is a sine sweep signal from 100 Hz to 1 kHz in the embodiment, the system main control triggers the noise playback at the same time, and the reference microphone and the noise microphone synchronously collect the noise signal to obtain the reference noise signal sequence and the residual noise signal sequence respectively. The noise signal acquisition frequency is 48 kHz, which can be set by the implementer according to the actual situation, and the embodiment does not limit this.

[0049] S2, in the static noise test process, the environment noise is divided into each signal interval based on the frequency of the environment noise; the symmetry degree of the environment noise in each signal interval and the similarity degree of the environment noise with the adjacent signal interval are analyzed to determine the standard degree of each signal interval noise to determine the standard interval corresponding to the frequency of each signal interval.

[0050] Since the noise signal played by the test system control speaker is first passed through the reference microphone and then collected by the noise microphone through the analog ear canal, there is a certain time difference between the reference microphone and the noise microphone when collecting the signal. When the signal strength difference of the signal points at the same time is directly used to represent the static performance of the noise reduction earphone, the static performance evaluation accuracy is low. Therefore, in the embodiment, the reference noise signal sequence and the residual noise signal sequence are analyzed to obtain the matching residual noise point corresponding to each reference noise point, so as to adaptively complete the construction of the static noise reduction performance evaluation index, and the specific process is as follows:

[0051] For the reference noise signal sequence, since the noise signal played by the test system control speaker is a sine sweep signal, the instantaneous waveform of the sine sweep signal is a sine wave, but its frequency changes with time. First, according to the characteristics of the sine wave, the reference noise signal sequence is divided into multiple signal intervals, wherein the maximum points and the minimum points of the reference noise signal sequence are obtained first, and the method for obtaining the maximum points and the minimum points is a known technology, which will not be described here. The interval composed of the reference noise signal points between two adjacent minimum points is called a signal interval, so the reference noise signal sequence can be divided into multiple signal intervals. Since the signal emitted by the test system is a sine sweep signal, the frequency of the signal will change constantly. According to the characteristics of the sine sweep signal, it can be known that part of the noise signal in the obtained signal interval is in the frequency change process, and the static noise reduction performance of the earphone at this frequency cannot be accurately reflected. Therefore, the embodiment further analyzes the signal interval to obtain the standard interval at different frequencies in the signal interval.

[0052] According to the signal characteristics of the sine wave, each signal interval contains a maximum value point, and the maximum value point is usually distributed at the center position of the signal interval. Therefore, in this embodiment, the maximum value point is used as the feature point of the signal interval. When the frequency of the signal interval does not change, the signal interval has periodicity, that is, the maximum value point is the center point and symmetry is presented. Therefore, the standard degree of noise of each signal interval is constructed by the symmetry condition of the signal interval and the approximate condition of the signal interval and the adjacent signal interval. Specifically, the following is performed.

[0053] First, the distance difference between the maximum value point and the left and right boundary points of the signal interval is calculated, the proportion of the distance difference in the total length of the signal interval is calculated, and the difference between the natural number 1 and the proportion is used as the symmetry degree of each signal interval.

[0054] It should be noted that the difference represents the difference between two variables, which can be calculated by using the absolute value of the difference, the square of the difference, the ratio, etc. This embodiment does not limit this.

[0055] In this embodiment, the symmetry degree of each signal interval is expressed as: In the formula, is the distance between the maximum value point of each signal interval and the left boundary of the signal interval to which the maximum value point belongs, is the distance between the maximum value point of each signal interval and the right boundary of the signal interval to which the maximum value point belongs, represents the distance difference between the maximum value point and the left and right boundary points of the signal interval, is the total length of each signal interval. The greater the distance difference, the smaller the symmetry degree of the signal interval.

[0056] Secondly, the frequency difference between each signal interval and its adjacent signal interval is determined, and the correlation coefficient of the environmental noise of each signal interval and its adjacent signal interval is determined. The noise similarity between each signal interval and its adjacent signal interval is determined in combination with the frequency difference and the correlation coefficient. The noise similarity is positively correlated with the correlation coefficient and negatively correlated with the frequency difference.

[0057] In this embodiment, the noise similarity between each signal interval and its adjacent signal interval is expressed as: In the formula, is the Pearson correlation coefficient of the reference noise of each signal interval and its adjacent signal interval. The implementer can select other existing correlation coefficient calculation methods, and this embodiment does not limit this, is the reference noise signal frequency of each signal interval, is the reference noise signal frequency of the adjacent signal interval of each signal interval, The frequency difference between each signal interval and its adjacent signal intervals is considered. The smaller the frequency difference, the more likely it is to represent noise information at the same frequency. To ensure that the value is greater than 0 and to avoid a denominator of 0, this embodiment... The implementer can set this according to the actual situation; this embodiment does not impose any restrictions on it. `norm()` is the normalization function. It should be noted that if the Pearson correlation coefficient between each signal interval and the reference noise of its adjacent signal intervals is negative, then during the noise similarity calculation process... The value is recorded as 0.

[0058] The standard degree of noise for each signal interval is obtained by fusing the symmetry of each signal interval and the noise similarity between each signal interval and all its adjacent signal intervals. Here, fusion means combining multiple variables, which can be calculated by methods such as addition, multiplication, a mixture of addition and multiplication, or averaging.

[0059] In this embodiment, the mean noise similarity between each signal interval and all its adjacent signal intervals is calculated. In this embodiment, adjacent signal intervals refer to the two preceding signal intervals; the implementer can set the number of adjacent signal intervals themselves. The product of the mean and the symmetry of each signal interval is used as the standard degree of each signal interval. The larger the standard degree, the more likely the signal interval is to be a noise signal collected during frequency stabilization, and the more likely it is to be a standard interval. The smaller the standard degree, the more likely the signal within the signal interval is to be in a state of frequency variation, and the less it can characterize the change in noise information at that frequency.

[0060] The standard degree of each signal interval in the reference noise signal sequence can be obtained by following the above steps. For any given signal interval, each neighboring signal interval is obtained, and the signal interval with the largest standard degree among all neighboring signal intervals is taken as the standard interval at the corresponding frequency of the given signal interval. It should be noted that, in this embodiment, each neighboring signal interval refers to each signal interval whose signal frequency differs from that of the given signal interval by less than 0.1 Hz. The implementer can set the selection of each neighboring signal interval according to the actual situation.

[0061] S3. By obtaining the correspondence between environmental noise and residual noise at each time point within the standard interval, the matching residual noise of the maximum point noise within the standard interval is determined. The time interval between the maximum point of the standard interval and its matching residual noise is used to construct time consistency. Combined with the correspondence, the matching residual noise of the environmental noise at each time point within the standard interval is obtained.

[0062] According to the above steps, the standard interval at different frequencies in the reference noise signal sequence can be obtained, and then the residual noise signal points corresponding to the signal points in the standard interval at different frequencies can be further obtained. In this embodiment, the environmental noise at the a time, i.e., the reference noise, is taken as an example to obtain the residual noise at the b time after the a time, and the environmental noises at the M adjacent times of the a time are obtained, which are arranged in descending order of values to obtain a first noise sequence. Similarly, the residual noises at the M adjacent times of the b time are obtained, which are also arranged in descending order of values to obtain a second noise sequence. The arrangement order of the first noise sequence and the second noise sequence can also be in ascending order, as long as the arrangement manners of the first noise sequence and the second noise sequence are the same. In this embodiment, M=10, which can be set by the implementer according to the actual situation, and this embodiment does not limit this.

[0063] The number of equal elements at the same position in the first noise sequence and the second noise sequence is counted, the absolute value of the difference between the environmental noise at the a time and the residual noise at the b time is calculated, and is recorded as a first difference. The ratio of the first difference to the environmental noise at the a time is taken as the noise attenuation amplitude between the a time and the b time. .

[0064] Based on the number and the noise attenuation amplitude, the correspondence H between the environmental noise at the a time and the residual noise at the b time is calculated, and the expression is:

[0065] where h is the number, M is the preset number, the equal elements at the same position in the first noise sequence and the second noise sequence are recorded as each adjacent point pair, is the noise attenuation amplitude between the mth adjacent point pair at the a time and the b time, is a preset value greater than 0, which avoids the denominator being 0, and in this embodiment, which can be set by the implementer according to the actual situation. Wherein, the b time is after the a time.

[0066] For noise signals of the same frequency component, the active noise control system in the earphone will produce a relatively consistent attenuation amount, and the attenuation amplitude is roughly the same, that is, The smaller the noise attenuation amplitude is, the greater the correspondence is.

[0067] The greater the correspondence is, the more likely the environmental noise at the a time and the residual noise at the b time are the same sound signal point. The smaller the correspondence is, the less likely the environmental noise at the a time and the residual noise at the b time are the same sound signal point.

[0068] Further, the residual noise in a preset time interval after the time corresponding to the maximum point noise in each standard interval is obtained, the correspondence between the time corresponding to the maximum point noise and the residual noise at each time is calculated, and the residual noise corresponding to the maximum value of the correspondence is taken as the matching residual noise of the maximum point noise. The preset time interval in this embodiment is 2 ms, and the implementer can set it according to the actual situation, which is not limited in this embodiment.

[0069] The time interval between each maximum point and its matching residual noise in all standard intervals is counted, the occurrence frequency of each time interval is counted, and the time consistency expression is constructed. The expression is , wherein the maximum value of the occurrence frequency, A represents the number of standard intervals, the time interval between the maximum point of the i th standard interval and its matching residual noise, the time interval corresponding to the maximum value of the occurrence frequency, and is recorded as the second difference. The smaller the second difference is, the closer the time interval between each maximum point and its matching residual noise in all standard intervals is, and the greater the time consistency is. That is, the time interval corresponding to the maximum point of the standard interval has greater reference significance for the subsequent. It should be noted that, in order to avoid meaningless phenomenon of denominator being 0 in the calculation process, a preset minimum value can be added to the denominator in the calculation process. In this embodiment, the value is 0.01, and the implementer can set it.

[0070] Further, the search range of each reference noise signal point in the standard interval is obtained according to the time consistency, the correspondence between the residual noise in the search range and the reference noise is obtained, and the matching residual noise of the environmental noise at each time is obtained. For the environmental noise at the a th time in any standard interval, the time interval between the maximum point in the any standard interval and its matching residual noise is obtained , and the multiplication result of is recorded as the first product. The time length corresponding to the first product is expanded before and after the a th time centering on the a th time, thereby obtaining the time interval of the a th time as the search range of the a th time.

[0071] The correspondence between the environmental noise at the a th time and the residual noise at all times in the time interval of the a th time is calculated, and the residual noise corresponding to the maximum value of the correspondence is taken as the matching residual noise of the environmental noise at the a th time. Thus, the matching residual noise of the environmental noise at each time in each standard interval can be obtained.

[0072] S4, analyze the difference between the ambient noise at each time in the standard interval and the matching residual noise, fuse the correspondence, and obtain the static noise reduction performance factor of the earphone.

[0073] According to the above steps, the residual noise signal point corresponding to the reference noise signal point in the standard interval at each frequency can be obtained, that is, the matching residual noise. Then, the static noise reduction performance factor can be obtained. Specifically, the absolute value of the difference between the ambient noise at each time in each standard interval and the matching residual noise is calculated, denoted as a third difference. The product of the third difference and the correspondence between the ambient noise at each time and the matching residual noise is determined, denoted as a second product. The sum of all second products at all times in all standard intervals is taken as the static noise reduction performance factor of the earphone.

[0074] The greater the value of the second product, the better the static noise reduction performance of the earphone. The greater the static noise reduction performance factor of the earphone, the better the noise reduction performance of the intelligent dynamic flow noise reduction earphone in a static environment.

[0075] S5, during the dynamic noise test process, corresponding to the switching process of the dynamic noise, determine the dynamic noise reduction performance factor of the earphone, fuse the static noise reduction performance factor, and evaluate the noise reduction performance of the earphone.

[0076] In order to accurately reflect the noise reduction performance of the intelligent dynamic flow noise reduction earphone, the embodiment further constructs the dynamic noise reduction performance factor of the earphone by the change of the noise signal in the noise reduction process of the intelligent dynamic flow noise reduction earphone in a dynamic noise environment. The specific process is as follows:

[0077] During the dynamic noise test process of the earphone, the test system first controls the noise source to switch different types of noise at a preset time point. For example, in the first period of time: play the steady-state airplane engine noise. In the second period of time: switch to the subway track impact sound instantly. In the third period of time: add sudden human voice conversation. In this process, the reference microphone and the noise microphone continuously collect time-domain audio signals to obtain the corresponding reference noise signal sequence and residual noise signal sequence. The type and switching time point of the dynamic noise can be set by the implementer according to the actual situation, and the embodiment does not limit this.

[0078] Since the dynamic noise changes complexly, there is time error between the time domain noise signals collected by the reference microphone and the noise microphone, which cannot be directly evaluated, therefore, in the embodiment, the time interval between the reference noise signal and the matching residual noise at each time point obtained in the static noise test process is acquired, the time interval with the largest occurrence frequency is recorded as the characteristic interval, and the residual noise signal point at the characteristic interval length after each reference noise signal point in the dynamic noise is taken as the matching residual noise of the reference noise signal.

[0079] According to the above, the switching process and the characteristic interval are acquired, then the dynamic noise reduction performance factor of the earphone can be constructed according to the change of the noise signal value in the switching process , and the specific expression is: , wherein R represents the number of switching processes of the dynamic noise, the absolute value of the difference between the signal value of each reference noise signal point and the signal value of the matching residual noise signal point in each switching process is calculated, and the corresponding degree between the two is multiplied to obtain the product, which is recorded as the dynamic noise matching degree, , wherein the dynamic noise matching degree of all reference noise signal points and the matching residual noise signal points in the rth switching process is recorded as the dynamic noise matching degree of all reference noise signal points and the matching residual noise signal points in the rth switching process, The greater the value is, the greater the dynamic noise reduction performance factor is. , wherein the switching length of the rth switching process is recorded as the switching length of the rth switching process, the shorter the switching length is, the faster the dynamic noise reduction performance factor is, and the better the performance is. The switching length of the rth switching process is recorded as the first ratio.

[0080] At this point, the static noise reduction performance factor and the dynamic noise reduction performance factor of the intelligent dynamic noise reduction earphone are obtained, and the product of the two is taken as the evaluation index of the noise reduction performance of the dynamic noise reduction earphone, the greater the value of the evaluation index is, the better the noise reduction performance of the earphone is, and the smaller the value of the evaluation index is, the worse the noise reduction performance of the earphone is.

[0081] ​In the embodiment, the average of the evaluation indexes of the N noise reduction performance qualified intelligent dynamic guiding noise reduction earphones is taken as the discrimination threshold. In the noise reduction performance test process, if the evaluation index of the noise reduction performance of the intelligent dynamic guiding noise reduction earphone is greater than or equal to the discrimination threshold, it is determined that the noise reduction performance of the intelligent dynamic guiding noise reduction earphone is qualified, otherwise, the noise reduction performance is unqualified. The implementer can evaluate the noise reduction performance of the dynamic guiding noise reduction earphone in other feasible ways based on the evaluation index of the noise reduction performance of the dynamic guiding noise reduction earphone. In the embodiment, N = 10, which can be set by the implementer according to the actual situation, and the embodiment does not limit this.

[0082] Based on the same inventive concept as the above method, the embodiment of the present application also provides an intelligent dynamic guiding noise reduction earphone noise reduction performance test system, which comprises a memory, a processor and a computer program stored in the memory and running on the processor, and the processor implements the steps of any one of the above intelligent dynamic guiding noise reduction earphone noise reduction performance test methods when executing the computer program.

[0083] It should be noted that the above-mentioned embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments. The above description is for a specific embodiment of the present application. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are possible or may be advantageous.

[0084] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments.

[0085] The above is only the preferred embodiment of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for testing the noise reduction performance of intelligent dynamic guiding noise reduction earphones, characterized in that, The method comprises the following steps: The performance of the noise-cancelling earphone is tested by using static noise and dynamic noise respectively, and the environmental noise entering the earphone at each time and the residual noise after noise reduction by the earphone are collected; In the static noise test process, the environmental noise is divided into signal intervals based on the frequency of the environmental noise; the symmetry degree of the environmental noise in each signal interval and the similarity degree of the environmental noise in adjacent signal intervals are analyzed, and the standard degree of the noise in each signal interval is determined to determine the standard interval corresponding to the frequency of each signal interval; The correspondence between the environmental noise and the residual noise is obtained by the difference between the environmental noise and the residual noise in the standard interval at each time, so as to determine the matching residual noise of the maximum point noise in the standard interval; the time consistency is constructed by using the time interval between the maximum point of the standard interval and the matching residual noise thereof, and the matching residual noise of the environmental noise in the standard interval at each time is obtained in combination with the correspondence; The difference between the environmental noise and the matching residual noise thereof in the standard interval at each time is analyzed, and the static noise reduction performance factor of the earphone is obtained by fusing the correspondence; In the dynamic noise test process, the dynamic noise reduction performance factor of the earphone is determined for the switching process of the dynamic noise, and the noise reduction performance of the earphone is evaluated by fusing the static noise reduction performance factor; The static noise reduction performance factor of the earphone is obtained by calculating the difference between the environmental noise and the matching residual noise thereof in each signal interval at each time, denoted as a third difference, determining the product of the third difference and the correspondence between the environmental noise and the matching residual noise thereof at each time, denoted as a second product, and taking the sum of the second product of all times in all standard intervals as the static noise reduction performance factor of the earphone; The dynamic noise reduction performance factor of the earphone is determined by: For each switching process of the dynamic noise, the sum of the second product of the environmental noise at all times is calculated, the ratio of the sum to the switching time length of each switching process is calculated, denoted as a first ratio, and the sum of the first ratios of all switching processes is taken as the dynamic noise reduction performance factor of the earphone; The noise reduction performance of the earphone is evaluated by calculating the product of the dynamic noise reduction performance factor of the earphone and the static noise reduction performance factor, as an evaluation index of the noise reduction performance of the earphone.

2. The method of claim 1, wherein the method is a method for testing the noise reduction performance of an intelligent dynamic guide flow noise reduction earphone. The environmental noise is divided into signal intervals based on the frequency of the environmental noise, comprising: Identifying each minimum point of the environmental noise, and taking the environmental noise between adjacent minimum points as each signal interval.

3. The method of claim 1, wherein the method further comprises: The standard degree of the noise in each signal interval is determined by: Identifying the maximum point of the environmental noise in each signal interval, calculating the distance difference between the maximum point and the left and right boundary points of the signal interval, calculating the proportion of the distance difference in the total length of the signal interval, and taking the difference between the natural number 1 and the proportion as the symmetry degree of each signal interval. Determine the frequency difference between each signal interval and its adjacent signal interval, and the correlation coefficient of the ambient noise between each signal interval and its adjacent signal interval, combine the frequency difference and the correlation coefficient to determine the noise similarity between each signal interval and its adjacent signal interval, wherein the noise similarity is positively correlated with the correlation coefficient and negatively correlated with the frequency difference; Fuse the symmetry of each signal interval and the noise similarity between each signal interval and all its adjacent signal intervals to obtain the standard degree of the noise of each signal interval.

4. The method of claim 1, wherein the method further comprises: determining the noise reduction performance of the intelligent dynamic guiding noise reduction earphone based on the noise reduction performance of the intelligent dynamic guiding noise reduction earphone. The determination of the standard interval under the corresponding frequency of each signal interval comprises: For any signal interval, obtain each adjacent signal interval of the any signal interval, and take the signal interval with the maximum standard degree among all adjacent signal intervals as the standard interval under the corresponding frequency of the any signal interval.

5. The method of claim 1, wherein the method further comprises: determining the noise reduction performance of the intelligent dynamic guiding noise reduction earphone based on the noise reduction performance of the intelligent dynamic guiding noise reduction earphone. The determination of the corresponding degree between the ambient noise and the residual noise comprises: For the ambient noise at the a-th moment and the residual noise at the b-th moment, obtain the ambient noise at the preset number of adjacent moments of the ambient noise at the a-th moment, arrange them according to the numerical value to obtain a first noise sequence; correspondingly, obtain the residual noise at the same number of adjacent moments of the residual noise at the b-th moment to obtain a second noise sequence; The number of elements at the same position in the first noise sequence and the second noise sequence is counted, the difference between the environmental noise at the a-th moment and the residual noise at the b-th moment is calculated, denoted as a first difference, and the ratio of the first difference to the environmental noise at the a-th moment is taken as the noise attenuation amplitude between the a-th moment and the b-th moment ; Based on the number and the noise attenuation amplitude, calculate the corresponding degree H between the ambient noise at the a-th moment and the residual noise at the b-th moment, and the expression is: ; h is the number of the first noise sequence and the second noise sequence in the same position element is recorded as each adjacent point pair, is the noise attenuation amplitude between the mth adjacent point pair at the a time and the b time, is a preset value greater than 0, wherein the b time is located after the a time.

6. The method of claim 1, wherein the method is a method for testing the noise reduction performance of an intelligent dynamic waveguide noise-cancelling earphone. The determination of the matching residual noise of the maximum point noise in the standard interval comprises: Obtain each moment residual noise within a preset time interval after the corresponding moment of the maximum point noise in the standard interval, calculate the corresponding degree between the corresponding moment of the maximum point noise and each moment residual noise, and take the residual noise corresponding to the maximum value of the corresponding degree as the matching residual noise of the maximum point noise.

7. The method of claim 1, wherein the method further comprises: determining the noise reduction performance of the intelligent dynamic guiding noise reduction earphone based on the noise reduction performance of the intelligent dynamic guiding noise reduction earphone. The determination of the matching residual noise of each moment ambient noise in the standard interval comprises: Determine the time interval between the maximum point noise in each standard interval and its matching residual noise, count the occurrence frequency of each time interval, calculate the difference of the time interval corresponding to the maximum value of the occurrence frequency, denoted as the second difference, and take the ratio of the maximum value of the occurrence frequency to the sum of the second differences corresponding to all standard intervals as the time consistency; Calculate the subtraction result of the natural number 1 and the normalized value of the time consistency, for the ambient noise at the a-th moment in the standard interval, obtain the time interval between the maximum point noise in the standard interval to which the ambient noise belongs and its matching residual noise, and multiply the time interval by the subtraction result to obtain a first product; expand the time length corresponding to the first product to both sides with the a-th moment as the center to obtain a time interval at the a-th moment; Calculate the corresponding degree between the ambient noise at the a-th moment and the residual noise at all moments in the time interval at the a-th moment, and take the residual noise corresponding to the maximum value of the corresponding degree as the matching residual noise of the ambient noise at the a-th moment.

8. A smart dynamic guide noise-reducing earphone noise reduction performance test system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, The processor executes the computer program to realize the steps of the method of any one of claims 1-7. The processor executes the computer program to realize the steps of the method of any one of claims 1-7.

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