Microphone diaphragm acoustic figure measurement system and method
Patent Information
- Application Number
- CN202611001466.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-07
- Publication Date
- 2026-09-25
AI Technical Summary
[0003]相关技术中，传声器振膜的检测主要通过共振设备进行检测，而共振设备一般只能对组装好的传声器进行检测，即对传声器本身进行测试，测试过程为将传声器设置在测试平台上，对应设置拾音原件，与发声单元相对设置，发声单元与测试平台之间设置共振膜片，发声单元发生后通过共振膜片传递到传声器上，进而检测谐振频率，得出检测结果，该种机构必须将待测膜片组装到传声器中才能实现，因此，浪费大量组装时间，并且在检测过程中，设置共振膜片，检测过程中容易发生干扰，导致检测结构不准确
[0016]根据本公开的实施方式，该系统具有如下优点：其包括音源设备，通过控制装置控制，用于发出检测音频；待测膜片，与音源设备相对设置；光源设备，设置于待测膜片的侧方，检测端延长线与待测膜片的处于同一平面；图像采集设备，设置在待测膜片的另一侧，与音源设备相对设置；同步控制器，与光源设备和图像采集设备分别连接，用于调节光源设备和图像采集设备的工作状态的同步；其中，同步控制器通过图像采集卡连接控制装置，控制装置根据在音源设备的音频作用下的待测膜片发生变化的图像信息确定待测膜片的振动位移，进而计算出待测膜片的振幅。系统能够完成对声音信息进行检测和恢复，具有抵抗远距离衰减、非接触式测量等特点，在光声传声器制作中振膜的选择提供了高效的筛选方法，提高效率。
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Figure CN122813987A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of microphone diaphragm testing technology, specifically to a microphone diaphragm acoustic imaging system and method. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of this disclosure and is not necessarily an admission or implication in any way that such information constitutes related technology that is already known to those skilled in the art.
[0003] In related technologies, the testing of microphone diaphragms is mainly carried out through resonance equipment. However, resonance equipment can generally only test assembled microphones, that is, test the microphone itself. The testing process involves placing the microphone on a test platform, setting up a corresponding pickup element, and positioning it opposite the sound-generating unit. A resonance diaphragm is placed between the sound-generating unit and the test platform. After the sound is emitted by the sound-generating unit, it is transmitted to the microphone through the resonance diaphragm, and then the resonant frequency is detected to obtain the test result. This mechanism requires the diaphragm to be assembled into the microphone to achieve this, thus wasting a lot of assembly time. Furthermore, the use of a resonance diaphragm during the testing process makes it prone to interference, leading to inaccurate test results.
[0004] Traditional testing methods are mostly contact-based measurements, and the sensor structure can significantly affect the vibration characteristics of lightweight diaphragms, further reducing the accuracy of the tests. Therefore, developing a system and method for non-contact, high-precision vibration characteristic testing of microphone diaphragms before assembly is of great significance for microphone R&D screening and production quality control. Summary of the Invention
[0005] Therefore, this disclosure provides a microphone diaphragm acoustic imaging system and method to achieve accurate detection of the comprehensive performance of the microphone diaphragm.
[0006] To achieve the above objectives, the embodiments of this disclosure provide the following technical solutions: In a first aspect of the embodiments of this disclosure, a microphone diaphragm acoustic graph vibration measurement system is provided, including... A sound source device, controlled by a control unit, is used to emit detection audio. The diaphragm to be tested is positioned opposite to the sound source device; A light source device is disposed to the side of the diaphragm to be tested, and the extension line of the detection end is in the same plane as the diaphragm to be tested; An image acquisition device is located on the other side of the diaphragm to be tested, opposite to the sound source device; A synchronization controller, connected to the light source device and the image acquisition device respectively, is used to adjust the synchronization of the working states of the light source device and the image acquisition device; The synchronization controller is connected to the control device via an image acquisition card. The control device determines the vibration displacement of the diaphragm under test based on the image information of the changes in the diaphragm under the influence of the audio source device, and then calculates the amplitude of the diaphragm under test.
[0007] In one disclosed embodiment, the system is set in an ultra-quiet room without natural light, the diaphragm to be tested is set on a vibration damping support, the distance between the sound source device and the diaphragm to be tested is 20cm, and the distance between the image acquisition device and the diaphragm to be tested is 10cm.
[0008] In one disclosed embodiment, the image acquisition device is an industrial camera, the light source device is a helium-neon laser with a wavelength of 633nm, and the control device is a storable computer device.
[0009] In one disclosed embodiment, the test film is an embossed film with a thickness of 6 μm, and the surface of the test film has multiple sets of inclined elliptical indentations with an aspect ratio of 0.08 × 0.03 meters and a depth of 0.5 μm.
[0010] In a second aspect of the embodiments of this disclosure, a method for measuring the acoustic vibration of a microphone diaphragm is provided, applied to the aforementioned vibration measurement system, characterized by comprising the following steps. Step 1: Establish a microphone acoustic vibration measurement system, select the appropriate diaphragm to be tested, and adjust and set it on the vibration damping support for testing; Step two: Under the audio effect of the sound source device, the image acquisition device will transmit the vibration image under the light source device to the control device. Step 3: The control device determines the pixel displacement of the film under test based on the image signal analysis; Step four: Process the acquired image and determine the fundamental frequency of the membrane under test based on the pixel displacement of the membrane under test.
[0011] In one disclosed embodiment, the image processing method includes... The acquired image signals are preprocessed, including binarization, median filtering, histogram equalization, and erosion and dilation processing.
[0012] In one disclosed implementation, the histogram equalization process includes: By selecting an appropriate threshold, the pixel displacement of the diaphragm vibration point is calculated to obtain the specific values of pixel displacement changes under silent excitation and vibration.
[0013] In one disclosed embodiment, the image signal analysis method includes: Extracting the pixel displacement of the diaphragm: The relationship between pixel displacement and diaphragm motion displacement is used to obtain the pixel displacement of the selected vibration point of the diaphragm.
[0014] In one disclosed embodiment, the image signal analysis method includes: Displacement signal transduction: The image acquisition device captures and picks up the video signal of the microphone diaphragm vibration state in a certain time sequence. The static image is used as the reference frame. The motion image of each frame is differentially processed with the reference frame to obtain the real-time displacement of the diaphragm point vibration.
[0015] In one disclosed embodiment, the pixel displacement of the film under test is determined by: including After image information is preprocessed, the instantaneous displacement of the microphone diaphragm vibration point is obtained using the frame difference method. The instantaneous displacement amplitude of the diaphragm center point at different frequencies is obtained by fitting the instantaneous displacement amplitude to obtain the fundamental frequency of the diaphragm under test.
[0016] According to the embodiments of this disclosure, the system has the following advantages: it includes a sound source device controlled by a control device for emitting detection audio; a diaphragm to be tested, disposed opposite to the sound source device; a light source device disposed to the side of the diaphragm to be tested, with the extension line of the detection end on the same plane as the diaphragm to be tested; an image acquisition device disposed on the other side of the diaphragm to be tested, disposed opposite to the sound source device; and a synchronization controller connected to the light source device and the image acquisition device respectively, used to synchronize the working states of the light source device and the image acquisition device; wherein, the synchronization controller is connected to the control device through an image acquisition card, and the control device determines the vibration displacement of the diaphragm to be tested based on the image information of the changes in the diaphragm to be tested under the audio action of the sound source device, and then calculates the amplitude of the diaphragm to be tested. The system can detect and recover sound information, and has the characteristics of resisting long-distance attenuation and non-contact measurement. It provides an efficient screening method for diaphragm selection in the manufacture of photoacoustic microphones, improving efficiency. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.
[0018] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which this disclosure can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effectiveness and purpose that this disclosure can achieve, should still fall within the scope of the technical content disclosed herein.
[0019] Figure 1 As illustrated in an exemplary embodiment; Figure 2 The embossed pattern structure of the diaphragm under test in a microphone diaphragm acoustic imaging system according to an exemplary embodiment is shown. Figure 3 This is an image of the diaphragm center position at a moment of silent excitation, obtained in a microphone diaphragm acoustic vibration measurement method according to an exemplary embodiment. Figure 4 This is an image of the diaphragm edge position at a moment of silent excitation, obtained in a microphone diaphragm acoustic imaging vibration measurement method according to an exemplary embodiment. Figure 5 The image showing the center position of the diaphragm at a certain moment during a 2 kHz acoustic excitation in a microphone diaphragm acoustic imaging method. Figure 6 The image of the diaphragm edge position at a certain moment of 2 kHz acoustic excitation is obtained in the microphone diaphragm acoustic vibration measurement method. Figure 7 This is a histogram distribution of the diaphragm at the moment of silent excitation in the acoustic imaging method for measuring the vibration of a microphone diaphragm. Figure 8 The histogram distribution of the diaphragm at the 2kHz acoustic excitation moment in the microphone diaphragm acoustic vibration measurement method; Figure 9 This is a schematic diagram of displacement signal transduction in a microphone diaphragm acoustic imaging method according to an exemplary embodiment. Figure 10 The instantaneous displacement amplitude of the diaphragm center point at different frequencies is measured in the acoustic vibration measurement method of microphone diaphragm. Figure 11 The instantaneous displacement amplitude at different frequencies of the diaphragm edge position is measured in the acoustic imaging method for microphone diaphragm vibration measurement. Figure 12 The frequency displacement of diaphragms of different diameters was measured in the acoustic imaging method for microphone diaphragms.
[0020] In the diagram: 1. Sound source device; 2. Diaphragm under test; 3. Light source device; 4. Image acquisition device; 5. Synchronization controller; 6. Control device; 7. Image acquisition card. Detailed Implementation
[0021] The following specific embodiments illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0022] The terms “upper,” “lower,” “left,” “right,” and “middle” used in this specification are merely for clarity of description and are not intended to limit the scope of this disclosure. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of this disclosure.
[0023] like Figure 1 As shown, this embodiment of the present disclosure provides a microphone diaphragm acoustic graph vibration measurement system, including... A sound source device, controlled by a control unit, is used to emit detection audio. The diaphragm to be tested is positioned relative to the sound source device; The light source device is positioned to the side of the film under test, with the extension line of the detection end and the film under test on the same plane; An image acquisition device is set on the other side of the diaphragm to be tested, opposite to the sound source device; A synchronization controller, connected to both the light source device and the image acquisition device, is used to synchronize the working states of the light source device and the image acquisition device. The synchronous controller is connected to the control device via an image acquisition card. The control device determines the vibration displacement of the diaphragm under test based on the image information of the changes in the diaphragm under the action of the audio source device, and then calculates the amplitude of the diaphragm under test.
[0024] In this embodiment, the distance between the laser and the diaphragm under test is adjusted according to the focusing requirements, with a typical working distance range of 20-40cm.
[0025] Specifically, this acoustic vibration measurement system consists of main components such as a light source, a sound source, a diaphragm under test, and an image acquisition device. The system is housed in an ultra-quiet chamber without natural light. The diaphragm under test is mounted on a vibration-damping support. To avoid interfering with the operation of the CCD industrial camera, a darkroom environment, i.e., without natural light, is selected. Figure 1As shown, the light source is a 633nm helium-neon laser (model: DH-HH250, wavelength 633nm), which provides the light beam and illuminates the vibration location of the selected point on the diaphragm. The distance between the speaker and the diaphragm under test is 20cm. The image acquisition device is a CCD industrial camera, and the distance between the CCD industrial camera and the diaphragm under test is 10cm. When the signal reproduced by the speaker is a pure tone signal, the diaphragm undergoes forced vibration. Simultaneously, the CCD industrial camera behind the diaphragm records the vibration state of the diaphragm via the microphone. The control device is a storable computer device, thus completing the acquisition of the video signal and storing it on the computer.
[0026] In one disclosed embodiment, the test film used is an embossed film with a diameter of 34 mm and a thickness of 6 μm. The surface of the test film has multiple sets of tilted, elliptical indentations with an aspect ratio of 0.08 × 0.03 meters and a depth of 0.5 μm. See [link to relevant documentation]. Figure 2 As shown.
[0027] A sound signal acts on the embossed diaphragm of a microphone, causing it to vibrate under forced conditions. A CCD industrial camera captures video signals of the diaphragm's vibration state at various moments. As the intensity of the sound signal changes, the number of embossed patterns on the diaphragm surface in the video signal varies at different times. Simultaneously, this video signal is decomposed into individual still images. Based on a differential algorithm, digital image processing technology is used to measure the displacement amplitude of the microphone diaphragm, obtaining the instantaneous displacement of the microphone diaphragm's vibration point in each still image.
[0028] In a second aspect of the embodiments of this disclosure, a method for measuring the acoustic vibration of a microphone diaphragm is provided, applied to the aforementioned vibration measurement system, characterized by comprising the following steps. Step 1: Establish a microphone acoustic vibration measurement system, select the appropriate diaphragm to be tested, and adjust and set it on the vibration damping support for testing; Step two: Under the audio effect of the sound source device, the image acquisition device will transmit the vibration image under the light source device to the control device. Step 3: Preprocess the acquired image, and the control device determines the pixel displacement of the film under test based on the image signal analysis; Step 4: Determine the fundamental frequency of the film under test based on the pixel displacement of the film under test.
[0029] Under the same experimental conditions, data were collected from the edge region and center point region of the diaphragm under test (effective vibration area < 1.0 mm). 2) vibration displacement, and the optimal shooting area is determined by comparing and analyzing the displacement conditions of different areas. The Galaxy Viewer image acquisition software matched with Daheng Mercury series CCD sensors is used for shooting in the sequence of motion occurrence, and images at the silent excitation moment are acquired respectively, such as Figure 3 , Figure 4 shown, and images at the motion moment as shown in Figure 5 , Figure 6 .
[0030] Preprocessing the acquired image signals: including binarization, median filtering, histogram equalization, and erosion and dilation processing; wherein the binarization processing is to enable identification of image features and facilitate collection of motion image information under acoustic excitation; the erosion and dilation processing is to smooth the contour of motion pixels, remove pixel "noise", and facilitate extraction of motion pixel information.
[0031] In a disclosed embodiment, the image signal analysis method comprises Extracting the pixel displacement of the diaphragm: eliminating the influence of the shooting frame rate and shooting angle of the image acquisition device on the relationship between the pixel displacement and the motion displacement of the diaphragm, to obtain the pixel displacement of the selected vibration point of the diaphragm; the calculation formula is as follows
[0032]
[0033] Wherein, m is the surface magnification of the microphone diaphragm by the camera, expressed in millimeters per pixel, that is, how many pixels are contained per millimeter. The pixel size of the CCD industrial camera used herein is 6μm*6μm, so m=27. The CCD industrial camera shoots and captures the effective area of diaphragm vibration, and the embossed pattern is used to calibrate the effective area. The shooting angle of the CCD industrial camera only needs to be flush and aligned with the effective area, so equals 1. The pixel displacement of the center point of the microphone diaphragm is obtained through calculation, and all displacements described hereinafter in this paper are converted target motion displacements.
[0034] Next, an appropriate threshold is selected, and the selection of the threshold is determined by the gray distribution of the histogram, as shown in Figure 7 , Figure 8 shown. Comparing the histograms of the silent moment ( Figure 7 ) and the 2kHz acoustic excitation ( Figure 8 ), it can be seen that the gray values of the images are all above 50. Therefore, when the frame difference threshold is less than 50, it is considered that there is no gray value distribution in the image, so there is "no" image presentation.
[0035] According to the gray value distribution in the histogram (using the covariance matrix formula), an appropriate threshold is selected to calculate the pixel displacement of the diaphragm vibration point, and the specific values of pixel displacement changes under silent excitation and vibration are obtained.
[0036] Displacement signal transduction: The CCD industrial camera captures video signals of the microphone diaphragm vibration state in a specific time sequence. Using the static image as a reference frame, the real-time displacement of the diaphragm point vibration is obtained by differential processing between each moving image and the reference frame. For example... Figure 9 As shown, it is a schematic diagram of displacement signal transduction in the microphone diaphragm acoustic vibration measurement method.
[0037] Assume that a frame of the diaphragm at time t is The static image of the diaphragm before vibration can be represented as Let i and j represent the positional changes along the x-axis and y-axis, respectively. Therefore, the covariance matrix C between them is defined and calculated as follows:
[0038] It is a column vector. Let be the mean of the column vectors, T denote the transpose of the matrix, and the gray values of the image follow a normal distribution. The probability density function is defined as follows:
[0039] The grayscale value is calculated based on the acquired image signal. Assume the grayscale value at time t is... The gray value at t=0 is By differentiating the two, the change in microphone diaphragm displacement can be obtained. By comparing the image signals of the diaphragm under forced vibration and at rest at time t, the image difference operation is performed, and the displacement of the diaphragm point vibration is calculated according to the following formula:
[0040] After image information is preprocessed, the instantaneous displacement of the microphone diaphragm vibration point is obtained using the frame difference method. The instantaneous displacement amplitude at different frequencies of the diaphragm center point is then fitted to obtain the fundamental frequency of the diaphragm under test. For example... Figure 10 , Figure 11 As shown.
[0041] The displacement amplitude change at the center of the microphone diaphragm is greater than that at the edge. When sound signals of different frequencies are applied to the diaphragm, the diaphragm vibration displacement will first increase and then decrease with the increase of frequency. The area at the center of the diaphragm is more likely to vibrate.
[0042] The extreme values of the fitted curve were obtained using MATLAB. MATLAB's curve fitting tool was used to perform polynomial fitting on the experimental data. The maximum points of the fitted curve were obtained by differentiation or direct optimization, and their x-axis represents the fundamental frequency of the membrane under test. Figure 10The maximum value of the fitted curve corresponds to an abscissa of 1712Hz, meaning that the displacement of the embossed patterned film with a diameter of 34mm and a thickness of 6μm reaches its maximum at a frequency of 1712Hz. This can be obtained using the function edcvf(). Figure 11 The maximum value of the fitted curve corresponds to the x-axis at 1700Hz. Therefore, it can be concluded that... Figure 10 , 11 The difference in fundamental frequency obtained is small.
[0043] This function uses MATLAB's curve fitting tool to perform polynomial fitting on the experimental data. The maximum point of the fitted curve is obtained by differentiation or direct optimization, and its x-axis is the fundamental frequency of the diaphragm under test.
[0044] Using the above method, the fundamental frequency of diaphragms with diameters of 6mm, 10mm, and 14mm was measured. Specifically, an industrial CCD camera was used to capture image signals without external excitation, and vibration images of the diaphragm were taken at various times. The vibration displacement at the diaphragm's center point was analyzed, and the structure was measured as follows: Figure 12 As shown.
[0045] thus: The diaphragm displacement increases with increasing diameter; with increasing frequency, all three diaphragm displacements show a trend of first increasing and then decreasing, with the diaphragm displacement being the largest at one of the frequencies. The maximum vibration displacements of diaphragms with diameters of 14mm, 10mm, and 6mm are approximately 0.09μm, 0.04μm, and 0.02μm, respectively. A CCD industrial camera can capture the vibration states of different diaphragms. By measuring the fundamental frequency of the diaphragms using a graphical method, the fundamental frequencies of the 6mm, 10mm, and 14mm diameter diaphragms are found to be 10416Hz, 8098Hz, and 4032Hz, respectively.
[0046] The CCD acoustic vibration measurement system picks up the vibration state of the microphone diaphragm at a specific moment and uses digital image processing technology to obtain the fundamental frequency of the diaphragm, solving the problem of difficulty in measuring the fundamental frequency of diaphragms with small diameter and light weight.
[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0048] Although the present disclosure has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of the present disclosure are all within the scope of protection claimed by the present disclosure.
Claims
1. A microphone diaphragm acoustic imaging system, characterized in that, include A sound source device, controlled by a control unit, is used to emit detection audio. The diaphragm to be tested is positioned opposite to the sound source device; A light source device is disposed to the side of the diaphragm to be tested, and the extension line of the detection end is in the same plane as the diaphragm to be tested; An image acquisition device is located on the other side of the diaphragm to be tested, opposite to the sound source device; A synchronization controller, connected to the light source device and the image acquisition device respectively, is used to adjust the synchronization of the working states of the light source device and the image acquisition device; The synchronization controller is connected to the control device via an image acquisition card. The control device determines the vibration displacement of the diaphragm under test based on the image information of the changes in the diaphragm under the influence of the audio source device, and then calculates the amplitude of the diaphragm under test.
2. The microphone diaphragm acoustic imaging system according to claim 1, characterized in that, The system is set up in an ultra-quiet room without natural light. The diaphragm under test is placed on a vibration damping support. The distance between the sound source device and the diaphragm under test is 20cm, and the distance between the image acquisition device and the diaphragm under test is 10cm.
3. The microphone diaphragm acoustic graph vibration measurement system according to claim 2, characterized in that, The image acquisition device is an industrial camera, the light source is a helium-neon laser with a wavelength of 633nm, and the control device is a computer device capable of storage.
4. The microphone diaphragm acoustic imaging system according to claim 3, characterized in that, The test film is an embossed film with a thickness of 6 μm. The surface of the test film has multiple sets of tilted elliptical indentations with an aspect ratio of 0.08 × 0.03 meters and a depth of 0.5 μm.
5. A method for measuring the vibration of a microphone diaphragm using acoustic imaging, applied to the vibration measurement system described in any one of claims 1-4, characterized in that, Includes the following steps Step 1: Establish a microphone acoustic vibration measurement system, select the appropriate diaphragm to be tested, and adjust and set it on the vibration damping support for testing; Step two: Under the audio effect of the sound source device, the image acquisition device will transmit the vibration image under the light source device to the control device. Step 3: The acquired image is processed, and the control device determines the pixel displacement of the film under test based on the image signal analysis. Step 4: Determine the fundamental frequency of the film under test based on the pixel displacement of the film under test.
6. The method for measuring the vibration of a microphone diaphragm using acoustic imaging according to claim 5, characterized in that, The image processing method includes The acquired image signals are preprocessed, including binarization, median filtering, histogram equalization, and erosion and dilation processing.
7. The method for measuring the vibration of a microphone diaphragm using acoustic imaging according to claim 6, characterized in that, The histogram equalization process includes: By selecting an appropriate threshold, the pixel displacement of the diaphragm vibration point is calculated to obtain the specific values of pixel displacement changes under silent excitation and vibration.
8. The method for measuring the vibration of a microphone diaphragm using acoustic imaging according to claim 7, characterized in that, The image signal analysis method includes Extracting the pixel displacement of the diaphragm: The relationship between pixel displacement and diaphragm motion displacement is used to obtain the pixel displacement of the selected vibration point of the diaphragm.
9. The method for measuring the vibration of a microphone diaphragm using acoustic imaging according to claim 8, characterized in that, The image signal analysis method includes Displacement signal transduction: The image acquisition device captures and picks up the video signal of the microphone diaphragm vibration state in a certain time sequence. The static image is used as the reference frame. The motion image of each frame is differentially processed with the reference frame to obtain the real-time displacement of the diaphragm point vibration.
10. The method for measuring the acoustic waveform of a microphone diaphragm according to claim 5, characterized in that, The displacement of the pixel point of the film under test is determined, including: After image information is preprocessed, the instantaneous displacement of the microphone diaphragm vibration point is obtained using the frame difference method. The instantaneous displacement amplitude of the diaphragm center point at different frequencies is obtained by fitting the instantaneous displacement amplitude to obtain the fundamental frequency of the diaphragm under test.