A three-dimensional dynamic imaging characterization device for micro-nano bubbles

Abstract

The invention discloses a three-dimensional dynamic imaging characterization device for micro-nano bubbles. The device comprises: a light source, a convex lens group, a sample pool, an objective lens and an image sensor. The method comprises the following steps: light emitted by the light source passes through the lens group and is used as incident light to irradiate micro-nano bubbles in a solution in a sample pool, and object light is generated, and then the object light is collected by the objective lens to the image sensor, and the image sensor records the interference between the object light and the incident light to obtain a hologram. Finally, a three-dimensional positioning algorithm, a trajectory tracking algorithm and a particle size measurement algorithm are used to obtain the real-time dynamic individual size, particle size distribution, three-dimensional position and three-dimensional motion trajectory of the micro-nano bubbles. The device can realize three-dimensional real-time imaging and tracking of micro-nano bubbles, and is suitable for water treatment, industrial processing, agricultural production, life sciences, medical health and other micro-nano bubble related application fields.

Description

Technical Field

[0001] The invention relates to a device and method for measuring individual size, particle size distribution, three-dimensional position and three-dimensional motion trajectory of micro-nano bubbles in a solution and on a surface. Background Art

[0002] Compared with other particles such as solid particles and oil droplets, micro-nano bubbles have physical characteristics such as small size, susceptibility to disturbance, variable morphology, wide particle size distribution, and a refractive index lower than that of water. At present, there are several methods for characterizing micro-nano bubbles, such as atomic force microscopy for surface bubbles; for solution bubbles, there are laser light scattering measurement methods, multi-wavelength extinction methods, two-dimensional imaging methods, low-field nuclear magnetic resonance methods, etc. The above characterization methods all have their own advantages, but there are still common limitations, that is, it is impossible to accurately and comprehensively observe the in-situ and real-time changes of individual micro-nano bubbles in three-dimensional scales, and it is also impossible to distinguish bubbles from other solid or liquid impurities of similar sizes. Therefore, we have developed a three-dimensional dynamic imaging technology for solution and surface micro-nano bubbles based on digital holographic microscopy (DHM). It uses light interference to record real-time holographic images of multiple microscale particles, and reconstructs them in three dimensions to obtain their motion trajectory, morphology and phase. It has the advantages of high flux, large depth of field, high precision, non-destructiveness, and can provide material information (optical refractive index).

[0003] In the prior art, a system and method for observing micro-nano bubbles in water bodies discloses the function of being able to image micro-nano bubbles with a diameter greater than 900 nanometers and obtain the particle size distribution and motion trajectory. The present invention can image micro-nano bubbles with a diameter as small as 200 nanometers based on holography, and can obtain the particle size distribution and three-dimensional dynamic trajectory of the micro-nano bubbles. In addition, the device of the present invention has the characteristics of high observation accuracy. Summary of the invention

[0004] The present invention proposes a set of three-dimensional dynamic imaging and characterization devices and methods for micro-nano bubbles. The main purpose of the present invention is to make up for the common shortcomings of the prior art, and to achieve three-dimensional dynamic observation of micro-nano bubbles, with the advantages of simple optical path, large flux and high resolution. The present invention provides a method for dynamically observing micro-nano bubbles in solution and on the surface based on three-dimensional holographic microscopy imaging, which can be used to characterize the physicochemical properties of micro-nano bubbles and study their interaction mechanism with the surrounding medium.

[0005] The present invention is implemented through the following technical solutions.

[0006] A three-dimensional dynamic imaging characterization device for micro-nano bubbles comprises: a light source, a convex lens group, a sample pool, an objective lens and an image sensor; the light source, the convex lens group, the sample pool, the objective lens and the image sensor are sequentially located on the same horizontal line, and the centers of the light source, the convex lens group, the objective lens and the image sensor are all located on a dotted optical axis (dash-dot line) in the figure, and the surface of the sample pool is perpendicular to the optical axis; the optical path is simple.

[0007] The light emitted by the light source passes through the convex lens group and converges into a converged parallel light with higher energy density. This incident light enters the sample pool, and a part of the incident light is scattered after being irradiated by the micro-nano bubbles. The scattered light is used as the object light. The object light interferes with the incident light at the defocused position of the objective lens on the image sensor to form a holographic interference pattern, which is recorded by the image sensor.

[0008] The method of using the device comprises the following steps:

[0009] S1, turning on the power of the light source (1) and the image sensor (5);

[0010] S2, adjusting the parameters of the image sensor (5) so that the brightness of the field of view is uniform and appropriate;

[0011] S3, adding a solution rich in micro-nano bubbles to the sample pool (3), or adding the solution and then producing micro-nano bubbles by injection or stirring, leaving the solution to stand for a suitable period of time, and controlling the image sensor (5) to record the sample hologram in a high-speed continuous shooting manner;

[0012] S4, using a difference method to obtain a hologram with the background subtracted from the hologram;

[0013] S5, using a three-dimensional reconstruction algorithm to reconstruct a three-dimensional light field from the hologram with the background subtracted;

[0014] S6. Using a trajectory tracking algorithm to process and reconstruct the light field, obtain the motion trajectory information of the micro-nano bubbles;

[0015] S7. Use a particle size measurement algorithm to process the reconstructed light field to obtain the size information of each micro-nano bubble.

[0016] Furthermore, the light source is coherent light or partially coherent light; the central wavelength of the light source is selected in the range of 200nm<λ<1000nm.

[0017] Furthermore, the centers of the light source, convex lens group, objective lens, and image sensor units are on the same vertical line. The distances of the light source, convex lens group, objective lens, and image sensor units in the optical axis direction should satisfy the following imaging position: the focusing position is located on the inner wall of the sample pool close to the objective lens side, so that the micro-nano bubble imaging is moderately defocused.

[0018] Furthermore, the incident light spot can be further homogenized by replacing the convex lens group with a beam expander or adding a spatial filter in the optical path.

[0019] Furthermore, the objective lens may use an air medium objective lens or a liquid medium objective lens. When a liquid medium objective lens is used, the front end of the objective lens may directly contact the liquid in the sample pool through a special sample pool.

[0020] Furthermore, the optical path length can be shortened by adding a prism group between the objective lens and the image sensor.

[0021] Furthermore, the device can increase the functions of focusing and field of view movement by adding a displacement device in the optical path.

[0022] Furthermore, the specific process of step S4 is: average the light intensity of the hologram to obtain the background image, which is calculated as follows:

[0023]

[0024] Among them, I b (x, y) is the gray value of the pixel at the position (x, y) in the background image, N is the total number of frames of the hologram taken at high speed, i is the specific frame number, I i (x, y) is the gray value of the pixel at the position (x, y) in the original holographic image of the i-th frame.

[0025] Furthermore, the specific process of step S4 is: subtracting the background image from the hologram to obtain a hologram with the background subtracted.

[0026] Furthermore, the specific process of step S5 is: numerically reconstructing the holographic image after deducting the background to obtain the information of the three-dimensional reconstructed intensity distribution of micro-nano bubbles, which is calculated as follows:

[0027] U(r,-z)=FT -1 (FT(I s (r,0)·H(q,-z)))

[0028] Among them, is the initial coordinate of the micro-nano bubble in the horizontal direction, z is the initial axial coordinate of the micro-nano bubble; FT -1 is the inverse Fourier transform; FT is the Fourier transform; H(q,-z) is the Fourier transform of h(r,-z).

[0029] Furthermore, in step S5, the value of the reconstructed axial interval is greater than the axial imaging range of the instrument, and the step is the size of the pixel divided by the magnification of the objective lens.

[0030] Furthermore, in step S6, the three-dimensional positions of the signal points of the micro-nano bubbles are connected in series according to the correlation between adjacent frames in the three-dimensional light field to obtain a three-dimensional motion trajectory.

[0031] Further, in step S7, for the signal point of the micro-nano bubble in the light field, the light intensity curve thereof is fitted by a function to obtain the half-peak width of the signal point;

[0032] According to the proportionality coefficient between the corrected half-peak width and the size of the micro-nano bubble, the size of each micro-nano bubble is obtained from the half-peak width of each micro-nano bubble.

[0033] The image sensor collects the interference light of the object light scattered by the micro-nano bubbles and the incident light near the focal plane as a hologram.

[0034] The hologram is processed by the difference method to obtain a hologram with the background subtracted.

[0035] The background-subtracted interference pattern is reconstructed into a three-dimensional light field using a three-dimensional reconstruction algorithm including Fourier transform and inverse Fourier transform.

[0036] The three-dimensional light field is processed using a three-dimensional trajectory tracking algorithm to obtain the three-dimensional trajectory of the micro-nano bubble.

[0037] The particle size measurement algorithm is used to process the three-dimensional light field to obtain the individual size and particle size distribution of micro-nano bubbles.

[0038] Furthermore, the Gaussian fitting position of the micro-nano bubble obtained by the particle size measurement algorithm can be used to correct and verify the trajectory tracking algorithm.

[0039] In summary, by using the hologram of micro-nano bubbles, the individual size distribution, three-dimensional density distribution and three-dimensional motion trajectory of micro-nano bubbles can be obtained, and the three-dimensional imaging observation of a large number of micron and submicron sized micro-nano bubbles can be realized.

[0040] Compared with the prior art, the advantages of the present invention are: it can image micro-nano bubbles with a diameter as small as 200 nanometers at the liquid surface and in the bulk phase based on holography, and can obtain the particle size distribution and three-dimensional dynamic trajectory of the micro-nano bubbles. In addition, the device design is simple and feasible, and the observation accuracy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the three-dimensional digital holographic imaging characterization device of the micro-nano bubbles of the present invention;

[0042] Figure 2 It is the original hologram of micro-nano bubbles collected by the three-dimensional digital holographic imaging characterization device of micro-nano bubbles in Example 1 of the present invention. The numbers represent the time sequence, and the holograms of some bubbles have been framed;

[0043] Figure 3 It is a background-subtracted hologram of micro-nano bubbles obtained by data processing of the three-dimensional digital holographic imaging characterization device of micro-nano bubbles in Example 1 of the present invention. The numbers represent the time sequence, and the diffraction rings of some bubbles have been framed;

[0044] Figure 4 is a three-dimensional trajectory diagram of micro-nano bubbles collected by the three-dimensional digital holographic imaging characterization device of micro-nano bubbles in Example 1 of the present invention, and the size of the small ball in the diagram is the size of the micro-nano bubbles;

[0045] Figure 5 It is the size distribution of micro-nano bubbles collected by the three-dimensional digital holographic imaging characterization device of micro-nano bubbles in Example 1 of the present invention.

[0046] Figure 6 It is a background-subtracted hologram of the micro-nano bubbles in Example 2 of the present invention and a three-dimensional trajectory diagram of a nano bubble in the hologram, and the size of the small ball in the figure is the size of the micro-nano bubbles;

[0047] Figure 7 It is a background-subtracted hologram of the micro-nano bubbles in Example 3 of the present invention and a three-dimensional trajectory diagram of a nano bubble in the hologram, and the size of the small ball in the figure is the size of the micro-nano bubble;

[0048] Figure 8 It is a background-subtracted hologram of the micro-nano bubbles in Example 4 of the present invention and a three-dimensional trajectory diagram of a nano bubble in the hologram, and the size of the small ball in the figure is the size of the micro-nano bubbles;

[0049] Fig. 9 This is the size distribution of micro-nano bubbles captured by the three-dimensional digital holographic imaging characterization device for micro-nano bubbles in Example 4 of the present invention for a total of 6 recordings. DETAILED DESCRIPTION

[0050] The following is a detailed description of the micro-nano bubble three-dimensional imaging characterization device and image acquisition method involved in the present invention with reference to the accompanying drawings.

[0051] A three-dimensional dynamic imaging characterization device for micro-nano bubbles comprises: a light source 1, a convex lens group 2, a sample pool 3, an objective lens 4 and an image sensor 5; the light source 1, the convex lens group 2, the sample pool 3, the objective lens 4 and the image sensor 5 are sequentially located on the same horizontal line, and the centers of the light source (1), the convex lens group 2, the objective lens 4 and the image sensor 5 are all located on the dotted optical axis in the figure, and the surface of the sample pool 3 is perpendicular to the optical axis; the distance between the light source 1, the convex lens group 2, the objective lens 4 and the image sensor 5 in the direction of the optical axis should satisfy the following imaging position: the focusing position is located on the inner wall of the sample pool close to the objective lens side, so that the imaging of the micro-nano bubbles is moderately defocused. The light source is coherent light or partially coherent light. The central wavelength of the light source is selected in the range of 200nm<λ<1000nm.

[0052] The method of using the device comprises the following steps:

[0053] S1, turn on the power of the light source 1 and the image sensor 5;

[0054] S2, adjusting the parameters of the image sensor 5 to make the brightness of the field of view uniform and appropriate;

[0055] S3, adding a solution rich in micro-nano bubbles to the sample pool 3, or adding a solution and then producing micro-nano bubbles by injection or stirring, leaving the solution to stand, and controlling the image sensor 5 to record the sample hologram in a high-speed continuous shooting manner;

[0056] S4, obtaining a background-subtracted hologram from the original hologram;

[0057] S5, using a three-dimensional reconstruction algorithm to reconstruct a three-dimensional light field from the hologram after subtracting the background;

[0058] S6. Using a trajectory tracking algorithm to process the three-dimensional reconstructed light field, obtain the motion trajectory information of the micro-nano bubbles;

[0059] S7. Use a particle size measurement algorithm to process the reconstructed light field to obtain the size information of each micro-nano bubble.

[0060] The specific process of step S4 is: average the light intensity of the hologram to obtain a background image, and subtract the background image from the hologram to obtain a hologram with the background subtracted.

[0061] The specific process of step S5 is: numerically reconstruct the holographic image after deducting the background to obtain the information of the three-dimensional reconstruction intensity distribution of micro-nano bubbles, which is calculated as follows:

[0062] U(r,-z)=FT -1 (FT(I s (r,0)·H(q,-z)))

[0063] Among them, is the initial coordinate of the micro-nano bubble in the horizontal direction, z is the initial axial coordinate of the micro-nano bubble; FT -1 is the inverse Fourier transform; FT is the Fourier transform; H(q,-z) is the Fourier transform of h(r,-z).

[0064] In step S5, the value of the reconstructed axial interval is greater than the axial imaging range of the instrument, and the step is the size of the pixel divided by the magnification of the objective lens.

[0065] In step S6, according to the correlation between adjacent frames in the three-dimensional light field, the three-dimensional positions of adjacent micro-nano bubble signal points are connected to obtain a three-dimensional motion trajectory.

[0066] In step S7, for the signal points of the micro-nano bubbles in the light field, the light intensity is fitted by a function to obtain the half-peak width of the signal points.

[0067] According to the proportionality coefficient between the corrected half-peak width and the size of the micro-nano bubble, the size of each micro-nano bubble is obtained from the half-peak width of each micro-nano bubble.

[0068] Example 1

[0069] Figure 1 The schematic diagram of the micro-nano bubble three-dimensional imaging characterization device of the present invention is shown in the figure. The device comprises a light source 1, a convex lens group 2, a sample pool 3, an objective lens 4, and an image sensor 5.

[0070] Light source 1 uses a partially coherent LED light source, and the central wavelength of the light source is selected in the range of 200nm<λ<1000nm. Here, a blue LED light source is used. The light emitted by the light source passes through a beam expander on the optical axis to obtain a parallel light beam.

[0071] The parallel light beam passes through the convex lens group 2 on the optical axis and becomes the incident light for irradiating the sample pool 3. The convex lens group 2 is composed of 2 or 3 convex lenses arranged front and back on the optical axis. The convex lens group 2 needs to collect the light intensity of the above-mentioned uniform parallel light beam as much as possible. The light beam is converged and adjusted to parallel light again. The converged parallel light obtained must have excellent parallelism in the space where the sample pool 3 is located.

[0072] The focused parallel light is used as incident light to illuminate the sample pool 3. Both surfaces of the sample pool 3 in the optical axis direction must be perpendicular to the optical axis, and the two surfaces are made of high-transmittance quartz glass with an optical surface flatness better than 1 / 4 of the central wavelength of the light source 1.

[0073] Pure water containing micro-nano bubbles generated by the micro-nano bubble generator is injected into the sample pool 3. The incident light irradiated to the micro-nano bubbles is scattered and becomes object light, that is, the propagation direction of the dotted object light in the figure is related to the micro-nano bubbles, and contains the three-dimensional position and size information of the micro-nano bubbles. The wavelength of the object light is the same as the original incident light.

[0074] The object light is converged by the objective lens 4 on the optical axis. In this embodiment, a 40x objective lens is used to take into account both the magnification and the field of view clarity under high-speed shooting to obtain high resolution.

[0075] The high-speed image sensor 5 on the optical axis records the object light converged by the objective lens 4 as an original hologram, and obtains a hologram group, such as Figure 2 The image sensor 5 can be a CMOS, CCD or other image sensor.

[0076] The computer serves as a control device to control the image acquisition of the image sensor 5. The computer can also control the light source 1 that supports digital control.

[0077] The computer, as a data analysis device, uses an algorithm to process the collected original holograms according to the principle of holography. Suppose the gray value of the pixel at the position (x, y) in the i-th frame of the original hologram is I i (x, y), the background image is obtained by the following calculation:

[0078]

[0079] I b (x, y) is the gray value of the pixel at the position (x, y) in the background image, and N is the total number of frames of the hologram taken at high speed. Using the difference method, the background image is subtracted from the hologram group to obtain the hologram with the subtracted background.

[0080] The obtained background-subtracted holographic interference pattern is a series of light and dark interference rings. The background-subtracted holographic image is numerically reconstructed using a 3D reconstruction algorithm based on Fourier transform, and the calculation is as follows:

[0081] U(r,-z)=FT -1 (FT(I s (r,0)·H(q,-z)))

[0082] is the propagation operator, r is the initial coordinate of the micro-nano bubble in the horizontal direction, and z is the initial axial coordinate of the micro-nano bubble; I s is the light intensity of the sample; FT -1 is the inverse Fourier transform; FT is the Fourier transform; H(q,-z) is the Fourier transform of the light field propagation factor h(r,-z). In terms of parameter setting, the value of the reconstructed axial interval is larger than the axial imaging range of the instrument, and the step distance is the same as the pixel size of the image.

[0083] Run the three-dimensional reconstruction algorithm to obtain and export the three-dimensional reconstructed light intensity distribution information of each frame of the hologram in the micro-nano bubble group image.

[0084] For the information of the three-dimensional reconstruction intensity distribution of the micro-nano bubbles obtained by reconstructing the light field above, the local maximum value of the light intensity is found through threshold filtering, the noise points with low reconstructed light intensity are filtered out, and the three-dimensional position of the micro-nano bubble point is obtained.

[0085] According to the correlation of the signal points of the micro-nano bubbles in adjacent frames in the background-subtracted hologram group in the three-dimensional light field, the trajectory tracking algorithm is run on the information of the three-dimensional reconstructed light intensity distribution. The tracking step size is set according to the approximate movement speed of the micro-nano bubbles, and the three-dimensional positions of the signal points of the micro-nano bubbles are connected in series to obtain the three-dimensional motion trajectory.

[0086] The size measurement algorithm is run on the signal points of the micro-nano bubbles in the light field. First, the light intensity curve is fitted with a function to obtain the half-peak width of the signal point. According to the proportional coefficient between the corrected half-peak width and the size of the micro-nano bubbles, the size of each micro-nano bubble is obtained from the half-peak width of each micro-nano bubble.

[0087] Finally, a three-dimensional trajectory diagram of micro-nano bubbles containing size information is obtained, such as Figure 4 , the ball size in the figure is the size of the micro-nano bubble, and the size distribution diagram of the micro-nano bubble is as follows: Figure 5.

[0088] Example 2

[0089] The light source 1 in Example 1 is replaced with a green LED light source, and the sample pool 3 is injected with an ethanol aqueous solution containing micro-nano bubbles produced by the alcohol-water replacement method, while the rest remains unchanged, to obtain a micro-nano bubble hologram with background subtracted and a three-dimensional trajectory diagram of one of the bubbles as shown in FIG. Figure 6 .

[0090] Example 3

[0091] The light source 1 in Example 1 is replaced with an ultraviolet LED light source, and the sample pool 3 is injected with an ethanol aqueous solution containing micro-nano bubbles produced by the alcohol-water replacement method, and the rest remains unchanged to obtain a micro-nano bubble hologram with background subtracted and a three-dimensional trajectory diagram of one of the bubbles as shown in FIG. Figure 7 .

[0092] Example 4

[0093] The objective lens 4 in Example 3 is changed to a 100x oil medium objective lens to achieve the highest possible magnification. Then, an image is collected under a 100x lens to obtain a micro-nano bubble hologram with background subtracted and a three-dimensional trajectory diagram of a bubble as shown in FIG. Figure 8 The size distribution of 649 micro / nano bubble trajectories obtained from 6 shots for a total of 6 minutes is shown in the following figure: Fig. 9 .

[0094] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for using a three-dimensional dynamic imaging characterization device for micro-nano bubbles, characterized in that: include: A light source (1), a convex lens group (2), a sample pool (3), an objective lens (4) and an image sensor (5); the light source (1), the convex lens group (2), the sample pool (3), the objective lens (4) and the image sensor (5) are sequentially located on the same horizontal line, and the centers of the light source (1), the convex lens group (2), the objective lens (4) and the image sensor (5) are all located on the dotted optical axis in the figure, and the surface of the sample pool (3) is perpendicular to the optical axis; The method of using the device comprises the following steps: S1, turning on the power of the light source (1) and the image sensor (5); S2, adjusting the parameters of the image sensor (5) so that the brightness of the field of view is uniform and appropriate; S3, adding a solution rich in micro-nano bubbles to the sample pool (3), or adding the solution and then producing micro-nano bubbles by injection or stirring, allowing the solution to stand, and controlling the image sensor (5) to record the sample hologram in a high-speed continuous shooting manner; S4, obtaining a background-subtracted hologram from the original hologram; S5, using a three-dimensional reconstruction algorithm to reconstruct a three-dimensional light field from the hologram after subtracting the background; S6. Using a trajectory tracking algorithm to process the three-dimensional reconstructed light field, obtain the motion trajectory information of the micro-nano bubbles; S7, using a particle size measurement algorithm to process the reconstructed light field to obtain size information of each micro-nano bubble; The specific process of step S5 is: numerically reconstruct the holographic image after deducting the background to obtain the information of the three-dimensional reconstruction intensity distribution of micro-nano bubbles, which is calculated as follows: Among them, is the initial coordinate of the micro-nano bubble in the horizontal direction, z is the initial axial coordinate of the micro-nano bubble; FT -1 is the inverse Fourier transform; FT is the Fourier transform; H(q ,-z) is the Fourier transform of h(r ,-z).

2. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: The distances between the light source (1), the convex lens group (2), the objective lens (4), and the image sensor (5) in the direction of the optical axis should satisfy the following imaging position: the focusing position is located on the inner wall of the sample pool close to the objective lens side, so that the imaging of the micro-nano bubbles is moderately defocused.

3. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: The light source is coherent light or partially coherent light.

4. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: The central wavelength of the light source is selected in the range of 200nm<λ<1000nm.

5. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: The specific process of step S4 is: average the light intensity of the hologram to obtain a background image, and subtract the background image from the hologram to obtain a hologram with the background subtracted.

6. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: In step S5, the value of the reconstructed axial interval is greater than the axial imaging range of the instrument, and the step is the size of the pixel divided by the magnification of the objective lens.

7. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: In step S6, according to the correlation between adjacent frames in the three-dimensional light field, the three-dimensional positions of adjacent micro-nano bubble signal points are connected to obtain a three-dimensional motion trajectory.

8. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 1, characterized in that: In step S7, for the signal points of the micro-nano bubbles in the light field, the light intensity is fitted by a function to obtain the half-peak width of the signal points.

9. The method for using the three-dimensional dynamic imaging characterization device of micro-nano bubbles according to claim 8, characterized in that: According to the proportionality coefficient between the corrected half-peak width and the size of the micro-nano bubble, the size of each micro-nano bubble is obtained from the half-peak width of each micro-nano bubble.

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