WO2023283752A1

WO2023283752A1 - Rotation control module, method, and system

Info

Publication number: WO2023283752A1
Application number: PCT/CN2021/105675
Authority: WO
Inventors: 郑海荣; 黄来鑫; 李飞; 蔡飞燕; 孟龙; 牛丽丽; 周伟; 林争荣
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2023-01-19

Abstract

A rotation control module, method and system: pre-filling a liquid containing a target object into a cavity container, and placing a structural body into the cavity container; then using ultrasound waves to excite the structural body to produce resonance, and using the spatially distributed local strong sound field produced by the resonance to form an acoustic radiation force and acoustic flow on the surface of the structural body; under the action of the acoustic radiation force and acoustic flow, the target object can be controlled to rotate on the surface of the structural body to facilitate observation of the target object from multiple angles.

Description

A rotation control module, method and system

technical field

The present application relates to the technical field of microscopic observation, in particular to a rotation control module, method and system.

Background technique

Caenorhabditis elegans is a model organism with a simple body structure. Accurate and multi-view observation of the body structure of the nematode is of great significance to the study of the nematode. However, due to the small size of nematodes, how to manipulate the nematodes to rotate for multi-angle microscopic observation has become a problem that technicians need to consider.

technical problem

In view of this, the embodiment of the present application provides a rotation control module, method and system, which can control tiny objects such as nematodes to rotate at a designated position, so as to observe the object from multiple angles.

technical solution

The first aspect of the embodiments of the present application provides a rotation control module, which includes a cavity container and an ultrasonic excitation module, and a structure is arranged in the cavity container;

The cavity container is used for containing the liquid containing the target object;

The ultrasonic excitation module is used to emit ultrasonic waves to the cavity container, and excite the structure body to resonate through the ultrasonic waves, so that the surface of the structure body generates a sound field, and control the target object to move on the surface of the structure body through the sound field. The surface of the structure is rotated.

In the embodiment of the present application, a liquid containing a target object (such as a nematode) is preliminarily filled into a cavity container, and a structure is put into the cavity container. Then, the ultrasonic wave is used to excite the structure to generate resonance, and the spatially distributed local strong sound field generated by the resonance will form the acoustic radiation force and the acoustic flow on the surface of the structure. Under the action of the acoustic radiation force and the acoustic flow, it can The target object is controlled to rotate on the surface of the structure so as to observe the target object from multiple angles.

In an implementation manner of the rotation control module, the bottom of the cavity container is provided with a piezoelectric sheet, and the ultrasonic excitation module may include:

a signal generator, configured to output a pulse signal of a specified frequency, and the specified frequency is set according to the resonant frequency of the structure;

The power amplifier is used to amplify the pulse signal to obtain an excitation signal, so that the piezoelectric sheet generates an ultrasonic wave under the action of the excitation signal, and the ultrasonic wave is used to excite the structure to resonate.

In actual operation, the ultrasonic excitation module can be composed of a signal generator and a power amplifier, where the signal generator is used to output a pulse signal of a specified frequency (set based on the resonance frequency of the structure), and the power amplifier is used to amplify the pulse signal , to obtain an amplified excitation signal, which can then be converted into ultrasonic waves through piezoelectric sheets.

In an implementation manner of the rotation control module, the cavity container may be composed of a quartz base, a container wall and a detachable top cover.

Since the top cover of the cavity container is detachable, it is convenient to realize micro-operations such as micro-injection in an open space.

In an implementation manner of the rotation control module, the structure body may be a rectangular plate-shaped structure, and the plate-shaped structure is provided with multiple columns of grids arranged at equal intervals.

Using this structure can excite the non-leaky Lamb wave in the structure to generate a localized strong transmission sound field, thereby generating strong sound radiation force and sound flow.

The second aspect of the embodiment of the present application provides a rotation control method, which is applied to the rotation control module provided in the first aspect of the embodiment of the present application, and the method includes:

using the ultrasonic excitation module to transmit ultrasonic waves to the cavity container;

The structure is excited to resonate by ultrasonic waves, so that the surface of the structure generates a sound field, and the target object is controlled to rotate on the surface of the structure through the sound field.

During operation, the ultrasonic excitation module is used to emit ultrasonic waves to the cavity container, and the structure is resonated by the ultrasonic excitation, and a periodic sound field of sufficient intensity will be formed on the surface of the structure, thereby generating periodic sound radiation force and sound flow . Under the action of the acoustic radiation force and the acoustic flow, the target object can be controlled to rotate on the surface of the structure, so as to microscopically take images of the target object at multiple different rotation angles.

In one implementation of the method, the bottom of the cavity container is provided with a piezoelectric sheet, the ultrasonic excitation module includes a signal generator and a power amplifier; the ultrasonic excitation module is used to emit ultrasonic waves to the cavity container , which can include:

using the signal generator to output a pulse signal of a specified frequency, and the specified frequency is set according to the resonant frequency of the structure;

The power amplifier is used to amplify the pulse signal to obtain an excitation signal, so that the piezoelectric sheet generates ultrasonic waves under the action of the excitation signal.

A signal generator can be used to output a pulse signal of a specified frequency, and then a power amplifier is used to amplify the pulse signal to obtain an excitation signal; when the excitation signal acts on the piezoelectric sheet, ultrasonic waves will be generated.

In an implementation manner of the method, controlling the rotation of the target object on the surface of the structure through the sound field may include:

adsorbing the target object floating in the liquid to the surface of the structure by the acoustic radiation force of the sound field;

Acoustic flow through the sound field controls the rotation of the target object.

Under the action of the acoustic radiation force, the target object floating in the liquid can be adsorbed to the surface of the structure. Under the action of the sound flow, the target object can be controlled to rotate.

In an implementation manner of the method, after controlling the rotation of the target object on the surface of the structure through the sound field, it may further include:

taking a video of the target object rotating on the surface of the structure;

Images of the target object at multiple different rotation angles are extracted from the video, and a three-dimensional model of the target object is reconstructed according to the images of the target object at multiple different rotation angles.

A camera can be used to take a video of the target object rotating on the surface of the structure, and then a computer can be used to extract images of the target object at multiple different rotation angles from the video, and complete the reconstruction of the 3D model based on these images.

Further, obtaining the three-dimensional model of the target object according to image reconstruction of the target object at multiple different rotation angles may include:

Reconstructing an initial three-dimensional model by using a three-dimensional reconstruction algorithm according to images of the target object at multiple different rotation angles;

Perform texture mapping and rendering processing on the initial 3D model to obtain a 3D model of the target object.

According to the images of the target object at multiple different rotation angles, the existing 3D reconstruction algorithm can be used to reconstruct the 3D appearance (initial 3D model) of the target object, and finally texture mapping and rendering processing are performed to obtain the final 3D Model.

The third aspect of the embodiment of the present application provides a rotation control system, which includes an imaging module, a three-dimensional reconstruction module and the rotation control module provided in the first aspect of the embodiment of the present application;

The imaging module is used to take a video of the target object rotating on the surface of the structure;

The three-dimensional reconstruction module is configured to extract images of the target object at multiple different rotation angles from the video, and reconstruct images of the target object at multiple different rotation angles to obtain an image of the target object 3D model.

It can be understood that, for the beneficial effects of the above third aspect, reference may be made to relevant descriptions in the above first aspect or the second aspect, which will not be repeated here.

Description of drawings

Fig. 1 is a schematic diagram of a rotation control system provided by an embodiment of the present application;

Fig. 2 is a schematic diagram of the rotation control module in Fig. 1;

Fig. 3 is a schematic diagram of a plate-shaped structure provided by an embodiment of the present application;

Fig. 4 is the transmission spectrum of the structure shown in Fig. 3;

Fig. 5 is a flow chart of a rotation control method provided by an embodiment of the present application;

Figure 6(a) is a schematic diagram of the sound pressure distribution on the surface of the structure simulated by the multi-physics simulation software;

Figure 6(b) is a schematic diagram of the acoustic radiation force received by different positions on the surface of the structure simulated by the multi-physics simulation software;

Fig. 7 is a schematic diagram of a target object rotating under the action of an acoustic flow;

FIG. 8 is a schematic diagram of a three-dimensional model reconstruction process of a target object;

Figure 9 is an image of nematodes and glass rods vertically arranged along the surface of the structure observed under a microscope;

Fig. 10 is a schematic diagram of images of nematodes at different rotation angles and the reconstructed three-dimensional model.

Embodiments of the present invention

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail. In addition, in the description of the specification and appended claims of the present application, the terms "first", "second", "third" and so on are only used to distinguish descriptions, and should not be understood as indicating or implying relative importance.

The present application proposes a rotation control module, method and system, the purpose of which is to control tiny objects such as nematodes to rotate at designated positions so as to observe the objects from multiple angles. This application mainly uses ultrasonic waves to excite the structure (which can be a phononic crystal plate) in the cavity container to resonate, and uses the periodically distributed strong sound field generated by the resonance to capture the tiny objects in the liquid in the cavity container and arrangement, while using the torque generated by the asymmetrically distributed acoustic flow induced by the sound field around the object to rotate the object. For specific implementation methods, please refer to the following.

As shown in FIG. 1 , it is a schematic diagram of a rotation control system provided by an embodiment of the present application. The system includes three functional modules, namely a rotation control module, an imaging module and a three-dimensional reconstruction module. Among them, the rotation control module is used to manipulate the object to be observed to change its posture, such as moving and rotating; the imaging module is used to take images of the object to be observed in different postures; the three-dimensional reconstruction module is used to reconstruct the object to be observed according to the captured images 3D model of .

The schematic diagram of the rotation control module in Fig. 1 is shown in Fig. 2. It mainly includes two parts: an ultrasonic excitation module and a cavity container. The cavity container can be a container with a cavity structure of a specified shape (such as a rectangle or a square, etc.), and its size It can be reasonably set according to the size of the object to be observed, and its material can be glass or polydimethylsiloxane. The cavity container is mainly used for containing the liquid containing the target object to be observed, and during operation, the liquid containing the target object is filled into the cavity container. In addition, put a structure into the cavity container, the size and shape of the structure can be set according to actual needs, and the material of the structure can be stainless steel, brass or silicon. Exemplarily, the structure may be a phononic crystal plate, that is, a material or structure with a periodic distribution of elastic constant and density.

The ultrasonic excitation module is used to emit ultrasonic waves to the cavity container, and excite the structure inside the cavity container to generate resonance. The resonance phenomenon will cause the surface of the structure to generate an acoustic field, through which the target object can be controlled to rotate on the surface of the structure. In actual operation, the ultrasonic excitation module can be composed of a signal generator and a power amplifier, where the signal generator is used to output a pulse signal of a specified frequency (set based on the resonance frequency of the structure), and the power amplifier is used to amplify the pulse signal , to obtain an amplified excitation signal, and then convert the excitation signal into an ultrasonic wave through a piezoelectric sheet (or other ultrasonic transducers, such as a Gaussian beam sound source, etc.), and excite the structure through the generated ultrasonic wave to generate resonance.

In an implementation manner of the rotation control module, the cavity container may be composed of a quartz base, a container wall and a detachable top cover, and a piezoelectric sheet is bonded on the quartz base. Wherein, the container wall may be bonded to the quartz base and the top cover. With this arrangement, on the one hand, the ultrasonic waves generated by the piezoelectric sheet can directly act on the structure to generate a sound field of sufficient intensity; on the other hand, since the top cover of the cavity container is detachable, it can be easily realized Micromanipulation such as microinjection in open space.

In an implementation manner of the rotation control module, the structure body is a rectangular plate-shaped structure, and the plate-shaped structure is provided with multiple columns of grids arranged at equal intervals. As shown in FIG. 3 , it is a schematic diagram of a plate-like structure provided in the embodiment of the present application. Figure 3 shows the cross-section of the plate structure, where t is the thickness of the plate, a is the distance between two grids, w is the width of the grid, and h is the height of the grid. According to the size of the cavity container and the target object, the length and width of the plate-like structure and various dimensional parameters in FIG. 3 can be reasonably set. For example, if the target object is a nematode, usually the adult nematode has a body diameter of about 50 μm and a body length of about 1 mm, then the various size parameters of the plate-like structure in Figure 3 can be set to t=60 μm, h=40 μm, w=70 μm and a=300 μm. Using the structure shown in Figure 3 can excite the non-leaky Lamb waves in the structure to generate a localized (sub-wavelength) strong transmission sound field, thereby generating strong sound radiation force and sound flow. It should be noted that Fig. 3 is only a form of expression of the plate-shaped structure, and the plate-shaped structure can also be set to be curved according to requirements, and its grid can also be curved or non-equidistant, The present application does not limit the specific shape and structure of the structure.

As shown in FIG. 4, it is the transmission spectrum of the structure shown in FIG. 3 (made of stainless steel material). From the transmission spectrum, it can be known that the resonant frequency of the structure is about 4.6MHz, that is, the ultrasonic wave with a frequency of about 4.6MHz can cause the structure to resonate, thereby generating a sound field with sufficient intensity. Obtain strong acoustic radiation force and acoustic flow to manipulate the movement of the target object.

The imaging module in Figure 1 can be composed of bright field light source, optical lens, camera and other components, and is mainly used to shoot the video of the target object rotating on the surface of the structure. In addition, for the application of three-dimensional reconstruction of tissues, organs or cells in nematodes, a fluorescent light source can also be added to the imaging module. Since the target object rotates by itself under the action of the sound field, there is no need to move the camera during video shooting.

The 3D reconstruction module in Figure 1 can use equipment such as a computer, by using a camera calibration algorithm and a 3D reconstruction algorithm, running image processing software and texture mapping and rendering software on the computer, based on the rotation video of the target object collected by the imaging module, Images of the target object at multiple different rotation angles can be extracted, and then a three-dimensional model corresponding to the target object can be reconstructed based on these images.

Regarding the working principle and specific operation steps of the system shown in FIG. 1 , reference may be made to the method embodiments described below.

As shown in FIG. 5 , it is a flowchart of a rotation control method provided by an embodiment of the present application, and the method is applied to the rotation control module or system described above. The method includes:

501. Use the ultrasonic excitation module to emit ultrasonic waves to the cavity container;

For the above-mentioned rotation control module, first, fill the cavity container with liquid containing the target object, specifically, use a pipette gun or other equipment to mix tiny objects (generally cylindrical or approximately cylindrical particles, such as Nematodes, as a target object to be observed) liquid (such as water) is moved into the cavity container. A structure (for example, a plate-like structure as shown in Figure 3 can be used) is placed in the cavity container, and the liquid can be injected directly onto the structure with a pipette gun, and the liquid can be used as an acoustic transmission in the subsequent process. medium.

During operation, the ultrasonic excitation module is used to emit ultrasonic waves to the cavity container, and the ultrasonic waves can excite the structure in the cavity container to generate resonance, thereby forming an acoustic field on the surface of the structure. In one implementation of the present application, the bottom of the cavity container is provided with a piezoelectric sheet, the ultrasonic excitation module includes a signal generator and a power amplifier, and the ultrasonic excitation module is used to transmit ultrasonic waves to the cavity container, which may include:

(1) using a signal generator to output a pulse signal of a specified frequency, the specified frequency is set according to the resonant frequency of the structure;

(2) Use a power amplifier to amplify the pulse signal to obtain an excitation signal, so that the piezoelectric sheet generates ultrasonic waves under the action of the excitation signal.

The ultrasonic excitation module can be composed of a signal generator and a power amplifier, wherein the signal generator is used to generate a pulse signal of a specified frequency (set based on the resonant frequency of the structure and the center frequency of the piezoelectric sheet); for example, if the resonant frequency of the structure is 4.6MHz, and the center frequency of the piezoelectric film is 4.5MHz, then a pulse signal with a frequency of 4.577MHz can be output by a signal generator. The pulse signal is amplified by a power amplifier to obtain an excitation signal, which is used to excite the piezoelectric sheet (as an ultrasonic transducer) to generate ultrasonic waves.

502. Excite the structure to resonate through ultrasonic waves, so that the surface of the structure generates a sound field, and control the rotation of the target object on the surface of the structure through the sound field.

When the structure is excited by ultrasonic waves to generate resonance, a periodic sound field of sufficient intensity will be formed on the surface of the structure, thereby generating periodic sound radiation force and sound flow. Under the action of the acoustic radiation force and the acoustic flow, the target object can be controlled to rotate on the surface of the structure, so as to microscopically take images of the target object at multiple different rotation angles. For the specific principle of controlling the rotation of the target object on the surface of the structure through the sound field, please refer to the following description.

In an implementation manner of the present application, controlling the rotation of the target object on the surface of the structure through the sound field may include:

(1) adsorbing the target object floating in the liquid to the surface of the structure by the acoustic radiation force of the sound field;

(2) Controlling the rotation of the target object through the sound flow of the sound field.

Under the action of the acoustic radiation force, the target object floating in the liquid can be adsorbed to the surface of the structure. Under the action of the sound flow, the target object can be controlled to rotate. Taking the plate-shaped structure shown in Figure 3 as an example, the sound field generated on the surface of the plate-shaped structure can be calculated and simulated by using multi-physics simulation software (such as COMSOL), including sound pressure field and velocity field, etc., and the target object can also be further calculated The sound radiation force received in the sound field can explain the principle of target object movement and rotation according to the results of software simulation.

Considering the periodicity and symmetry of the structure, a two-dimensional calculation model is used, and the calculation area includes liquid (usually water) and structure, where the liquid is simulated by pressure acoustics (frequency domain), and the structure is simulated by a solid mechanics model. Set the plane wave incident on the bottom area of the structure (simulating the ultrasonic wave generated by the piezoelectric sheet), and set the plane wave radiation on the top area of the structure. Assuming that the ultrasonic wave has no reflection, the sound pressure on the surface of the structure is simulated by the multi-physics simulation software The schematic diagram of the distribution is shown in Fig. 6(a). In Fig. 6(a), the sound pressure distribution near the two grid surfaces of the structure is shown, where the two small white circles mark the capture position of the target object (such as nematode), which can be regarded as the cross-section of the target object , which is approximately regarded as a cylinder in calculations. In addition, the schematic diagram of the acoustic radiation force at different positions on the surface of the structure in Fig. 6(a) can be simulated by multi-physics simulation software, as shown in Fig. 6(b). In Fig. 6(b), Fx is the two-dimensional acoustic radiation force component received in the x direction, Fy is the two-dimensional acoustic radiation force component received in the y direction, and the x direction and y direction can refer to Fig. 6(a) indicated direction. It can be seen that the position where Fx is 0 in Figure 6(b) is the equilibrium position of the target object in the x direction (the gray circle in the figure). Since the acoustic radiation force on both sides of the equilibrium position points to the equilibrium position, it will Force the target object to move towards the equilibrium position. In addition, because at the position where Fx is 0, the corresponding Fy is a negative value, that is, the acoustic radiation force in the y direction points to the surface of the structure, so the floating target object will be adsorbed to the surface of the structure. Looking down from the top of the structure, it can be observed that the target objects are arranged at a certain interval.

Next, the principle of controlling the rotation of the target object through the sound field will be described. The radiation stress suffered by particles in the sound field can be expressed by the following formula:

Among them, σ represents the radiation stress, <*> represents the time average operator, I represents the unit tensor,

is the dyadic symbol; ρ ₀ and c ₀ are the density and sound velocity of the sound propagation medium, respectively, which are fixed parameters of the medium at room temperature and can be obtained by querying the data; p and v are the first-order sound pressure and velocity field, respectively.

According to the wave equation and the momentum conservation equation, the following two formulas can be obtained:

Among them, t represents the partial derivative in the time dimension. Based on the above three formulas, the radiation stress σ can be obtained by numerical solution methods such as finite element method and finite difference method.

After calculating the radiation stress of the particles in the sound field, the following formulas can be used to calculate the radiation force and radiation moment of the target object in the sound field:

F _rad = -∫∫S _σdS

T _rad ＝ _-∫∫S r×σdS

Among them, F _rad represents the radiation force, T _rad represents the radiation moment, r represents the direction vector from the center of mass of the target object (under the two-dimensional calculation model, the center of mass can be the center of the cross section of the target object) to a point on the surface of the target object, dS is the The product of the normal vector of a surface point and the area element.

After simulated numerical calculation, it is found that the radiation moment of the target object is close to 0. In the current theoretical system, it is believed that the moment in the sound field comes from the radiation force and the acoustic flow. Therefore, if the radiation moment is close to 0, the target can be determined The rotation of the object is caused by the acoustic flow, and the following calculates the distribution of the acoustic flow generated by the sound field on the surface of the structure.

The viscous stress (viscous stress) of an incompressible fluid can be expressed as:

τ _ij = μ(u _i,j +u _j,i )

Among them, τ _ij represents the viscous stress, μ is the hydrodynamic viscosity, which is a fixed parameter of the medium at room temperature, and can be obtained by consulting the data; u represents the velocity of the acoustic flow; the values of subscript i and subscript j can be 1, 2 Or 3, respectively represent the components of the variable along the three coordinate axes x, y and z in space, and the comma between i and j represents the partial derivative of the variable on the coordinates. For example, the viscous stress between x-direction and y-direction can be expressed as:

τ ₁₂ = μ(u _1,2 +u _2,1 )

Among them, u _1,2 represents the partial derivative of u _x in the y direction, u _2,1 represents the partial derivative of u _y in the x direction, u _x represents the component of the acoustic flow velocity in the x direction, and u _y represents the acoustic flow The component of the velocity in the y direction.

Specifically, the acoustic flow velocity u can be calculated using the following formula:

Among them, p ₂ is the second-order pressure field, <*> is the time average operator,

is the dyadic symbol, _ρ0 is the density of the sound propagation medium, μ is the fluid dynamic viscosity, v is the velocity field, this formula can be solved by using the peristaltic flow module in the software COMSOL, and can be calculated after solving the acoustic flow velocity u Viscous stress, according to the viscous stress, the acoustic viscous torque on the target object can be obtained as:

T _vis ＝ _∫∫S r×τdS

Since the acoustic flow on both sides of the captured target object is asymmetrically distributed, that is, one side is strong and the other is weak, this leads to the torque generated by the two sides of the acoustic flow on the surface of the target object in opposite directions, but with different magnitudes, so that the acoustic viscous torque is different. is zero, thus causing the target object to rotate.

Figure 7 is a schematic diagram of the target object rotating under the action of the acoustic flow, wherein the target object 1 on the left of Figure 7 (the circle represents the cross section of the target object) rotates clockwise along its own center, and the target object 2 on the right of Figure 7 Rotate counterclockwise around its own center. In Fig. 7, arrows are also used to mark the sound flow near the target object and the moment of the target object. It can be seen that for the target object 1 on the left, the sound flow on the left side is stronger, while the sound flow on the right side is weaker , so a clockwise moment will be generated, making the target object rotate clockwise, and the conclusion is opposite for the target object on the right.

In an implementation manner of the present application, after controlling the rotation of the target object on the surface of the structure through the sound field, it may further include:

(1) taking a video of the target object rotating on the surface of the structure;

(2) Extract images of the target object at multiple different rotation angles from the video, and reconstruct a 3D model of the target object from the images of the target object at multiple different rotation angles.

In order to reconstruct the three-dimensional model of the target object, a camera can be used to take a video of the target object rotating on the surface of the structure, and then a computer can be used to extract the target object from the video at multiple different rotation angles (such as 0°, 90°, 180°, 270° and 360°) images, this process is also called frame splitting, and then the image can be cropped, enhanced, filtered or edge recognition and other preprocessing processes; then, use 3D reconstruction algorithms (such as Marching Cube algorithm, Ball Pivoting algorithm and Screened Poisson algorithm, etc.) to reconstruct the three-dimensional shape of the target object, and finally perform texture mapping and rendering processing to obtain the corresponding three-dimensional model. The corresponding model reconstruction process schematic diagram is shown in Figure 8.

On the other hand, before reconstructing the 3D model of the target object, the camera parameters need to be calibrated and solved, that is, the camera matrix P needs to be obtained to describe the pixel coordinates (x, y) and The corresponding relationship of the actual space coordinates (X, Y, Z). The specific form of the camera matrix can be expressed as P=K[R|t], where K is the internal reference matrix of the camera, which can be obtained by existing camera calibration methods, and [R|t] is the external parameter matrix, which represents the world coordinate system and the camera The transformation matrix of the coordinate system, where R is the rotation matrix, which can be obtained according to the rotation angle of the target object, and t is the translation matrix, which can be obtained according to the positions of the origin of the world coordinate system and the origin of the camera coordinate system. After obtaining the camera matrix, combined with the image coordinates of the target object at different rotation angles obtained by image processing, the coordinates of the target object at different rotation angles in the world coordinate system can be calculated, and then the reconstruction process of the 3D model is performed.

In the embodiment of the present application, ultrasound is used to excite the structural body to resonate, and the spatially distributed local strong sound field generated by the resonance will form an acoustic radiation force and an acoustic flow on the surface of the structure. Under the action of the acoustic radiation force and the acoustic flow, The target object can be controlled to rotate on the surface of the structure so as to observe the target object from multiple angles. Furthermore, cavity containers with removable top lids can be used to enable micromanipulation such as microinjection in an open space. In addition, after controlling the rotation of the target object, images of different rotation angles of the target object can also be taken through the microscope camera, and the three-dimensional reconstruction algorithm is used to reconstruct these images to obtain the corresponding three-dimensional model.

It should be understood that the sequence numbers of the steps in the above embodiments do not mean the order of execution, and the execution order of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application .

In order to facilitate understanding of the technical solution proposed in this application, a practical application scenario is listed below. First, using C304 stainless steel, based on the standard chemical etching process, a structure with a periodic grid is produced as shown in Figure 3. The specific size parameters are t=60 μm, h=40 μm, w=70 μm, a=300 μm . The structure is put into a cavity container, which is composed of a quartz glass substrate, a container wall of polydimethylsiloxane material, and a glass top cover, and the container wall can be bonded to the base and the top cover. The ultrasonic transducer uses a PZT4 piezoelectric ceramic sheet with a center frequency of 4.5MHz, which is bonded to the glass substrate of the cavity container through epoxy resin. A signal generator is used to generate a pulse signal with a frequency of 4.577MHz, and after being amplified by a power amplifier, the piezoelectric ceramic sheet is excited to generate ultrasonic waves. The structure generates resonance under the action of ultrasonic waves, so that the surface of the structure forms a strong sound field.

During operation, the glass top cover of the cavity container was first opened, water mixed with nematodes and glass rods was injected onto the surface of the structure using a pipette gun, and then the glass top cover was covered. Under the action of the sound field, the nematode and the glass rod will move to the surface of the structure and rotate. The specific principle can be referred to the above. Among them, the glass rod is used to assist in verifying the calculation conclusions, proving that the scheme proposed in this application can be used to observe any cylindrical or nearly cylindrical tiny objects. Put the whole cavity container under the microscope, it can be observed that the nematodes and the glass round rods are arranged vertically along the surface of the structure, as shown in Figure 9 .

Next, use a microscope to observe one of the nematodes, take a video of the nematode rotating, and split the frame of the video to obtain images of the nematode at different rotation angles, and then reconstruct the nematode according to the process shown in Figure 8. A 3D model of a nematode. The obtained images of nematodes at different rotation angles and the schematic diagram of the reconstructed three-dimensional model are shown in FIG. 10 .

The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still implement the foregoing Modifications to the technical solutions described in the examples, or equivalent replacement of some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application, and should be included in the Within the protection scope of this application.

Claims

A rotation control module, characterized in that it includes a cavity container and an ultrasonic excitation module, the cavity container is provided with a structure;

The cavity container is used for containing the liquid containing the target object;

The ultrasonic excitation module is used to emit ultrasonic waves to the cavity container, and excite the structure body to resonate through the ultrasonic waves, so that the surface of the structure body generates a sound field, and control the target object to move on the surface of the structure body through the sound field. The surface of the structure is rotated.
The rotation control module according to claim 1, wherein the bottom of the cavity container is provided with a piezoelectric sheet, and the ultrasonic excitation module comprises:

a signal generator, configured to output a pulse signal of a specified frequency, and the specified frequency is set according to the resonant frequency of the structure;

The power amplifier is used to amplify the pulse signal to obtain an excitation signal, so that the piezoelectric sheet generates an ultrasonic wave under the action of the excitation signal, and the ultrasonic wave is used to excite the structure to resonate.
The rotary control module of claim 1, wherein the cavity container is composed of a quartz base, container walls and a removable top cover.
The rotation control module according to any one of claims 1 to 3, wherein the structure is a rectangular plate structure, and the plate structure is provided with multiple columns of grids arranged at equal intervals.
A rotation control method applied to the rotation control module according to any one of claims 1 to 4, characterized in that the method comprises:

using the ultrasonic excitation module to transmit ultrasonic waves to the cavity container;

The structure is excited to resonate by ultrasonic waves, so that the surface of the structure generates a sound field, and the target object is controlled to rotate on the surface of the structure through the sound field.
The rotation control method according to claim 5, wherein the bottom of the cavity container is provided with a piezoelectric sheet, and the ultrasonic excitation module includes a signal generator and a power amplifier;

Using the ultrasonic excitation module to transmit ultrasonic waves to the cavity container, including:

using the signal generator to output a pulse signal of a specified frequency, and the specified frequency is set according to the resonant frequency of the structure;

The power amplifier is used to amplify the pulse signal to obtain an excitation signal, so that the piezoelectric sheet generates ultrasonic waves under the action of the excitation signal.
The rotation control method according to claim 5, wherein controlling the rotation of the target object on the surface of the structure through the sound field comprises:

adsorbing the target object floating in the liquid to the surface of the structure by the acoustic radiation force of the sound field;

Acoustic flow through the sound field controls the rotation of the target object.
The rotation control method according to any one of claims 5 to 7, characterized in that, after controlling the rotation of the target object on the surface of the structure through the sound field, further comprising:

taking a video of the target object rotating on the surface of the structure;

Images of the target object at multiple different rotation angles are extracted from the video, and a three-dimensional model of the target object is reconstructed according to the images of the target object at multiple different rotation angles.
The rotation control method according to claim 8, wherein the three-dimensional model of the target object is obtained according to image reconstruction of the target object at multiple different rotation angles, comprising:

Reconstructing an initial three-dimensional model by using a three-dimensional reconstruction algorithm according to images of the target object at multiple different rotation angles;

Perform texture mapping and rendering processing on the initial 3D model to obtain a 3D model of the target object.
A rotation control system, characterized in that it includes an imaging module, a three-dimensional reconstruction module, and the rotation control module according to any one of claims 1 to 4;

The imaging module is used to take a video of the target object rotating on the surface of the structure;

The three-dimensional reconstruction module is configured to extract images of the target object at multiple different rotation angles from the video, and reconstruct images of the target object at multiple different rotation angles to obtain an image of the target object 3D model.