Ultrasonic three-dimensional circumferential scanning imaging device and imaging method

Abstract

The present invention discloses an ultrasonic three-dimensional circumferential scanning imaging device and an imaging method. The device includes: a capsule body; an annular track; an ultrasonic transducer, which is arranged on the annular track, and guided by the annular track, the ultrasonic transducer can perform a circumferential scanning motion around the capsule body; a driving mechanism and a housing. The present invention can be adapted to mainstream ultrasonic probes and cooperate with three-dimensional reconstruction methods to achieve three-dimensional ultrasonic imaging, can break through the limitation of the high cost of three-dimensional ultrasonic probes, and realize the circumferential three-dimensional scanning and reconstruction work that is difficult to complete by conventional methods; the present invention uses a capsule body structure as a medium between the object to be measured and the ultrasonic transducer, solves the problem that it is difficult for the ultrasonic probe to fit with the object to be measured with an irregular shape in the traditional scheme, and can effectively improve the quality of ultrasonic echo signals; the three-dimensional reconstruction method provided by the present invention can generate an intuitive three-dimensional structure of the tissue to be measured, which is convenient for realizing multi-modal ultrasonic visualization diagnosis.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic imaging, and particularly to an ultrasonic three-dimensional circumferential scanning imaging device and an imaging method. Background Art

[0002] Ultrasonic imaging technology is a technology widely used in the fields of clinical examination and non-destructive testing and flaw detection. Its advantages lie in real-time imaging, non-invasive and non-radiative, low cost, and no need for complex imaging conditions such as magnetic fields and radiation sources. The generation of ultrasonic waves is excited by the piezoelectric effect in the ultrasonic transducer. The transducer converts electrical energy into mechanical energy, causing the sound waves to be emitted at a higher frequency and capturing the reflected sound waves of the object to be measured and converting them back into electrical energy. According to the principle of ultrasonic wave generation, the transmission and reception of the ultrasonic beam need to be maintained within the working plane of the ultrasonic transducer, which also results in two-dimensional imaging in most cases of ultrasonic imaging. To achieve three-dimensional ultrasonic imaging to obtain more intuitive three-dimensional spatial information, one method is to design a more complex ultrasonic transducer and supporting algorithms to expand the field of view, and the other method is to improve the mechanical structure to enable the ultrasonic transducer to complete multi-slice scanning and develop corresponding algorithms to achieve the registration and fusion of tomographic images. However, there is currently a lack of a reliable solution. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an ultrasonic three-dimensional circumferential scanning imaging device and an imaging method for the deficiencies in the above-mentioned prior art.

[0004] To solve the above technical problem, the technical solution adopted by the present invention is: an ultrasonic three-dimensional circumferential scanning imaging device, comprising:

[0005] A bladder, which includes a cylindrical outer surface and a flexible inner surface for wrapping the object to be detected, and the bladder is filled with a liquid having acoustic impedance characteristics;

[0006] An annular track, which is arranged around the bladder;

[0007] An ultrasonic transducer, which is arranged on the annular track. Under the guidance of the annular track, the ultrasonic transducer can perform a circumferential scanning movement around the bladder;

[0008] A driving mechanism, which provides the driving function for the ultrasonic transducer to perform a circumferential scanning movement on the annular track and the driving function for the ultrasonic transducer to move radially along the annular track, so that while the ultrasonic transducer performs a circumferential scanning movement around the bladder, the inner side of the ultrasonic transducer always remains in contact with the outer surface of the bladder;

[0009] And a housing, which is arranged on the outermost layer.

[0010] Preferably, the driving mechanism includes a circumferential sub-driving mechanism provided on the annular track for providing a circumferential motion driving function, and a radial sub-driving mechanism provided on the circumferential sub-driving mechanism for providing a linear motion function along the radial direction of the annular track. The ultrasonic transducer is provided on the radial sub-driving mechanism.

[0011] Preferably, the liquid having acoustic impedance characteristics is water or an ultrasonic coupling liquid.

[0012] Preferably, the material of the bladder is rubber or resin.

[0013] Preferably, the ultrasonic transducer is one or more of a linear array probe, a convex array probe, and a phased array probe.

[0014] The present invention also provides an ultrasonic three-dimensional circumferential scanning imaging method, which uses the device described above for ultrasonic three-dimensional circumferential scanning imaging. The method includes the following steps:

[0015] S1. Open the outer shell, place the object to be detected into the bladder, the ultrasonic transducer operates, and the driving mechanism drives the ultrasonic transducer to perform a circumferential scanning motion on the annular track to realize ultrasonic detection and obtain a two-dimensional ultrasonic image.

[0016] S2. Perform three-dimensional reconstruction based on the two-dimensional ultrasonic image to obtain a three-dimensional ultrasonic image.

[0017] The step S2 specifically includes:

[0018] S2-1. In each frame of two-dimensional ultrasonic image, select a set of feature points W i ={S1, S2, S3... S n}, where S n represents the nth feature, n is the number of feature classifications, and i represents the ith frame of image; perform the above operations in each frame of image in sequence to extract the set of feature points W n of each frame of image;

[0019] S2-2. Compare the sets of feature points of all frames of images. When the Hausdorff distance H between two sets of feature points satisfies H≤ε j , determine that these two sets of feature points are the sets of feature points of adjacent frames of images, where ε j is a preset distance threshold; denote these two sets of feature points as W n and W n+1 , and denote the Hausdorff distance between these two sets of feature points as H(W n , W n+1 ), then:

[0020] H(W n , Wn+1 ) = max(h(W n , W n+1 ), h(W n+1 , W n ) (1)

[0021]

[0022]

[0023] where, ‖β - α‖ is the distance norm between point sets W n and W n+1 , ‖α - β‖ is the distance norm between point sets W n+1 and W n , h(W n , W n+1 ) and h(W n+1 , W n ) are the one-way Hausdorff distances from point set W n to W n+1 and from point set W n+1 to W n respectively;

[0024] S2 - 3. After determining the feature point sets of all adjacent frame images according to step S2 - 2, perform statistics according to the classification index, and classify the feature points of the same category into one class: For the feature point set W i = {S i,1 , S i,2 , S i,3 ... S i,k} in the i - th frame image, which contains k feature classifications. Extract all the feature points S i,1 of the first feature classification. Similarly, extract all the feature points S i+1,1 of the first feature classification from the feature point set of the (i + 1) - th frame image, and so on, to obtain the total set of the first feature classification points {S 1,1 , S 2,1 ,..., S k,1}; Obtain the total sets of all feature classification points according to this method;

[0025] S2 - 4. Convert the two - dimensional coordinates of all the total sets of feature classification points into a three - dimensional coordinate system, and connect the feature points in each total set of feature classifications in the three - dimensional space in a proximity manner, that is, connect the two feature points with a relatively short Euclidean distance in the space in sequence, so that each set of classified feature points is transformed into a point cloud data set of dense three - dimensional feature vectors;

[0026] Then remove the noise points in the point cloud data set and describe the key points;

[0027] The point cloud dataset is rasterized, and texture information is added to draw an isosurface, reconstructing the three-dimensional surface of the target tissue to obtain a three-dimensional ultrasound image.

[0028] Preferably, in the step S2-4, the method for converting two-dimensional coordinates to a three-dimensional coordinate system is as follows:

[0029] Obtain the relative angle θ between the i-th frame image and the starting zero position through the ultrasonic three-dimensional circumferential scanning imaging device i ;

[0030] Set the sound wave reflection direction of the two-dimensional image as the x-axis, define the imaging width direction as the y-axis, and obtain the two-dimensional coordinates corresponding to each feature point;

[0031] Set the sound wave reflection direction of the two-dimensional image as the x-axis, define the imaging width direction as the y-axis, and define the central axis direction of the cyst as the Z-axis to establish a three-dimensional coordinate system;

[0032] Convert a point A(a, b) in the i-th frame image of the two-dimensional image to the three-dimensional coordinate system, then the coordinates of the point A mapped to the three-dimensional coordinate system are A′(acosθ i , b, asinθ i ).

[0033] Preferably, in the step S2-4, voxel filtering and Gaussian filtering are used to remove the noise points in the point cloud dataset, and the SHOT method is used to describe the key points.

[0034] Preferably, the method further includes the following step: S2-5, attaching physiological parameters and functional information to the obtained three-dimensional ultrasound image.

[0035] Preferably, among them, the attached physiological parameters and functional information include at least one or more of elastic modulus, blood flow velocity, pixel value, and thermal distribution information.

[0036] The present invention also provides a storage medium, on which a computer program is stored, and when the program is executed, it is used to implement the method described above.

[0037] The beneficial effects of the present invention are:

[0038] The ultrasonic three-dimensional circumferential scanning imaging device provided by the present invention can be adapted to a mainstream ultrasonic probe and cooperate with a three-dimensional reconstruction method to realize three-dimensional ultrasonic imaging. The present invention can break through the limitation of the high cost of three-dimensional ultrasonic probes and realize the circumferential three-dimensional scanning and reconstruction work that is difficult to complete by conventional methods;

[0039] The present invention uses a capsule structure as a medium between the object to be measured and the ultrasonic transducer. By virtue of the deformation characteristics of the capsule structure, it is possible to achieve the fitting of the ultrasonic probe to different objects to be measured (such as the human neck, limbs, etc.), solving the problem that it is difficult for the ultrasonic probe to fit the object to be measured with an irregular shape in the traditional solution, and effectively improving the quality of the ultrasonic echo signal;

[0040] The three-dimensional reconstruction method provided by the present invention can extract a set of feature points from multi-slice two-dimensional ultrasonic images, and perform operations such as three-dimensional mapping and rasterization to generate an intuitive three-dimensional structure of the tissue to be measured; it can also attach functional pathophysiological information to the three-dimensional graph, facilitating the realization of multimodal ultrasonic visualization diagnosis, and can be applied to scenarios such as ultrasonic circumferential scanning of human limbs to examine blood flow and bones, ultrasonic circumferential scanning of the human neck to examine blood flow and perform thyroid imaging, and ultrasonic circumferential flaw detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic structural diagram of the ultrasonic three-dimensional circumferential scanning imaging device in Embodiment 1 of the present invention;

[0042] Figure 2 is a schematic diagram of the spatial distribution of multi-frame scanning images in Embodiment 2 of the invention;

[0043] Figure 3 is a schematic diagram of the three-dimensional coordinate system established in Embodiment 2 of the invention.

[0044] DESCRIPTION OF THE REFERENCE NUMERALS

[0045] 1 - capsule; 2 - annular track; 3 - ultrasonic transducer; 4 - drive mechanism; 5 - housing; 10 - outer surface; 11 - flexible inner surface; 40 - circumferential sub-drive mechanism; 41 - radial sub-drive mechanism. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following further describes the present invention in detail with reference to the embodiments, so that those skilled in the art can implement it according to the text of the specification.

[0047] It should be understood that the terms such as "having", "comprising" and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0048] Embodiment 1

[0049] As Figure 1 shown, an ultrasonic three-dimensional circumferential scanning imaging device in this embodiment includes:

[0050] A capsule 1, which includes a cylindrical outer surface 10 and a flexible inner surface 11 for wrapping the object to be detected. The capsule 1 is filled with a liquid having acoustic impedance characteristics;

[0051] An annular track 2, which is arranged around the capsule 1;

[0052] An ultrasonic transducer 3 is disposed on an annular track 2. Under the guidance of the annular track 2, the ultrasonic transducer 3 can perform a circumferential scanning motion around the capsule 1;

[0053] A driving mechanism 4 provides a driving function for the ultrasonic transducer 3 to perform a circumferential scanning motion on the annular track 2 and a driving function for the ultrasonic transducer 3 to move radially along the annular track 2, so that while the ultrasonic transducer 3 performs a circumferential scanning motion around the capsule 1, the inner side of the ultrasonic transducer 3 always remains in contact with the outer surface 10 of the capsule 1;

[0054] And a housing 5, which is disposed on the outermost layer.

[0055] In a preferred embodiment, the ultrasonic three-dimensional circumferential scanning imaging device has an overall cylindrical structure.

[0056] Wherein, the capsule 1 is overall annular, with a cavity formed in the middle and having a flexible inner surface 11, while the outer surface 10 is stably cylindrical; The purpose is that when the parts to be detected such as human limbs and necks are placed in the cavity in the middle of the capsule 1, the pressure of the liquid inside the capsule 1 enables the flexible inner surface 11 to well wrap the main part to be detected and fit with the part to be detected, so that the acoustic signal will not be excessively attenuated; And the stable cylindrical outer surface 10 can match the circumferential scanning motion of the ultrasonic transducer 3 and always remain in contact with the inner side of the ultrasonic transducer 3.

[0057] In a preferred embodiment, the liquid with acoustic impedance characteristics is water or ultrasonic coupling liquid or other liquids that meet the acoustic impedance matching for ultrasonic wave propagation. The material of the water sac can be selected from rubber, resin, etc. and other materials with appropriate elasticity, ductility, good acoustic impedance and good biocompatibility; The thickness of the water sac wall needs to be moderate, which not only maintains the stability of the water sac structure but also does not excessively attenuate the acoustic signal and affect the fitting with the tissue to be detected. The size of the water sac is adjustable, the filling degree is adjustable, and the water sac is replaceable.

[0058] In a preferred embodiment, to keep the outer surface 10 of the water sac in a stable cylindrical shape, it can be achieved by selecting the wall material and thickness of the outer surface 10 that can form a stable structure, or by setting an annular support structure in the water sac to make the outer surface 10 present a cylindrical shape.

[0059] The annular track 2 provides a guiding function for the movement of the ultrasonic transducer 3. During the movement, the emission direction of the ultrasonic transducer 3 always points to the center of the circle or forms a certain angle with the radius to meet requirements such as Doppler scanning.

[0060] In a preferred embodiment, the drive mechanism 4 includes a circumferential sub-drive mechanism 4004 provided on the annular track 2 for providing a circumferential motion driving function, and a radial sub-drive mechanism 41 provided on the circumferential sub-drive mechanism 4004 for providing a linear motion function along the radial direction of the annular track 2. The ultrasonic transducer 3 is arranged on the radial sub-drive mechanism 41 through a clamping mechanism. By controlling the drive mechanism 4, the movement speed of the ultrasonic transducer 3 can be adjusted, and the movement scanning angle can also be set. For example, to achieve a scan within a range of 120 degrees starting from the starting position. The drive mechanism 4 can be driven by an external power supply or a rechargeable battery, etc.

[0061] In a preferred embodiment, the ultrasonic transducer 3 is one or more of a linear array probe, a convex array probe, and a phased array probe, and can also be any other form of probe. The adopted scanning imaging modes also include but are not limited to B-mode scanning, color Doppler scanning, spectral Doppler scanning, ultrasonic flaw detection, etc. The size of the ultrasonic transducer 3 only needs to match the overall structure, and the ultrasonic transducer 3 can be connected to the ultrasonic host in various ways such as wired connection and wireless connection.

[0062] The outer shell 5 is used to protect internal components such as the capsule body 1, the annular track 2, the ultrasonic transducer 3, and the drive mechanism 4. The outer shell 5 has adjustability, and its size only needs to match the overall structure. The outer shell 5 can be opened to facilitate putting the component to be tested into the capsule body 1 and to achieve the maintenance and repair of internal devices.

[0063] In a preferred embodiment, the ultrasonic three-dimensional circumferential scanning imaging device further includes a host computer, which is used to control the ultrasonic transducer 3 and the drive mechanism 4 and to achieve ultrasonic imaging.

[0064] Embodiment 2

[0065] This embodiment provides an ultrasonic three-dimensional circumferential scanning imaging method, which uses the device of Embodiment 1 to perform ultrasonic three-dimensional circumferential scanning imaging. The method includes the following steps:

[0066] S1. Open the outer shell 5, put the object to be detected into the capsule body 1, the ultrasonic transducer 3 works, and the drive mechanism 4 drives the ultrasonic transducer 3 to perform a circumferential scanning motion on the annular track 2 to achieve ultrasonic detection and obtain a two-dimensional ultrasonic image;

[0067] S2. Perform three-dimensional reconstruction based on the two-dimensional ultrasonic image to obtain a three-dimensional ultrasonic image.

[0068] According to the physical characteristics of sound wave conduction and the structure of a conventional linear array ultrasonic probe, after being emitted by the transducer, ultrasonic waves propagate along a plane, are reflected after passing through the object to be measured, and return along the original path to be received by the transducer. This results in the conventional ultrasonic transducer 3 imaging a two-dimensional image with a limited field of view, only showing the depth information on one section. On the other hand, a matrix array ultrasonic transducer 3 can achieve real-time three-dimensional imaging, but it is expensive, the imaging method is complex, and there are fewer mainstream ultrasonic devices that support it. Considering that the propagation of ultrasonic waves requires a medium, it is necessary to ensure the adhesion of the ultrasonic transducer 3 to the tissue to be measured to achieve the expected imaging effect. When facing typical structures such as human limbs and necks, the matrix array probe has certain limitations. In the present invention, using a water sac as the medium between the object to be measured and the ultrasonic transducer 3 can overcome the above defects of the matrix array probe, can better reduce the attenuation of ultrasonic waves during transmission and reception, and present higher imaging quality.

[0069] When using a linear array ultrasonic probe, the image directly obtained by the device in Embodiment 1 is a two-dimensional image. It is necessary to perform post-processing on the two-dimensional image based on this, and combine information such as spatial position to complete mapping and three-dimensional reconstruction work, and then a three-dimensional ultrasonic image can be obtained.

[0070] Specifically, the three-dimensional reconstruction method adopted in step S2 includes:

[0071] S2-1. First, extract the feature information from multi-slice two-dimensional ultrasonic images. Deep learning networks and feature extraction methods based on imaging can be used to extract information such as blood vessels, bones (target tissues), etc. in the ultrasonic images, especially tissues with significant distinguishability under ultrasonic images such as the intima, media, and adventitia of blood vessels, bone contours, nerve bundles, and the thyroid gland.

[0072] Specifically, in this embodiment, first, in each frame of two-dimensional ultrasonic image, a feature point set W i ={S1, S2, S3……S n} is selected, where S n represents the nth feature, n is the number of feature classifications, and i represents the ith frame of image; the above operation is performed sequentially in each frame of image to extract the feature point set W n of each frame of image; when the number of feature points in a single frame of image is large, the sparse sampling matrix M s can be used to sparsely sample the feature point set, and then subsequent processing is performed to reduce the data volume on the premise of maximizing the retention of the original image feature information and improve the operation speed.

[0073] S2-2. Compare the feature point sets of all frames of images. When the Hausdorff distance H between two feature point sets satisfies H≤ε j , it is determined that these two feature point sets are the feature point sets of adjacent frame images, where ε jis a preset distance threshold; denote these two sets of feature points as W n and W n+1 , and denote the Hausdorff distance between these two sets of feature points as H(W n ,W n+1 ), then:

[0074] H(W n ,W n+1 ) = max(h(W n ,W n+1 ), h(W n+1 ,W n ) (1)

[0075]

[0076]

[0077] where, ‖β - α‖ is the distance norm between the point sets W n and W n+1 , ‖α - β‖ is the distance norm between the point sets W n+1 and W n , h(W n ,W n+1 ) and h(W n+1 ,W n ) are the one-way Hausdorff distances from the point set W n to W n+1 and from the point set W n+1 to W n respectively; the two-way Hausdorff distance H(W n ,W n+1 ) represented by formula (1) measures the maximum mismatch degree between two point sets. When H(W n ,W n+1 ) ≤ ε j , it can be determined that the feature points between adjacent frames meet the matching requirements.

[0078] S2-3. After determining the sets of feature points of all adjacent frame images according to step S2-2, perform statistics according to the classification index, and classify the feature points of the same category into one class: For the set of feature points W i = {S i,1 , S i,2 , S i,3 ... S i,k} in the i-th frame image, which contains k feature classifications, extract all the feature points S i,1 of the first feature classification. Similarly, extract all the feature points S i+1,1 of the first feature classification from the set of feature points of the (i + 1)-th frame image, and so on, to obtain the total set of the first feature classification points {S1,1 , S 2,1 , ……, S k,1}; Obtain the total set of all feature classification points according to this method;

[0079] S2-4. Convert the two-dimensional coordinates of the total set of all feature classification points into a three-dimensional coordinate system, and connect the feature point sets in the total set of each feature classification point pairwise in the three-dimensional space, that is, connect two feature points with a relatively short Euclidean distance in space in sequence, so that each classified feature point set is transformed into a point cloud data set of dense three-dimensional feature vectors;

[0080] Then, use voxel filtering and Gaussian filtering to remove the noise points in the point cloud data set, and use the SHOT method to describe the key points;

[0081] Then rasterize the point cloud data set, add texture information to draw an isosurface, reconstruct the three-dimensional surface of the target tissue, and obtain a three-dimensional ultrasound image. Among them, the density of the point cloud data is related to the feature point sampling method and the complexity of the connection of the feature point set. The denser the point cloud data, the smoother the reconstructed surface; The methods of three-dimensional texture rendering include but are not limited to surface rendering method, ray casting method, etc.

[0082] S2-5. Attach physiological parameters and functional information to the obtained three-dimensional ultrasound image.

[0083] Among them, the attached physiological parameters and functional information include at least one or more of elastic modulus, blood flow velocity, pixel value, thermal distribution information, etc. The ultrasonic transducer 35 used in this embodiment supports Doppler blood flow imaging, ultrasonic elastography, etc., so as to be able to represent information such as elastic modulus and blood flow velocity in the form of pixel values and thermal distribution on the three-dimensional model, providing multi-modal pathophysiological information, which is more intuitive and concrete.

[0084] In step S2-4, the method for converting two-dimensional coordinates into a three-dimensional coordinate system is:

[0085] Obtain the relative angle θ between the i-th frame image and the starting zero position through the ultrasonic three-dimensional circumferential scanning imaging device i ; Refer to Figure 2 ;

[0086] Set the sound wave reflection direction of the two-dimensional image as the x-axis, and define the imaging width direction as the y-axis to obtain the two-dimensional coordinates corresponding to each feature point;

[0087] Set the sound wave reflection direction of the two-dimensional image as the x-axis, define the imaging width direction as the y-axis, and define the central axis direction of the cyst 1 as the Z-axis to establish a three-dimensional coordinate system; Refer to Figure 3 ;

[0088] If a point A(a, b) in the i-th frame of a two-dimensional image is transformed into a three-dimensional coordinate system, the coordinates of the point A mapped to the three-dimensional coordinate system are A′(acosθ i , b, asinθ i ).

[0089] Embodiment 3

[0090] A storage medium stores a computer program, and the storage medium is stored in a host computer. When the program is executed, it is used to implement the method of Embodiment 2.

[0091] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to specific details.

Claims

1. An ultrasonic three-dimensional circumferential scanning imaging method, characterized in that The method includes the following steps: S1. Open the outer shell, place the object to be detected into the capsule body, the ultrasonic transducer operates, and the driving mechanism drives the ultrasonic transducer to perform a circumferential sweeping motion on the circular track to achieve ultrasonic detection and obtain a two-dimensional ultrasonic image; S2. Perform three-dimensional reconstruction based on the two-dimensional ultrasonic image to obtain a three-dimensional ultrasonic image; Step S2 specifically includes: S2-1. Select the feature point set of the target tissue in each frame of two-dimensional ultrasound image , , …… , where represents the nth feature, n is the number of feature classifications, and i represents the ith frame of image; perform the above operations in sequence for each frame of image to extract the feature point set of each frame of image ; S2-2. Compare the feature point sets of all frame images. When the Hausdorff distance between two feature point sets is less than , which is a preset distance threshold, determine that these two feature point sets are the feature point sets of adjacent frame images. Denote these two feature point sets as and , and denote the Hausdorff distance between these two feature point sets as . Then: ； Among them, is the distance norm between point sets and ; is the distance norm between point sets and ; and are the one-way Hausdorff distances from point set to and from point set to respectively. S2-3. After determining the feature point sets of all adjacent frame images according to step S2-2, perform statistics according to the classification index, and classify the feature points of the same classification into one category: for the feature point set in the i-th frame image , , …… , which contains k feature classifications, extract all the feature points of the first feature classification among them , and similarly extract all the feature points of the first feature classification from the feature point set of the (i + 1)-th frame image , and so on, to obtain the total set of the first feature classification points { }; obtain the total sets of all feature classification points according to this method; S2-4. Convert the two-dimensional coordinates of the total set of all feature classification points into a three-dimensional coordinate system, and connect the feature point sets in each total set of feature classification points in the three-dimensional space in a proximity manner, that is, connect the two feature points with a relatively short Euclidean distance in space in sequence, so that each classified feature point set is transformed into a point cloud data set of dense three-dimensional feature vectors; Then remove the noise points in the point cloud data set and describe the key points; Then rasterize the point cloud data set and add texture information to draw an isosurface to reconstruct the three-dimensional surface of the target tissue and obtain a three-dimensional ultrasonic image.

2. The ultrasonic three-dimensional circumferential scanning imaging method according to claim 1, characterized in that, In the step S2-4, the method for converting the two-dimensional coordinates into a three-dimensional coordinate system is: Obtain the relative angle between the nth frame image and the starting zero position ; Set the sound wave reflection direction of the two-dimensional image as the x-axis, define the imaging width direction as the y-axis, and obtain the two-dimensional coordinates corresponding to each feature point; Set the sound wave reflection direction of the two-dimensional image as the x-axis, define the imaging width direction as the y-axis, and define the central axis direction of the capsule body as the Z-axis to establish a three-dimensional coordinate system; A point in the i-th frame of a two-dimensional image is transformed into a three-dimensional coordinate system, and the point is mapped to the coordinates in the three-dimensional coordinate system as .

3. The ultrasonic three-dimensional circumferential scanning imaging method according to claim 2, characterized in that, In the step S2-4, voxel filtering and Gaussian filtering are used to remove the noise points in the point cloud data set, and the SHOT method is used to describe the key points.

4. The ultrasonic three-dimensional circumferential scanning imaging method according to claim 3, wherein It further includes the following steps: S2-5. Attach physiological parameters and functional information to the obtained three-dimensional ultrasonic image.

5. The ultrasonic three-dimensional circumferential scanning imaging method according to claim 4, wherein Among them, The attached physiological parameters and functional information include at least one or more of elastic modulus, blood flow velocity, pixel value, and thermal distribution information.

6. An ultrasonic three-dimensional circumferential scanning imaging device for implementing the method according to any one of claims 1-5, characterized in that, It includes: A capsule body, which includes a cylindrical outer surface and a flexible inner surface for wrapping the object to be detected, and the capsule body is filled with a liquid having acoustic impedance characteristics; A circular track, which is arranged around the capsule body; An ultrasonic transducer, which is arranged on the circular track, and under the guidance of the circular track, the ultrasonic transducer can perform a circumferential sweeping motion around the capsule body; A driving mechanism, which provides the driving function for the ultrasonic transducer to perform a circumferential sweeping motion on the circular track and the driving function for the ultrasonic transducer to move radially along the circular track, so that while the ultrasonic transducer performs a circumferential sweeping motion around the capsule body, the inner side of the ultrasonic transducer always remains in contact with the outer surface of the capsule body; And an outer shell, which is arranged on the outermost layer.

7. The ultrasonic three-dimensional circumferential scanning imaging device according to claim 6, characterized in that, The driving mechanism includes a circumferential sub-driving mechanism arranged on the circular track for providing the driving function of circular motion and a radial sub-driving mechanism arranged on the circumferential sub-driving mechanism for providing the function of linear motion along the radial direction of the circular track, and the ultrasonic transducer is arranged on the radial sub-driving mechanism.

8. The ultrasonic three-dimensional circumferential scanning imaging device according to claim 6, wherein The liquid having acoustic impedance characteristics is water or an ultrasonic coupling liquid.

9. The ultrasonic three-dimensional circumferential scanning imaging device according to claim 8, characterized in that, The material of the capsule body is rubber or resin.

10. The ultrasonic three-dimensional circumferential scanning imaging device according to claim 6, wherein, The ultrasonic transducer is one or more of a linear array probe, a convex array probe, and a phased array probe.

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