A method and apparatus for reconstructing region division

Abstract

The present invention discloses a method and apparatus for reconstructing region division. Among them, a method for reconstructing region division, which relates to the field of biomedical engineering, includes: selecting a region to be reconstructed and detecting the shape of the region to be reconstructed; finding the geometric center of the region to be reconstructed; establishing a two-dimensional polar coordinate system with the geometric center as the pole; in the two-dimensional polar coordinate system, with the geometric center as the pole, reducing the shape according to a plurality of scales to obtain a plurality of scale shapes; starting from the pole and using the ray where the polar axis is located as a side, rotating in the two-dimensional polar coordinate system according to a set angle to obtain a plurality of polar radii; the plurality of polar radii respectively divide the plurality of scale shapes into a plurality of regions, and the plurality of regions are the reconstructed regions. This is to solve the problem that the existing method of reconstructing region division has strong subjectivity of humans, which affects the scientific nature of measurement results.

Description

Technical Field

[0001] The present invention relates to the field of biomedical engineering, and in particular, to a method and device for reconstructing region division. Background Art

[0002] According to Faraday's law of electromagnetic induction, when a conductor passes through a constant magnetic field at a certain speed, an induced potential difference perpendicular to the magnetic field direction will be generated at both ends of the conductor. The magnitude of the induced potential difference has a linear relationship with the product of the magnetic field strength and the conductor speed. This is the basic principle for measuring fluid velocity based on electromagnetic induction.

[0003] The blood flow measurement technology based on electromagnetic induction can be applied to the early diagnosis and prevention of human artery stenosis. However, the existing blood flow measurement technology based on electromagnetic induction is limited by the contradiction between the small amount of induced potential difference data and the increased cost caused by adding measurement electrodes. Currently, it can only measure the blood flow or flow velocity in a local area. Although it can judge the degree of artery stenosis, it cannot determine the specific stenosis location.

[0004] The patent with the application number 201810927376.5 discloses a method and device for measuring human blood flow velocity. By setting multiple electrodes and multiple measurement regions, it breaks the limitation of the flow pattern of traditional multi - electrode electromagnetic flowmeters, converts the average velocity of the entire measurement cross - section focused on by traditional flowmeters into the average axial velocity within each micro - element, and solves the problem of blood flow velocity detection in medical treatment. However, there are problems such as the dependence of electromagnetic induction measurement accuracy and the reconstructed region on the number of electrodes, and the strong subjectivity of the reconstructed region division method. For example: the above - mentioned method and device can only obtain 15 effective potential difference data, and can accurately reconstruct at most 15 reconstructed regions. And 15 reconstructed regions are artificially selected, including regions with blood vessels and regions without blood vessels. The artificial selection has strong subjectivity, and the specific position of blood vessels is unknown during the actual measurement process, making it difficult to be applied in practice. Summary of the Invention

[0005] In view of this, the present invention provides a method and device for reconstructing region division to solve the problem that the existing reconstructed region division method has strong subjectivity and affects the scientific nature of measurement results.

[0006] In a first aspect, the present invention provides a method for reconstructing region division, including:

[0007] Select a region to be reconstructed, and detect the shape of the region to be reconstructed;

[0008] Find the geometric center of the region to be reconstructed;

[0009] Establish a two - dimensional polar coordinate system with the geometric center as the pole;

[0010] In the two-dimensional polar coordinate system, with the geometric center as the pole, the shape is reduced according to a plurality of scales to obtain shapes of a plurality of scales;

[0011] Taking the pole as the starting point and the ray where the polar axis is located as the edge, rotating in the two-dimensional polar coordinate system according to the set angle to obtain a plurality of polar diameters;

[0012] The plurality of polar diameters respectively divide the plurality of scale shapes into a plurality of regions, and the plurality of regions are reconstruction regions;

[0013] The region to be reconstructed is a region where blood flow velocity distribution needs to be measured.

[0014] Preferably, the cross section of the region to be reconstructed is equivalent to a circle, and the shape of the region to be reconstructed is a circle; or

[0015] The cross section of the region to be reconstructed is equivalent to a circle, and the shape of the region to be reconstructed is a circle; in the two-dimensional polar coordinate system, with the geometric center as the pole, the shape is reduced according to a plurality of scales to obtain the plurality of scale shapes. The specific method is as follows: determining the number h of the plurality of scale shapes, and sequentially drawing concentric circles outward with the pole as the center and k*R / h as the radius to obtain the plurality of scale shapes;

[0016] The multiple scale shapes are circular; R is the radius of the area to be reconstructed, and the coefficient k=1, 2...h.

[0017] Preferably, before selecting the area to be reconstructed, the number M of divisions of the reconstructed area is set, and the number h of the plurality of scale shapes and the set angle 2π / m are determined according to the number M of divisions of the reconstructed area;

[0018] Where, m=M / (h+1).

[0019] In a second aspect, the present invention provides an apparatus for reconstructing region division, comprising:

[0020] a detection unit, a calculation unit, a polar coordinate system establishment unit, a scale shape unit, a polar diameter unit, and a division unit; the detection unit is connected to the calculation unit and the scale shape unit respectively, the calculation unit is connected to the polar coordinate system establishment unit, the polar coordinate system establishment unit is also connected to the scale shape unit and the polar diameter unit, and the scale shape unit and the polar diameter unit are also connected to the division unit;

[0021] The detection unit is used to select a region to be reconstructed and detect the shape of the region to be reconstructed;

[0022] The calculation unit is used to find the geometric center of the area to be reconstructed;

[0023] The polar coordinate system establishing unit is used to establish a two-dimensional polar coordinate system with the geometric center as the pole;

[0024] The scale and shape unit is used to reduce the shape by several scales with the geometric center as the pole in the two-dimensional polar coordinate system to obtain several scale shapes;

[0025] The polar radius unit is used to rotate in the two-dimensional polar coordinate system at a set angle with the pole as the starting point and the ray where the polar axis is located as the side to obtain several polar radii;

[0026] The dividing unit is used to divide the several scale shapes into several regions by the several polar radii, and the several regions are reconstruction regions;

[0027] Wherein, the region to be reconstructed is the region where the blood flow velocity distribution needs to be measured.

[0028] Preferably, the detection unit includes: an equivalent unit;

[0029] The equivalent unit is used to equivalent the cross-section of the region to be reconstructed to a circle, and the shape of the region to be reconstructed is circular; or

[0030] The equivalent unit is used to equivalent the cross-section of the region to be reconstructed to a circle, and the scale and shape unit performs the following operations: determining the number h of the several scale shapes, and successively making concentric circles outward with the pole as the center and k*R / h as the radius to obtain the several scale shapes;

[0031] Wherein, the several scale shapes are circular shapes; R is the radius of the region to be reconstructed, and the coefficient k = 1, 2... h.

[0032] Preferably, the device further includes:

[0033] A determination unit;

[0034] The determination unit is connected to the calculation unit. Before selecting the region to be reconstructed, the determination unit is used to set or determine the number M of the reconstruction region divisions, and according to the number M of the reconstruction region divisions, determine the number h of the several scale shapes and the set angle 2π / m;

[0035] Wherein, m = M / (h + 1).

[0036] In a third aspect, the present invention provides a device for dividing a reconstruction region, including:

[0037] A memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being the method as described above, and when the processor executes the program, the following steps are implemented:

[0038] Select the area to be reconstructed and detect the shape of the area to be reconstructed;

[0039] Find the geometric center of the area to be reconstructed;

[0040] Establish a two-dimensional polar coordinate system with the geometric center as the pole;

[0041] In the two-dimensional polar coordinate system, with the geometric center as the pole, scale down the shape by several scales to obtain several scaled shapes;

[0042] Starting from the pole and using the ray where the polar axis is located as a side, rotate in the two-dimensional polar coordinate system by a set angle to obtain several polar radii;

[0043] The several polar radii divide the several scaled shapes into several regions respectively, and the several regions are the reconstructed regions;

[0044] Wherein, the area to be reconstructed is the area where the blood flow velocity distribution needs to be measured.

[0045] The present invention has at least the following beneficial effects:

[0046] The present invention provides a method and device for dividing a reconstructed region to solve the problem that the existing method for dividing a reconstructed region has strong human subjectivity and affects the scientific nature of the measurement result. Description of the Drawings

[0047] Through the following description of the embodiments of the present invention with reference to the drawings, the above and other objects, features, and advantages of the present invention will become clearer. In the drawings:

[0048] Figure 1 is a flowchart of a method for dividing a reconstructed region according to an embodiment of the present invention;

[0049] Figure 2 is a schematic diagram of a device for dividing a reconstructed region according to an embodiment of the present invention;

[0050] Figure 3 is a schematic diagram of the division of the reconstructed region when the cross-section of the shape of the area to be reconstructed according to the present invention is equivalently a circle;

[0051] Figure 4 is a flowchart of a method for measuring blood flow velocity distribution according to an embodiment of the present invention;

[0052] Figure 5 is a schematic diagram of the principle of a method for reconstructing blood flow velocity distribution in the upper limb based on electromagnetic induction according to an embodiment of the present invention; Detailed implementation manners

[0053] The present invention will be described below based on embodiments. However, it should be noted that the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail. However, for the parts not described in detail, those skilled in the art can also fully understand the present invention.

[0054] In addition, those of ordinary skill in the art should understand that the provided drawings are only for illustrating the purpose, features, and advantages of the present invention, and the drawings are not actually drawn to scale.

[0055] At the same time, unless the context clearly requires otherwise, words such as "including" and "comprising" in the entire specification and claims should be interpreted as having an inclusive meaning rather than an exclusive or exhaustive meaning; that is, it is the meaning of "including but not limited to".

[0056] Figure 1 is a flowchart of a method for reconstructing region division according to an embodiment of the present invention. As Figure 1 shown, a method for reconstructing region division includes: Step 101: Select a region to be reconstructed, and detect the shape of the region to be reconstructed; Step 102: Find the geometric center of the region to be reconstructed; Step 103: Establish a two-dimensional polar coordinate system with the geometric center as the pole; Step 104: In the two-dimensional polar coordinate system, with the geometric center as the pole, reduce the shape by several scales to obtain several scale shapes; Step 105: Starting from the pole, with the ray where the polar axis is located as the side, rotate in the two-dimensional polar coordinate system according to a set angle to obtain several polar radii; Step 106: The several polar radii divide the several scale shapes into several regions respectively, and the several regions are the reconstructed regions; wherein, the region to be reconstructed is a region where the blood flow velocity distribution needs to be measured.

[0057] The specific method for Step 101 to select a region to be reconstructed and detect the shape of the region to be reconstructed is: For example, select the upper limb (arm) of the human body as the region to be reconstructed, that is, the region where the blood flow velocity distribution needs to be measured is the upper limb of the human body, and use the edge detection method to detect the shape of the upper limb of the human body, detect and draw the edge lines of the cross-section to be reconstructed of the upper limb of the human body to obtain the region to be reconstructed.

[0058] The specific method for Step 102 to find the geometric center of the region to be reconstructed is: Equivalent the region to be reconstructed to a regular figure. For example, if the upper limb (arm) of the human body is selected as the region to be reconstructed, it can be equivalent to a circle or an ellipse. If the region to be reconstructed is equivalent to a circle, the geometric center of the region to be reconstructed is at the center of the circle; if the region to be reconstructed is equivalent to an ellipse, the geometric center of the region to be reconstructed is at the center of the line connecting the two foci of the ellipse.

[0059] Step 103: Establish a two-dimensional polar coordinate system with the geometric center as the pole. The specific method is as follows: Take the geometric center of the region to be reconstructed as the pole O, draw a ray from the pole to the outside of the region to be reconstructed as the polar axis Ox, and then select a unit length and the positive direction of the angle (counterclockwise or clockwise). For any point P in the plane, use r to represent the length of the line segment OP, and θ to represent the angle from Ox to OP. r is called the polar radius of point P, and θ is called the polar angle of point P. The ordered pair (r, θ) is called the polar coordinates of point M. The coordinate system established in this way is called a polar coordinate system. Since the method of establishing a two-dimensional polar coordinate system is relatively simple, no illustration is given here. For specific reference, please refer to Figure 3 Understanding.

[0060] Step 104: In the two-dimensional polar coordinate system, with the geometric center as the pole, scale down the shape by several scales. The specific method is as follows: With the pole at the geometric center as the center, select several points on the edge of the shape of the region to be reconstructed, calculate the several distances from these several points to the center, and scale down the shape of the region to be reconstructed according to a certain proportional coefficient (i.e., several scales) of these several distances to obtain several scaled shapes, where the proportional coefficient is less than 1.

[0061] Step 105: Rotate in the two-dimensional polar coordinate system with the pole as the starting point and the ray where the polar axis is located as the side according to a set angle to obtain several polar radii. The specific method is as follows: With the pole as the starting point and the ray where the polar axis is located as the side, rotate in the two-dimensional polar coordinate system according to a set angle, which can be rotated counterclockwise or clockwise. Taking clockwise rotation as an example: When starting from the pole and rotating in the two-dimensional polar coordinate system with the ray where the polar axis is located as the side according to a set angle, after intersecting with the edge of the region to be reconstructed, the first polar radius is obtained. Then, starting from the pole and rotating in the two-dimensional polar coordinate system with the ray where the first polar radius is located as the side according to a set angle, the second polar radius is obtained, and so on, until the Nth polar radius is obtained. That is to say, the number of polar radii is 360° / set angle. If the set angle is 20°, then the number of polar radii is 18.

[0062] Step 106: The several polar radii divide the several scaled shapes into several regions, and these several regions are the reconstructed regions; among them, the method for the region to be reconstructed to be the region where the blood flow velocity distribution needs to be measured is as follows: For example, if the number of polar radii is 3 and the number of scaled shapes is 1, then 3*(1 + 1) = 6 reconstructed regions are obtained.

[0063] Select a number of points on the shape edge of the to-be-reconstructed region, calculate the distances from the number of points to the center, and reduce the shape of the to-be-reconstructed region by a certain proportional coefficient (i.e., a number of scales) of the number of distances to obtain a number of scaled shapes, where the proportional coefficient is less than 1.

[0064] In step 101, the cross-section of the to-be-reconstructed region is equivalent to a circle, and the shape of the to-be-reconstructed region is circular; that is, after selecting the to-be-reconstructed region, the cross-section of the to-be-reconstructed region is equivalent to a circle, and at this time, the detected shape of the to-be-reconstructed region is circular; or the cross-section of the to-be-reconstructed region is equivalent to a circle, and the shape of the to-be-reconstructed region is circular; in the two-dimensional polar coordinate system, with the geometric center as the pole, the specific method for reducing the shape by a number of scales to obtain a number of scaled shapes is: determine the number h of the number of scaled shapes, and successively draw concentric circles outward with the pole as the center and k*R / h as the radius to obtain the number of scaled shapes; where the number of scaled shapes is a circular shape; R is the radius of the to-be-reconstructed region, and the coefficient k = 1, 2... h.

[0065] At the same time, before selecting the to-be-reconstructed region, set the number M of the reconstructed region divisions. According to the number M of the reconstructed region divisions, determine the number h of the number of scaled shapes and the set angle 2π / m; where m = M / (h + 1).

[0066] Figure 2 It is a schematic diagram of a device for dividing a reconstructed region in an embodiment of the present invention. As Figure 2As shown in the figure, a device for reconstructing regional division includes: a detection unit 201, a calculation unit 202, a polar coordinate system establishment unit 203, a scale and shape unit 204, a polar radius unit 205, and a division unit 206; the detection unit 201 is respectively connected to the calculation unit 202 and the scale and shape unit 204, the calculation unit 202 is connected to the polar coordinate system establishment unit 203, the polar coordinate system establishment unit 203 is further connected to the scale and shape unit 204 and the polar radius unit 205, and the scale and shape unit 204 and the polar radius unit 205 are also connected to the division unit 206; the detection unit 201 is used to select a region to be reconstructed and detect the shape of the region to be reconstructed; the calculation unit 202 is used to find the geometric center of the region to be reconstructed; the polar coordinate system establishment unit 203 is used to establish a two-dimensional polar coordinate system with the geometric center as the pole; the scale and shape unit 204 is used to reduce the shape by several scales with the geometric center as the pole in the two-dimensional polar coordinate system to obtain several scale shapes; the polar radius unit 205 is used to rotate in the two-dimensional polar coordinate system with the pole as the starting point and the ray where the polar axis is located as the side according to a set angle to obtain several polar radii; the division unit 206 is used to divide the several scale shapes into several regions by the several polar radii, and the several regions are reconstruction regions; wherein, the region to be reconstructed is a region where the blood flow velocity distribution needs to be measured. The specific implementation method can refer to Figure 1 the detailed description in

[0067] In Figure 2 it, the detection unit 201 includes: an equivalent unit; the equivalent unit is used to equivalently convert the cross-section of the region to be reconstructed into a circle, and the shape of the region to be reconstructed is circular; or the equivalent unit is used to equivalently convert the cross-section of the region to be reconstructed into a circle, and the scale and shape unit 204 performs the following operations: determine the number h of the several scale shapes, and successively draw concentric circles outward with the pole as the center and k*R / h as the radius to obtain the several scale shapes; wherein, the several scale shapes are circular shapes; R is the radius of the region to be reconstructed, and the coefficient k = 1, 2... h. The specific implementation method can refer to Figure 1 the detailed description in

[0068] In Figure 2 it, a device for reconstructing regional division further includes: a determination unit; the determination unit is connected to the calculation unit 202, and before selecting the region to be reconstructed, the determination unit is used to set or determine the number M of reconstructed regional divisions, and according to the number M of reconstructed regional divisions, determine the number h of the several scale shapes and the set angle 2π / m; wherein, m = M / (h + 1). The specific implementation method can refer to Figure 1 the detailed description in

[0069] Figure 3 It is a schematic diagram of the reconstruction area division when the cross-section of the shape of the area to be reconstructed in the present invention is equivalent to a circle. As Figure 3 shown, if the cross-section of the upper limb of the human body is divided into M reconstruction areas, taking Figure 3 the division method as an example, the area to be reconstructed is divided into 64 reconstruction areas, where the number h of the shapes of several scales is 3 and the set angle is 2π / 16.

[0070] In Figure 3 , before calculating the blood flow velocity value of each reconstruction area, the area to be reconstructed is divided to obtain several areas, and the several areas are reconstruction areas, so as to calculate the contribution weight of the blood flow velocity in each reconstruction area to the n*(n - 1) induced potential differences. For example, if the number M of the reconstruction areas is 64, the labeling method of each reconstruction area is as follows: the area where the polar axis, the first polar radius intersect with the smallest scale shape is the first reconstruction area 1, the area where the polar axis, the first polar radius intersect with the adjacent next scale shape is the second reconstruction area 2, and they are the third reconstruction area 3 and the fourth reconstruction area 4 in turn from the inside to the outside. Then, in the counterclockwise order, the area where the first polar radius, the second polar radius intersect with the smallest scale shape is the fifth reconstruction area 5, and they are the sixth reconstruction area 6, the seventh reconstruction area 7 and the eighth reconstruction area 8 in turn from the inside to the outside according to the same method as above. Then, in the counterclockwise order according to the above method, they are labeled 9, 10....64 (not shown in the figure) as the ninth reconstruction area and the tenth reconstruction area.... the sixty-fourth reconstruction area. Among the 64 reconstruction areas, if the number n of the electrodes is 16, the contribution weight of the blood flow velocity in each reconstruction area to the 16*(16 - 1) induced potential differences.

[0071] The present invention also proposes another device for reconstructing area division, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. The computer program is the method as described above. When the processor executes the program, the following steps are implemented: select the area to be reconstructed, and detect the shape of the area to be reconstructed; find the geometric center of the area to be reconstructed; establish a two-dimensional polar coordinate system with the geometric center as the pole; in the two-dimensional polar coordinate system, with the geometric center as the pole, reduce the shape by several scales to obtain several scale shapes; with the pole as the starting point and the ray where the polar axis is located as the side, rotate in the two-dimensional polar coordinate system according to the set angle to obtain several polar radii; the several polar radii divide the several scale shapes into several areas respectively, and the several areas are reconstruction areas; wherein, the area to be reconstructed is the area where the blood flow velocity distribution needs to be measured. For the specific implementation method, reference can be made to Figure 1 the detailed description in

[0072] Figure 4It is a flowchart of a method for measuring blood flow velocity distribution according to an embodiment of the present invention. As Figure 4 shown, a method for measuring blood flow velocity distribution includes: Step 401, setting a constant and uniform magnetic field at the cross-section of the region to be reconstructed; Step 402, arranging n electrodes outside the cross-section; Step 403, taking one of the electrodes as a reference electrode and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences; Step 404, selecting the adjacent electrode of the reference electrode as the new reference electrode in a clockwise or counterclockwise direction, and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences; Step 405, until all electrodes are traversed as new reference electrodes, finally obtaining n*(n - 1) induced potential differences; Step 406, taking the n*(n - 1) induced potential differences as input data, and calculating the blood flow velocity value of each reconstructed region through a reconstruction equation, thereby obtaining the blood flow velocity distribution of the region to be reconstructed; wherein, the region to be reconstructed is the region to be measured, and n > 2.

[0073] In Figure 4 , taking the human upper limb (arm) as an example of the region to be reconstructed for illustration: Step 401, setting a constant and uniform magnetic field at the cross-section of the region to be reconstructed, that is, using an excitation device to set a constant and uniform magnetic field at the cross-section of the human upper limb. Step 402, arranging n electrodes outside the cross-section, and the outside of the cross-section is the outside of the skin of the region to be reconstructed. For example, when the region to be reconstructed is the human upper limb, n electrodes are arranged outside the skin of the human upper limb, that is, on the surface layer of the upper limb skin; Step 403, taking one of the electrodes as a reference electrode and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences, that is, taking one of the electrodes as a reference electrode and the remaining electrodes as measurement electrodes to obtain n - 1 effective induced potential differences; Step 404, selecting the adjacent electrode of the reference electrode as the new reference electrode in a clockwise or counterclockwise direction, and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences. For example, in the counterclockwise order, selecting the next electrode as the reference electrode and all the remaining electrodes as measurement electrodes to obtain n - 1 effective induced potential differences again; Step 405, until all electrodes are traversed as new reference electrodes, finally obtaining n*(n - 1) induced potential differences. Repeating Step 404 until all electrodes are traversed as reference electrodes, finally obtaining n*(n - 1) effective induced potential differences, and all the effective induced potential differences N = n*(n - 1); Step 40, taking the n*(n - 1) induced potential differences as input data, and calculating the blood flow velocity value of each reconstructed region through a reconstruction equation, thereby obtaining the blood flow velocity distribution of the region to be reconstructed, that is, calculating the blood flow velocity values of each reconstructed region through a reconstruction equation, and thereby obtaining the blood flow velocity distribution of the entire upper limb cross-section. Wherein, the region to be reconstructed is the region to be measured, and n > 2.

[0074] InFigure 4 In this method, before setting a constant and uniform magnetic field at the cross-section of the region to be reconstructed, the region to be reconstructed is divided into several regions, and these several regions are the reconstruction regions. The cross-section of the upper limb described in step 101 is divided into M reconstruction regions, where M ≤ N; among them, all the effective induced potential differences N = n*(n - 1).

[0075] In Figure 4 this method, the method for dividing the reconstruction region is as follows: select the region to be reconstructed and detect the shape of the region to be reconstructed; find the geometric center of the region to be reconstructed; establish a two-dimensional polar coordinate system with the geometric center as the pole; in the two-dimensional polar coordinate system, with the geometric center as the pole, scale down the shape by several scales to obtain several scaled shapes; with the pole as the starting point and the ray where the polar axis is located as the side, rotate in the two-dimensional polar coordinate system by a set angle to obtain several polar radii; the several polar radii divide the several scaled shapes into several regions respectively, and these several regions are the reconstruction regions; among them, the region to be reconstructed is the region where the blood flow velocity distribution needs to be measured. The specific implementation method can refer to Figure 1 or Figure 2 the detailed description in

[0076] In Figure 4 this method, the cross-section of the region to be reconstructed is equivalent to a circle, and the shape of the region to be reconstructed is circular; or the cross-section of the region to be reconstructed is equivalent to a circle, and the shape of the region to be reconstructed is circular; in the two-dimensional polar coordinate system, with the geometric center as the pole, the specific method for scaling down the shape by several scales to obtain several scaled shapes is as follows: determine the number h of the several scaled shapes, and successively draw concentric circles outward with the pole as the center and k*R / h as the radius to obtain the several scaled shapes; among them, the several scaled shapes are circular shapes; R is the radius of the region to be reconstructed, and the coefficient k = 1, 2...h. The specific implementation method can refer to Figure 1 or Figure 2 the detailed description in

[0077] In a method for measuring blood flow velocity distribution, the reconstruction equation is as follows:

[0078]

[0079] Among them, V M represents the axial average velocity of the Mth reconstruction region, W NM represents the contribution weight of the flow in the Mth region to the Nth induced potential difference, A M represents the area of the Mth reconstruction region, and ΔU N represents the Nth measured induced potential difference.

[0080] The present invention also provides a device for measuring blood flow velocity distribution, comprising: a magnetic field unit for setting a constant and uniform magnetic field at the cross-section of the region to be reconstructed; an electrode unit arranging n electrodes outside the cross-section; an induced potential difference acquisition unit for taking one of the electrodes as a reference electrode and the remaining n - 1 electrodes as measurement electrodes to acquire n - 1 induced potential differences; an update unit for selecting the adjacent electrode of the reference electrode as the new reference electrode in a clockwise or counterclockwise manner, and the remaining n - 1 electrodes as measurement electrodes to acquire n - 1 induced potential differences; a traversal unit for traversing until all electrodes are new reference electrodes, and finally acquiring n*(n - 1) induced potential differences; a calculation unit using the n*(n - 1) induced potential differences as input data and calculating the blood flow velocity value of each reconstructed region through a reconstruction equation, thereby obtaining the blood flow velocity distribution of the region to be reconstructed; wherein the region to be reconstructed is the region to be measured, and n > 2. The specific implementation manner can refer to Figure 4 and Figure 5 the detailed description in

[0081] A device for measuring blood flow velocity distribution further comprises: a reconstructed region division unit or device; the reconstructed region division unit or device divides the region to be reconstructed into several regions, which are the reconstructed regions, before calculating the blood flow velocity value of each reconstructed region, so as to calculate the contribution weight of the blood flow velocity in each reconstructed region to the n*(n - 1) induced potential differences.

[0082] The reconstructed region division unit or device can adopt Figure 2An apparatus for reconstructing region division, comprising: a detection unit 201, a calculation unit 202, a polar coordinate system establishment unit 203, a scale shape unit 204, a polar radius unit 205, and a division unit 206; the detection unit 201 is respectively connected to the calculation unit 202 and the scale shape unit 204, the calculation unit 202 is connected to the polar coordinate system establishment unit 203, the polar coordinate system establishment unit 203 is further connected to the scale shape unit 204 and the polar radius unit 205, and the scale shape unit 204 and the polar radius unit 205 are further connected to the division unit 206; the detection unit 201 is configured to select a region to be reconstructed and detect the shape of the region to be reconstructed; the calculation unit 202 is configured to find the geometric center of the region to be reconstructed; the polar coordinate system establishment unit 203 is configured to establish a two-dimensional polar coordinate system with the geometric center as the pole; the scale shape unit 204 is configured to reduce the shape by several scales with the geometric center as the pole in the two-dimensional polar coordinate system to obtain several scale shapes; the polar radius unit 205 is configured to rotate in the two-dimensional polar coordinate system with the pole as the starting point and the ray where the polar axis is located as the side according to a set angle to obtain several polar radii; the division unit 206 is configured to divide the several scale shapes into several regions by the several polar radii, and the several regions are reconstruction regions; wherein, the region to be reconstructed is a region where the blood flow velocity distribution needs to be measured. The specific implementation manner can be referred to Figure 1 or Figure 2 the detailed description in

[0083] Wherein, the detection unit 201 includes: an equivalent unit; the equivalent unit is configured to equivalent the cross-section of the region to be reconstructed to a circle, and the shape of the region to be reconstructed is circular; or the equivalent unit is configured to equivalent the cross-section of the region to be reconstructed to a circle, and the scale shape unit 204 performs the following operations: determine the number h of the several scale shapes, and successively draw concentric circles outward with the pole as the center and k*R / h as the radius to obtain the several scale shapes; wherein, the several scale shapes are circular shapes; R is the radius of the region to be reconstructed, and the coefficient k = 1, 2... h. The specific implementation manner can be referred to Figure 1 or Figure 2 the detailed description in

[0084] The reconstruction equation of an apparatus for measuring blood flow velocity distribution is:

[0085]

[0086] Wherein, V1...V M respectively represent the axial average velocities of the first to the Mth reconstruction regions, W NMIndicates the contribution weight value of the flow in the Mth region to the Nth induced potential difference, A1...A M Indicates the areas of the 1st to Mth reconstructed regions, ΔU1...ΔU N Indicates the 1st to Nth measured induced potential differences.

[0087] Among them, the weight value of the change in the induced potential difference caused by the flow in different regions is calculated according to the positions of the measurement electrodes and the reconstructed regions, and the calculation formula is as follows:

[0088]

[0089] In the formula, ψ in Indicates the angle between the line connecting the pole and the position of the measurement electrode and the polar axis, ψ out Indicates the angle between the line connecting the pole and the position of the reference electrode and the polar axis, (r,θ) represents the coordinates of the geometric center of the reconstructed region in the polar coordinates established with the geometric center of the region to be reconstructed as the pole, t represents the iteration coefficient, and its value range is from 1 to infinity, B represents the magnitude of the constant magnetic field, and R represents the cross-sectional radius of the human upper limb.

[0090] Figure 5 This is a schematic diagram of the principle of the method for reconstructing the blood flow velocity distribution of the upper limb based on electromagnetic induction in the embodiments of the present invention. As Figure 4 and 5 shown, taking the human upper limb (arm) as the region to be reconstructed as an example for illustration, in Figure 5 there are the first energized coil a, the second energized coil b, the measurement electrode c, the arterial region d, and the skin f of the human upper limb, Figure 5 is Figure 4 a specific illustration.

[0091] In Figure 4 and Figure 5 step 401 sets a constant and uniform magnetic field at the cross-section of the region to be reconstructed. Specifically, current is passed through the first energized coil a and the second energized coil b to generate a constant magnetic field B in the direction from the second energized coil b to the first energized coil a in the region to be reconstructed.

[0092] In Figure 4 and Figure 5In step 402, n electrodes are arranged outside the cross-section, and the outside of the cross-section is the outside of the skin of the area to be reconstructed. For example, when the area to be reconstructed is the upper limb of the human body, the n electrodes are arranged outside the skin of the upper limb of the human body. Specifically, the n electrodes are 16 electrodes, and the 16 electrodes c are evenly arranged outside the skin f of the upper limb of the human body. The labels of the 16 electrodes are the zeroth electrode e0, the first electrode e1... the fifteenth electrode e15, and the interval between every two electrodes is 22.5 degrees. When there is blood flow in the artery area d, the arterial blood flows in a direction perpendicular to the paper surface to cut the magnetic induction line. According to the principle of electromagnetic induction, a stable induced potential field will be generated at the cross-section of the upper limb, and the 16 electrodes will detect the induced potential. Taking one of the two electrodes as the measuring electrode and the other as the reference electrode and connecting them to the signal acquisition device at the same time will obtain the required induced potential difference signal.

[0093] In Figure 4 and Figure 5 in step 403, taking one of the electrodes as the reference electrode and the remaining n - 1 electrodes as the measuring electrodes, n - 1 induced potential differences are obtained. Specifically, the n electrodes are 16 electrodes. First, taking the zeroth electrode e0 as the reference electrode and the remaining 15 electrodes (the first electrode e1... the fifteenth electrode e15) as the measuring electrodes, 15 potential difference signals will be obtained.

[0094] In Figure 4 and Figure 5 in step 404, in a clockwise or counterclockwise direction, the adjacent electrode of the reference electrode is selected as the new reference electrode, and the remaining n - 1 electrodes are the measuring electrodes, and n - 1 induced potential differences are obtained. Specifically, taking the first electrode e1 as the reference electrode and the remaining 15 electrodes (the zeroth electrode e0, the second electrode e2... the fifteenth electrode e15) as the measuring electrodes, 15 potential difference signals are obtained again.

[0095] In Figure 4 and Figure 5 in step 405, until all the electrodes are traversed as the new reference electrodes, finally n*(n - 1) induced potential differences are obtained. Specifically, then taking the second electrode e2, the third electrode e3... the fifteenth electrode e15 as the reference electrodes in turn, and finally 240 induced potential difference signals are obtained. The traditional measurement method only takes one of the electrodes as the reference electrode and can only obtain 15 induced potential difference signals. The number of induced potential difference signals obtained by this method is 16 times that of the traditional measurement method. In the electromagnetic induction measurement technology, the more effective the number of induced potential difference data, the higher the measurement accuracy.

[0096] If the cross-section of the upper limb of the human body is divided into M reconstructed areas, with Figure 3Taking the partitioning method as an example, the area to be reconstructed is divided into 64 reconstruction areas, where the number h of several scale shapes is 3 and the set angle is 2π / 16. As Figure 3 shown, before calculating the blood flow velocity value of each reconstruction area, the area to be reconstructed is partitioned to obtain several areas, and these several areas are the reconstruction areas, in order to calculate the contribution weight of the blood flow velocity in each reconstruction area to the n*(n - 1) induced potential differences. The labeling method for each reconstruction area is as follows: The area where the polar axis, the first polar radius intersect with the smallest scale shape is the first reconstruction area 1, the area where the polar axis, the first polar radius intersect with the next adjacent scale shape is the second reconstruction area 2, and they are the third reconstruction area 3 and the fourth reconstruction area 4 in sequence from the inside to the outside. After that, in the counterclockwise order, the area where the first polar radius, the second polar radius intersect with the smallest scale shape is the fifth reconstruction area 5, and they are the sixth reconstruction area 6, the seventh reconstruction area 7 and the eighth reconstruction area 8 in sequence from the inside to the outside according to the same method as above. Then, in the counterclockwise order according to the above method, they are labeled 9, 10....64 (not shown in the figure) as the ninth reconstruction area and the tenth reconstruction area.... the sixty-fourth reconstruction area. Among the 64 reconstruction areas, taking the number of electrodes n = 16 as an example, the contribution weight of the blood flow velocity in each reconstruction area to the 16*(16 - 1) induced potential differences is calculated.

[0097] In Figure 4 and Figure 5 taking the n*(n - 1) induced potential differences in step 406 as input data, through the reconstruction equation, calculate the blood flow velocity value of each reconstruction area, and then obtain the blood flow velocity distribution of the area to be reconstructed; where the area to be reconstructed is the area to be measured, and n > 2. Specifically, import the 240 measured induced potential differences as input data into the following reconstruction equation, calculate the blood flow velocity values of each reconstruction area, and then obtain the blood flow velocity distribution at the cross-section of the entire upper limb of the human body.

[0098]

[0099] Among them, V1...V M respectively represent the axial average velocities of the 1st to the Mth reconstruction areas, W NM represents the contribution weight of the flow in the Mth area to the Nth induced potential difference, A1...A M represent the areas of the 1st to the Mth reconstruction areas, and ΔU1...ΔU N represent the 1st to the Nth measured induced potential differences.

[0100] Among them, according to the positions of the measurement electrodes and the reconstruction areas, calculate the weight values of the changes in the induced potential differences caused by the flows in different areas, and the calculation formula is as follows:

[0101]

[0102] In the formula, ψ in represents the angle between the line connecting the pole and the position of the measurement electrode and the polar axis, ψ out represents the angle between the line connecting the pole and the position of the reference electrode and the polar axis, (r, θ) represents the coordinates of the geometric center of the reconstruction area in the polar coordinates established with the geometric center of the area to be reconstructed as the pole, t represents the iteration coefficient, and its value range is from 1 to infinity, B represents the magnitude of the constant magnetic field; the cross-section of the area to be reconstructed is equivalent to a circle, the shape of the area to be reconstructed is circular, R represents the cross-sectional radius of the cross-section of the area to be reconstructed, that is, the cross-sectional radius of the upper limb of the human body.

[0103] At the same time, the cross-section of the area to be reconstructed is equivalent to a circle, and the shape of the area to be reconstructed is circular; the areas A of M reconstruction areas M are calculated as follows:

[0104]

[0105]

[0106]

[0107] The induced potential difference ΔU N is obtained by actual measurement. Finally, the calculated W NM and A M are substituted into the reconstruction equation, and the velocity values V of each reconstruction area can be obtained M , and finally the blood flow velocity distribution of the area to be reconstructed is obtained.

[0108] The above embodiments are only for expressing the implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations, equivalent replacements, improvements, etc. can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A method for reconstructing regional division, applied to blood flow velocity measurement, characterized in that, Including: Before calculating the blood flow velocity value, divide the region to be reconstructed to obtain a number of reconstructed regions; wherein, the step of dividing the region to be reconstructed to obtain a number of reconstructed regions includes: selecting the region to be reconstructed, and detecting the shape of the region to be reconstructed by using an edge detection method; wherein, the region to be reconstructed is the region where the blood flow velocity distribution needs to be measured; find the geometric center of the region to be reconstructed, and establish a two-dimensional polar coordinate system with the geometric center as the pole; in the two-dimensional polar coordinate system, with the geometric center as the pole, scale down the shape according to a number of scales to obtain a number of scaled shapes; with the pole as the starting point and the ray where the polar axis is located as the side, rotate in the two-dimensional polar coordinate system according to a set angle to obtain a number of polar radii; the number of polar radii respectively divide the number of scaled shapes into a number of regions, and the number of regions are the reconstructed regions; after obtaining the number of reconstructed regions, label each reconstructed region, calculate the contribution weights of the blood flow velocity in each labeled reconstructed region to n*(n - 1) induced potential differences, and further obtain the blood flow velocity distribution of the region to be reconstructed; Wherein, the method for calculating the contribution weights of the blood flow velocity in each labeled reconstructed region to the n*(n - 1) induced potential differences and further obtaining the blood flow velocity distribution of the region to be reconstructed includes: setting a constant and uniform magnetic field at the cross-section of the region to be reconstructed; arranging n electrodes outside the cross-section; using one of the electrodes as a reference electrode and the remaining n - 1 electrodes as measuring electrodes to obtain n - 1 induced potential differences; selecting the adjacent electrode of the reference electrode as the new reference electrode in a clockwise or counterclockwise manner, and the remaining n - 1 electrodes as measuring electrodes to obtain n - 1 induced potential differences; until all electrodes are traversed as the new reference electrode, finally obtaining n*(n - 1) induced potential differences; calculating the contribution weights of the changes in the induced potential differences caused by the flow in different regions according to the positions of the measuring electrodes and the reconstructed regions; using the n*(n - 1) induced potential differences and the contribution weights as input data, and calculating the blood flow velocity value of each reconstructed region through a reconstruction equation, and further obtaining the blood flow velocity distribution of the region to be reconstructed; wherein, the region to be reconstructed is the region to be measured, and n > 2; wherein, the formula for calculating the contribution weights corresponding to the changes in the induced potential differences caused by the flow in different regions according to the positions of the measuring electrodes and the reconstructed regions is configured as: Among them, ψ in represents the angle between the line connecting the pole and the position of the measurement electrode and the polar axis, and ψ out represents the angle between the line connecting the pole and the position of the reference electrode and the polar axis. (r, θ) represents the coordinates of the geometric center of the reconstruction area in the polar coordinates established with the geometric center of the area to be reconstructed as the pole; r represents the polar radius; θ represents the polar angle; t represents the iteration coefficient, and its value range is from 1 to infinity; B represents the magnitude of the constant magnetic field; R represents the cross-sectional radius of the upper limb of the human body.

2. The method according to claim 1, wherein With the pole as the starting point and the ray where the polar axis is located as the side, rotating in the two-dimensional polar coordinate system according to a set angle to obtain a number of polar radii, includes: When starting from the pole and using the ray where the polar axis is located as the side, after rotating counterclockwise or clockwise in the two-dimensional polar coordinate system according to the set angle and intersecting with the edge of the region to be reconstructed to obtain the first polar radius, then starting from the pole and using the ray where the first polar radius is located as the side and rotating in the two-dimensional polar coordinate system according to the set angle to obtain the second polar radius, and so on, until obtaining the Nth polar radius; wherein, the number N of the number of polar radii is 360° / set angle.

3. The method according to claim 1, wherein Equivalent the cross-section of the region to be reconstructed to a circle, and the shape of the region to be reconstructed is circular; or Equivalent the cross-section of the region to be reconstructed to a circle, and the shape of the region to be reconstructed is circular; in the two-dimensional polar coordinate system, with the geometric center as the pole, shrink the shape by several scales, and the specific method for obtaining several scale shapes is as follows: determine the number h of the several scale shapes, and use the pole as the center of the circle, and successively draw concentric circles outward with a radius of k*R / h to obtain the several scale shapes; where the several scale shapes are circular shapes; R is the radius of the region to be reconstructed, and the coefficient k = 1, 2... h.

4. The method according to any one of claims 1 to 3, characterized in that Before selecting the region to be reconstructed, set the number M of the reconstructed region partitions, and according to the number M of the reconstructed region partitions, determine the number h of the several scale shapes and the set angle 2π / m; Where, m = M / (h + 1).

5. A device for reconstructing regional division, which is applied to blood flow velocity measurement, is characterized in that Including: Before calculating the blood flow velocity value, divide the region to be reconstructed to obtain several reconstructed regions; where the dividing the region to be reconstructed to obtain several reconstructed regions includes: a detection unit (201), a calculation unit (202), a polar coordinate system establishment unit (203), a scale shape unit (204), a polar radius unit (205) and a dividing unit (206); The detection unit (201) is respectively connected to the calculation unit (202) and the scale shape unit (204), the calculation unit (202) is connected to the polar coordinate system establishment unit (203), the polar coordinate system establishment unit (203) is also connected to the scale shape unit (204) and the polar radius unit (205), and the scale shape unit (204) and the polar radius unit (205) are also connected to the dividing unit (206); The detection unit (201) is used to select the region to be reconstructed and detect the shape of the region to be reconstructed by using an edge detection method; where the region to be reconstructed is the region where the blood flow velocity distribution needs to be measured; The calculation unit (202) is used to find the geometric center of the region to be reconstructed; The polar coordinate system establishment unit (203) is used to establish a two-dimensional polar coordinate system with the geometric center as the pole; The scale shape unit (204) is used to shrink the shape by several scales with the geometric center as the pole in the two-dimensional polar coordinate system to obtain several scale shapes; The polar radius unit (205) is used to rotate in the two-dimensional polar coordinate system with the pole as the starting point and the ray where the polar axis is located as the side according to the set angle to obtain several polar radii; The dividing unit (206) is used to divide the several scale shapes into several regions by the several polar radii, and the several regions are reconstructed regions; After obtaining the several reconstructed regions, label each reconstructed region, calculate the contribution weights of the blood flow velocity in each labeled reconstructed region to n*(n - 1) induced potential differences, and further obtain the blood flow velocity distribution of the region to be reconstructed; Among them, calculating the contribution weights of the blood flow velocity in each reconstructed region after numbering to the n*(n - 1) induced potential differences, and then obtaining the blood flow velocity distribution in the region to be reconstructed, includes: setting a constant and uniform magnetic field at the cross-section of the region to be reconstructed; arranging n electrodes outside the cross-section; taking one of the electrodes as a reference electrode and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences; selecting the adjacent electrode of the reference electrode as the new reference electrode in a clockwise or counterclockwise manner, and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences; until all electrodes are traversed as new reference electrodes, finally obtaining n*(n - 1) induced potential differences; calculating the contribution weights of the changes in the induced potential differences caused by the flow in different regions according to the positions of the measurement electrodes and the reconstructed regions; using the n*(n - 1) induced potential differences and the contribution weights as input data, and calculating the blood flow velocity values in each reconstructed region through a reconstruction equation, and then obtaining the blood flow velocity distribution in the region to be reconstructed; where the region to be reconstructed is the region to be measured, and n > 2; among them, the formula for calculating the contribution weights corresponding to the changes in the induced potential differences caused by the flow in different regions according to the positions of the measurement electrodes and the reconstructed regions is configured as: Among them, ψ in represents the angle between the line connecting the pole and the position of the measurement electrode and the polar axis, ψ out represents the angle between the line connecting the pole and the position of the reference electrode and the polar axis, (r, θ) represents the coordinates of the geometric center of the reconstruction area in the polar coordinates established with the geometric center of the area to be reconstructed as the pole; r represents the polar radius; θ represents the polar angle; t represents the iteration coefficient, and its value range is from 1 to infinity; B represents the magnitude of the constant magnetic field; R represents the cross-sectional radius of the human upper limb.

6. The apparatus for reconstructing region division according to claim 5, wherein The polar radius unit (205) includes: a rotation unit; The rotation unit, when starting from the pole and using the ray where the polar axis is located as a side, rotates counterclockwise or clockwise in the two-dimensional polar coordinate system according to the set angle, intersects with the edge of the region to be reconstructed to obtain the first polar radius, and then starts from the pole and rotates in the two-dimensional polar coordinate system according to the set angle with the ray where the first polar radius is located as a side to obtain the second polar radius, and so on, to obtain the Nth polar radius; where the number N of the several polar radii is 360° / set angle.

7. The apparatus for reconstructing region division according to claim 5, wherein The detection unit (201) includes: an equivalent unit; The equivalent unit is used to equivalently transform the cross-section of the region to be reconstructed into a circle, and the shape of the region to be reconstructed is circular; or The equivalent unit is used to equivalently transform the cross-section of the region to be reconstructed into a circle, and the scale shape unit (204) performs the following operations: determining the number h of the several scale shapes, and successively making concentric circles with a radius of k*R / h centered at the pole to obtain the several scale shapes; where the several scale shapes are circular; R is the radius of the region to be reconstructed, and the coefficient k = 1, 2... h.

8. The apparatus for reconstructing region division according to any one of claims 5-7, characterized in that, It further includes: A determination unit; The determination unit is connected to the calculation unit (202). Before selecting the region to be reconstructed, the determination unit is used to set or determine the number M of the reconstructed region divisions, and according to the number M of the reconstructed region divisions, determine the number h of the several scale shapes and the set angle 2π / m; where m = M / (h + 1).

9. An apparatus for reconstructing region division, characterized in that It includes: A memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being the method for reconstructing region division as described in any one of claims 1 to 4, and when the processor executes the computer program, the following steps are implemented: Before calculating the blood flow velocity value, divide the to-be-reconstructed region to obtain a plurality of reconstructed regions; wherein, dividing the to-be-reconstructed region to obtain a plurality of reconstructed regions includes: selecting the to-be-reconstructed region, and detecting the shape of the to-be-reconstructed region by using an edge detection method; wherein, the to-be-reconstructed region is a region where the blood flow velocity distribution needs to be measured; find the geometric center of the to-be-reconstructed region, and establish a two-dimensional polar coordinate system with the geometric center as the pole; in the two-dimensional polar coordinate system, with the geometric center as the pole, reduce the shape by a plurality of scales to obtain a plurality of scale shapes; starting from the pole, with the ray where the polar axis is located as the side, rotate in the two-dimensional polar coordinate system according to a set angle to obtain a plurality of polar radii; the plurality of polar radii respectively divide the plurality of scale shapes into a plurality of regions, and the plurality of regions are the reconstructed regions; after obtaining the plurality of reconstructed regions, number each reconstructed region, calculate the contribution weight of the blood flow velocity in each numbered reconstructed region to n*(n - 1) induced potential differences, and further obtain the blood flow velocity distribution of the to-be-reconstructed region; Wherein, the method for calculating the contribution weight of the blood flow velocity in each numbered reconstructed region to the n*(n - 1) induced potential differences and further obtaining the blood flow velocity distribution of the to-be-reconstructed region includes: setting a constant and uniform magnetic field at the cross-section of the to-be-reconstructed region; arranging n electrodes outside the cross-section; taking one of the electrodes as a reference electrode and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences; in a clockwise or counterclockwise direction, select the adjacent electrode of the reference electrode as the new reference electrode, and the remaining n - 1 electrodes as measurement electrodes to obtain n - 1 induced potential differences; until all electrodes are traversed as the new reference electrode, finally obtain n*(n - 1) induced potential differences; calculate the contribution weight of the change in the induced potential difference caused by the flow in different regions according to the positions of the measurement electrodes and the reconstructed regions; the n*(n - 1) induced potential differences and the contribution weights are used as input data, and through a reconstruction equation, calculate the blood flow velocity value of each reconstructed region, and further obtain the blood flow velocity distribution of the to-be-reconstructed region; wherein, the to-be-reconstructed region is the to-be-measured region, n > 2; wherein, the formula for calculating the contribution weight corresponding to the change in the induced potential difference caused by the flow in different regions according to the positions of the measurement electrodes and the reconstructed regions is configured as: where ψ in represents the angle between the line connecting the pole and the position of the measurement electrode and the polar axis, and ψ out represents the angle between the line connecting the pole and the position of the reference electrode and the polar axis. (r, θ) represents the coordinates of the geometric center of the reconstruction region in the polar coordinates established with the geometric center of the region to be reconstructed as the pole; r represents the radial distance; θ represents the polar angle; t represents the iteration coefficient, with a value range from 1 to infinity; B represents the magnitude of the constant magnetic field; and R represents the cross-sectional radius of the human upper limb.

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