Marker body positioning method, geometric spacing measurement method and device

Abstract

The present invention provides a method for locating a marker body, a method for measuring geometric spacing, and a device. The positioning method is applied to a scanning system for locating a marker body embedded in a phantom. The scanning system includes a receiver. The method for locating the marker body includes: obtaining a plurality of two-dimensional projection coordinates of the marker body projected on a first reference coordinate system where the receiver is located at a plurality of different preset scanning angles; determining a plurality of three-dimensional projection coordinates of the marker body in a second reference coordinate system according to the plurality of two-dimensional projection coordinates; and determining the three-dimensional true coordinates of the marker body in the second reference coordinate system according to the plurality of three-dimensional projection coordinates. The present invention avoids the influence of artifacts in tomographic images on the accuracy of the three-dimensional true coordinates of the marker body, improves the reliability of the three-dimensional true coordinates of the marker body, thereby improving the accuracy of marker body positioning. Moreover, since there is no need to reconstruct tomographic images through a reconstruction algorithm, the efficiency of marker body positioning is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of scanning imaging, and particularly relates to a method for positioning a marker body, a method and device for measuring geometric spacing. Background Art

[0002] In the field of scanning technology, the accuracy of the processed phantom has a great influence on the scanning accuracy. However, the existing processing accuracy is limited, so it is very necessary to determine whether the processing accuracy of the processed product meets the requirements. Specifically, the judgment of the processing accuracy of the phantom can be carried out by positioning the marker body in the phantom and comparing the positioning value with the design value to test the processing accuracy of the phantom to ensure the reliability of the processing accuracy.

[0003] In the prior art, there are two methods for positioning the marker body in the phantom. One method is to scan the marker body by a CT scanning system, and then obtain the tomographic image of the marker body through a CT reconstruction algorithm, and position the marker body through the tomographic image. Another method is to directly position the marker body by using a high-precision three-dimensional laser scanner in a laser scanning manner.

[0004] The above methods have the following problems: In the first method, since the reconstruction of the tomographic image takes a long time, the calculation efficiency is low. Moreover, the quality of the tomographic image depends on the correction of the scanning data, and the correction result directly affects the quality of the tomographic image. When the correction is inaccurate, the presence of artifacts in the tomographic image will cause a large positioning error of the marker body. In the second method, since it uses a laser scanning method, the spectral band cannot penetrate the phantom, resulting in the inability to position the marker body embedded in the phantom. Summary of the Invention

[0005] In view of this, it is necessary to provide a method for positioning a marker body, a method and device for measuring geometric spacing to solve the technical problem of inaccurate positioning of the marker body in the prior art.

[0006] On the one hand, the present invention provides a method for positioning a marker body, which is applied to a scanning system and is used for positioning a marker body embedded in a phantom. The scanning system includes a receiver, and the marker body positioning method includes:

[0007] Obtaining a plurality of two-dimensional projection coordinates of the marker body projected on a first reference coordinate system where the receiver is located at a plurality of different preset scanning angles;

[0008] Determining a plurality of three-dimensional projection coordinates of the marker body in a second reference coordinate system according to the plurality of two-dimensional projection coordinates;

[0009] Determining the three-dimensional true coordinates of the marker body in the second reference coordinate system according to the plurality of three-dimensional projection coordinates.

[0010] In a possible implementation, determining multiple three-dimensional projection coordinates of the marker body in the second reference coordinate system based on multiple two-dimensional projection coordinates includes:

[0011] Establish a one-to-one correspondence between the multiple two-dimensional projection coordinates and the multiple three-dimensional projection coordinates;

[0012] Determine the multiple three-dimensional projection coordinates corresponding one-to-one to the multiple two-dimensional projection coordinates in the second reference coordinate system according to the multiple two-dimensional projection coordinates and the correspondence.

[0013] In a possible implementation, the receiver includes a projection pixel area. Establishing a one-to-one correspondence between the multiple two-dimensional projection coordinates and the multiple three-dimensional projection coordinates includes:

[0014] Establish a one-to-one indexing relationship between the multiple two-dimensional projection coordinates and the multiple pixels in the projection pixel area;

[0015] Establish a one-to-one mapping relationship between the multiple pixels and the multiple three-dimensional projection coordinates;

[0016] Establish the correspondence according to the indexing relationship and the mapping relationship.

[0017] In a possible implementation, the scanning system further includes a transmitter for emitting rays. Establishing a one-to-one correspondence between the multiple two-dimensional projection coordinates and the multiple three-dimensional projection coordinates is:

[0018] Determine a first distance between the transmitter and the receiver and a second distance between the transmitter and the phantom;

[0019] Determine multiple ideal projection coordinates according to the multiple two-dimensional projection coordinates, the first distance, the second distance, the pixel sizes of the multiple pixels in the projection pixel area, and the origin of the first reference coordinate system;

[0020] Determine the deflection angle of the receiver, and determine the multiple three-dimensional projection coordinates according to the deflection angle and the multiple ideal projection coordinates.

[0021] In a possible implementation, the scanning system further includes a transmitter for emitting rays. Determining the three-dimensional true coordinates of the marker body according to the multiple three-dimensional projection coordinates includes:

[0022] Determine the transmitter coordinates of the transmitter;

[0023] Determine at least one scanning model at multiple different preset scanning angles according to the transmitter coordinates and the multiple three-dimensional projection coordinates;

[0024] Based on the least squares method, determine the three-dimensional true coordinates of the marker body according to at least one scanning model.

[0025] In a possible implementation manner, at least one scanning model is a plurality of linear equations between the emitter coordinates and a plurality of three-dimensional projection coordinates. Determining the three-dimensional true coordinates of the marker body according to at least one scanning model includes:

[0026] Determine the optimal intersection point of the plurality of linear equations, and the optimal intersection point coordinates are the three-dimensional true coordinates of the marker body.

[0027] In a possible implementation manner, before obtaining the plurality of two-dimensional projection coordinates of the marker body on the receiver at a plurality of different preset scanning angles, it further includes:

[0028] When the emitter emits rays at a plurality of different trial scanning angles, pre-scan the marker body to determine the target relative position between the phantom and the receiver.

[0029] In a possible implementation manner, the receiver includes a projection pixel area. Pre-scanning the marker body includes:

[0030] Obtain a plurality of trial projection coordinates of the marker body in the first reference coordinate system where the receiver is located at a plurality of different trial scanning angles;

[0031] Judge whether all the plurality of trial projection coordinates are located within the projection pixel area;

[0032] If all the plurality of trial projection coordinates are not located within the projection pixel area, then adjust the relative position between the phantom and the receiver;

[0033] If the trial projection coordinates are all located within the projection pixel area of the receiver, then the current relative position of the phantom and the receiver is the target relative position.

[0034] On the other hand, the present invention also provides a geometric spacing measurement method, including:

[0035] Determine the three-dimensional true coordinates of at least two marker bodies in the phantom through the marker body positioning method;

[0036] Determine the spacing between at least two marker bodies according to the three-dimensional true coordinates of at least two marker bodies;

[0037] Wherein, the marker body positioning method is any one of the above-mentioned marker body positioning methods that can be realized.

[0038] On the other hand, the present invention also provides a marker body positioning device, which is applied to a scanning system and is used to position the marker body embedded in the phantom. The scanning system includes a receiver, and the marker body positioning device includes:

[0039] A scanning unit, configured to obtain a plurality of two-dimensional projection coordinates of the marker body projected in the first reference coordinate system where the receiver is located at a plurality of different preset scanning angles;

[0040] A three-dimensional projection coordinate determination unit, configured to determine a plurality of three-dimensional projection coordinates of a marker body in a second reference coordinate system according to a plurality of two-dimensional projection coordinates;

[0041] A first positioning unit, configured to determine the three-dimensional true coordinates of the marker body in the second reference coordinate system according to a plurality of three-dimensional projection coordinates.

[0042] On the other hand, the present invention further provides a geometric spacing measurement device, including:

[0043] A second positioning unit, configured to determine the three-dimensional true coordinates of at least two marker bodies in a phantom by a marker body positioning method;

[0044] A spacing measurement unit, configured to determine the spacing between at least two marker bodies according to the three-dimensional true coordinates of at least two marker bodies;

[0045] Wherein, the marker body positioning method is any one of the above-mentioned marker body positioning methods that can be implemented.

[0046] On the other hand, the present invention further provides a medical imaging system, including a memory and a processor, wherein,

[0047] The memory is configured to store programs;

[0048] The processor is coupled to the memory and configured to execute the programs stored in the memory to implement the steps in the marker body positioning method and / or the geometric spacing measurement method in any one of the above implementation manners.

[0049] The present invention further provides a computer-readable storage medium, configured to store computer-readable programs or instructions, and when the programs or instructions are executed by a processor, the steps in the marker body positioning method and / or the geometric spacing measurement method in any one of the above implementation manners can be implemented.

[0050] The beneficial effects of adopting the above embodiments are as follows: The marker body positioning method provided by the present invention determines a plurality of three-dimensional projection coordinates of a marker body in a second reference coordinate system according to a plurality of two-dimensional projection coordinates of the projection of the marker body obtained by scanning in a first reference coordinate system where the receiver is located, and directly determines the three-dimensional true coordinates of the marker body according to the plurality of three-dimensional projection coordinates, without reconstructing a tomographic image according to the two-dimensional projection coordinates, avoiding the influence of artifacts existing in the tomographic image on the accuracy of the three-dimensional true coordinates of the marker body, improving the reliability of the three-dimensional true coordinates of the marker body, and further improving the accuracy of marker body positioning. Moreover, without reconstructing a tomographic image through a reconstruction algorithm, the efficiency of marker body positioning is also improved. Further, the marker body positioning method provided by the present invention positions the marker body embedded in the phantom through a scanning system. Compared with the laser scanning method, it can penetrate the phantom, improving the applicability and accuracy of marker body positioning.

[0051] Further, the geometric spacing measurement method provided by the present invention determines the spacing between at least two marker bodies according to the three-dimensional true coordinates of the at least two marker bodies, compares the measured spacing with the theoretical spacing, and uses this to evaluate the machining accuracy of the phantom. On the basis of evaluating the machining accuracy of the phantom by the marker body positioning method, the applicability and diversity of the evaluation of the machining accuracy of the phantom are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0053] Figure 1 It is a schematic structural diagram of an embodiment of the scanning system provided by the present invention;

[0054] Figure 2 It is a schematic flowchart of an embodiment of the marker body positioning method provided by the present invention;

[0055] Figure 3 For the present invention Figure 2 It is a schematic flowchart of an embodiment of S202 in the present invention;

[0056] Figure 4 For the present invention Figure 3 It is a schematic flowchart of an embodiment of S301 in the present invention;

[0057] Figure 5 For the present invention Figure 3 It is a schematic flowchart of another embodiment of S301 in the present invention;

[0058] Figure 6 It is a schematic structural diagram of an embodiment of the two-dimensional scanning coordinates provided by the present invention;

[0059] Figure 7 For the present invention Figure 3 It is a schematic flowchart of an embodiment of S302 in the present invention;

[0060] Figure 8 For the present invention Figure 4 It is a schematic flowchart of an embodiment of S401 in the present invention;

[0061] Figure 9 It is a schematic flowchart of an embodiment of the geometric spacing measurement method provided by the present invention;

[0062] Figure 10 It is a schematic structural diagram of an embodiment of the marker body positioning device provided by the present invention;

[0063] Figure 11 Schematic structural diagram of an embodiment of the geometric spacing measurement device provided by the present invention;

[0064] Figure 12 Schematic structural diagram of an embodiment of the medical imaging system provided by the present invention. Detailed implementation manners

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0066] In the description of the embodiments of the present application, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example: A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0067] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0068] The present invention provides a method for positioning a marker body, a method for measuring geometric spacing, and a device, which will be described separately below.

[0069] Before presenting the embodiments, the scanning system will be described first. As Figure 1 shown, it is a schematic structural diagram of an embodiment of the scanning system provided by an embodiment of the present invention. The scanning system 10 includes: a transmitter 100, a receiver 200, and a stage 300. The stage 300 is arranged between the transmitter 100 and the receiver 200. The transmitter 100 is used to emit rays, the stage 300 is used to carry the phantom 11 or other objects to be scanned and imaged, and the receiver 200 is used to receive the transmitted rays after the rays emitted by the transmitter 100 pass through the phantom 11 and detect the amplitude of the transmitted rays after passing through the phantom 11. Optionally, in an embodiment of the present invention, the receiver is an X-ray detector.

[0070] Among them, the stage 300 rotates relative to the emitter 100, and the receiver 200 is fixed relative to the light source 100. In a specific embodiment of the present invention, as Figure 1 shown, the stage 300 can rotate along the rotation axis 301, where the rotation axis 301 is perpendicular to the first connection line 13, and the first connection line 13 is the connection line between the emitter 100 and the projection point of the emitter 100 projected onto the receiver 200.

[0071] It should be noted that: in a specific embodiment, if the scanning system 10 is a CT scanning system, the rays emitted by the emitter 100 are x-rays.

[0072] It should be understood that: the scanning system 10 in the embodiments of the present invention does not require all the shown components to be implemented, and more or fewer components can be alternatively implemented. For example, in one of the embodiments, if only the receiver 200 needs to be used, then in this embodiment, the scanning system 10 only includes the receiver 200. Similarly, in one of the embodiments, if the scanning system 10 must include other components such as a processor in addition to the above shown components, then the scanning system 10 can also include a processor in addition to the above components.

[0073] Figure 2 It is a schematic flowchart of an embodiment of the marker positioning method provided by the present invention, as Figure 2 shown, the method includes:

[0074] S201. Obtain multiple two-dimensional projection coordinates of the marker 12 projected in the first reference coordinate system where the receiver 200 is located at multiple different preset scanning angles;

[0075] S202. Determine multiple three-dimensional projection coordinates of the marker 12 in the second reference coordinate system according to the multiple two-dimensional projection coordinates;

[0076] S203. Determine the three-dimensional true coordinates of the marker 12 in the second reference coordinate system according to the multiple three-dimensional projection coordinates.

[0077] As a specific embodiment, in step S201, the multiple different preset scanning angles are obtained along a preset direction. Specifically, the preset direction is the circumferential direction of the phantom 11, that is: the angular difference between the starting preset scanning angle and the ending preset scanning angle is 360°.

[0078] In a specific embodiment, the first reference coordinate system is a two-dimensional projection coordinate, represented by (u, v), as Figure 1 shown, the two-dimensional projection coordinate system includes a U axis and a V axis. The U axis and the V axis are the row and column directions of the pixel area of the receiver 200's projection image respectively. When the projection pixel area is rectangular, the origin of the two-dimensional projection coordinate system is located at a vertex of the pixel area of the receiver 200's projection image.

[0079] In a specific embodiment, the second reference coordinate system is a three-dimensional space coordinate system, represented by (x, y, z). As Figure 1 shown, the origin of the second reference coordinate system is located within the phantom 11. The second reference coordinate system includes an X-axis, a Y-axis, and a Z-axis, and the X-axis is parallel to the U-axis, the Z-axis is parallel to the V-axis, and the Y-axis is perpendicular to the X-axis and the Y-axis.

[0080] It should be noted that the first reference coordinate system and the second reference coordinate system can be adjusted according to the actual situation, and are not limited to the above limitations, which will not be elaborated here.

[0081] Among them, in order to improve the reliability of the obtained two-dimensional projection coordinates, the contrast between the rays passing through the phantom 11 and the rays passing through the marker 12 should be increased, so that the two-dimensional projection coordinates of the marker 12 can be more easily obtained.

[0082] Specifically, the attenuation coefficient of the marker 12 for the rays emitted by the emitter 100 is greater than the attenuation coefficient of the phantom 11 for the rays emitted by the emitter 100.

[0083] It should be understood that: the marker 12 is made of a material with a high attenuation property for rays, and the phantom 11 is made of a material with a low attenuation property for rays. Specifically, the marker 12 can be made of any one of tungsten carbide, steel, or gold. The phantom 11 can be made of any one of poly(methyl methacrylate) (PMMA), polystyrene, plastic, or ceramic.

[0084] Among them, in some embodiments of the present invention, the phantom 11 is a cylinder, and the marker 12 is a sphere.

[0085] In a specific embodiment of the present invention, the marker 12 is a steel ball, and the steel ball is embedded in the cylindrical phantom 11.

[0086] Compared with the prior art, the marker body positioning method provided by the embodiment of the present invention determines multiple three-dimensional projection coordinates of the marker body 12 in the second reference coordinate system according to multiple two-dimensional projection coordinates of the marker body 12 projected in the first reference coordinate system where the receiver 200 is located obtained by scanning, and directly determines the three-dimensional true coordinates of the marker body 12 according to the multiple three-dimensional projection coordinates, without reconstructing a tomographic image according to the two-dimensional projection coordinates, avoiding the influence of artifacts in the tomographic image on the accuracy of the three-dimensional true coordinates of the marker body 12, improving the reliability of the three-dimensional true coordinates of the marker body 12, and further improving the accuracy of the positioning of the marker body 12. Moreover, without reconstructing the tomographic image through a reconstruction algorithm, the efficiency of the positioning of the marker body 12 is also improved. Further, the marker body positioning method provided by the present invention positions the marker body 12 embedded in the phantom 11 through a scanning system. Compared with the laser scanning method, it can penetrate the phantom 11, improving the applicability and accuracy of the marker body positioning.

[0087] It should be understood that: after determining the three-dimensional true coordinates of the marker body 12 through the above steps, they can be compared with the theoretical space coordinates of the marker body 12 to evaluate the machining accuracy of the phantom 11.

[0088] It should be noted that: in order to improve the reliability of the three-dimensional true coordinates, the number of two-dimensional projection coordinates should not be too small, and the specific number should be adjusted according to the actual situation and will not be specifically limited here.

[0089] In some embodiments of the present invention, as Figure 3 shown, step S202 includes:

[0090] S301. Establish a one-to-one correspondence between multiple two-dimensional projection coordinates and multiple three-dimensional projection coordinates;

[0091] S302. Determine multiple three-dimensional projection coordinates corresponding one-to-one to the multiple two-dimensional projection coordinates in the second reference coordinate system according to the multiple two-dimensional projection coordinates and the corresponding relationship.

[0092] It should be noted that: the one-to-one correspondence between the multiple two-dimensional projection coordinates and the multiple three-dimensional projection coordinates can be obtained through a conversion formula, or a table can be constructed according to the conversion formula, and the multiple three-dimensional projection coordinates corresponding one-to-one to the multiple two-dimensional projection coordinates can be obtained by looking up the table.

[0093] Obtaining multiple three-dimensional projection coordinates corresponding one-to-one to the multiple two-dimensional projection coordinates according to the conversion formula can save the table building work before positioning the marker body 12, and at the same time, can also save the table storage space.

[0094] By constructing a table and using the table lookup method to obtain multiple three-dimensional true coordinates corresponding one-to-one to the multiple two-dimensional projection coordinates, the determination speed of the three-dimensional true coordinates can be improved, thereby improving the positioning speed of the marker body.

[0095] In some embodiments of the present invention, a plurality of three-dimensional projection coordinates corresponding one-to-one thereto are obtained according to a conversion formula from a plurality of two-dimensional projection coordinates, as Figure 4 shown, step S301 includes:

[0096] S401. Determine a first distance between the transmitter 100 and the receiver 200 and a second distance between the transmitter 100 and the phantom 11;

[0097] S402. Determine a plurality of ideal projection coordinates according to the plurality of two-dimensional projection coordinates, the first distance, the second distance, the pixel sizes of a plurality of pixels within the projection pixel region, and the origin of the first reference coordinate system;

[0098] S403. Determine the deflection angle of the receiver 200, and determine a plurality of three-dimensional projection coordinates according to the deflection angle and the plurality of ideal projection coordinates.

[0099] As a specific embodiment, in step S402, the ideal projection coordinates refer to a plurality of projection coordinates corresponding one-to-one to the plurality of two-dimensional projection coordinates when the deflection angle of the receiver 200 is 0, that is, when the receiver 200 does not deflect.

[0100] In step S402, the pixel size is equal to the area of the projection pixel region divided by the number of pixels. The first distance refers to the distance between the center of the transmitter 100 and the receiver 200, and the second distance refers to the distance between the center of the transmitter 100 and the phantom 11.

[0101] As a specific embodiment, in step S301, the conversion formula between the plurality of two-dimensional projection coordinates and the plurality of three-dimensional projection coordinates is:

[0102] x1 = ρ * cos(θ - μ)

[0103] y1 = y0

[0104] z1 = ρ * sin(θ - μ)

[0105]

[0106]

[0107] x0 = (u - u0) * pixelsize - pixelsize / 2

[0108] y0 = SDD - SID

[0109] z0 = (v0 - v) * pixelsize - pixelsize / 2

[0110] Wherein, x1, y1, z1 are three-dimensional projection coordinates; μ is the deflection angle of the receiver 200; x0, y0, z0 are the three-dimensional projection coordinates when the deflection angle is 0; u, v are two-dimensional projection coordinates; u0, v0 are the origin coordinates of the two-dimensional projection coordinate system; pixelsize is the pixel size of multiple pixels in the internal projection pixel area of the receiver 200; SDD is the distance between the transmitter 100 and the receiver 200, i.e., the first distance; SID is the distance between the transmitter 100 and the phantom 11, i.e., the second distance.

[0111] It should be noted that: in the embodiments of the present invention, the positioning of the marker 12 is realized through coordinate transformation to improve the positioning accuracy and speed of the marker 12. Therefore, it is necessary to determine the conversion relationship between the two-dimensional projection coordinates in the first reference coordinate system and the three-dimensional projection coordinates in the second reference coordinate system. Usually, each position on the projection pixel area is characterized by pixels. Therefore, the three-dimensional projection coordinates can be determined through the pixel size of the pixels, the origin coordinates of the two-dimensional coordinate system, and the two-dimensional projection coordinates.

[0112] In some other embodiments of the present invention, as Figure 5 shown, step S301 includes:

[0113] S501. Establish a one-to-one indexing relationship between multiple two-dimensional projection coordinates and multiple pixels in the projection pixel area on the receiver 200;

[0114] S502. Establish a one-to-one mapping relationship between multiple pixels and multiple three-dimensional projection coordinates;

[0115] S503. Establish a corresponding relationship according to the indexing relationship and the mapping relationship.

[0116] In some embodiments of the present invention, in step S501, multiple pixels in the projection pixel area are pre-numbered. In a specific embodiment, the projection pixel area includes 513 * 2084 pixels. Then, the pixel number corresponding to the pixel can be determined according to the two-dimensional projection coordinates, which is the indexing relationship between the two-dimensional projection coordinates and the pixels.

[0117] In a specific embodiment of the present invention, the pixel number is represented by row * column. For example, the pixel number of one pixel is (1 * 513), which means the pixel in the 1st row and the 513th column. The two-dimensional projection coordinates corresponding to this pixel are (1, 513).

[0118] In a specific embodiment of the present invention, as Figure 6 shown, are the multiple two-dimensional projection coordinates of 4 markers 12 in the phantom 11 on the projection pixel area of the receiver 200 after scanning. From Figure 6It can be seen that multiple two-dimensional projection coordinates correspond one-to-one with multiple pixels, that is: the abscissa of the two-dimensional projection coordinate is the row number of the pixel, and the ordinate of the two-dimensional projection coordinate is the column number of the pixel.

[0119] It should be understood that: the number of pixels within the projected pixel region can be adjusted according to the resolution of the receiver 200. If a larger resolution is required, the number of pixels within the projected pixel region is increased; if a smaller resolution is required, the number of pixels within the projected pixel region is decreased. The specific number of pixels within the projected pixel region will not be elaborated here.

[0120] In a specific embodiment of the present invention, in step S301, the one-to-one correspondence between multiple two-dimensional projection coordinates and multiple three-dimensional projection coordinates is shown in Table 1:

[0121] Table 1 One-to-one correspondence between multiple two-dimensional projection coordinates and multiple three-dimensional projection coordinates

[0122]

[0123] In a specific embodiment, in step S503, after the indexing relationship and the mapping relationship are determined, the one-to-one correspondence between multiple two-dimensional projection coordinates and multiple three-dimensional projection coordinates can be further determined. As can be learned from Table 1, when the two-dimensional projection coordinate is (1, 513), the corresponding three-dimensional projection coordinate is (-97.5519, 235.9240, -28.5772).

[0124] In some embodiments of the present invention, as Figure 7 shown, step S203 includes:

[0125] S701. Determine the transmitter coordinates of the transmitter 100;

[0126] S702. Determine at least one scanning model at multiple different preset scanning angles according to the transmitter coordinates and the multiple three-dimensional projection coordinates of the marker body 12;

[0127] S703. Based on the least squares method, determine the three-dimensional true coordinates of the marker body 12 according to at least one scanning model.

[0128] In step S701, after the scanning system 10 is calibrated, the distance between the transmitter 100 and the origin of the three-dimensional coordinate system at the phantom 11 is known, so the transmitter coordinates of the transmitter 100 can be determined. It can be understood that the transmitter coordinates are the coordinates in the second reference coordinate system.

[0129] In an embodiment of the present invention, in step S702, each three-dimensional projection coordinate and the transmitter coordinates form a scanning model.

[0130] In a specific embodiment of the present invention, if the scanning model is a plurality of linear equations between the emitter coordinates and a plurality of three-dimensional projection coordinates, then step S702 includes:

[0131] Determine the optimal intersection point of the plurality of linear equations, and the coordinates of the optimal intersection point are the three-dimensional true coordinates of the marker body 12.

[0132] Specifically, when the emitter coordinates are (x b , y b , z b ), and the three-dimensional projection coordinates under one of the preset scanning angles are (x c , y c , z c ), the coefficients a, b, and c of the linear equation are respectively (x c - x b ), (y c - y b ), (z c - z b ), then the linear equation is:

[0133] (x - x b ) / a = (y - y b ) / b = (z - z b ) / c

[0134] After obtaining the linear equation, the coordinates of the optimal intersection point are:

[0135]

[0136] d n = |(P c - P b ) × (P b - P a )| / |P c - P b |

[0137] P a = (x a , y a , z a )

[0138] P b = (x b , y b , z b )

[0139] P c = (x c , y c , z c )

[0140] Wherein, (x', y', z') are the three-dimensional true coordinates of the marker body 12; N is the number of multiple straight-line equations; P a is the intersection coordinate of multiple straight-line equations; P b is the emitter coordinate; P c is the three-dimensional projection coordinate of the marker body 12; d n is the distance between the intersection coordinate of multiple straight-line equations and multiple straight-line equations.

[0141] Since the methods in the embodiments of the present invention are all based on the two-dimensional projection coordinates of the marker body 12 projected on the receiver 200, therefore, in order to avoid the technical problem that the projection coordinates of the marker body 12 are not projected within the projection pixel area of the marker body 12 due to the unreasonable positions of the phantom 11 and the scanning system 10, resulting in the inability to determine the three-dimensional true coordinates of the marker body 12, in some embodiments of the present invention, before step S201, it further includes:

[0142] Pre-scanning the marker body 12 at multiple different test scanning angles to determine the target relative position between the phantom 11 and the receiver 200.

[0143] Wherein, the target relative position is the relative position between the phantom 11 and the receiver 200 when multiple two-dimensional scanning coordinates are all within the projection pixel area of the receiver 200.

[0144] In a specific embodiment of the present invention, as Figure 8 shown, pre-scanning the marker body 12 includes:

[0145] S801. Obtaining multiple test projection coordinates of the marker body 12 in the first reference coordinate system where the receiver 200 is located at multiple different test scanning angles;

[0146] S802. Judging whether multiple test projection coordinates are all within the projection pixel area;

[0147] S803. If multiple test projection coordinates are not all within the projection pixel area, then adjusting the relative position between the phantom 11 and the receiver 200;

[0148] S804. If the test projection coordinates are all within the projection pixel area, then the current relative position of the phantom 11 and the receiver 200 is the target relative position.

[0149] By pre-scanning the marker body 12 before positioning the marker body 12, to ensure that when positioning the marker body 12, the two-dimensional projection coordinates are all within the projection pixel area of the receiver 200, ensuring the positioning reliability of the marker body 12.

[0150] Among them, in step S803, the relative positions of the phantom 11 and the receiver 200 can be adjusted by adjusting the position of the stage 300 and / or the position of the receiver 200. Specifically, how to adjust can be determined according to the actual structure of the scanning system 10, and no specific limitation is provided here.

[0151] It should be understood that the first angular differences between adjacent two of multiple different test scanning angles may be equal or unequal. However, in order to avoid the distances between multiple two-dimensional projection coordinates of the marker 12 on the projection pixel area of the receiver 200 being too large or too small, which may affect the recognition of the two-dimensional projection coordinates, in the preferred embodiment of the present invention, the first angular differences are equal.

[0152] Similarly, the second angular differences between adjacent two of multiple different preset scanning angles are also equal.

[0153] Furthermore, in order to improve the speed of pre-scanning, in some embodiments of the present invention, the first angular difference is greater than the second angular difference.

[0154] Since the purpose of pre-scanning is to ensure that multiple two-dimensional scanning coordinates are all within the projection pixel area of the receiver 200, there is no requirement for the number of test scanning angles during the pre-scanning process. Therefore, setting the first angular difference greater than the second angular difference can improve the speed of pre-scanning.

[0155] On the other hand, in some existing technologies, the machining accuracy is evaluated by measuring the distances between multiple markers 12 in the phantom 11. There are two methods for measuring the set distances between multiple markers 12 in the phantom 11. One method is that after scanning the marker 12 by a CT scanning system, the scanning data is processed through a CT reconstruction algorithm to obtain the tomographic image of the marker 12, and the set distances between the markers 12 are located through the tomographic image. Another method is to directly measure the distances between the markers 12 by using a high-precision three-dimensional laser scanner in a laser scanning manner. The geometric distances between the markers 12 measured by the above two methods are inaccurate. And since in the design drawings of some phantoms 11, the theoretical coordinates of each marker 12 are not given, only the distances between the markers 12 are given. Therefore, the present invention also provides a geometric distance measurement method, which is applied to the scanning system 10 in the above embodiments and is used to measure the distances between at least two markers 12 embedded in the phantom 11. As Figure 9 shown, the geometric distance measurement method includes:

[0156] S901. Determine the three-dimensional true coordinates of at least two markers 12 in the phantom 11 through a marker positioning method;

[0157] S902. Determine the distances between at least two markers 12 according to the three-dimensional true coordinates of at least two markers 12.

[0158] Specifically, the distance between two of the at least two marker bodies 12 is:

[0159]

[0160] where (x1’, y1’, z1’) are the three-dimensional true coordinates of the first marker body 12; (x2’, y2’, z2’) are the three-dimensional true coordinates of the second marker body 12.

[0161] That is: In the embodiments of the marker body positioning method of the present invention, based on the three-dimensional true coordinates of each marker body 12, the distance between at least two marker bodies 12 embedded in the phantom 11 is calculated and compared with the theoretical distance value to evaluate the machining accuracy of the phantom 11.

[0162] Evaluating the machining accuracy of the phantom 11 by calculating the distance between at least two marker bodies 12 can improve the diversity of the machining accuracy evaluation method.

[0163] It should be noted that: For the principle and specific embodiments of each step of the marker body positioning method in the embodiments of the present invention, reference can be made to the corresponding content in the embodiments of the above-mentioned marker body positioning method, which will not be elaborated here.

[0164] In order to better implement the marker body positioning method in the embodiments of the present invention, correspondingly, on the basis of the marker body positioning method, as Figure 10 shown, the embodiments of the present invention further provide a marker body positioning device 1000, including:

[0165] A scanning unit 1001, configured to obtain a plurality of two-dimensional projection coordinates of the marker body 12 projected on the receiver 200 at a plurality of different preset scanning angles; the plurality of two-dimensional projection coordinates are based on a two-dimensional projection coordinate system;

[0166] A three-dimensional projection coordinate determination unit 1002, configured to determine a plurality of three-dimensional projection coordinates of the marker body 12 according to the plurality of two-dimensional projection coordinates;

[0167] A first positioning unit 1003, configured to determine the three-dimensional true coordinates of the marker body 12 according to the plurality of three-dimensional projection coordinates; the plurality of three-dimensional projection coordinates and the three-dimensional true coordinates are based on the three-dimensional true coordinates.

[0168] The marker body positioning device 1000 provided in the above embodiments can implement the technical solutions described in the embodiments of the above marker body positioning method. For the principle of specific implementation of each of the above modules or units, reference can be made to the corresponding content in the above method geometric distance measurement method and / or the embodiments of the marker body positioning method, which will not be elaborated here.

[0169] To better implement the geometric distance measurement method in the embodiments of the present invention, correspondingly, based on the geometric distance measurement method, as Figure 11 shown, the embodiments of the present invention further provide a geometric distance measurement device 1100, including:

[0170] A second positioning unit 1101, configured to determine the three-dimensional true coordinates of at least two marker bodies 12 in the phantom 11 through a marker body positioning method;

[0171] A distance measurement unit 1102, configured to determine the distance between at least two marker bodies 12 according to the three-dimensional true coordinates of the at least two marker bodies 12.

[0172] The geometric distance measurement device 1100 provided in the above embodiments can implement the technical solutions described in the embodiments of the above geometric distance measurement method. For the specific implementation principles of the above modules or units, reference can be made to the corresponding content in the above method embodiments of the geometric distance measurement method and / or the marker body positioning method, which will not be elaborated here.

[0173] As Figure 12 shown, the present invention also correspondingly provides a medical imaging system 1200. The medical imaging system 1200 includes a processor 1201, a memory 1202, and a display 1203. Figure 12 Only some components of the medical imaging system 1200 are shown, but it should be understood that it is not required to implement all the shown components, and more or fewer components can be alternatively implemented.

[0174] In some embodiments, the memory 1202 may be an internal storage unit of the medical imaging system 1200, such as the hard disk or memory of the medical imaging system 1200. In other embodiments, the memory 1202 may also be an external storage device of the medical imaging system 1200, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the medical imaging system 1200.

[0175] Furthermore, the memory 1202 may also include both an internal storage unit and an external storage device of the medical imaging system 1200. The memory 1202 is used to store the application software installed in the medical imaging system 1200 and various types of data.

[0176] In some embodiments, the processor 1201 may be a central processing unit (CPU), a microprocessor, or other data processing chips, configured to run the program code stored in the memory 1202 or process data, such as the marker body positioning method and / or the geometric distance measurement method in the present invention.

[0177] In some embodiments, the display 1203 may be an LED display, a liquid crystal display, a touch liquid crystal display, an OLED (Organic Light-Emitting Diode) touch display, etc. The display 1203 is used to display information of the medical imaging system 1200 and to display a visual user interface. The components 1201 - 1203 of the medical imaging system 1200 communicate with each other via a system bus.

[0178] In one embodiment, when the processor 1201 executes the marker body positioning program in the memory 1202, the following steps can be implemented:

[0179] Obtain a plurality of two-dimensional projection coordinates of the marker body 12 projected in the first reference coordinate system where the receiver 200 is located at a plurality of different preset scanning angles;

[0180] Determine a plurality of three-dimensional projection coordinates of the marker body 12 in the second reference coordinate system according to the plurality of two-dimensional projection coordinates;

[0181] Determine the three-dimensional true coordinates of the marker body 12 in the second reference coordinate system according to the plurality of three-dimensional projection coordinates.

[0182] In one embodiment, when the processor 1201 executes the geometric spacing measurement program in the memory 1202, the following steps can be implemented:

[0183] Determine the three-dimensional true coordinates of at least two marker bodies 12 in the phantom 11 by the marker body positioning method;

[0184] Determine the spacing between at least two marker bodies 12 according to the three-dimensional true coordinates of the at least two marker bodies 12.

[0185] It should be understood that when the processor 1201 executes the marker body positioning program and / or the geometric spacing measurement program in the memory 1202, in addition to the above functions, other functions can also be implemented. For details, refer to the description of the corresponding method embodiments above.

[0186] Furthermore, embodiments of the present invention do not specifically limit the type of the mentioned medical imaging system 1200. The medical imaging system 1200 can be a mobile phone, a tablet computer, a personal digital assistant (PDA), a wearable device, a laptop computer, or other portable medical imaging systems. Exemplary embodiments of the portable medical imaging system include, but are not limited to, portable medical imaging systems running IOS, android, microsoft, or other operating systems. The above-mentioned portable medical imaging systems can also be other portable medical imaging systems, such as a laptop computer with a touch-sensitive surface (such as a touch panel). It should also be understood that in some other embodiments of the present invention, the medical imaging system 1200 may not be a portable medical imaging system, but a desktop computer with a touch-sensitive surface (such as a touch panel).

[0187] Correspondingly, embodiments of the present application further provide a computer-readable storage medium, which is used to store computer-readable programs or instructions. When the programs or instructions are executed by a processor, the method steps or functions provided by the above-mentioned method embodiments can be implemented.

[0188] Those skilled in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a magnetic disk, an optical disk, a read-only memory, or a random access memory, etc.

[0189] The above has introduced in detail the marker body positioning method, geometric spacing measurement method and device provided by the present invention. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for locating a marker body, which is applied to a scanning system and used to locate the marker body embedded in a phantom. The scanning system includes a receiver, and is characterized in that, The method for positioning the marker body includes: Obtaining a plurality of two-dimensional projection coordinates of the marker body projected on the first reference coordinate system where the receiver is located at a plurality of different preset scanning angles; Determining a plurality of three-dimensional projection coordinates of the marker body in the second reference coordinate system according to the plurality of two-dimensional projection coordinates; Determining the three-dimensional true coordinates of the marker body in the second reference coordinate system according to the plurality of three-dimensional projection coordinates; The scanning system further includes a transmitter for emitting rays, and the determining the three-dimensional true coordinates of the marker body in the second reference coordinate system according to the plurality of three-dimensional projection coordinates includes: Determining the transmitter coordinates of the transmitter; Determining at least one scanning model at a plurality of different preset scanning angles according to the transmitter coordinates and the plurality of three-dimensional projection coordinates; Based on the least squares method, determining the three-dimensional true coordinates of the marker body according to the at least one scanning model; The at least one scanning model is a plurality of linear equations between the transmitter coordinates and the plurality of three-dimensional projection coordinates.

2. The method for locating a marker body according to claim 1, characterized in that, The determining the plurality of three-dimensional projection coordinates of the marker body in the second reference coordinate system according to the plurality of two-dimensional projection coordinates includes: Establishing a one-to-one correspondence between the plurality of two-dimensional projection coordinates and the plurality of three-dimensional projection coordinates; Determining the plurality of three-dimensional projection coordinates corresponding one-to-one to the plurality of two-dimensional projection coordinates in the second reference coordinate system according to the plurality of two-dimensional projection coordinates and the corresponding relationship.

3. The method for locating a marker body according to claim 2, characterized in that, The receiver includes a projection pixel area, and the establishing the one-to-one correspondence between the plurality of two-dimensional projection coordinates and the plurality of three-dimensional projection coordinates includes: Establishing a one-to-one indexing relationship between the plurality of two-dimensional projection coordinates and a plurality of pixels in the projection pixel area; Establishing a one-to-one mapping relationship between the plurality of pixels and the plurality of three-dimensional projection coordinates; Establishing the corresponding relationship according to the indexing relationship and the mapping relationship.

4. The method for locating a marker body according to claim 3, characterized in that, The scanning system further includes a transmitter for emitting rays, and the establishing a one-to-one correspondence between the plurality of two-dimensional projection coordinates and the plurality of three-dimensional projection coordinates is: Determining a first distance between the transmitter and the receiver and a second distance between the transmitter and the phantom; Determining a plurality of ideal projection coordinates according to the plurality of two-dimensional projection coordinates, the first distance, the second distance, the pixel sizes of a plurality of pixels in the projection pixel area, and the origin of the first reference coordinate system; Determining the deflection angle of the receiver, and determining the plurality of three-dimensional projection coordinates according to the deflection angle and the plurality of ideal projection coordinates.

5. The method for locating a marker body according to claim 1, characterized in that, The determining the three-dimensional true coordinates of the marker body according to the at least one scanning model includes: Determining the optimal intersection point of the plurality of linear equations, and the coordinates of the optimal intersection point are the three-dimensional true coordinates of the marker body.

6. The method for locating a marker body according to claim 1, characterized in that, Before the obtaining the plurality of two-dimensional projection coordinates of the marker body on the receiver at a plurality of different preset scanning angles, it further includes: Performing a pre-scan on the marker body at a plurality of different trial scanning angles to determine the target relative position between the phantom and the receiver.

7. The method for locating a marker body according to claim 6, characterized in that, The receiver includes a projection pixel area, and the performing a pre-scan on the marker body includes: Obtain multiple test projection coordinates of the marker body in the first reference coordinate system where the receiver is located at multiple different test scanning angles; Determine whether the multiple test projection coordinates are all located within the projection pixel region; If the multiple test projection coordinates are not all located within the projection pixel region, adjust the relative position of the phantom and the receiver; If the test projection coordinates are all located within the projection pixel region of the receiver, the current relative position of the phantom and the receiver is the target relative position.

8. A method for measuring geometric spacing, characterized in that, Includes: Determine the three-dimensional true coordinates of at least two marker bodies in the phantom by the marker body positioning method; Determine the distance between the at least two marker bodies according to the three-dimensional true coordinates of the at least two marker bodies; Wherein, the marker body positioning method is the marker body positioning method described in any one of claims 1-7.

9. A marker body positioning device is applied to a scanning system for positioning a marker body embedded in a phantom. The scanning system includes a receiver, and is characterized in that, The marker body positioning device includes: A scanning unit for obtaining multiple two-dimensional projection coordinates of the marker body projected in the first reference coordinate system where the receiver is located at multiple different preset scanning angles; A three-dimensional projection coordinate determination unit for determining multiple three-dimensional projection coordinates of the marker body in the second reference coordinate system according to the multiple two-dimensional projection coordinates; A first positioning unit for determining the three-dimensional true coordinates of the marker body in the second reference coordinate system according to the multiple three-dimensional projection coordinates; The scanning system further includes a transmitter for emitting rays, and determining the three-dimensional true coordinates of the marker body in the second reference coordinate system according to the multiple three-dimensional projection coordinates includes: Determine the transmitter coordinates of the transmitter; Determine at least one scanning model at multiple different preset scanning angles according to the transmitter coordinates and the multiple three-dimensional projection coordinates; Based on the least squares method, determine the three-dimensional true coordinates of the marker body according to the at least one scanning model; The at least one scanning model is multiple linear equations between the transmitter coordinates and the multiple three-dimensional projection coordinates.

10. A geometric spacing measuring device, and is characterized in that, Includes: A second positioning unit for determining the three-dimensional true coordinates of at least two marker bodies in the phantom by the marker body positioning method; A spacing measurement unit for determining the distance between the at least two marker bodies according to the three-dimensional true coordinates of the at least two marker bodies; Wherein, the marker body positioning method is the marker body positioning method described in any one of claims 1-7.

11. A medical imaging system, and is characterized in that, Includes a memory and a processor, wherein, The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps in the marker body positioning method described in any one of claims 1 to 7 and / or the steps in the geometric spacing measurement method described in claim 8.

12. A computer-readable storage medium, and is characterized in that, For storing computer-readable programs or instructions, and when the programs or instructions are executed by a processor, they can implement the steps in the marker body positioning method described in any one of claims 1 to 7 and / or the steps in the geometric spacing measurement method described in claim 8.

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