Hip joint registration point screening method and device

Abstract

This application relates to the field of image processing and provides a method and apparatus for screening hip joint registration points. The method includes: acquiring point cloud data points on the surface of a target acetabulum; performing spherical fitting on the surface point cloud data points; if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then selecting intra-points based on the number of surface point cloud data points less than the first threshold; performing bounding sphere fitting on the intra-points; if the distance between the intra-point and the center of the fitted bounding sphere is within a target distance range, then using the intra-point as a hip joint registration point. The hip joint registration point screening method and apparatus provided in this application can quickly screen hip joint registration points, improving the screening efficiency.

Description

Technical Field

[0001] This application relates to the field of image processing technology, specifically to a method and apparatus for selecting hip joint registration points. Background Technology

[0002] Currently, in hip replacement surgery, registration methods are used to match the digital 3D model of the bone with the actual bone, so that the pose of the digital 3D model can express the pose of the actual bone, making it easier for doctors to locate the surgical site during surgery and improving the accuracy of the surgery.

[0003] Before registration, registration points need to be selected on the 3D skeleton model. Then, coarse and fine registration are performed based on the registration points and the actual skeleton. However, existing registration point selection methods are mostly based on surface extraction. The covariance matrix of a point on the surface and its k neighboring points is used to calculate the curvature change and normal vector of the point. The registration point is determined based on the curvature change and normal vector. Since there are many initial point cloud data points and a lot of noise, the number of points required by this method is also large. There are also many invalid calculations at noisy points, which is time-consuming and has low efficiency in selecting registration points. Summary of the Invention

[0004] This application provides a method and apparatus for screening hip joint registration points, which solves the technical problem of low screening efficiency in traditional registration point screening methods.

[0005] In a first aspect, embodiments of this application provide a method for selecting hip joint registration points, including:

[0006] Acquire point cloud data points on the surface of the target acetabulum;

[0007] Spherical fitting is performed on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0008] The in-game point is fitted with a bounding sphere. If the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, the in-game point is used as the hip joint registration point.

[0009] In one embodiment, when performing spherical fitting on the surface point cloud data points, if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are filtered out based on the number of surface point cloud data points less than the first threshold, including:

[0010] Spherical fitting is performed on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0011] In one embodiment, when performing spherical fitting on four non-coplanar points in the surface point cloud data points, if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold, including:

[0012] Step 1: Select any four non-coplanar points from the surface point cloud data points;

[0013] Step 2: Perform spherical fitting on the four non-coplanar points;

[0014] Step 3: If the shortest distance between the surface point cloud data points and the fitted sphere is less than the first threshold, then the surface point cloud data is determined to be data points to be processed;

[0015] Step 4: Record the number of data points to be processed. If the number of data points to be processed is less than the total number of surface point cloud data points, select four non-coplanar points from the surface point cloud data points and return to step 2 until the number of data points to be processed corresponding to the sphere fitted by any four non-coplanar points in the surface point cloud data points has been recorded. The four non-coplanar points selected each time are not completely consistent.

[0016] Step 5: Select the data point corresponding to the spherical fitting with the largest number of data points to be processed as the in-place point.

[0017] In one embodiment, after recording the number of data points to be processed, the process includes:

[0018] If the number of data points to be processed is equal to the total number of surface point cloud data points, then the data points to be processed corresponding to this spherical fitting are taken as in-place points.

[0019] In one embodiment, when performing spherical fitting on four non-coplanar points in the surface point cloud data points, if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold, including:

[0020] Select all combinations of four non-coplanar points from the surface point cloud data points;

[0021] Perform spherical fitting on the four non-coplanar points in each of the aforementioned combinations;

[0022] If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then the surface point cloud data is determined to be the data points to be processed for the corresponding fitted sphere.

[0023] Record the number of data points to be processed corresponding to each fitted sphere;

[0024] The data point corresponding to the fitted sphere with the largest number of data points to be processed is selected as the in-place point.

[0025] In one embodiment, the minimum value of the target distance range is a second threshold, and the maximum value of the target distance range is the radius of the fitted bounding sphere.

[0026] Secondly, embodiments of this application provide a hip joint registration point screening device, comprising:

[0027] The data acquisition module is used to: acquire point cloud data points on the surface of the target acetabulum;

[0028] The in-situ point filtering module is used to: perform spherical fitting on the surface point cloud data points; if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then filter out in-situ points based on the number of surface point cloud data points that are less than the first threshold.

[0029] The registration point filtering module is used to: perform bounding sphere fitting on the in-game point; if the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, then the in-game point is used as the hip joint registration point.

[0030] In one embodiment, the in-place point filtering module is further configured to: filter the surface points

[0031] Four non-coplanar points in the cloud data points are fitted to a sphere. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then the local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0032] Thirdly, embodiments of this application provide an electronic device, including a processor and a memory storing a computer program, wherein the processor executes the program to implement the steps of the hip joint registration point screening method described in the first aspect.

[0033] Fourthly, embodiments of this application provide a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the hip joint registration point screening method described in the first aspect.

[0034] The hip joint registration point screening method and apparatus provided in this application first acquires point cloud data points on the surface of the target acetabulum, then performs spherical fitting on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then intra-points are selected based on the number of surface point cloud data points less than the first threshold. Finally, bounding sphere fitting is performed on the intra-points. If the distance between the intra-point and the center of the fitted bounding sphere is within the target distance range, then the intra-point is used as a hip joint registration point. This application fully utilizes the hemispherical shape of the acetabulum, directly performing spherical fitting on its surface point cloud data points, and then performing bounding sphere fitting. Since the shape of the sphere and the bounding sphere are very close to the shape of the acetabulum, they can maximize the approximation of the actual shape of the acetabulum during each fitting, improving the fitting accuracy. Furthermore, since spherical fitting and bounding sphere fitting are performed on multiple points, unlike the traditional method of calculating curvature and normal vector point by point, the hip joint registration points can be quickly screened, improving the screening efficiency of registration points. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is one of the flowcharts illustrating the hip joint registration point screening method provided in the embodiments of this application;

[0037] Figure 2 This is a second schematic flowchart of the hip joint registration point screening method provided in the embodiments of this application;

[0038] Figure 3 This is the third flowchart illustrating the hip joint registration point screening method provided in the embodiments of this application;

[0039] Figure 4 This is a schematic diagram of the hip joint registration point screening device provided in the embodiments of this application;

[0040] Figure 5 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Figure 1 This is one of the flowcharts illustrating the hip joint registration point selection method provided in this application embodiment. (Refer to...) Figure 1 This application provides a method for selecting hip joint registration points, which may include:

[0043] 101. Obtain point cloud data points on the surface of the target acetabulum;

[0044] The CT data obtained from the bone scan is converted into point cloud data, and the point cloud data points on the surface of the acetabulum are extracted. These surface point cloud data points include the point cloud data points on the inner surface of the acetabulum and the point cloud data points on the outer surface of the acetabulum.

[0045] 102. Perform spherical fitting on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than the first threshold, then filter out the in-place points based on the number of surface point cloud data points that are less than the first threshold.

[0046] It should be noted that the method of spherical fitting is not limited here. In this embodiment, the Random Sample Consensus (RANSAC) algorithm combined with the least squares method for fitting circles is used to perform spherical fitting on the surface point cloud data points.

[0047] In this embodiment, a spherical fitting can be performed on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then the local points are selected based on the number of surface point cloud data points less than the first threshold.

[0048] 103. Fit the in-game point to the bounding ball. If the distance between the in-game point and the center of the fitted bounding ball is within the target distance range, then use the in-game point as the hip joint registration point.

[0049] It should be noted that the fitted bounding ball is the bounding ball with the smallest radius that can enclose all in-game points.

[0050] The hip joint registration point selection method provided in this embodiment first acquires the surface point cloud data points of the target acetabulum, then performs spherical fitting on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then intra-points are selected based on the number of surface point cloud data points less than the first threshold. Finally, bounding sphere fitting is performed on the intra-points. If the distance between the intra-point and the center of the fitted bounding sphere is within the target distance range, then the intra-point is used as the hip joint registration point. This embodiment fully utilizes the hemispherical shape of the acetabulum, directly performing spherical fitting on its surface point cloud data points, and then performing bounding sphere fitting. Since the shape of the sphere and the bounding sphere are very close to the shape of the acetabulum, it can maximize the approximation of the actual shape of the acetabulum during each fitting, improving the fitting accuracy. Furthermore, since spherical fitting and bounding sphere fitting are performed on multiple points, unlike the traditional method of calculating curvature and normal vector point by point, it can quickly select the hip joint registration points, improving the selection efficiency of registration points.

[0051] Figure 2 This is a second schematic flowchart illustrating the hip joint registration point selection method provided in this application embodiment. (Refer to...) Figure 2 For four non-coplanar points in the surface point cloud data, a spherical fit is performed. If the shortest distance between the surface point cloud data point and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold. These local points may include:

[0052] 201. Select any four non-coplanar points from the surface point cloud data points;

[0053] 202. Perform spherical fitting on the four non-coplanar points;

[0054] Let the center of the fitted sphere be... , radius is Then the difference between the actual positions and the fitted positions of the four non-coplanar points is:

[0055] (2-1)

[0056] in, The difference between the actual positions and the fitted positions of the four non-coplanar points is given by: ;

[0057] Constructor Where N equals 4;

[0058] To find the parameter that minimizes the positional difference, i.e., to find the minimum value of E, we let E be the parameter that minimizes the positional difference. and Taking the partial derivatives, and assuming the partial derivatives are equal to 0, we get:

[0059] (2-2)

[0060] make:

[0061]

[0062] Furthermore, all the above equations are collectively referred to as equation (2-3).

[0063] Substituting (2-1) and (2-3) into (2-2), we get:

[0064] (2-4)

[0065] (2-5)

[0066] (2-6)

[0067] (2-7)

[0068] Solving equations (2-4), (2-5), and (2-6) simultaneously yields the solution. and Substituting it into (2-7), we can obtain the result. The value of is thus confirmed, allowing us to identify the sphere fitted by the four non-coplanar points.

[0069] 203. If the shortest distance between a surface point cloud data point and the fitted sphere is less than the first threshold, then the surface point cloud data point is determined to be a data point to be processed.

[0070] The shortest distance between each surface point cloud data point and the fitted sphere can be obtained by calculating the distance from the center of the fitted sphere to each surface point cloud data point and then subtracting the radius of the sphere from that distance.

[0071] The first threshold can be determined by calculating the average distance between all the nearest neighbor point cloud data points in the surface point cloud data points. That is, each pair of nearest neighbor point cloud data points is treated as a pair, and the sum of the distances between all the pair of nearest neighbor point cloud data points is divided by the number of such pairs.

[0072] If the shortest distance between the surface point cloud data point and the fitted sphere is less than the first threshold, it means that the surface point cloud data point is not far from the sphere and can be counted as a data point to be processed on the sphere.

[0073] It should be noted that the data points to be processed include data points inside and outside the sphere, that is, data points surrounded by the sphere and data points outside the sphere.

[0074] 204. Record the number of data points to be processed;

[0075] 205. If the number of data points to be processed is less than the total number of surface point cloud data points, then select four more non-coplanar points from the surface point cloud data points and return to step 202.

[0076] The number of data points to be processed corresponding to the sphere fitted by any four non-coplanar points in the surface point cloud data points has been recorded. The four non-coplanar points selected in each iteration are not completely consistent.

[0077] 206. Select the data points corresponding to the spherical fitting with the largest number of data points as the in-place points;

[0078] If, through comparison, the number of data points corresponding to the fitted sphere is the largest, it means that the number of data points closest to the sphere is the largest, indicating that the fitting effect of this fitting is the best. Therefore, the data points to be processed in this fitting are selected as in-place points.

[0079] 207. If the number of data points to be processed is equal to the total number of surface point cloud data points, then the data points to be processed corresponding to this spherical fitting will be taken as in-place points.

[0080] If the number of data points to be processed is equal to the total number of surface point cloud data points, it means that all surface point cloud data points are close to the sphere being fitted this time, and the current fitting has achieved the best effect. There is no need to perform the next fitting, and the data points to be processed corresponding to the current fitting can be directly used as in-place points.

[0081] This embodiment performs cyclic spherical fitting on surface point cloud data points. By calculating the number of surface point cloud data points closest to the fitted sphere, it finds the fit with the most corresponding data points to be processed and selects the data points to be processed corresponding to the fit of this fit as inliers. This method of selecting inliers can exhaustively cover various spheres in the surface point cloud data points, and judge the fitting effect of each fitted sphere by distance. It selects the data points to be processed corresponding to the sphere with the best fitting effect as inliers, thereby improving the accuracy of inlier selection.

[0082] Figure 3 This is the third flowchart illustrating the hip joint registration point selection method provided in this application embodiment. (Refer to...) Figure 3 For four non-coplanar points in the surface point cloud data, a spherical fit is performed. If the shortest distance between the surface point cloud data point and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold. This may also include:

[0083] 301. Select all combinations of four non-coplanar points from the surface point cloud data points;

[0084] First, select all combinations of four non-coplanar points from the point cloud data.

[0085] 302. Perform spherical fitting on the four non-coplanar points in each combination;

[0086] The method of spherical fitting is not limited here. The spherical fitting process can be performed sequentially on the four non-coplanar points in each combination, or it can be performed simultaneously on the four non-coplanar points in each combination.

[0087] 303. If the shortest distance between the surface point cloud data points and the fitted sphere is less than the first threshold, then the surface point cloud data is determined to be the data points to be processed for the corresponding fitted sphere.

[0088] 304. Record the number of data points to be processed corresponding to each fitted sphere;

[0089] 305. Select the data point corresponding to the fitted sphere with the largest number of data points to be processed as the in-place point.

[0090] This embodiment first selects all combinations of four non-coplanar points from the point cloud data, then performs spherical fitting on the four non-coplanar points in each combination, calculates the number of surface point cloud data points that are closest to the fitted sphere, finds the sphere that fits the data point to be processed the most, and takes the data point to be processed corresponding to the fitted sphere as an inlier. This method of selecting inliers avoids the use of looping processes, making the whole process direct and clear.

[0091] In one embodiment, the in-game points can be fitted with a bounding ball using the following method:

[0092] In the in-game points, select the two points furthest apart in the X direction, namely the first and second points; select the two points furthest apart in the Y direction, namely the third and fourth points; and select the two points furthest apart in the Z direction, namely the fifth and sixth points. Select the line segment corresponding to the maximum value among the first line segment length between the first and second points, the second line segment length between the third and fourth points, and the third line segment length between the fifth and sixth points as the diameter of the enclosing ball. If there are in-game points located outside the enclosing ball, connect the center of the enclosing ball with the in-game point outside the enclosing ball to form a fourth line segment. Extend the fourth line segment in the direction from the in-game point outside the enclosing ball to the center of the enclosing ball so that the fourth line segment intersects with the enclosing ball. The line segment between the intersection point and the in-game point outside the enclosing ball is the diameter of the new enclosing ball. The new enclosing ball has a longer diameter and a larger enclosing range than the original enclosing ball, and can enclose the in-game points outside the original enclosing ball. Continue to expand the size of the enclosing ball until all in-game points are enclosed within the ball. The enclosing ball at this time is the fitted enclosing ball.

[0093] This embodiment, by continuously expanding the size of the enclosing ball and moving the center of the enclosing ball to surround all in-game points, can obtain an enclosing ball with the smallest radius surrounding all in-game points, making the enclosing ball more compact.

[0094] In one embodiment, the minimum value of the target distance range is a second threshold, and the maximum value of the target distance range is the radius of the fitted bounding sphere.

[0095] If an intra-point is located within or on the fitted bounding sphere and is at a certain distance from the center of the fitted bounding sphere, then the intra-point is considered to meet the characteristics of a point taken from the bone surface, and is thus determined as a hip joint registration point.

[0096] In this embodiment, the minimum value of the target distance range is the second threshold, and the maximum value of the target distance range is the radius of the fitted bounding sphere. When comparing the distance between the inlier and the center of the fitted bounding sphere, registration points that conform to the characteristics of the bone surface can be selected, providing accurate data point support for subsequent registration.

[0097] The hip joint registration point screening device provided in the embodiments of this application is described below. The hip joint registration point screening device described below and the hip joint registration point screening method described above can be referred to in correspondence.

[0098] Figure 4 This is a schematic diagram of the hip joint registration point screening device provided in an embodiment of this application. (Refer to...) Figure 4 This application provides a hip joint registration point screening device, which may include:

[0099] Data acquisition module 401 is used to: acquire point cloud data points on the surface of the target acetabulum;

[0100] The in-situ point filtering module 402 is used to: perform spherical fitting on the surface point cloud data points; if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then filter out in-situ points based on the number of surface point cloud data points less than the first threshold.

[0101] The registration point filtering module 403 is used to: perform bounding sphere fitting on the in-game point; if the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, then the in-game point is used as the hip joint registration point.

[0102] The hip joint registration point screening device provided in this embodiment first acquires the surface point cloud data points of the target acetabulum, then performs spherical fitting on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then intra-points are screened based on the number of surface point cloud data points less than the first threshold. Finally, bounding sphere fitting is performed on the intra-points. If the distance between the intra-point and the center of the fitted bounding sphere is within the target distance range, then the intra-point is used as the hip joint registration point. This embodiment fully utilizes the hemispherical shape of the acetabulum, directly performing spherical fitting on its surface point cloud data points, and then performing bounding sphere fitting. Since the shape of the sphere and the bounding sphere are very close to the shape of the acetabulum, it can maximize the approximation of the actual shape of the acetabulum during each fitting, improving the fitting accuracy. Furthermore, since spherical fitting and bounding sphere fitting are performed on multiple points, unlike the traditional method of calculating curvature and normal vector point by point, it can quickly screen out the hip joint registration points, improving the screening efficiency of registration points.

[0103] In one embodiment, the in-spot filtering module 402 is specifically used for:

[0104] Spherical fitting is performed on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0105] In one embodiment, the in-spot filtering module 402 is specifically used for:

[0106] Step 1: Select any four non-coplanar points from the surface point cloud data points;

[0107] Step 2: Perform spherical fitting on the four non-coplanar points;

[0108] Step 3: If the shortest distance between the surface point cloud data points and the fitted sphere is less than the first threshold, then the surface point cloud data is determined to be data points to be processed;

[0109] Step 4: Record the number of data points to be processed. If the number of data points to be processed is less than the total number of surface point cloud data points, select four non-coplanar points from the surface point cloud data points and return to step 2 until the number of data points to be processed corresponding to the sphere fitted by any four non-coplanar points in the surface point cloud data points has been recorded. The four non-coplanar points selected each time are not completely consistent.

[0110] Step 5: Select the data point corresponding to the spherical fitting with the largest number of data points to be processed as the in-place point.

[0111] In one embodiment, the in-spot filtering module 402 is specifically used for:

[0112] If the number of data points to be processed is equal to the total number of surface point cloud data points, then the data points to be processed corresponding to this spherical fitting are taken as in-place points.

[0113] In one embodiment, the in-spot filtering module 402 is specifically used for:

[0114] Select all combinations of four non-coplanar points from the surface point cloud data points;

[0115] Perform spherical fitting on the four non-coplanar points in each of the aforementioned combinations;

[0116] If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then the surface point cloud data is determined to be the data points to be processed for the corresponding fitted sphere.

[0117] Record the number of data points to be processed corresponding to each fitted sphere;

[0118] The data point corresponding to the fitted sphere with the largest number of data points to be processed is selected as the in-place point.

[0119] In one embodiment, the minimum value of the target distance range in the registration point filtering module 403 is a second threshold, and the maximum value of the target distance range is the radius of the fitted bounding sphere.

[0120] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5 As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other via the communication bus 540. The processor 510 can call a computer program in the memory 530 to execute steps of the hip joint registration point selection method, such as including:

[0121] Acquire point cloud data points on the surface of the target acetabulum;

[0122] Spherical fitting is performed on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0123] The in-game point is fitted with a bounding sphere. If the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, the in-game point is used as the hip joint registration point.

[0124] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0125] On the other hand, this application also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can perform the steps of the hip joint registration point screening method provided in the above embodiments, such as including:

[0126] Acquire point cloud data points on the surface of the target acetabulum;

[0127] Spherical fitting is performed on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0128] The in-game point is fitted with a bounding sphere. If the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, the in-game point is used as the hip joint registration point.

[0129] On the other hand, embodiments of this application also provide a processor-readable storage medium storing a computer program for causing a processor to perform the steps of the methods provided in the above embodiments, such as including:

[0130] Acquire point cloud data points on the surface of the target acetabulum;

[0131] Spherical fitting is performed on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold.

[0132] The in-game point is fitted with a bounding sphere. If the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, the in-game point is used as the hip joint registration point.

[0133] The processor-readable storage medium can be any available medium or data storage device that the processor can access, including but not limited to magnetic memory (e.g., floppy disk, hard disk, magnetic tape, magneto-optical disk (MO)), optical memory (e.g., CD, DVD, BD, HVD), and semiconductor memory (e.g., ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid-state drive (SSD)).

[0134] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0135] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for selecting hip joint registration points, characterized in that, include: Acquire point cloud data points on the surface of the target acetabulum; Spherical fitting is performed on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold. A bounding sphere is fitted to the in-game point. If the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, then the in-game point is used as the hip joint registration point. The process involves performing spherical fitting on the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold, including: Spherical fitting is performed on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points that are less than the first threshold. The process involves performing spherical fitting on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold, including: Step 1: Select any four non-coplanar points from the surface point cloud data points; Step 2: Perform spherical fitting on the four non-coplanar points; Step 3: If the shortest distance between the surface point cloud data points and the fitted sphere is less than the first threshold, then the surface point cloud data is determined to be data points to be processed; Step 4: Record the number of data points to be processed. If the number of data points to be processed is less than the total number of surface point cloud data points, select four non-coplanar points from the surface point cloud data points and return to step 2 until the number of data points to be processed corresponding to the sphere fitted by any four non-coplanar points in the surface point cloud data points has been recorded. The four non-coplanar points selected each time are not completely consistent. Step 5: Select the data point corresponding to the spherical fitting with the largest number of data points to be processed as the in-place point; After recording the number of data points to be processed, the process includes: If the number of data points to be processed is equal to the total number of surface point cloud data points, then the data points to be processed corresponding to this spherical fitting are taken as in-place points. The minimum value of the target distance range is the second threshold, and the maximum value of the target distance range is the radius of the fitted bounding sphere.

2. The method for selecting hip joint registration points according to claim 1, characterized in that, The process involves performing spherical fitting on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold, including: Select all combinations of four non-coplanar points from the surface point cloud data points; Perform spherical fitting on the four non-coplanar points in each of the aforementioned combinations; If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then the surface point cloud data is determined to be the data points to be processed for the corresponding fitted sphere. Record the number of data points to be processed corresponding to each fitted sphere; The data point corresponding to the fitted sphere with the largest number of data points to be processed is selected as the in-place point.

3. A hip joint registration point screening device, characterized in that, include: The data acquisition module is used to: acquire point cloud data points on the surface of the target acetabulum; The in-situ point filtering module is used to: perform spherical fitting on the surface point cloud data points; if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then filter out in-situ points based on the number of surface point cloud data points that are less than the first threshold. The registration point filtering module is used to: fit a bounding sphere to the in-game point; if the distance between the in-game point and the center of the fitted bounding sphere is within the target distance range, then the in-game point is used as a hip joint registration point. The in-situ point filtering module is further configured to: perform spherical fitting on four non-coplanar points in the surface point cloud data points; if the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then filter out in-situ points based on the number of surface point cloud data points less than the first threshold. The process involves performing spherical fitting on four non-coplanar points in the surface point cloud data points. If the shortest distance between the surface point cloud data points and the fitted sphere is less than a first threshold, then local points are selected based on the number of surface point cloud data points less than the first threshold, including: Step 1: Select any four non-coplanar points from the surface point cloud data points; Step 2: Perform spherical fitting on the four non-coplanar points; Step 3: If the shortest distance between the surface point cloud data points and the fitted sphere is less than the first threshold, then the surface point cloud data is determined to be data points to be processed; Step 4: Record the number of data points to be processed. If the number of data points to be processed is less than the total number of surface point cloud data points, select four non-coplanar points from the surface point cloud data points and return to step 2 until the number of data points to be processed corresponding to the sphere fitted by any four non-coplanar points in the surface point cloud data points has been recorded. The four non-coplanar points selected each time are not completely consistent. Step 5: Select the data point corresponding to the spherical fitting with the largest number of data points to be processed as the in-place point; After recording the number of data points to be processed, the process includes: If the number of data points to be processed is equal to the total number of surface point cloud data points, then the data points to be processed corresponding to this spherical fitting are taken as in-place points. The minimum value of the target distance range is the second threshold, and the maximum value of the target distance range is the radius of the fitted bounding sphere.

4. An electronic device comprising a processor and a memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the hip joint registration point screening method according to any one of claims 1 to 2.

5. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the hip joint registration point screening method as described in any one of claims 1 to 2.

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