A standard block for detecting registration accuracy

Abstract

The present invention provides a standard block for detecting registration accuracy and an applicable method thereof, characterized in that: it comprises a standard block body; wherein the standard block body is a boat-shaped body; the bottom of the standard block body has at least one hollow structure; the top surface of the standard block body is a plane structure, on which scale holes, angle holes and mounting holes are arranged; the scale holes, angle holes and mounting holes do not contact each other. The standard block has a stable structure and is easy to use. After testing, it is found that the image shooting will not be incomplete due to the standard block being too large, nor will the image shooting be unclear due to being too small.

Description

Technical Field

[0001] The present invention relates to the field of medical instruments, and in particular to a standard block for detecting registration accuracy. Background Art

[0002] In orthopedic surgical navigation systems, virtual images are registered with real images through registration algorithms, and bone block models are usually used for testing. However, there is no specific registration error value, which makes it impossible to judge the accuracy of the registration. In order to verify the accuracy of the registration, standard blocks are used for simulation testing to detect the accuracy of image registration. However, due to the shape and structure of existing standard blocks, after X-ray shooting, the image captured is a single black color. In addition, the existing standard blocks are large in size, which may result in incomplete images and are difficult to distinguish during registration, which increases the difficulty of registration and affects the accuracy of registration. Summary of the invention

[0003] The present invention aims to overcome the above-mentioned defects and provides a standard block for detecting the registration accuracy.

[0004] The present invention provides a standard block for detecting registration accuracy, characterized by comprising a standard block body;

[0005] Wherein, the above-mentioned standard block body is in the shape of a ship;

[0006] The bottom of the standard block body has at least one hollow structure;

[0007] The top surface of the standard block body is a plane structure, on which scale holes, angle holes and mounting holes are arranged;

[0008] The scale holes, angle holes and mounting holes do not contact each other.

[0009] Furthermore, the present invention provides a standard block for detecting registration accuracy, which is also characterized by:

[0010] The bottom of the standard block body includes a first side block and a second side block;

[0011] The first side block and the second side block are respectively arranged on two opposite sides of the bottom of the standard block body;

[0012] A passage is provided between the first side block and the second side block.

[0013] Furthermore, the present invention provides a standard block for detecting registration accuracy, which is also characterized by:

[0014] The first side block has at least one hollow structure and / or through hole;

[0015] and / or

[0016] The second side block has at least one hollow structure and / or through hole.

[0017] Furthermore, the present invention provides a standard block for detecting registration accuracy, which is also characterized by:

[0018] The scale hole is composed of a first cross scale and a second cross scale;

[0019] The first cross scale and the second cross scale are evenly arranged on the top surface of the standard block body;

[0020] The ends of the first cross scale and the second cross scale intersect at the center of the top surface of the standard block body.

[0021] Furthermore, the present invention provides a standard block for detecting registration accuracy, which is also characterized by:

[0022] The mounting hole has a mounting mechanism for mounting with other devices.

[0023] Furthermore, the present invention provides a standard block for detecting registration accuracy, which is also characterized by:

[0024] The edge of the top surface of the standard block body is also provided with a protrusion;

[0025] The above-mentioned protrusions include a first protrusion and a second protrusion;

[0026] The second protruding part is arranged at the angle between the first protruding part and the standard block body.

[0027] The purpose of using the first protrusion and the second protrusion in combination is to improve the recognition of the direction of the standard block. For example, one side of the circular protrusion is on the center line of the standard block, while the right-angle protrusion is located on the side of the standard block. This allows for higher recognition and prevents difficulty in identifying the direction due to images taken at different angles.

[0028] In addition, the present invention also provides a method for using the above-mentioned standard block for detecting registration accuracy, which is characterized in that the specific steps are as follows:

[0029] S1. Install the reference frame and the standard block through the connecting rod. After the reference frame is installed, ensure that the reference frame does not overlap with the standard block in the image after shooting;

[0030] S2. Place the standard block stably in the shooting area of ​​the X-ray machine to shoot images and obtain N real two-dimensional images at different angles;

[0031] S3. Sending the real two-dimensional image information obtained by S2 to the registration system;

[0032] S4. Constructing a virtual three-dimensional model according to the standard block size information pre-set in the system;

[0033] S5. Perform image matching between the real two-dimensional image and the virtual three-dimensional model to obtain N first virtual two-dimensional images that are most similar to the real two-dimensional image and the virtual three-dimensional model;

[0034] S6. Based on the first virtual two-dimensional image obtained, the virtual three-dimensional model is rotated and translated according to the custom rotation angle and translation distance, and M second virtual two-dimensional images are captured;

[0035] S7. Align the second virtual two-dimensional image with the real two-dimensional image, and determine the registration accuracy of the system based on the matching result.

[0036] Furthermore, the present invention provides a method for using a standard block for detecting registration accuracy, which is also characterized by:

[0037] The image matching rules in S5 above include one or more of the following rules:

[0038] Rule 1. According to the deformation degree of the standard block surface on the image;

[0039] Rule 2. Determine the posture of the standard block based on the position of the protruding piece;

[0040] Rule 3. The posture of the standard block is determined by the different grayscale values ​​of hollows, depressions, through holes and similar shapes in the captured image.

[0041] Furthermore, the present invention provides a method for using a standard block for detecting registration accuracy, which is also characterized by:

[0042] S8. Select an angle hole on the virtual model, obtain the angle value information of the angle hole, set the virtual angle hole to A1, select the corresponding angle hole on the physical standard block, make the probe tracking ball face ND I, insert the probe into the angle hole, obtain the angle value information of the angle hole, set the real angle hole to A2, and obtain an angle error value by calculating the formula e1 = |A1-A2|;

[0043] S9. Select a scale hole position on the virtual model, obtain the scale value information of the scale hole, set the virtual scale hole as P1, find the corresponding scale hole on the physical standard block, make the probe tracking ball face ND I, insert the probe into the angle hole, obtain the scale value information of the scale hole, set the real scale hole as P2, and obtain a displacement error value by calculating the formula e2=|P1-P2|;

[0044] S10. Compare the angle error value and the displacement error value with the error value required by the technology to determine whether the registration accuracy meets the technical requirements.

[0045] Furthermore, the present invention provides a method for using a standard block for detecting registration accuracy, which is also characterized by:

[0046] S8. Select an angle hole on the physical standard block, obtain the angle value information of the angle hole, set the real angle hole to A1, select the corresponding angle hole on the virtual model, make the probe tracking sphere face NDI, insert the probe into the angle hole, obtain the angle value information of the angle hole, set the virtual angle hole to A2, and obtain an angle error value by calculating the formula e1 = |A1-A2|;

[0047] S9. Select a scale hole position on the physical standard block, obtain the scale value information of the scale hole, set the real scale hole as P1, find the corresponding scale hole on the virtual model, make the probe tracking ball face ND I, insert the probe into the angle hole, obtain the scale value information of the scale hole, set the virtual scale hole as P2, and obtain a displacement error value by calculating the formula e2 = |P1-P2|;

[0048] S10. Compare the angle error value and the displacement error value with the error value required by the technology to determine whether the registration accuracy meets the technical requirements.

[0049] Function and effect of the present invention:

[0050] Through this design, the present invention provides a standard block for detecting registration accuracy points, which has a stable structure and is easy to use. The size of the standard block has been tested and it will not cause incomplete image capture due to the standard block being too large, nor will it cause unclear image capture due to the standard block being too small.

[0051] The angle hole is a through-hole structure. After the probe is inserted, the probe can be inserted deeper into the hole. The size of the hole matches the instrument. Therefore, it can prevent the surgical probe from shaking after being inserted into the angle hole and affecting the image shooting.

[0052] The cross scale covers the entire surface of the standard block, making it more convenient to use.

[0053] The partition design of the standard block can facilitate users to distinguish the standard blocks; the mounting holes are set at the edge of the standard block, and after the positioning reference frame is installed, the obstruction of the reference frame to the standard block can be reduced; one side of the standard block is a curved surface, and the curvature of the curved surface is different at different shooting angles, which can better identify and distinguish the graphics. The pits and hollow design of the standard block can produce different color differences and shapes in the captured image, allowing users to better identify the graphics. The raised design on one side of the standard block can be provided to the user as a reference during image registration, avoiding the reduction of recognition due to the captured image being a regular shape, thereby enabling more accurate image matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of the structure of the standard block provided in this embodiment.

[0055] Among them, 1 is a standard block, 2 is a first protrusion, 3 is a second protrusion, 4 is an angle hole, 5 is a center point, 6 is a cross scale, 7 is a sail-shaped hollow, 8 is a mounting hole, 9 is a through hole, and 10 is a sail-shaped depression.

[0056] Figure 2 A schematic diagram of the use status of the standard block provided in this embodiment.

[0057] Figure 3 A schematic diagram of the installation structure of the standard block provided in this embodiment. DETAILED DESCRIPTION

[0058] like Figure 1 As shown, this embodiment provides a standard block for detecting alignment accuracy.

[0059] The standard block 1 has a flat upper side (i.e., top surface) and a curved lower side (i.e., bottom surface), and has a ship-like shape in overall appearance.

[0060] In this embodiment, the size of the standard block is 120mm*70mm*40mm, and the size can be adjusted according to actual needs.

[0061] The top surface of the standard block is provided with at least three angle holes 4 in a transverse direction near the edge, and the angle holes are used to detect the angle of the surgical instrument;

[0062] The top surface of the standard block is also provided with a cross scale 6 for detecting the position of the surgical instrument. In the present embodiment, the standard block is divided into a left half and a right half based on the center line; the cross scale is a pair, located on both sides of the center point 5 of the left half and the right half, respectively. During use, the center point scale is generally set to 0, and the spacing between each scale is 5 mm. In actual use, the shape of the cross scale and the distance between the scale holes can be adjusted according to the needs of use.

[0063] The top surface of the standard block is also provided with a mounting hole 8 for mounting the positioning reference frame. Generally speaking, the mounting hole is arranged at any position of the edge or four corners of the upper side of the standard block. Figure 3 As shown in the interconnection with the reference frame, the mounting hole is generally designed with internal threads.

[0064] In addition, the bottom of the standard block, the right half of which has a depression 10 with a sail-shaped longitudinal section, the thickness of the front and rear sides of the depression is 1 cm. The corresponding left half can also have a similar structure.

[0065] The front (and / or rear) baffle of the left half region may also have a through hole 7 with a sail-shaped hollow design, as well as a through hole 8 and a through hole 9, and the diameter of the through hole 9 is not less than 20 mm.

[0066] In addition, a first protrusion 2 is provided on the top surface of the standard block, at the center position or the rear side position of the left half, and a second protrusion 3 is provided at an angle between the first protrusion 2 and the top surface, and the height of the second protrusion 3 is lower than that of the first protrusion 2 .

[0067] The specific usage of the above standard blocks is as follows:

[0068] like Figure 1 As shown, a standard block for detecting the registration accuracy includes a standard block, and the method of using the standard block is as follows:

[0069] Step 1: Figure 3 As shown, before image capture, the connecting rod of the reference frame is first installed in the mounting hole of the standard block, and then the reference frame is installed at the other end of the connecting rod. The connecting rod for positioning the reference frame and the mounting hole is in a "Z" shape or a "┓" shape. At least three tracking balls are provided on the reference frame. The tracking balls are used to receive and / or transmit infrared light to the tracking device to locate the position of the standard block. After the reference frame is installed, it is located above and outside the standard block to ensure that the reference frame will not overlap with the standard block in the captured image, thereby affecting the captured image.

[0070] Step 2: Figure 2 As shown, an anti-distortion cover and a target block are installed at the front end of the X-ray machine on the C-arm, and a tracking reference frame is also installed on the target block. The tracking ball on the reference frame faces the ND I device so that it can identify the tracking ball.

[0071] Step 3. After completing steps 1 and 2, place the standard block steadily in the shooting area of ​​the X-ray machine, ensure that the tracking ball on the reference frame can be recognized by the ND I device, and move the X-ray machine to shoot at different camera positions, at least from 2 different angles, and preferably from 3 different angles. After shooting, obtain a set of 3 images of the real two-dimensional image, and obtain the spatial position information of the standard block and the target block, determine the positional relationship between the standard block and the camera, and at the same time, the anti-distortion cover at the front end of the X-ray machine will perform distortion correction on the captured image.

[0072] Step 4: Send the three real two-dimensional image information and the position information of the standard block and the target block obtained in step 3 to the registration system. The image information can be sent through network transmission or USB flash drive copy.

[0073] Step 5. Construct a first virtual three-dimensional model according to the standard block size information pre-set in the system. In order to shorten the matching time between the first virtual three-dimensional model and the real two-dimensional image, the first virtual three-dimensional model can be manually translated and rotated to adjust the first virtual three-dimensional model to a similar surface to the real two-dimensional image to obtain the initial position information of the model. The system calculates the initial position information of the model and the spatial position information of the standard block and the target block obtained in step 3 to construct the spatial position relationship of the first virtual three-dimensional model and the three virtual camera positions in the virtual space.

[0074] Step 6. According to the spatial position relationship between the first virtual 3D model and the three virtual camera positions obtained in step 5, the system automatically rotates and translates the first virtual 3D model. For every 1 mm translation or 1 degree rotation, the system simultaneously records a group of first virtual 2D images obtained from the three camera positions. The system will record M groups of first virtual 2D images.

[0075] Step 7: Automatically match the M groups of first virtual two-dimensional images obtained in step 6 with a group of real two-dimensional images obtained in step 3. After matching, calculate the mean of the Euclidean distance between two images at the same angle in each group of images, select the image with the smallest mean value on the three camera positions, and form a group of registered second virtual two-dimensional images.

[0076] Step eight, the spatial position relationship between the first virtual three-dimensional model and the three virtual camera positions obtained in step five is combined with the spatial position relationship between the real standard block and the camera positions, and is registered through a registration system to obtain a registered second virtual three-dimensional model.

[0077] Step nine, select an angle hole on the second virtual 3D model, obtain the angle value information of the angle hole, set the virtual angle hole to A1, then find the corresponding angle hole on the physical standard block, hold the probe, and the probe tracking sphere faces NDI, insert the probe into the angle hole, obtain the angle value information of the angle hole, set the actual angle hole to A2, and obtain an angle error value through the calculation formula e1=|A1-A2|.

[0078] The process can also be carried out in reverse, that is, an angle hole is selected on the physical standard block, and the angle difference between the two is obtained by inserting a probe and collecting its angle value.

[0079] Select a scale hole on the virtual model, obtain the scale value information of the scale hole, set the virtual scale hole to P1, then find the corresponding scale hole on the physical standard block, hold the probe with the probe tracking sphere facing NDI, place the probe in the scale hole, obtain the scale value information of the scale hole, set the real scale hole to P2, and obtain a displacement error value through the calculation formula e2=|P1-P2|.

[0080] The angle error value and the displacement error value are compared with the error values ​​of the technical requirements (the angle error value is less than 2 degrees, and the displacement error value is less than 1.5 mm). When the angle error value and the displacement error value meet the technical requirements at the same time, it is determined that the alignment accuracy meets the technical requirements.

Claims

1. A method for using a standard block for detecting registration accuracy, characterized in that: The specific steps are as follows: S1. Install the reference frame and the standard block through the connecting rod. After the reference frame is installed, ensure that the reference frame does not overlap with the standard block in the image after shooting; S2. Place the standard block stably in the shooting area of ​​the X-ray machine to shoot images and obtain real two-dimensional images at N different angles; S3. Sending the real two-dimensional image information obtained by S2 to the registration system; S4. Constructing a virtual three-dimensional model according to the standard block size information pre-set in the system; S5. Perform image matching between the real two-dimensional image and the virtual three-dimensional model to obtain N first virtual two-dimensional images that are most similar to the real two-dimensional image and the virtual three-dimensional model; S6. Based on the first virtual two-dimensional image obtained, the virtual three-dimensional model is rotated and translated according to the custom rotation angle and translation distance, and M second virtual two-dimensional images are captured; S7. aligning the second virtual two-dimensional image with the real two-dimensional image, and judging the alignment accuracy of the system through the matching result. Wherein, the standard block for detecting the registration accuracy comprises a standard block body; The standard block body is in the shape of a ship, that is, its upper side is a plane and its lower side is a curved surface; The bottom of the standard block body has at least one hollow structure; The top surface of the standard block body is a plane structure, on which scale holes, angle holes and mounting holes are arranged; The scale holes, angle holes and mounting holes do not contact each other.

2. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: The image matching rules in S5 include one or more of the following rules: Rule 1. According to the deformation degree of the standard block surface on the image; Rule 2. Determine the posture of the standard block based on the position of the protruding piece; Rule 3. The posture of the standard block is determined by the different grayscale values ​​of hollows, depressions, through holes and similar shapes in the captured image.

3. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: S8. Select an angle hole on the virtual model, obtain the angle value information of the angle hole, set the virtual angle hole to A1, select the corresponding angle hole on the physical standard block, make the probe tracking ball face NDI, insert the probe into the angle hole, obtain the angle value information of the angle hole, set the real angle hole to A2, and obtain an angle error value by calculating the formula e1 = |A1-A2|; S9. Select a scale hole position on the virtual model, obtain the scale value information of the scale hole, set the virtual scale hole as P1, find the corresponding scale hole on the physical standard block, make the probe tracking sphere face NDI, insert the probe into the angle hole, obtain the scale value information of the scale hole, set the real scale hole as P2, and obtain a displacement error value by calculating the formula e2=|P1-P2|; S10. Compare the angle error value and the displacement error value with the error value required by the technology to determine whether the registration accuracy meets the technical requirements.

4. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: S8. Select an angle hole on the physical standard block, obtain the angle value information of the angle hole, set the real angle hole to A1, select the corresponding angle hole on the virtual model, make the probe tracking ball face NDI, insert the probe into the angle hole, obtain the angle value information of the angle hole, set the virtual angle hole to A2, and obtain an angle error value by calculating the formula e1=|A1-A2|; S9. Select a scale hole position on the physical standard block, obtain the scale value information of the scale hole, set the real scale hole as P1, find the corresponding scale hole on the virtual model, make the probe tracking sphere face NDI, insert the probe into the angle hole, obtain the scale value information of the scale hole, set the virtual scale hole as P2, and obtain a displacement error value by calculating the formula e2=|P1-P2|; S10. Compare the angle error value and the displacement error value with the error value required by the technology to determine whether the registration accuracy meets the technical requirements.

5. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: The bottom of the standard block body includes a first side block and a second side block; The first side block and the second side block are respectively arranged on two opposite sides of the bottom of the standard block body; A passage is defined between the first side block and the second side block.

6. The method for using a standard block for detecting registration accuracy according to claim 5, characterized in that: The first side block has at least one hollow structure and / or through hole; and / or The second side block has at least one hollow structure and / or through hole.

7. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: The scale hole consists of a first cross scale and a second cross scale; The first cross scale and the second cross scale are evenly arranged on the top surface of the standard block body; ends of the first cross scale and the second cross scale intersect at the center position of the top surface of the standard block body.

8. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: The mounting hole has a mounting mechanism for mutual mounting with other devices.

9. The method for using a standard block for detecting registration accuracy according to claim 1, characterized in that: The edge position of the top surface of the standard block body is also provided with a protrusion; The protrusions include a first protrusion and a second protrusion; The second protrusion is arranged at an angle between the first protrusion and the standard block body.

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