Surgical navigation robot system precision compensation method

Abstract

The invention discloses a precision compensation method for a surgical navigation robot system, which comprises the following steps of: 1, before an operation, setting a compensation die body which comprises a plurality of identification points; 2, the surgical navigation robot system collects a three-dimensional image of the compensation model body, and a conversion relation RT between a tracking device coordinate system and a three-dimensional image coordinate system in the surgical navigation robot system is established; step 3, obtaining coordinates of the identification points in the compensation motif in the coordinate system of the tracking device, obtaining coordinates of the identification points in the coordinate system of the three-dimensional image through the conversion relation RT, and recording the coordinates as a first point set A1; step 4, performing image recognition on the three-dimensional image acquired in the step 2, acquiring coordinates of the identification points in the three-dimensional image coordinate system, and recording the coordinates as a second point set A0; 5, judging according to the relationship between the first point set A1 and the second point set A0, and obtaining a compensation conversion relationship; and step 6, during an operation, performing precision compensation by using the compensation conversion relation.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and is a method for compensating a robot system, in particular a method for compensating the accuracy of a surgical navigation robot system. Background Art

[0002] The information provided in this part is only background information related to the present disclosure, and it is not necessarily prior art.

[0003] Surgical navigation robot systems are increasingly widely used clinically because they can position the robotic arm through planning and guidance during surgery and observe the position of surgical instruments in real time. Its principle is to establish an image coordinate system with the patient's fluoroscopic imaging data as the data source, establish a spatial coordinate system with the optical positioning system as the data source, and combine the position relationship between the positioning points on the registration target calibrated before surgery and the tracker and the coordinates of the positioning points identified on the fluoroscopic image to calculate the conversion relationship from the spatial point to the image, thereby realizing the conversion from the spatial coordinate system to the image coordinate system, that is, registration, so as to achieve the purpose of tracking and obtaining surgical instruments in real time during surgery.

[0004] Registration is an essential key step in the use of surgical navigation robot systems. However, in the prior art, various fixed errors will occur in the measurement and recognition data used in the registration process.

[0005] It should be noted that the information disclosed in the above background art section is only used to strengthen the understanding of the background of the present disclosure. Therefore, it may include information that does not constitute prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] Object of the Invention: The technical problem to be solved by the present invention is to provide a method for compensating the accuracy of a surgical navigation robot system in view of the deficiencies of the prior art.

[0007] To solve the above technical problem, the present invention discloses a method for compensating the accuracy of a surgical navigation robot system, including the following steps:

[0008] Step 1, before the surgical navigation robot system is used in surgery, a compensation phantom is set up for accuracy compensation; in the compensation phantom, a number of identification points are included;

[0009] Step 2, the surgical navigation robot system acquires a three-dimensional image of the compensation phantom and establishes a conversion relationship RT between the coordinate system of the tracking device in the surgical navigation robot system and the three-dimensional image coordinate system;

[0010] Step 3, obtain the coordinates of the identification points in the compensation phantom in the coordinate system of the tracking device, and through the conversion relationship RT, obtain the coordinates of the identification points in the three-dimensional image coordinate system, denoted as the first point set A1;

[0011] Step 4: Perform image recognition on the three-dimensional image collected in Step 2 to obtain the coordinates of the identification points in the three-dimensional image coordinate system, denoted as the second point set A0;

[0012] Step 5: Judge according to the relationship between the first point set A1 and the second point set A0, and obtain the compensation conversion relationship;

[0013] Step 6: When using the surgical navigation robot system for surgery, use the compensation conversion relationship for accuracy compensation.

[0014] Furthermore, the obtaining of the compensation conversion relationship in Step 5 includes:

[0015] Step 5-1: If the first point set A1 does not coincide with the second point set A0, define the coordinate system determined by the first point set A1 as the virtual image coordinate system, and execute Step 5-2; otherwise, set the conversion relationship RT1 as the identity matrix, that is, no compensation is performed, and execute Step 5-3;

[0016] Step 5-2: Calculate the conversion relationship RT1 from the virtual image coordinate system to the three-dimensional image coordinate system by the SVD method;

[0017] Step 5-3: Use the conversion relationship RT1 as the compensation conversion relationship.

[0018] Furthermore, the compensation phantom in Step 1 includes:

[0019] A first tracer and a plurality of identification points that form a rigid relationship with it, the number of the identification points is greater than or equal to 4 and they are not coplanar.

[0020] Furthermore, the using of the compensation conversion relationship for accuracy compensation in Step 6 includes:

[0021] Use the surgical navigation robot system to obtain the conversion relationship RT between the tracking device coordinate system and the image coordinate system, and multiply RT by RT1 to obtain the conversion relationship after accuracy compensation.

[0022] Furthermore, the establishing of the conversion relationship RT between the tracking device coordinate system and the three-dimensional image coordinate system in Step 2 is calculated by collecting the C-arm trajectory data through a second tracer installed at the C-arm image receiving end of the surgical navigation robot system.

[0023] Furthermore, the obtaining of the coordinates of the identification points in the compensation phantom in Step 3 is calculated through the coordinates of the first tracer in the compensation phantom coordinate system scanned by the tracking device and the coordinates of the identification points in the coordinate system determined by the first tracer pre-calibrated in the compensation phantom.

[0024] Further, coordinates of the identification points in the pre-calibrated compensation phantom in the coordinate system determined by the first tracer are measured and calibrated using a coordinate measuring machine.

[0025] Further, coordinates of the identification points in the pre-calibrated compensation phantom in the coordinate system determined by the first tracer are measured and calibrated using a tracking device.

[0026] Further, the identification points are steel balls.

[0027] Further, the identification points are evenly distributed in the three-dimensional space.

[0028] Beneficial effects:

[0029] 1. The method proposed by the present invention can effectively eliminate the fixed error in spatial registration of the surgical navigation robot system and improve the registration accuracy.

[0030] 2. The method proposed by the present invention has a simple process and high efficiency. Description of the drawings

[0031] The following further specifically describes the present invention in conjunction with the drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0032] Figure 1 It is a schematic diagram of the work flow of the present invention.

[0033] Figure 2 It is a schematic diagram of the compensation phantom.

[0034] Figure 3 It is a schematic diagram of the three-dimensional image of the compensation phantom obtained by three-dimensional C-arm scanning.

[0035] Figure 4 It is a schematic diagram of the comparison between the converted identification points on the compensation phantom before compensation in the image space and the three-dimensional imaging points of the identification points on the compensation phantom.

[0036] Figure 5 It is a schematic diagram of the comparison between the converted identification points on the compensation phantom after compensation in the image space and the three-dimensional imaging points of the identification points on the compensation phantom. Specific embodiments

[0037] The general idea of the present invention is to provide a method that is simple and convenient to operate, can effectively reduce the fixed error in the registration process, and improve the system accuracy. As Figure 1 shown, a method for compensating the accuracy of a surgical navigation robot system includes the following steps:

[0038] Step 1: Set up the compensation phantom. The compensation phantom includes: a first tracer, and a number of fiducial points rigidly arranged near the first tracer. The number of fiducial points (which can be steel balls or other materials that can be captured by the surgical navigation robot system) are arranged in a three-dimensional manner, where any three different fiducial points are not coplanar, and the number of fiducial points are distributed as evenly as possible in a three-dimensional space (which can be a cube or other shapes);

[0039] The number of fiducial points can be set to more than 4 according to actual needs.

[0040] Step 2: Fix the compensation phantom at the position where the target to be scanned is placed in the surgical navigation robot system, and use a coordinate measuring machine or the tracking device in the surgical navigation robot system to calibrate the three-dimensional coordinates of a number of fiducial points on the compensation phantom in the three-dimensional coordinate system determined by the first tracer and save them;

[0041] Step 3: Before surgery, use the three-dimensional C-arm of the surgical navigation robot system to scan and acquire the three-dimensional images of a number of fiducial points on the compensation phantom, and simultaneously collect the C-arm trajectory data through the second tracer installed at the C-arm image receiving end of the surgical navigation robot system. By using the method described in the prior art "Registration Method and System for Three-Dimensional Orthopaedic Surgical Navigation" (Publication No. CN105997246B), establish the conversion relationship RT between the tracking device coordinate system and the three-dimensional image coordinate system of the compensation phantom;

[0042] Step 4: The tracking device obtains the coordinates of a number of fiducial points on the compensation phantom in the tracking device coordinate system through the coordinates of the first tracer on the compensation phantom obtained by scanning and the coordinates of a number of fiducial points on the compensation phantom calibrated in the coordinate system determined by the first tracer in Step 2, and through the conversion relationship RT obtained in Step 2, convert the coordinates of the number of fiducial points in the tracking device coordinate system to the three-dimensional image coordinate system of the compensation phantom, denoted as point set A1;

[0043] Step 5: Identify the image coordinates of a number of fiducial points in the three-dimensional image of the compensation phantom, denoted as point set A0;

[0044] Step 6: If point set A1 does not coincide with A0, define the coordinate system determined by coordinate set A1 as the compensation image coordinate system, and calculate the conversion relationship RT1 from the compensation image coordinate system to the three-dimensional image coordinate system of the compensation phantom through the SVD algorithm, that is, the compensation conversion relationship; if they coincide, the registration has no error and no compensation is required;

[0045] During the operation, the scanned images can be registered in real time. After the scanned images are obtained, the compensation conversion relationship RT1 can be used for compensation to obtain the final accurate images.

[0046] Example:

[0047] According to the foregoing technical solution, the present invention provides a specific embodiment for further illustration. As Figure 1 shown, the precision compensation method includes the following specific steps:

[0048] Step 1: Set up a compensation phantom. As Figure 2 shown, the compensation phantom includes six steel balls arranged in a three-dimensional manner and rigidly connected to the first tracer, where any three different marking points are not coplanar, and several marking points are distributed as evenly as possible in a cubic space of 18CM * 18CM * 18CM;

[0049] Step 2: Fix the compensation phantom in the surgical navigation robot system, and calibrate the coordinates (x0, y0, z0) of the six steel balls on the compensation phantom in the coordinate system determined by the first tracer using a coordinate measuring machine or a tracking device 1-6 and save them;

[0050] Step 3: Collect the three-dimensional image of the compensation phantom. As Figure 3 shown, synchronously collect the C-arm trajectory data through the tracer installed at the C-arm image receiving end, compare it with the trajectory data during C-arm calibration, and establish the conversion relationship RT between the tracking device coordinate system and the three-dimensional image coordinate system of the compensation phantom through the SVD and ICP algorithms;

[0051] Step 4: The tracking device obtains the coordinates (x1, y1, z1) of the six steel balls on the compensation phantom in the tracking device coordinate system through the tracer coordinates on the compensation phantom and the coordinates (x0, y0, z0) of the six steel balls on the compensation phantom calibrated in the coordinate system determined by the tracer in the first step 1-6 , and through the conversion relationship RT obtained in the second step, convert the coordinates (x1, y1, z1) of the six steel balls (marking points) in the tracking device coordinate system 1-6 to the image coordinate system, denoted as point set A1, represented as (x2, y2, z2) 1-6 , such as 1-6 the magenta points shown in Figure 4 ;

[0052] Step 5: Identify the image coordinates (x3, y3, z3) of several steel balls (marking points) in the three-dimensional image of the compensation phantom 1-6 , such as Figure 3 shown, denoted as point set A0, such as Figure 4 the white points shown in

[0053] Step 6: Compare whether point set A1 and A0 coincide, as Figure 4 shown;

[0054] Step 7: If the point set A1 does not coincide with A0, define the coordinate system determined by the coordinate set A1 as the virtual image coordinate system, and calculate the conversion relationship RT1 from the virtual image coordinate system to the image coordinate system through the SVD algorithm, that is, the compensation conversion relationship;

[0055] Step 8: During each intraoperative image registration, after obtaining the conversion relationship RT between the tracking device coordinate system and the image coordinate system, multiply RT by RT1 to obtain the compensated conversion relationship;

[0056] Step 9: If they coincide, the registration has no error and no compensation is required.

[0057] In summary, as Figure 4 and Figure 5 , the image point set A2 ([ Figure 5 the green points in Figure 4 ) obtained by calculating with the compensated conversion relationship obtained in Step 8 of this embodiment, by observing the coincidence degree of the set A0 (white points) and the point set A1 before compensation ([ Figure 5 the magenta points in

[0058] ), and the point set A2 after supplementation ([

[0059] the green points in

[0060] ), it is concluded that the accuracy after compensation is significantly better than that before compensation. Specifically, the present application provides a computer storage medium and a corresponding data processing unit. Among them, the computer storage medium can store a computer program, and when the computer program is executed by the data processing unit, it can run the content of the present invention and some or all of the steps in each embodiment of a method for accuracy compensation of a surgical navigation robot system. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc. Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present invention can be implemented by means of a computer program and its corresponding general hardware platform. Based on such an understanding, the essence of the technical solutions in the embodiments of the present invention, or the part that contributes to the prior art, can be embodied in the form of a computer program, that is, a software product. The computer program software product can be stored in the storage medium, including several instructions for causing a device (which can be a personal computer, a server, a single-chip microcomputer, an MCU, or a network device, etc.) including a data processing unit to execute the methods described in each embodiment or some parts of the embodiments of the present invention.

[0060] The present invention provides an idea and method for accuracy compensation of a surgical navigation robot system. There are many methods and ways to specifically implement this technical solution. The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by using existing technologies.

Claims

1. A method for compensating the accuracy of a surgical navigation robot system, characterized in that: The following steps are involved: Step 1: before the surgical navigation robot system is used in surgery, a compensation phantom is set up for precision compensation; the compensation phantom includes a plurality of marking points; Step 2, the surgical navigation robot system collects a three-dimensional image of the compensation phantom, and establishes a conversion relationship RT between a tracking device coordinate system and a three-dimensional image coordinate system in the surgical navigation robot system; Step 3, obtaining the coordinates of the identification points in the compensation phantom in the tracking device coordinate system, and obtaining the coordinates of the identification points in the three-dimensional image coordinate system through the transformation relationship RT, which is recorded as the first point set A1; Step 4, performing image recognition on the three-dimensional image collected in step 2, obtaining the coordinates of the identification points in the three-dimensional image coordinate system, recorded as the second point set A0; Step 5, judging based on the relationship between the first point set A1 and the second point set A0, and obtaining a compensation conversion relationship; Step 6: When performing surgery using the surgical navigation robot system, use the compensation conversion relationship to perform accuracy compensation.

2. A method for precision compensation of a surgical navigation robot system according to claim 1, characterized in that: The obtaining of the compensation conversion relationship described in step 5 includes: Step 5-1, if the first point set A1 does not coincide with the second point set A0, define the coordinate system determined by the first point set A1 as the virtual image coordinate system, and execute step 5-2; otherwise, set the transformation relationship RT1 to the unit matrix, that is, do not perform compensation, and execute step 5-3; Step 5-2, calculating the transformation relationship RT1 from the virtual image coordinate system to the three-dimensional image coordinate system by using the SVD method; Step 5-3: Use the conversion relationship RT1 as the compensation conversion relationship.

3. The method for compensating the accuracy of a surgical navigation robot system according to claim 1, characterized in that: The compensation phantom described in step 1, comprising: The first tracer and a plurality of identification points forming a rigid relationship therewith, wherein the number of the identification points is greater than or equal to 4 and the identification points are not coplanar.

4. The method for compensating the accuracy of a surgical navigation robot system according to claim 1, characterized in that: Step 6, using the compensation conversion relationship to perform accuracy compensation, includes: The surgical navigation robot system is used to obtain the conversion relationship RT between the tracking device coordinate system and the image coordinate system, and RT is multiplied by RT1 to obtain the conversion relationship after accuracy compensation.

5. The method for accuracy compensation of a surgical navigation robot system according to claim 1, characterized in that: The transformation relationship RT between the tracking device coordinate system and the three-dimensional image coordinate system in the surgical navigation robot system described in step 2 is established by collecting C-arm trajectory data through a second tracer installed at the C-arm image receiving end of the surgical navigation robot system.

6. The method for accuracy compensation of a surgical navigation robot system according to claim 1, characterized in that: The coordinates of the identification point in the compensation phantom in the tracking device coordinate system obtained in step 3 are calculated by the coordinates of the first tracer in the compensation phantom coordinate system scanned by the tracking device and the coordinates of the identification point in the compensation phantom in the coordinate system determined by the first tracer which is pre-calibrated.

7. The method for accuracy compensation of a surgical navigation robot system according to claim 6, characterized in that: The coordinates of the identification points in the pre-calibrated compensation phantom in the coordinate system determined by the first tracer are measured and calibrated using a three-coordinate measuring machine.

8. The method for compensating the accuracy of a surgical navigation robot system according to claim 7, characterized in that: The coordinates of the identification points in the pre-calibrated compensation phantom in the coordinate system determined by the first tracer are measured and calibrated using a tracking device.

9. The method for compensating the accuracy of a surgical navigation robot system according to claim 3, characterized in that: The marking point is a steel ball.

10. The method for accuracy compensation of a surgical navigation robot system according to claim 3, characterized in that: The marking points are evenly distributed in the three-dimensional space.

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