Angle calibration method and system, and tracers

Abstract

An angle calibration method and system, and tracers. The method comprises: fixedly arranging a first tracer on a surgical instrument, acquiring an intraoperative scanned image, and calibrating a first conversion relationship between a first coordinate system and an imaging coordinate system by means of the first tracer; and acquiring a first angle of the surgical instrument in the first coordinate system by means of the first tracer, and acquiring, on the basis of the first angle and the first conversion relationship, a second angle of the surgical instrument in the imaging coordinate system. At least one second tracer is fixedly arranged on an imaging device. The imaging coordinate system is calibrated by means of the second tracer. A second conversion relationship between the imaging coordinate system after movement and the imaging coordinate system before movement is acquired. When the imaging device moves, the first conversion relationship is corrected on the basis of the second conversion relationship, thereby correcting the second angle of the surgical instrument in the imaging coordinate system. For a movable imaging device, an accurate angle can be acquired without repeated calibration.

Description

An angle calibration method, system, and tracer

[0001] This application claims priority to Chinese patent application 2024110527151, filed on August 2, 2024. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of medical devices, and more specifically, to an angle calibration method, system, and tracer. Background Technology

[0003] In interventional surgery, it is typically necessary to acquire the position and orientation of surgical instruments within the body to achieve precise control and guide them to their target locations. However, due to factors such as radiation levels and operating table space, real-time imaging is not possible during the procedure. Therefore, angle sensors are required for instrument calibration. Current surgical positioning and navigation systems, which require precise spatial displacement information, can only utilize expensive optical / infrared / millimeter-wave positioning systems. Therefore, we explored using angle sensors to detect angle changes in imaging equipment to ensure precise angle control of surgical instruments during imaging.

[0004] In practice, the data returned by the angle sensor chip is obtained based on measurements of Earth's gravity or angular acceleration. However, CBCT imaging requires imaging based on the coordinate system of the CBCT equipment. If the image coordinate system and the sensor coordinate system do not coincide, the real-time angle fed back by the angle sensor chip cannot match the image data before recalibration. Therefore, the angle sensor chip and equipment need to be calibrated before use to unify the two coordinate systems.

[0005] However, in some mobile CBCT devices, the equipment needs to frequently change its working location or adjust its position to achieve a larger imaging range. Each move results in a change in position, therefore the coordinate system of the equipment is different after each move, requiring re-scanning of the calibration fixture with the angle sensor for recalibration. This is not only cumbersome but also increases the overall imaging process and time. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides an angle calibration method, system, and tracer. The tracer is used to achieve image recognition and angle calibration of surgical instruments. Once calibration is successful, even if the imaging device moves or its angle changes, the angle of the surgical instruments in the imaging coordinate system can be automatically corrected without recalibration.

[0007] Specifically, the technical solution of this application is as follows:

[0008] Firstly, this application discloses an angle calibration method, which includes:

[0009] The surgical instrument is placed within the imaging range of the imaging device for scanning to acquire a scanned image; a first tracer is fixedly mounted on the surgical instrument.

[0010] Based on the scanned image, a first transformation relationship between the first coordinate system and the imaging coordinate system is determined;

[0011] The first coordinate system takes the location of the first tracer chip in the first tracer as its origin, and the imaging coordinate system takes the imaging center point of the imaging device as its origin and the length, width, and height directions of the imaging device as its axes.

[0012] The first angle of the surgical instrument in the first coordinate system is obtained by the first tracer;

[0013] Based on the first angle and the first transformation relationship, the second angle of the surgical instrument in the imaging coordinate system is obtained.

[0014] In some embodiments, determining the first transformation relationship between the first coordinate system and the imaging coordinate system based on the scanned image includes:

[0015] The positions of at least three positioning metals in the first tracer are obtained in the first coordinate system, and the first angular feature data of the at least three positioning metals in the first coordinate system are obtained.

[0016] The scanned image is identified, the positions of the at least three positioning metals in the imaging coordinate system are obtained, and the second-direction feature data of the at least three positioning metals in the imaging coordinate system are obtained.

[0017] Based on the first direction feature data and the second direction feature data, a rotation matrix between the first coordinate system and the imaging coordinate system is constructed, and the first transformation relationship between the first coordinate system and the imaging coordinate system is obtained by solving.

[0018] In some embodiments, obtaining the first angle of the surgical instrument in the first coordinate system via the first tracer includes:

[0019] The first angle of the surgical instrument in the first coordinate system is measured by the angle measurement module in the first tracer chip.

[0020] Angle data is uploaded through the transceiver module in the first tracer chip.

[0021] In some embodiments, the angle calibration method further includes:

[0022] At least one second tracer is fixedly mounted on the imaging device;

[0023] The imaging coordinate system is calibrated using the second tracer; when the imaging device moves, a second transformation relationship is obtained between the imaging coordinate system after the movement and the imaging coordinate system before the movement.

[0024] In some embodiments, the angle calibration method further includes:

[0025] Based on the second transformation relationship, the first transformation relationship is corrected;

[0026] Based on the first angle and the corrected first transformation relationship, the second angle of the surgical instrument in the imaging coordinate system is obtained.

[0027] In some embodiments, obtaining the second transformation relationship between the imaging coordinate system after movement and the imaging coordinate system before movement when the imaging device moves includes:

[0028] The second tracer measures the angular change of the imaging coordinate system in the second coordinate system; wherein the second coordinate system takes the location of the second tracer chip in the second tracer as its origin;

[0029] Construct a first rotation matrix between the second coordinate system and the pre-motion imaging coordinate system; construct a second rotation matrix between the second coordinate system and the post-motion imaging coordinate system;

[0030] Based on the first rotation matrix and the second rotation matrix, a third rotation matrix is ​​obtained between the imaging coordinate system after movement and the imaging coordinate system before movement; the third rotation matrix is ​​solved to obtain a second transformation relationship between the imaging coordinate system after movement and the imaging coordinate system before movement.

[0031] In some embodiments, the angle calibration method further includes:

[0032] Based on the second angle, a navigation path is planned for the surgical instrument from its current position to the target point.

[0033] Secondly, this application discloses an angle calibration system, which includes:

[0034] An imaging device is used to place surgical instruments within the imaging range of the imaging device for scanning and to acquire scanned images; a first tracer is fixedly mounted on the surgical instruments.

[0035] The processor is configured to calibrate a first transformation relationship between a first coordinate system and an imaging coordinate system based on the scanned image; wherein the first coordinate system takes the location of the first tracer chip in the first tracer as its origin; and the imaging coordinate system takes the imaging center point of the imaging device as its origin and the length, width, and height directions of the imaging device as its axes.

[0036] The first tracer is used to acquire the first angle of the surgical instrument in the first coordinate system;

[0037] The processor is further configured to obtain a second angle of the surgical instrument in the imaging coordinate system based on the first angle and the first transformation relationship.

[0038] In some embodiments, the angle calibration system further includes:

[0039] A second tracer is fixedly mounted on the imaging device; used to calibrate the imaging coordinate system.

[0040] The processor is further configured to acquire a second transformation relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement when the imaging device moves.

[0041] Thirdly, this application also discloses a tracer, including a main body, a tracer chip disposed in the main body, and a positioning metal;

[0042] The main body is used to fix itself on the target device;

[0043] The tracer chip includes an angle measurement module and a transceiver module; the angle measurement module is used to measure the angle of the target device; the transceiver module is used to upload the angle to the upper-level processor.

[0044] The positioning metal includes at least three positioning metals, which are fixed in position relative to the tracer chip and are used to calibrate the position of the tracer chip.

[0045] Compared with the prior art, this application has at least one of the following beneficial effects:

[0046] 1. The angle calibration algorithm provided in this application connects a tracer to the surgical instrument to provide angle data, thereby calibrating the position and angle of the surgical instrument in the imaging coordinate system. This is used in the imaging device to ensure precise angle control of the surgical instrument during surgery after image reception.

[0047] 2. The angle calibration algorithm provided in this application connects another set of tracers to the imaging equipment to provide feedback on the current position and attitude information of the mobile CBCT equipment. This data is transmitted to a computer to calculate the angle difference from the initial calibration. By establishing a permanent connection between the imaging coordinate system and the surgical instrument coordinate system through a one-time calibration during hospital admission, two sets of angle measurement devices can achieve real-time unification of the angle coordinate system at a very low cost. It eliminates the need for pre-operative calibration using optical or other equipment and also enables guidance of surgical instruments. This saves on the cost of expensive optical positioning instruments and the time spent on pre-operative calibration. Surgeons do not need to scan the angle sensors for calibration before each surgery, nor do they need to recalibrate after each movement during surgery, reducing surgical procedures and saving surgical time.

[0048] 3. This application can also generate a navigation path based on the current posture of the surgical instruments, thereby assisting in manipulating the surgical instruments to reach the target point. This improves the success rate of surgery and reduces surgical risks. Attached Figure Description

[0049] Figure 1 is a schematic diagram of the structure of a tracer provided in this application;

[0050] Figure 2 is a flowchart of the steps of an embodiment of an angle calibration method provided in this application;

[0051] Figure 3 is a flowchart of another embodiment of an angle calibration method provided in this application;

[0052] Figure 4 is a structural block diagram of an embodiment of an angle calibration system provided in this application. Detailed Implementation

[0053] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0054] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or sets.

[0055] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0056] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0057] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0058] In specific implementations, the terminal devices described in the embodiments of this application include, but are not limited to, other portable devices such as mobile phones, laptops, educational computers, or tablet computers with touch-sensitive surfaces (e.g., touchscreen displays and / or touchpads). It should also be understood that in some embodiments, the terminal device is not a portable communication device, but a desktop computer with touch-sensitive surfaces (e.g., touchscreen displays and / or touchpads).

[0059] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0060] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific implementation methods of this application will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort.

[0061] In interventional surgery, surgeons rely on imaging technology to obtain real-time images of the surgical area, ensuring that surgical instruments can be precisely navigated to the target region. These images allow surgeons to clearly see the position of the instruments relative to surrounding tissues, enabling them to perform precise operations, avoid unnecessary damage to surrounding healthy tissues, and ensure that the instruments safely and effectively reach their intended target location. However, due to limitations in available space, surgeons often cannot perform surgery with continuous CT imaging available.

[0062] Current surgical positioning and navigation systems require precise spatial displacement information, thus employing expensive optical / infrared / millimeter-wave positioning systems. Therefore, we attempt to use angle sensors to measure the angle data of surgical instruments and then import it into a 3D image of the human body captured at time t0 for display. Only one image is needed, after which the patient can be removed from the imaging device for surgery. The subsequent posture of the surgical instruments within the body is entirely displayed in the 3D image of the human body captured at time t0 using angle sensors. This significantly reduces radiation dose. Furthermore, the angle calibration method and system provided in this application only use angle sensors and angle information, making the cost extremely low—a fraction of that of commonly used optical positioning systems in the prior art.

[0063] The data transmitted by the angle sensor chip is obtained based on measurements of Earth's gravity or angular acceleration. However, CBCT imaging requires imaging based on the coordinate system of the CBCT equipment. Therefore, the angle data measured by the angle sensor cannot be directly applied to the imaging coordinate system.

[0064] Based on this, this application discloses an angle calibration method that can use a tracer to calibrate surgical instruments, so that the angle of the surgical instruments can be accurately reflected in the imaging coordinate system where the imaging device is located.

[0065] One type of tracer, as shown in Figure 1 of the specification, includes a main body, a tracer chip disposed within the main body, and a positioning metal.

[0066] The main body is used to fix itself on the target device.

[0067] The tracer chip includes an angle measurement module and a transceiver module. The angle measurement module is used to measure the angle of the target device. The transceiver module is used to upload the angle to the upper-level processor.

[0068] The positioning metal includes at least three positioning metals, which are fixed in position relative to the tracer chip and are used to calibrate the position of the tracer chip.

[0069] Specifically, in some embodiments, the tracer has a hollow structure, allowing it to be nested onto the target device. Its main body is a columnar structure, such as a prism or cylinder. It can also be spherical, polyhedral, etc. In other embodiments, the tracer body includes at least one side for attaching the tracer to the target device.

[0070] The tracer chip includes an angle measurement module and a transceiver module. The angle measurement module is used to determine the rotation angle of an object relative to a reference direction or another object, including measurement methods based on electromagnetic induction and inertial fields. Examples include compass chips based on magnetic field principles and IMUs (Inertial Measurement Units) based on inertial principles. Of course, methods using other existing angle measurement methods to obtain the angle or angle change of the target device should also be within the scope of this application. The transceiver module is a module with wireless communication capabilities, such as Bluetooth chips, NFC, and RFID.

[0071] The positioning metal has a predetermined position within the tracer body. Based on the position of the positioning metal, its directional characteristics in a coordinate system with the tracer chip as the origin can be inferred. In some embodiments, the directional characteristics include: a set of intersecting vectors formed by the connection of the positioning metal, or the calculation of quaternions, rotation angles, etc.

[0072] In other implementations, for ease of calculation, the intersecting vector group formed by the connection between the positioning metals is positively intersecting.

[0073] The tracer's structure is shown in Figure 1 of the instruction manual, where a square structure is used as an example. It includes a hollow structure 1, positioning metal 2, and a tracer chip 3. Specifically, four spherical positioning metals (positioning steel balls) form three intersecting vectors used to calibrate the position of the tracer chip 3. The tracer chip 3 is positioned close to the surface of the hollow structure of the main body, allowing it to be close to the target device.

[0074] Based on the tracer shown in Figure 1, one embodiment of the angle calibration method of this application, as shown in Figure 2 of the specification, includes the following steps:

[0075] S100, the surgical instrument is placed within the imaging range of the imaging device for scanning to acquire a scanned image. A first tracer is fixedly mounted on the surgical instrument.

[0076] Specifically, based on the scanned image, the position of the tracer in the imaging coordinate system can be obtained. Specifically, based on the positioning steel ball, the position of the tracer chip, i.e., the first coordinate system, in the imaging coordinate system can be accurately calculated. The first coordinate system has its origin at the location of the first tracer chip in the first tracer. Specifically, the angle measurement module in the tracer chip has at least two measurement modes: a magnetic field navigation mode based on the principle of electromagnetic induction and an inertial navigation mode based on the measurement method of inertial field. In the magnetic field navigation mode, the first coordinate system has its origin at the location of the first tracer chip in the first tracer, typically with east-west, north-south, and vertical directions as axes, but other directions can also be specifically set as references. In the inertial navigation mode, the direction of the coordinate system's axes does not need to be specified; any other orthogonal system can be used as the reference coordinate system. It is sufficient to measure the difference between the reference coordinate system and the image coordinate system during calibration.

[0077] The imaging coordinate system has the imaging center point of the imaging device as the origin and the length, width and height directions of the imaging device as the axes.

[0078] In this embodiment, the imaging equipment can be a CT scanner, a CBCT scanner, etc. Surgical instruments include guides, puncture needles, etc.

[0079] S200, based on the scanned image, calibrate the first transformation relationship between the first coordinate system and the imaging coordinate system.

[0080] Specifically, step S200 includes steps S210, S220 and S230, wherein step S210 involves obtaining the positions of at least three positioning metals in the first tracer in the first coordinate system, and obtaining the first angular feature data of the at least three positioning metals in the first coordinate system.

[0081] S220, Identify the scanned image, obtain the positions of the at least three positioning metals in the imaging coordinate system, and obtain the second direction feature data of the at least three positioning metals in the imaging coordinate system.

[0082] S230, based on the first direction feature data and the second direction feature data, construct a rotation matrix between the first coordinate system and the imaging coordinate system, and solve for the first transformation relationship between the first coordinate system and the imaging coordinate system.

[0083] In other implementations, the accuracy of the calculation can be improved by using four or even more positioning metals.

[0084] S300, the first angle of the surgical instrument in the first coordinate system is obtained through the first tracer.

[0085] Specifically, the angle measurement module in the first tracer chip measures the first angle of the surgical instrument in the first coordinate system. The angle data is then uploaded via the transceiver module in the first tracer chip.

[0086] S400, based on the first angle and the first transformation relationship, the second angle of the surgical instrument in the imaging coordinate system is obtained.

[0087] Specifically, by obtaining the angle of the current surgical instrument in the image coordinate system, the surgical instrument can be adjusted according to its current position to achieve a fixed insertion angle. More preferably, the angle calibration method further includes step S500, which, based on the second angle, plans the navigation path of the surgical instrument from its current position to the target point.

[0088] This application provides another embodiment of an angle calibration method. The content of the previous embodiment will be explained in more detail.

[0089] In the scanned image, the initial angle vector C of the tracer chip in the imaging coordinate system can be obtained by positioning the metal. Based on the angle measurement module in the tracer chip, the angle vector Z0 of the surgical instrument in the first coordinate system can be measured. However, due to minor errors in manufacturing and installation, the angles of the tracer chip and the surgical instrument are not necessarily perfectly perpendicular and horizontal; therefore, the angle vector measured by the angle measuring device is Z1. The inherent error between the angle measured by the tracer chip and the actual angle of the surgical instrument is determined by the error between Z0 and Z1. Since the angles of the surgical instrument and the tracer chip are fixedly connected, the magnitude of this inherent error remains constant. That is, the transformation relationship between the coordinate system of the tracer chip and the coordinate system of the surgical instrument can be considered unchanged, using the rotation matrix multiplication formula: S0 = C. 01 *S1; where S0 is the coordinate system of the surgical instruments, C 01 S1 represents the coordinate system of the tracer chip; S2 represents the transformation relationship between the coordinate system of the tracer chip and the coordinate system of the surgical instrument. All information required during the operation can be unified to the image coordinate system. Therefore, after the above calibration, we do not need to obtain the angle vector Z0 of the surgical instrument in the first coordinate system, but only the angle vector Z1 measured by the angle measuring device. This provides the unique angle vector of the surgical instrument in the imaging coordinate system. All errors and coordinate system discrepancies will be automatically corrected.

[0090] In the above embodiments, based on the tracer, calibration can be achieved between the tracer coordinate system (first coordinate system) and the imaging device coordinate system (imaging coordinate system). This makes angle measurements more accurate, provides higher quality imaging results, and helps doctors achieve precise control of surgical instruments.

[0091] However, in some mobile CBCT devices, the equipment needs to frequently change its working location or adjust its position to achieve a larger imaging range. The angles of the image coordinate system are rotated as the instrument moves during surgery. If the image coordinate system and the sensor coordinate system do not coincide, the real-time angle fed back by the angle sensor chip cannot match the image data before recalibration. Therefore, it is necessary to recalibrate the tracer coordinate system and the imaging device coordinate system before use to unify the two coordinate systems. This is not only troublesome but also increases the overall imaging process and time.

[0092] To address this technical problem, this application provides another embodiment of an angle calibration method. This method involves setting one or more tracers on a mobile imaging device to provide feedback on the attitude information of the current position of the mobile imaging device, and then transmitting the data to an upper-level processor to calculate the angle difference compared to the initial calibration. Referring to Figure 3 in the specification, this embodiment includes the following steps:

[0093] S100, the surgical instrument is placed within the imaging range of the imaging device for scanning to acquire a scanned image. A first tracer is fixedly mounted on the surgical instrument.

[0094] S200, based on the scanned image, calibrate the first transformation relationship between the first coordinate system and the imaging coordinate system.

[0095] S300, the first angle of the surgical instrument in the first coordinate system is obtained through the first tracer.

[0096] S400, based on the first angle and the first transformation relationship, the second angle of the surgical instrument in the imaging coordinate system is obtained.

[0097] S500, at least one second tracer is fixedly installed on the imaging device. The imaging coordinate system is calibrated using the second tracer. When the imaging device moves, a second transformation relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement is obtained.

[0098] S600, Based on the second conversion relationship, the first conversion relationship is corrected.

[0099] In some other embodiments of this example, the angle calibration method further includes the step: S700, obtaining the second angle of the surgical instrument in the imaging coordinate system based on the first angle and the corrected first transformation relationship.

[0100] S800, based on the corrected second angle, plans the navigation path of the surgical instrument from its current position to the target point.

[0101] Specifically, when the imaging equipment moves during the operation, that is, when the position of the equipment coordinate system transmitted by the imaging equipment tracer changes, the navigation computer obtains the transformation relationship between the position of the new equipment coordinate system and the angle of the old equipment coordinate system, thereby obtaining the transformation relationship between the position of the new equipment coordinate system and the angle of the surgical instrument coordinate system.

[0102] In some embodiments of this example, step S500, where the imaging device moves, involves obtaining a second transformation relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement, specifically includes:

[0103] S510, the angular change of the imaging coordinate system in the second coordinate system is measured using the second tracer. The second coordinate system has its origin at the location of the second tracer chip in the second tracer. Specifically, the angle measurement module in the tracer chip has at least two measurement modes: a magnetic field navigation mode based on electromagnetic induction and an inertial navigation mode based on an inertial field measurement method. In the magnetic field navigation mode, the second coordinate system can be set with its origin typically at the location of the second tracer chip in the second tracer, and its axes being the east-west, north-south, and vertical directions; alternatively, a specific coordinate system can be used as a reference. In the inertial navigation mode, the orientation of the coordinate system's axes does not need to be specified; any other orthogonal system can be used as the reference coordinate system. It is sufficient to measure the difference between the reference coordinate system and the image coordinate system during calibration.

[0104] S520, construct a first rotation matrix between the second coordinate system and the pre-motion imaging coordinate system. Construct a second rotation matrix between the second coordinate system and the post-motion imaging coordinate system.

[0105] S530, based on the first rotation matrix and the second rotation matrix, a third rotation matrix is ​​obtained between the post-motion imaging coordinate system and the pre-motion imaging coordinate system. Solving the third rotation matrix yields a second transformation relationship between the post-motion imaging coordinate system and the pre-motion imaging coordinate system.

[0106] The following content will further explain the specific calculation approach:

[0107] Implementation method one of this embodiment:

[0108] Assume the imaging coordinate system before movement is coordinate system S0. The imaging coordinate system after movement is coordinate system S1. The first coordinate system where the first tracer is located is coordinate system A.

[0109] First, the imaging coordinate system S0 before movement is calibrated with the first coordinate system A. The rotation matrix between S0 and A is then obtained as C1.

[0110] Suppose that the vector represented by the surgical instrument in the first coordinate system A is u3. Then, the vector represented by the surgical instrument vector in the imaging coordinate system S0 before movement can be calculated based on the following matrix multiplication, the expression of which is v3 = C1·u3.

[0111] Based on the rotation matrix M between the pre-motion imaging coordinate system S0 and the post-motion imaging coordinate system S1, the vector v33 represented by the surgical instrument vector in the post-motion imaging coordinate system S1 can be calculated using the following matrix multiplication, specifically v33 = M·v3.

[0112] Implementation method two of this embodiment:

[0113] If the coordinate system of the imaging device and the second angle sensor are not simultaneously zeroed during installation, resulting in inherent errors, then we cannot directly know M. We can use the following method to calculate M.

[0114] Assume the imaging coordinate system before movement is coordinate system S0. The imaging coordinate system after movement is coordinate system S1. The first coordinate system where the first tracer is located is coordinate system A. The second coordinate system where the second tracer is located is coordinate system B.

[0115] Assuming that the second coordinate system B is rigidly fixed to the imaging coordinate system S0 before the movement and rotates with it, after the device moves, the second coordinate system B1 after the movement is obtained through the function of the tracer.

[0116] Let R be the rotation matrix between the second coordinate system B and the second coordinate system B1 after the movement. Assume that the rotation matrix between the original imaging coordinate system S0 and the second coordinate system B is E. Then, the rotation matrix M between the original imaging coordinate system S0 and the new imaging coordinate system S1 can be calculated using the following matrix multiplication: M = E. -1 *R*E, where E -1 Let E be the inverse matrix. The rotation matrix E is the rotation matrix caused by the inherent error between the sensor coordinate system and the imaging instrument coordinate system when the angle sensor is mounted and fixed on the imaging instrument. E can be obtained from the angle difference between the quaternion / angle information reported by the positioning device on the instrument during the initial calibration of the imaging equipment and the axis of the imaging coordinate system S0.

[0117] After calculating M, the vector v33 represented by the surgical instrument vector in the imaging coordinate system S1 after movement is calculated by the following matrix multiplication. The specific expression of the matrix multiplication is v33 = M·v3.

[0118] To address the inconvenience of recalibrating the imaging coordinate system every time it moves from a first position to a second position in clinical use, we place a second tracer on the imaging equipment. The placement angle is arbitrary, but it must be rigidly fixed. During module production, the side in contact with the equipment can be glued with strong adhesive, facilitating modification of existing equipment. In other embodiments of the angle calibration method provided in this application, multiple second tracers can be installed on the imaging equipment, fixed at different positions, to provide feedback on multiple attitude information for calculating angle differences. The average value of the angles measured by the multiple second tracers is then used as a representative value, resulting in higher accuracy.

[0119] This embodiment allows for a single calibration after equipment production, enabling direct use of the navigation function without the need for secondary calibration. This achieves cost and time savings.

[0120] Based on the same technical concept, this application also discloses an angle calibration system, which can be used to implement any of the above-mentioned angle calibration methods. Specifically, an embodiment of the angle calibration system of this application is shown in Figure 4 of the specification, including:

[0121] An imaging device is used to place surgical instruments within the imaging range of the imaging device for scanning and to acquire scanned images. A first tracer is fixedly mounted on the surgical instruments.

[0122] The processor is used to calibrate a first transformation relationship between a first coordinate system and an imaging coordinate system based on the scanned image. The first coordinate system has its origin at the location of the first tracer chip in the first tracer. Specifically, the angle measurement module in the tracer chip has at least two measurement modes: a magnetic field navigation mode based on the principle of electromagnetic induction and an inertial navigation mode based on an inertial field measurement method. In the magnetic field navigation mode, the first coordinate system typically has its origin at the location of the first tracer chip in the first tracer, with east-west, north-south, and vertical directions as axes. In the inertial navigation mode, the orientation of the coordinate system's axes does not need to be specified; any other orthogonal system can be used as the reference coordinate system. It is sufficient to measure the difference between the reference coordinate system and the image coordinate system during calibration.

[0123] The imaging coordinate system has the imaging center point of the imaging device as the origin and the length, width and height directions of the imaging device as the axes.

[0124] The first tracer is used to acquire the first angle of the surgical instrument in the first coordinate system.

[0125] The processor is further configured to obtain a second angle of the surgical instrument in the imaging coordinate system based on the first angle and the first transformation relationship.

[0126] Another embodiment of the angle calibration system provided in this application, as shown in Figure 4 of the specification, further includes, based on the above system embodiment:

[0127] A second tracer is fixedly mounted on the imaging device. It is used to calibrate the imaging coordinate system.

[0128] The processor is further configured to acquire a second transformation relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement when the imaging device moves.

[0129] In the above embodiments, the processor includes a navigation calculation module, an imaging processing module, and a navigation display module.

[0130] The imaging processing module is used to reconstruct the tomographic images acquired by the imaging device.

[0131] The navigation calculation module is used to receive angle data sent by the first or second tracker, and to perform angle calibration on the surgical instruments and imaging equipment based on the angle data. It is also used to plan the navigation path of the surgical instruments from their current position to the target point based on the angle data.

[0132] The navigation display module is used to display the generated navigation path and the image generated by the imaging device on the screen so that doctors can view and obtain relevant information.

[0133] The angle calibration method, system and tracer of this application have the same technical concept, and the technical details of the embodiments of the two are applicable to each other. In order to reduce repetition, they will not be repeated here.

[0134] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of program modules is merely an example. In practical applications, the above functions can be assigned to different program modules as needed, that is, the internal structure of the device can be divided into different program units or modules to complete all or part of the functions described above. The program modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software program unit. Furthermore, the specific names of the program modules are only for easy differentiation and are not intended to limit the scope of protection of this application.

[0135] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0136] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0137] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; the division of modules or units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interface; the indirect coupling or communication connection of apparatus or units may be electrical, mechanical, or other forms.

[0138] 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; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0139] Furthermore, the functional units in the various embodiments of this application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The integrated unit described above can be implemented in hardware or as a software functional unit.

[0140] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0141] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. An angle calibration method, characterized in that, It includes: The surgical instrument is placed within the imaging range of the imaging device for scanning to acquire a scanned image; a first tracer is fixedly mounted on the surgical instrument. Based on the scanned image, a first transformation relationship between the first coordinate system and the imaging coordinate system is determined; The first coordinate system takes the location of the first tracer chip in the first tracer as its origin; the imaging coordinate system takes the imaging center point of the imaging device as its origin and the length, width, and height directions of the imaging device as its axes. The first angle of the surgical instrument in the first coordinate system is obtained by the first tracer; Based on the first angle and the first transformation relationship, the second angle of the surgical instrument in the imaging coordinate system is obtained.

2. The angle calibration method as described in claim 1, characterized in that, The step of calibrating the first transformation relationship between the first coordinate system and the imaging coordinate system based on the scanned image includes: The positions of at least three positioning metals in the first tracer are obtained in the first coordinate system, and the first directional feature data of the at least three positioning metals in the first coordinate system are obtained. The scanned image is identified, the positions of the at least three positioning metals in the imaging coordinate system are obtained, and the second-direction feature data of the at least three positioning metals in the imaging coordinate system are obtained. Based on the first direction feature data and the second direction feature data, a rotation matrix between the first coordinate system and the imaging coordinate system is constructed, and the first transformation relationship between the first coordinate system and the imaging coordinate system is obtained by solving.

3. The angle calibration method as described in claim 1 or 2, characterized in that, The step of obtaining the first angle of the surgical instrument in the first coordinate system through the first tracer includes: The first angle of the surgical instrument in the first coordinate system is measured by the angle measurement module in the first tracer chip. Angle data is uploaded through the transceiver module in the first tracer chip.

4. An angle calibration method as described in any one of claims 1-3, characterized in that, The angle calibration method also includes: At least one second tracer is fixedly mounted on the imaging device; The imaging coordinate system is calibrated using the second tracer; when the imaging device moves, a second transformation relationship is obtained between the imaging coordinate system after the movement and the imaging coordinate system before the movement.

5. The angle calibration method as described in claim 4, characterized in that, The angle calibration method also includes: Based on the second transformation relationship, the first transformation relationship is corrected; Based on the first angle and the corrected first transformation relationship, the second angle of the surgical instrument in the imaging coordinate system is obtained.

6. An angle calibration method as described in claim 4 or 5, characterized in that, The method of obtaining a second transformation relationship between the imaging coordinate system after movement and the imaging coordinate system before movement when the imaging device moves includes: The second tracer measures the angular change of the imaging coordinate system in the second coordinate system; wherein the second coordinate system takes the location of the second tracer chip in the second tracer as its origin; Construct a first rotation matrix between the second coordinate system and the pre-motion imaging coordinate system; construct a second rotation matrix between the second coordinate system and the post-motion imaging coordinate system; Based on the first rotation matrix and the second rotation matrix, a third rotation matrix is ​​obtained between the imaging coordinate system after movement and the imaging coordinate system before movement; the third rotation matrix is ​​solved to obtain a second transformation relationship between the imaging coordinate system after movement and the imaging coordinate system before movement.

7. An angle calibration method as described in any one of claims 1-6, characterized in that, The angle calibration method also includes: Based on the second angle, a navigation path is planned for the surgical instrument from its current position to the target point.

8. An angle calibration system, characterized in that, It includes: An imaging device is used to place surgical instruments within the imaging range of the imaging device for scanning and to acquire scanned images; a first tracer is fixedly mounted on the surgical instruments. The processor is configured to calibrate a first transformation relationship between a first coordinate system and an imaging coordinate system based on the scanned image; wherein the first coordinate system takes the location of the first tracer chip in the first tracer as its origin; and the imaging coordinate system takes the imaging center point of the imaging device as its origin and the length, width, and height directions of the imaging device as its axes. The first tracer is used to acquire the first angle of the surgical instrument in the first coordinate system; The processor is further configured to obtain a second angle of the surgical instrument in the imaging coordinate system based on the first angle and the first transformation relationship.

9. The angle calibration system as described in claim 8, characterized in that, The angle calibration system also includes: A second tracer is fixedly mounted on the imaging device; used to calibrate the imaging coordinate system. The processor is further configured to acquire a second transformation relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement when the imaging device moves.

10. A tracer, characterized in that, Includes a main body, a tracer chip disposed within the main body, and a positioning metal; The main body is used to fix itself on the target device; The tracer chip includes an angle measurement module and a transceiver module; The angle measurement module is used to measure the angle of the target device; the transceiver module is used to upload the angle to the upper-level processor. The positioning metal includes at least three positioning metals, which are fixed in position relative to the tracer chip and are used to calibrate the position of the tracer chip.

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