Angle calibration method, system and tracer

Abstract

The present application discloses an angle calibration method, system and tracer, wherein the method comprises: fixing a first tracer on a surgical instrument, acquiring an intraoperative scanning image, and calibrating a first conversion relationship between a first coordinate system and an imaging coordinate system through the first tracer; thereby acquiring a second angle of the surgical instrument in the imaging coordinate system. Fixing at least one second tracer on an imaging device, calibrating the imaging coordinate system through the second tracer; acquiring a second conversion relationship between the imaging coordinate system after movement and the imaging coordinate system before movement. When the imaging device moves, the first conversion relationship is corrected based on the second conversion relationship, thereby correcting the second angle of the surgical instrument in the imaging coordinate system. The present application is aimed at movable imaging devices, and accurate angles can be acquired without repeated calibration.

Description

Technical Field

[0001] The present application relates to the field of medical equipment, and in particular, to an angle calibration method, system and tracer. Background Art

[0002] During interventional surgery, it is usually necessary to obtain the position of surgical instruments in the human body in order to achieve precise control of the surgical instruments and make them reach the target position. However, due to the amount of radiation and the space of the operating table, real-time shooting is not possible during the operation, so angle sensors are needed to calibrate the surgical instruments. The currently used surgical positioning and navigation systems require precise spatial displacement information and can only use expensive optical / infrared / millimeter wave positioning systems. Therefore, we try to use angle sensors to detect angle changes, which are used in imaging equipment to ensure precise angle control of surgical instruments during imaging.

[0003] However, in actual practice, the data sent back by the angle sensor chip is measured based on the earth's gravity or angular acceleration. However, the imaging requirement of CBCT is to image based on the coordinate system of the CBCT device. 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 the device need to be calibrated before use to align the two coordinate systems.

[0004] However, in some mobile CBCT devices, the device needs to frequently change its working location or adjust its position to achieve a larger imaging range. The position will change after each move, so the coordinate system of the device will be different after each move, and the calibration tool with angle sensor needs to be re-scanned for calibration. This is not only troublesome but also increases the imaging process and time overall. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides an angle calibration method, system and tracer, which are combined with the tracer to realize imaging recognition and angle calibration of surgical instruments. After successful calibration, even if the imaging device moves or the angle changes, the angle of the surgical instrument can be automatically corrected in the imaging coordinate system without the need for re-calibration.

[0006] Specifically, the technical solution of this application is as follows:

[0007] In a first aspect, the present application discloses an angle calibration method, comprising:

[0008] Placing a surgical instrument within the imaging range of an imaging device for scanning to obtain a scanned image; a first tracer is fixedly provided on the surgical instrument;

[0009] Based on the scanned image, calibrate a first conversion relationship between the first coordinate system and the imaging coordinate system;

[0010] Wherein, the first coordinate system takes the position of the first tracer chip in the first tracer as the origin, the imaging coordinate system takes the imaging center point of the imaging device as the origin, and takes the length, width and height directions of the imaging device as the axes;

[0011] Acquire a first angle of the surgical instrument in the first coordinate system by using the first tracer;

[0012] Based on the first angle and the first conversion relationship, a second angle of the surgical instrument in the imaging coordinate system is obtained.

[0013] In some embodiments, the step of calibrating a first conversion relationship between a first coordinate system and an imaging coordinate system based on the scanned image includes:

[0014] Acquire positions of at least three positioning metals in the first tracer in the first coordinate system, and obtain first angle characteristic data of the at least three positioning metals in the first coordinate system;

[0015] Identify the scanned image, acquire positions of the at least three positioning metals in the imaging coordinate system, and obtain second directional feature data of the at least three positioning metals in the imaging coordinate system;

[0016] Based on the first directional feature data and the second directional feature data, a rotation matrix between the first coordinate system and the imaging coordinate system is constructed, and the first conversion relationship between the first coordinate system and the imaging coordinate system is obtained by solving the rotation matrix.

[0017] In some embodiments, obtaining the first angle of the surgical instrument in the first coordinate system by using the first tracer includes:

[0018] Measuring a first angle of the surgical instrument in the first coordinate system by using an angle measurement module in the first tracer chip;

[0019] The angle data is uploaded through the transceiver module in the first tracer chip.

[0020] In some embodiments, the angle calibration method further includes:

[0021] At least one second tracer is fixedly disposed on the imaging device;

[0022] The imaging coordinate system is calibrated by the second tracer; when the imaging device moves, a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement is obtained.

[0023] In some embodiments, the angle calibration method further includes:

[0024] Based on the second conversion relationship, correcting the first conversion relationship;

[0025] Based on the first angle and the corrected first conversion relationship, a second angle of the surgical instrument in the imaging coordinate system is obtained.

[0026] In some embodiments, when the imaging device moves, obtaining a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement includes:

[0027] The angle change of the imaging coordinate system in the second coordinate system is measured by the second tracer; wherein the second coordinate system takes the position of the second tracer chip in the second tracer as the origin;

[0028] Constructing a first rotation matrix between the second coordinate system and the imaging coordinate system before the movement; constructing a second rotation matrix between the second coordinate system and the imaging coordinate system after the movement;

[0029] Based on the first rotation matrix and the second rotation matrix, a third rotation matrix between the imaging coordinate system after movement and the imaging coordinate system before movement is obtained; and the third rotation matrix is ​​solved to obtain a second conversion relationship between the imaging coordinate system after movement and the imaging coordinate system before movement.

[0030] In some embodiments, the angle calibration method further includes:

[0031] Based on the second angle, a navigation path of the surgical instrument from the current position to the target point is planned.

[0032] In a second aspect, the present application discloses an angle calibration system, comprising:

[0033] An imaging device, used to place a surgical instrument within an imaging range of the imaging device for scanning and obtaining a scanned image; a first tracer is fixedly provided on the surgical instrument;

[0034] A processor, configured to calibrate a first conversion relationship between a first coordinate system and an imaging coordinate system based on the scanned image; wherein the first coordinate system takes the position of the first tracer chip in the first tracer as an origin; and the imaging coordinate system takes the imaging center point of the imaging device as an origin and the length, width and height directions of the imaging device as axes;

[0035] The first tracer is used to obtain a first angle of the surgical instrument in the first coordinate system;

[0036] 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 conversion relationship.

[0037] In some embodiments, the angle calibration system further includes:

[0038] A second tracer, which is fixedly disposed on the imaging device and is used to calibrate the imaging coordinate system;

[0039] The processor is further configured to obtain, when the imaging device moves, a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement.

[0040] In a third aspect, the present application further discloses a tracer, comprising a main body, a tracer chip and a positioning metal arranged in the main body;

[0041] The main body is used to fix itself on the target device;

[0042] 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 processor;

[0043] The positioning metal includes at least three positioning metals, and the at least three positioning metals are fixed relative to the position of the tracer chip and are used to calibrate the position of the tracer chip.

[0044] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0045] 1. The angle calibration algorithm provided in this application connects the tracer to the surgical instrument to feedback the angle data and calibrate the position and angle of the surgical instrument in the imaging coordinate system. This can be used in the imaging device to ensure accurate angle control of the surgical instrument during the operation after the imaging is received.

[0046] 2. The angle calibration algorithm provided in this application connects another set of tracers to the imaging device to feedback the posture information of the current position of the mobile CBCT device, and the data is transmitted to the computer to calculate the angle difference from the initial calibration. Through the one-time calibration of two sets of angle measurement devices during admission and debugging, a permanent connection between the imaging coordinate system and the surgical instrument coordinate system is established, which can achieve real-time unification of the angle coordinate system at a very low cost. It no longer relies on the calibration of optics or other equipment before surgery, and can also achieve the guidance of surgical instruments. It saves the cost of expensive optical positioning instruments and the time spent on preoperative calibration. Doctors do not need to scan the angle sensor for calibration before each operation, nor do they need to recalibrate after each movement during the operation, which reduces the surgical process and saves surgical time.

[0047] 3. This application can also generate a navigation path based on the current posture of the surgical instrument, so as to assist in manipulating the surgical instrument to reach the target point, thereby improving the success rate of the surgery and reducing the risk of the surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present application.

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

[0050] Figure 2 A flowchart of the steps of an embodiment of an angle calibration method provided by the present application;

[0051] Figure 3 A flowchart of another embodiment of an angle calibration method provided by the present application;

[0052] Figure 4 A structural block diagram of an embodiment of an angle calibration system provided in the present application. DETAILED DESCRIPTION

[0053] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[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, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.

[0055] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0056] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0057] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] In a specific implementation, the terminal device described in the embodiments of the present application includes, but is not limited to, other portable devices such as mobile phones, laptop computers, tutoring machines, or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and / or touch pads). It should also be understood that in some embodiments, the terminal device is not a portable communication device, but a desktop computer with a touch-sensitive surface (e.g., touch screen displays and / or touch pads).

[0059] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

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

[0061] In interventional surgery, doctors rely on imaging technology to obtain real-time images of the surgical area to ensure that surgical instruments can accurately navigate to the target area. Through these images, doctors need to clearly see the position of surgical instruments relative to surrounding tissues so that they can perform precise operations, avoid unnecessary damage to surrounding normal tissues, and ensure that surgical instruments can safely and effectively reach the predetermined target location. However, due to site conditions, in most cases doctors cannot perform surgery with continuous CT equipment.

[0062] The surgical positioning and navigation systems currently in use require precise spatial displacement information, and therefore use expensive optical / infrared / millimeter wave positioning systems. Therefore, we try to use angle sensors to measure the angle data of surgical instruments and then import it into the three-dimensional image of the human body taken at time t0 for display. Only one shot is needed, and then the patient can be removed from the imaging device for surgery. The posture of the surgical instrument in the human body is then completely displayed in the three-dimensional image of the human body taken at time t0 by the angle sensor. This can greatly reduce the radiation dose. In addition, the angle calibration method and system provided in this application only use angle sensors and angle information, and the cost is very low. It is a few hundredths of the optical positioning system commonly used in the prior art.

[0063] The data sent back by the angle sensor chip is measured based on the earth's gravity or angular acceleration. However, the imaging requirement of CBCT is to perform imaging based on the coordinate system of the CBCT device. Therefore, the angle data measured by the angle sensor cannot be directly applied to the imaging coordinate system.

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

[0065] Among them, a tracer, refer to the instructions attached Figure 1 , including a main body, a tracer chip and a positioning metal arranged in the main body.

[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 processor.

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

[0069] Specifically, in some embodiments, the tracer is a hollow structure, and the tracer can be nested on the target device. Its main body is a columnar structure, such as a prism or a cylinder. It can also be a sphere, a polyhedron, etc. In other embodiments, the tracer body includes at least one side surface for attaching the tracer to the target device.

[0070] The tracer chip includes an angle measurement module and a transceiver module. Among them, 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 the principle of electromagnetic induction and based on the inertial field. For example, a compass chip based on the principle of magnetic field, an IMU (inertial measurement unit) based on the principle of inertia, etc. 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 protection of this application. The transceiver module is a module with wireless communication function, such as a Bluetooth chip, NFC, RFID, etc.

[0071] The locating metal has a set position in the tracer body. According to the position of the locating metal, its directional characteristic data in the coordinate system with the tracer chip as the origin can be inferred. In some embodiments, the directional characteristic data includes: an intersecting vector group formed by the locating metal connection, or a quaternion, a rotation angle, etc.

[0072] In other implementations, for the convenience of calculation, the intersection vector group formed by the connection between the positioning metals is orthogonal.

[0073] The structure of the tracer is shown in the attached manual. Figure 1 , where the tracer takes a square structure as an example. It includes a hollow structure 1, a positioning metal 2, and a tracer chip 3. Specifically, four spherical positioning metals (positioning steel balls) form three intersecting vectors for calibrating the position of the tracer chip 3. The tracer chip 3 is close to the surface of the hollow structure of the main body, so that the tracer chip is close to the target device.

[0074] based on Figure 1 The tracer shown in the embodiment of the angle calibration method of the present application is shown in the appendix of the specification. Figure 2 As shown, the following steps are included:

[0075] S100, placing a surgical instrument within the imaging range of the imaging device for scanning to obtain a scanned image. A first tracer is fixedly disposed 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, that is, the first coordinate system in the imaging coordinate system can be accurately calculated. Among them, the first coordinate system takes the position of the first tracer chip in the first tracer as the origin. Specifically, the angle measurement module in the tracer chip has at least two measurement modes, including a magnetic field navigation mode based on the electromagnetic induction principle and an inertial navigation mode based on the inertial field measurement method. In the magnetic field navigation mode, the first coordinate system takes the position of the first tracer chip in the first tracer as the origin, usually with the east-west direction, the north-south direction, and the vertical direction as the axis, and other directions can also be specially set as the reference. In the inertial navigation mode, there is no need to specify the direction of the axis of the coordinate system, and any other orthogonal system can be used as the reference coordinate. It is sufficient to measure the difference between the reference coordinate system and the image coordinate system during calibration.

[0077] The imaging coordinate system takes 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 device may be a CT device, a CBCT device, etc. The surgical instrument includes a guide, a puncture needle, and the like.

[0079] S200: Calibrate a first conversion relationship between a first coordinate system and an imaging coordinate system based on the scanned image.

[0080] Specifically, it includes step S210, acquiring positions of at least three positioning metals in the first tracer in the first coordinate system, and obtaining first angle feature data of the at least three positioning metals in the first coordinate system.

[0081] S220, identifying the scanned image, acquiring positions of the at least three positioning metals in the imaging coordinate system, and obtaining second directional feature data of the at least three positioning metals in the imaging coordinate system.

[0082] S230: construct a rotation matrix between the first coordinate system and the imaging coordinate system based on the first directional feature data and the second directional feature data, and solve the first conversion 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 positioning metals or even more positioning metals.

[0084] S300: Acquire a first angle of the surgical instrument in the first coordinate system using the first tracer.

[0085] Specifically, the first angle of the surgical instrument in the first coordinate system is measured by an angle measurement module in the first tracer chip, and the angle data is uploaded by a transceiver module in the first tracer chip.

[0086] S400: Obtain a second angle of the surgical instrument in the imaging coordinate system based on the first angle and the first conversion relationship.

[0087] Specifically, the angle of the current surgical instrument in the image coordinate system is obtained, and the surgical instrument can be adjusted according to the current position to achieve a fixed insertion angle. Preferably, step S500 is also included to plan a navigation path of the surgical instrument from the current position to the target point based on the second angle.

[0088] Another embodiment of an angle calibration method provided by the present application explains the content of the previous embodiment 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 locating 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 slight errors in processing and installation, the angles of the tracer chip and the surgical instrument are not necessarily completely vertical and horizontal, so the angle vector measured by the angle measurer we obtained is Z1. The error between Z0 and Z1 is used to calculate the inherent error between the angle measured by the tracer chip and the true angle of the surgical instrument. Because the angle between the surgical instrument and the tracer chip is fixedly connected, the size of the inherent error is fixed. That is, it can be considered that the transformation relationship between the coordinate system of the tracer chip and the coordinate system where the surgical instrument is located remains unchanged. The rotation matrix multiplication relationship formula is: S0=C 01 *S1; S0 is the coordinate system where the surgical instrument is located, C 01 is the coordinate system of the tracer chip; S1 is the conversion relationship between the coordinate system of the tracer chip and the coordinate system where the surgical instrument is located. All the information required during the operation can be unified into 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. The unique angle vector of the surgical instrument in the imaging coordinate system can be obtained. All errors and different coordinate systems will quilt Automatic correction.

[0090] In the above embodiment, based on the tracer, calibration between the tracer coordinate system (first coordinate system) and the imaging device coordinate system (imaging coordinate system) can be achieved, so that angle measurement is more accurate, higher quality imaging results can be provided, and doctors can achieve precise control of surgical instruments.

[0091] However, in some mobile CBCT devices, the device needs to frequently change its working location or adjust its position to achieve a larger imaging range. The angle of the image coordinate system will be rotated with the instrument 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, the tracer coordinate system and the imaging device coordinate system need to be recalibrated before use to unify the two coordinate systems. This is not only troublesome but also increases the imaging process and time as a whole.

[0092] In order to solve this technical problem, the present application provides another embodiment of an angle calibration method, which can be provided by setting one or more tracers on the mobile imaging device to feedback the posture information of the current position of the mobile imaging device, and then transmit the data to the upper layer processor for calculating the angle difference from the initial calibration. Figure 3 As shown, this embodiment includes the following steps:

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

[0094] S200: Calibrate a first conversion relationship between a first coordinate system and an imaging coordinate system based on the scanned image.

[0095] S300: Acquire a first angle of the surgical instrument in the first coordinate system using the first tracer.

[0096] S400: Obtain a second angle of the surgical instrument in the imaging coordinate system based on the first angle and the first conversion relationship.

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

[0098] S600: Correct the first conversion relationship based on the second conversion relationship.

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

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

[0101] Specifically, when the imaging device moves during surgery, that is, when the device coordinate system position transmitted by the imaging device tracer changes, the navigation computer obtains the conversion relationship between the new device coordinate system position after the movement and the old device coordinate system angle, thereby obtaining the conversion relationship between the new device coordinate system position and the surgical instrument coordinate system angle.

[0102] In some implementations of this embodiment, the step S500: when the imaging device moves, obtaining a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement specifically includes:

[0103] S510, measuring the angular change of the imaging coordinate system in the second coordinate system through the second tracer. The second coordinate system takes the position of the second tracer chip in the second tracer as the origin. Specifically, the angle measurement module in the tracer chip has at least two measurement modes, including a magnetic field navigation mode based on the principle of electromagnetic induction and an inertial navigation mode based on the inertial field measurement method. In the magnetic field navigation mode, the second coordinate system can be set to usually take the position of the second tracer chip in the second tracer as the origin, and the east-west direction, north-south direction, and vertical direction as the axis, or a specific coordinate system can be set as the reference. In the inertial navigation mode, there is no need to specify the direction of the axis of the coordinate system, and any other orthogonal system can be used as the reference coordinate. It is sufficient to measure the difference between the reference coordinate system and the imaging coordinate system during calibration.

[0104] S520: Construct a first rotation matrix between the second coordinate system and the imaging coordinate system before the movement. Construct a second rotation matrix between the second coordinate system and the imaging coordinate system after the movement.

[0105] S530: Based on the first rotation matrix and the second rotation matrix, obtain a third rotation matrix between the imaging coordinate system after the movement and the imaging coordinate system before the movement. Solve the third rotation matrix to obtain a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement.

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

[0107] In the first implementation of this embodiment:

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

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

[0110] Assume that the vector represented by the surgical instrument in the first coordinate system A is known to be u3. Then the vector v3 represented by the surgical instrument vector in the imaging coordinate system S0 before movement can be calculated based on the following matrix multiplication: v3=C1·u3.

[0111] Based on the rotation matrix M between the imaging coordinate system S0 before movement and the imaging coordinate system S1 after movement, the vector v33 represented by the surgical instrument vector in the imaging coordinate system S1 after movement can be calculated based on the following matrix multiplication: v33=M·v3.

[0112] In the second implementation mode of this embodiment:

[0113] If the image device coordinate system and the second angle sensor are not reset to zero at the same time during installation and there is an inherent error, we cannot know M directly. We can use the following method to calculate M.

[0114] Assume that the imaging coordinate system before the movement is coordinate system S0. The imaging coordinate system after the 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 movement and rotates together, after the device moves, the second coordinate system B1 after movement is obtained through the function of the tracer.

[0116] The rotation matrix between the second coordinate system B and the moved second coordinate system B1 is calculated as R. Assume that the rotation matrix between the imaging coordinate system before the movement is the coordinate system S0 and the second coordinate system B is E. Then the rotation matrix M between the imaging coordinate system before the movement S0 and the imaging coordinate system after the movement S1 can be calculated based on the following matrix multiplication: M=E -1 *R*E, where E -1 It represents the inverse matrix of E. 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 installed and fixed on the imaging instrument. E can be obtained by the difference between the reported quaternion / angle information of the positioning device on the instrument during the initial calibration of the imaging device and the angle between the axes of the imaging coordinate system S0.

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

[0118] In order to solve the technical problem that each time the imaging coordinate system moves from the first position to the second position, it must be recalibrated. This is very inconvenient in clinical use. We place the second tracer on the imaging device. The placement angle is arbitrary and must be rigidly fixed. When the module is produced, the side that contacts the device can be veneered with strong glue, which is convenient for modifying existing equipment. In some other embodiments of an angle calibration method provided by the present application, multiple second tracers can be set on the imaging device and pasted and fixed at different positions of the imaging device to feedback multiple posture information for calculating the angle difference. The average value of the angles measured by the multiple second tracers is calculated as a representative value with higher accuracy.

[0119] Through this embodiment, only one calibration is required after the device is produced, so that the navigation function can be used directly without the need for a second calibration, thereby achieving the purpose of saving cost and time.

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

[0121] The imaging device is used to place the surgical instrument within the imaging range of the imaging device for scanning and obtaining a scanned image. A first tracer is fixedly arranged on the surgical instrument.

[0122] The processor is used to calibrate the first conversion relationship between the first coordinate system and the imaging coordinate system based on the scanned image. The first coordinate system takes the position of the first tracer chip in the first tracer as the origin. Specifically, the angle measurement module in the tracer chip has at least two measurement modes, including a magnetic field navigation mode based on the electromagnetic induction principle and an inertial navigation mode based on the inertial field measurement method. In the magnetic field navigation mode, the first coordinate system usually takes the position of the first tracer chip in the first tracer as the origin, and takes the east-west direction, the north-south direction, and the vertical direction as the axis. In the inertial navigation mode, there is no need to specify the direction of the axis of the coordinate system, and any other orthogonal system can be used as the reference coordinate. It is sufficient to measure the difference between the reference coordinate system and the imaging coordinate system during calibration.

[0123] The imaging coordinate system takes 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 obtain a 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 conversion relationship.

[0126] Another embodiment of an angle calibration system provided by the present application is shown in the attached specification. Figure 4 As shown, based on the above system embodiment, the angle calibration system further includes:

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

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

[0129] In the above embodiment, 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 collected by the imaging device.

[0131] The navigation calculation module is used to receive the angle data sent by the first tracer or the second tracer, and to calibrate the angle of the surgical instrument and the imaging device based on the angle data, and to plan the navigation path of the surgical instrument from the 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 a display screen so that the doctor can view and obtain relevant information.

[0133] An angle calibration method, system and tracer of the present 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 described again.

[0134] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned program modules is used as an example for illustration. In actual applications, the above-mentioned 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 embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into a processing unit, and the above-mentioned integrated unit can be implemented in the form of hardware or in the form of software program units. In addition, the specific names of the program modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0135] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

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

[0137] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. Exemplarily, the device embodiments described above are merely schematic. Exemplarily, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation. Exemplarily, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0138] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0139] In addition, each functional unit in each embodiment of the present 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 above integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0140] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0141] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. An angle calibration method, characterized in that: include: Placing a surgical instrument within the imaging range of an imaging device for scanning to obtain a scanned image; a first tracer is fixedly provided on the surgical instrument; Based on the scanned image, calibrate a first conversion relationship between the first coordinate system and the imaging coordinate system; The first coordinate system takes the position of the first tracer chip in the first tracer as the origin; the imaging coordinate system takes 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; Acquire a first angle of the surgical instrument in the first coordinate system by using the first tracer; Based on the first angle and the first conversion relationship, obtaining a second angle of the surgical instrument in the imaging coordinate system; Wherein, the step of calibrating a first conversion relationship between the first coordinate system and the imaging coordinate system based on the scanned image includes: Acquire positions of at least three positioning metals in the first tracer in the first coordinate system, and obtain first directional characteristic data of the at least three positioning metals in the first coordinate system; Identify the scanned image, acquire positions of the at least three positioning metals in the imaging coordinate system, and obtain second directional feature data of the at least three positioning metals in the imaging coordinate system; Based on the first directional feature data and the second directional feature data, a rotation matrix between the first coordinate system and the imaging coordinate system is constructed, and the first conversion relationship between the first coordinate system and the imaging coordinate system is obtained by solving the rotation matrix.

2. An angle calibration method as claimed in claim 1, characterized in that: The step of obtaining the first angle of the surgical instrument in the first coordinate system by using the first tracer includes: Measuring a first angle of the surgical instrument in the first coordinate system by using an angle measurement module in the first tracer chip; The angle data is uploaded through the transceiver module in the first tracer chip.

3. The angle calibration method according to claim 1, characterized in that: Also includes: At least one second tracer is fixedly disposed on the imaging device; calibrating the imaging coordinate system by means of the second tracer; When the imaging device moves, a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement is acquired.

4. An angle calibration method as claimed in claim 3, characterized in that: Also includes: Based on the second conversion relationship, correcting the first conversion relationship; Based on the first angle and the corrected first conversion relationship, a second angle of the surgical instrument in the imaging coordinate system is obtained.

5. The angle calibration method according to claim 3, characterized in that: When the imaging device moves, obtaining a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement includes: The angle change of the imaging coordinate system in the second coordinate system is measured by the second tracer; wherein the second coordinate system takes the position of the second tracer chip in the second tracer as the origin; Constructing a first rotation matrix between the second coordinate system and the imaging coordinate system before the movement; constructing a second rotation matrix between the second coordinate system and the imaging coordinate system after the movement; Based on the first rotation matrix and the second rotation matrix, a third rotation matrix between the imaging coordinate system after movement and the imaging coordinate system before movement is obtained; and the third rotation matrix is ​​solved to obtain a second conversion relationship between the imaging coordinate system after movement and the imaging coordinate system before movement.

6. An angle calibration method according to claim 1 or 4, characterized in that: Also includes: Based on the second angle, a navigation path of the surgical instrument from the current position to the target point is planned.

7. An angle calibration system, characterized in that: include: An imaging device, used to place a surgical instrument within an imaging range of the imaging device for scanning and obtaining a scanned image; a first tracer is fixedly provided on the surgical instrument; A processor, configured to calibrate a first conversion relationship between a first coordinate system and an imaging coordinate system based on the scanned image; wherein the first coordinate system takes the position of the first tracer chip in the first tracer as an origin; and the imaging coordinate system takes the imaging center point of the imaging device as an origin and the length, width and height directions of the imaging device as axes; The first tracer is used to obtain a 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 conversion relationship; The processor is further configured to perform the following steps: Acquire positions of at least three positioning metals in the first tracer in the first coordinate system, and obtain first directional characteristic data of the at least three positioning metals in the first coordinate system; Identify the scanned image, acquire positions of the at least three positioning metals in the imaging coordinate system, and obtain second directional feature data of the at least three positioning metals in the imaging coordinate system; Based on the first directional feature data and the second directional feature data, a rotation matrix between the first coordinate system and the imaging coordinate system is constructed, and the first conversion relationship between the first coordinate system and the imaging coordinate system is obtained by solving the rotation matrix.

8. An angle calibration system as claimed in claim 7, characterized in that: Also includes: A second tracer, which is fixedly disposed on the imaging device and is used to calibrate the imaging coordinate system; The processor is further configured to obtain, when the imaging device moves, a second conversion relationship between the imaging coordinate system after the movement and the imaging coordinate system before the movement.

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