Dynamic tracking method and system based on dual-plane X-ray system

Abstract

The present invention discloses a dynamic tracking method based on a dual-plane X-ray system. The dual-plane X-ray system comprises a transmitter for transmitting X-rays to a human body; a receiver for receiving X-rays attenuated by a human body to form an image, and calibrating the dual-plane X-ray system with the spatial position of a tracking device; obtaining the spatial position of a human joint through the tracking device; converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system through coordinate conversion, obtaining the predicted joint position and joint speed information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement; collecting X-ray images and obtaining dynamic X-ray images of human joint movement, obtaining the relative relationship between the joints in each frame through registration of the joint X-ray image and the three-dimensional model of each frame, thereby obtaining the kinematic parameters of the joints, and realizing dynamic analysis of the patient's movement.

Description

Technical Field

[0001] The present invention relates to the field of medical imaging technology, and in particular to a dynamic tracking method and system based on a dual-plane X-ray system. Background Art

[0002] The imaging diagnostic and treatment methods currently used in orthopedics mainly include X-rays, CT and MRI, which cannot reproduce the impact of diseases on joint movement function, and also limit the clinical efficacy of orthopedic diagnosis and treatment. In recent years, orthopedic physicians have pursued functional reconstruction, which requires not only the anatomical diagnosis of bones and joints, but also the quantitative functional evaluation of the functional alignment of their structures under stress and motion conditions.

[0003] Traditional medical imaging diagnostic tools, such as X-ray systems, can only see from one direction, and have problems such as small imaging range, high X-ray dose, and inconvenience in use. CT scanning can obtain three-dimensional imaging of joints, but the radiation dose is large. At the same time, CT can only obtain static images of patients in the supine position, and cannot obtain images of patients in the standing weight-bearing position, making it impossible to accurately evaluate the patient's joint movement function. MRI images have no radiation dose, but the scanning time is longer, and they can only obtain static images of patients in the supine position. These imaging systems do not have three-dimensional dynamic imaging capabilities, nor can they obtain cross-sectional images and three-dimensional structures of individualized bones and joints of patients. They are still insufficient for the three-dimensional structural information and dynamic functional information of bones and joints required by orthopedic surgeons.

[0004] In summary, it is necessary to propose a dynamic tracking method for the patient's imaging parts to solve the problem of insufficient acquisition of dynamic functional information between the patient's bones and joints. Summary of the invention

[0005] The object of the present invention is to provide a dynamic tracking method and system based on a dual-plane X-ray system.

[0006] The present invention provides a dynamic tracking method based on a dual-plane X-ray system, wherein the dual-plane X-ray system includes a transmitter for transmitting X-rays to a human body; and a receiver for receiving X-rays attenuated after passing through a human body to form an image, and includes the following steps:

[0007] Calibrate the dual-plane X-ray system and the tracking device spatial position;

[0008] Acquiring the spatial position of the human body joints by means of the tracking device;

[0009] The joint position fed back by the tracking device is converted into the coordinates of the dual-plane X-ray system, and the predicted joint position and joint velocity information at the next moment are obtained to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement;

[0010] X-ray images are collected and dynamic X-ray images of human joint movement are obtained. By aligning the joint X-ray images of each frame with the three-dimensional model, the relative relationship between the joints in each frame is obtained, thereby obtaining the kinematic parameters of the joints.

[0011] Preferably, the joint position and joint speed information includes: the joint center position and joint speed in the XYZ axis direction in the dual-plane X-ray system coordinate system, the Z axis direction is the vertical direction, that is, the transmission axis direction, and the XY axis direction is the horizontal direction, that is, the direction perpendicular to the Z axis.

[0012] Preferably, obtaining the predicted joint position and joint velocity information at the next moment includes:

[0013] Use Kalman filter to obtain the predicted value of the joint center state at the current moment According to the state measurement value y(t) of the joint center spatial position and velocity output by the tracking device at the current moment, the predicted value of the joint center state at the current moment is corrected To obtain the best estimate The specific implementation is as follows:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] Where, Q(t) is the input noise covariance matrix, and R(t) is the observation noise covariance matrix.

[0021] Represents the estimated value of the current state; a i is a constant;

[0022] represents the estimated position at time t, represents the estimated value of speed at time t;

[0023] represents the position measurement value at time t-1, represents the speed measurement value at time t-1;

[0024] represents the state error at time t; F represents the state transfer matrix; K represents the Kalman gain matrix; B represents the state control matrix; H represents the gain matrix.

[0025] Preferably, the calibrating the dual-plane X-ray system and the tracking device spatial position comprises:

[0026] A correction box is provided between the field of view of the biplane X-ray system and the tracking device instrument;

[0027] Capturing the spatial coordinates of the first marking body on the correction box by the dual-plane X-ray system and outputting the first coordinates;

[0028] Capturing the spatial coordinates of the first marking body on the correction box by the tracking device and outputting the second coordinates;

[0029] The spatial position of the first marker on the correction box is obtained and a third coordinate is output. When the third coordinate corresponds to the first coordinate and the second coordinate, a conversion matrix between the tracking device coordinate system and the dual-plane X-ray system coordinate system is obtained.

[0030] Preferably, in obtaining the spatial position of the human joint by the tracking device, if the tracking device adopts a photoelectric tracking device or an electromagnetic tracking device, a second marker is set at the human joint position, and the human joint position is located by the marker to obtain the spatial position of the human joint in a moving state.

[0031] Preferably, in acquiring the spatial positions of human joints by the tracking device, if the tracking device adopts a camera, the positions of human joints in a field of view are automatically located by the camera to obtain the spatial positions of human joints in a moving state.

[0032] Preferably, the step of converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system, obtaining the predicted joint position and joint velocity information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement comprises:

[0033] After obtaining the estimated joint positions and joint velocities, they are converted into joint positions and joint velocities in the XYZ three-axis directions in the coordinate system of the dual-plane X-ray system through coordinate transformation;

[0034] The joint position and joint speed information in the XYZ three-axis directions are sent to the motor driver to control the movement of the transmitter and the receiver.

[0035] Preferably, the obtaining of predicted joint position and joint velocity information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement further includes: arranging a plurality of the transmitters and a plurality of the receivers relatively to each other and arranging them on a transmission shaft, the transmission shaft being arranged on a mobile platform, the mobile platform motor driver driving the transmitters and the receivers to move along a plane according to the position and velocity components of the XY axes, and at the same time, according to the position and velocity components in the Z axis direction, the transmission shaft motor driver controls the transmitters and the receivers to move in the Z axis direction.

[0036] Preferably, the obtaining of predicted joint position and joint speed information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement further includes: arranging a plurality of the transmitters and a plurality of the receivers relative to each other and arranging them at the end of a robotic arm, and the robotic arm motor driver drives the transmitters and the receivers to move freely according to the position and speed components of the XYZ axes.

[0037] The present invention provides a dynamic tracking system based on a dual-plane X-ray system, wherein the dual-plane X-ray system includes a transmitter for transmitting X-rays to a human body; and a receiver for receiving X-ray images after passing through a human body. The dynamic tracking system includes:

[0038] A calibration module, used for calibrating the dual-plane X-ray system and the spatial position of the tracking device;

[0039] An acquisition module, used for acquiring the spatial position of a human body joint through the tracking device;

[0040] A coordinate conversion module, used to convert the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system, obtain the predicted joint position and joint speed information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement;

[0041] An adjustment module, used for adjusting the position of the dual-plane X-ray system according to the joint position and joint speed at the next moment predicted by the joint position so that the dual-plane X-ray system follows the joint movement;

[0042] The result output module is used to collect X-ray images and obtain dynamic X-ray images of human joint movement. By aligning the joint X-ray images of each frame with the three-dimensional model, the relative relationship between the joints in each frame is obtained, thereby obtaining the kinematic parameters of the joints.

[0043] With respect to the prior art, the present invention has the following beneficial effects:

[0044] The dynamic tracking method based on the dual-plane X-ray system provided by the present invention estimates the joint position, and then performs spatial conversion of the dual-plane X-ray system and the tracking device. The position and speed information are sent to the motor driver through the upper software, thereby realizing dynamic tracking of the joints during the patient's movement and obtaining the patient's joint part or the whole body frontal and lateral X-ray images in the weight-bearing position.

[0045] The present invention can obtain dynamic images during joint movement, obtain joint kinematic parameters under a complete natural movement of the human body, and accurately evaluate the patient's joint movement function;

[0046] The present invention can obtain the spatial position of the center of the human joint in real time, and can ensure that the center of the human joint is in the center of the frontal / lateral X-ray image, thereby increasing the proportion of useful information of the X-ray image in the entire X-ray image;

[0047] The present invention performs 2D to 3D registration of each frame of the collected dynamic image with the three-dimensional model, thereby obtaining the three-dimensional structural information and dynamic functional information of the bones and joints required by the doctor. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic diagram of the steps of a dynamic tracking method based on a dual-plane X-ray system according to Embodiment 1 of the present invention;

[0049] Figure 2 This is a flow chart of an automatic following system of a dynamic tracking method based on a dual-plane X-ray system according to the first embodiment of the present invention;

[0050] Figure 3 It is a schematic diagram of a dynamic tracking method based on a dual-plane X-ray system according to Embodiment 1 of the present invention;

[0051] Among them, 1-first receiver, 2-second receiver, 3-second transmitter, 4-first transmitter, 5-tracking device, 6-host computer, 7-first mobile platform, 8-second mobile platform, 9-third mobile platform, 10-fourth mobile platform, 11-first transmission shaft, 12-second transmission shaft, 13-third transmission shaft, 14-fourth transmission shaft. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Embodiment 1

[0054] like Figure 1 As shown, the present invention provides a dynamic tracking method based on a dual-plane X-ray system, wherein the dual-plane X-ray system includes a transmitter for transmitting X-rays to a human body; and a receiver for receiving X-rays attenuated after passing through a human body to form an image, including the following steps:

[0055] Step S1, calibrating the dual-plane X-ray system and the spatial position of the tracking device;

[0056] Step S2, obtaining the spatial position of the human body joints by means of the tracking device;

[0057] Step S3, converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system, obtaining the predicted joint position and joint velocity information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement;

[0058] Step S4, collect X-ray images and obtain dynamic X-ray images of human joint movement, that is, obtain dynamic images during joint movement, and obtain the relative relationship between joints in each frame by aligning the joint X-ray images of each frame with the three-dimensional model, thereby obtaining the kinematic parameters of the joints, and analyzing the patient's motor function. The collected X-ray images can be joint parts of the patient in the weight-bearing position or whole body frontal / lateral X-ray images.

[0059] The dynamic tracking method based on the dual-plane X-ray system provided by the present invention estimates the joint position, and then performs spatial conversion through the dual-plane X-ray system and the tracking device. The position and speed information are sent to the motor driver through the upper software, thereby realizing dynamic tracking of the patient's movement and obtaining the patient's joint part or the whole body frontal and lateral X-ray images in the weight-bearing position.

[0060] The present invention can obtain dynamic images during joint movement, obtain joint kinematic parameters under a complete natural movement of the human body, and accurately evaluate the patient's joint movement function; it can obtain the spatial position of the human joint center in real time, and can ensure that the human joint center is in the center of the frontal / lateral X-ray image, thereby increasing the proportion of useful information of the X-ray image in the entire X-ray image; each frame of the collected dynamic image is registered with the three-dimensional model from 2D to 3D, thereby obtaining the three-dimensional structural information and dynamic functional information of the bones and joints required by doctors.

[0061] like Figure 2 As shown, the calibrating the dual-plane X-ray system and the tracking device spatial position includes:

[0062] A correction box is provided between the field of view of the dual plane X-ray system and the tracking device;

[0063] Capturing the spatial coordinates of the first marking body on the correction box by the dual-plane X-ray system and outputting the first coordinates;

[0064] Capturing the spatial coordinates of the first marking body on the correction box by the tracking device and outputting the second coordinates;

[0065] The spatial position of the first marker on the correction box is obtained and a third coordinate is output. When the third coordinate corresponds to the first coordinate and the second coordinate, a conversion matrix between the tracking device coordinate system and the dual-plane X-ray system coordinate system is obtained.

[0066] In this embodiment, the dual-plane X-ray system is adjusted to the initial position, and the tracking device is fixed. Figure 3 As shown, ensure that the patient is in the imaging area of ​​the tracking device, and place a correction box in the field of view of the two devices. The surface of the correction box is inlaid with infrared reflective balls of known spatial distribution. The center of the reflective ball contains a metal steel ball. The metal steel ball and the reflective ball have the same center, which is the first marker. Use the dual-plane system to capture the spatial coordinates of the center of the metal steel ball; use the tracking device to capture the spatial coordinates of the reflective ball; use the spatial positions of all the reflective balls on the correction box to achieve spatial position correction of the tracking device and the dual-plane X-ray system, thereby obtaining the conversion matrix between the coordinate system of the tracking device and the coordinate system of the dual-plane X-ray system;

[0067] Specifically, in the process of obtaining the spatial position of a human joint by the tracking device, if the tracking device adopts a photoelectric tracking device or an electromagnetic tracking device, a second marker is set at the human joint, and the human joint position is located by the marker to obtain the spatial position of the human joint in a moving state. If an optical tracking device such as a photoelectric tracking device is used, a reflective ball, i.e., a second marker, needs to be installed at the patient's joint, such as a hip joint, a knee joint, etc.

[0068] Specifically, in the acquisition of the spatial position of the human joint by the tracking device, if an optical tracking device such as photoelectric tracking is used, it is necessary to install a reflective ball at the patient's joints, such as the hip joints, knee joints and other joints that need to be imaged. If the tracking device uses a camera, the camera automatically locates the position of the human joints in the field of view to obtain the spatial position of the human joints in motion. If a depth camera such as Kinect is used, it is not necessary to install markers at the joint positions. The Kinect camera can automatically locate the position of the human joints in the field of view; the patient stands in the imaging area and completes a squat-stand action; during the patient's movement, the tracking device obtains the spatial position of the joint center in its own coordinate system, and converts the spatial position to the dual-plane X-ray system coordinate system through the conversion matrix obtained by calibration in step S1.

[0069] Those skilled in the art can understand that the tracking device obtains the spatial position of the center of the human joint, the dual-plane X-ray system receives the joint center position fed back by the tracking device, predicts the joint center position and joint movement speed at the next moment, and adjusts the position of the transmitter and receiver to follow the joint movement; before the movement, the position of the tracking device and the dual-plane system is corrected to obtain the relative position relationship between the two. The tracking device includes but is not limited to cameras, photoelectric tracking, electromagnetic tracking, etc. After obtaining the three-dimensional coordinates of the joint center, the tracking device converts the coordinates to the dual-plane X-ray system coordinates. The dual-plane X-ray system adjusts the position of the transmitter and receiver according to the information of the three-axis XYZ of the predicted joint center position and joint speed at the next moment, thereby realizing dynamic tracking of the patient's movement.

[0070] In order to realize the coordinate transformation, the real-time spatial position p and velocity v of the human joint center can be regarded as the state function of time t

[0071] x(t)=(p(t),v(t)) T ,

[0072] The tracking device needs processing time to extract the transformed joint center coordinates, which has a time delay compared to the real-time tracking of the required spatial coordinates by the dual-plane X-ray system. Therefore, the optimal estimation of the joint center state based on the previous time sequence is

[0073] Use Kalman filter to obtain the predicted value of the joint center state at the current moment According to the state measurement value y(t) of the joint center spatial position and velocity output by the tracking device at the current moment, the predicted value of the joint center state at the current moment is corrected To obtain the best estimate The specific implementation is as follows:

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] Where, Q(t) is the input noise covariance matrix, and R(t) is the observation noise covariance matrix.

[0081] Represents the estimated value of the current state; a iis a constant;

[0082] represents the estimated position at time t, represents the estimated value of speed at time t;

[0083] represents the position measurement value at time t-1, represents the speed measurement value at time t-1;

[0084] represents the state error at time t; F represents the state transfer matrix; K represents the Kalman gain matrix; B represents the state control matrix; H represents the gain matrix.

[0085] Specifically, the joint position and joint speed information include: the joint center position and joint speed in the XYZ axis direction in the dual-plane X-ray system coordinate system, the Z axis direction is the vertical direction, that is, the transmission axis direction, and the XY axis direction is the horizontal direction, that is, the direction perpendicular to the Z axis. In this embodiment, the real-time acquisition is the spatial position of the center of the human joint, which can ensure that the center of the human joint is in the center of the frontal and lateral X-ray images, increasing the proportion of useful information of the X-ray image in the entire X-ray image. It can also be other positions except the spatial position of the center of the human joint, and the frontal / lateral X-ray images can also be obtained.

[0086] The step of converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system, and obtaining the predicted joint position and joint velocity information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement comprises:

[0087] After obtaining the estimated joint positions and joint velocities, they are converted into joint positions and joint velocities in the XYZ three-axis directions in the coordinate system of the dual-plane X-ray system through coordinate transformation;

[0088] The joint position and joint speed information in the XYZ three-axis direction are sent to the motor driver through the host computer to control the movement of the transmitter and the receiver, thereby realizing dynamic tracking of the patient's movement, thus forming a closed-loop control of the tracking device and the drive.

[0089] In one embodiment, the obtaining of predicted joint position and joint velocity information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement further includes: a plurality of the transmitters and a plurality of the receivers are arranged relative to each other and arranged on a transmission shaft, the transmission shaft is arranged on a mobile platform, the mobile platform motor driver drives the transmitter and the receiver to move along the plane according to the position and velocity components of the XY axis, and at the same time, according to the position and velocity components in the Z axis direction, the transmission shaft motor driver controls the transmitter and the receiver to move in the Z axis direction, that is, the transmission shaft direction, thereby realizing dynamic tracking of the patient's movement.

[0090] In one embodiment, the obtaining of predicted joint position and joint speed information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement further includes: arranging a plurality of the transmitters and a plurality of the receivers relative to each other and at the end of a robotic arm, and the robotic arm motor driver drives the transmitters and the receivers to move freely according to the position and speed components of the XYZ axes, thereby realizing dynamic tracking of the patient's movement.

[0091] In order to constantly track any joint position of the patient to take X-ray images and ensure that the patient is within the radiation range of the transmitter and receiver fields of view, one embodiment of the present invention uses a dual-plane X-ray system, such as Figure 3 As shown, a plurality of the transmitters and a plurality of the receivers are arranged opposite to each other and arranged on a transmission shaft. The dual-plane X-ray system includes at least one transmitter and at least one receiver, that is, in this embodiment, the first transmitter 4, the second transmitter 3, the first receiver 1, and the second receiver 2 can all be installed on the transmission shaft, the first transmitter 4 is installed on the fourth transmission shaft 14, the second transmitter 3 is installed on the second transmission shaft 12, the first receiver 1 is installed on the first transmission shaft 11, and the second receiver 2 is installed on the third transmission shaft 13, and the first transmission shaft 11, the second transmission shaft 12, the third transmission shaft 13, and the fourth transmission shaft 14 are respectively installed on the first mobile platform 7, the second mobile platform 8, the third mobile platform 9, and the third mobile platform 10, and the transmitter and the receiver are driven to move freely by the mobile platform and the transmission shaft. In this embodiment, the dual-plane X-ray system transmitter emits X-rays, and the optical axes of the two transmitters are 60 to 120 degrees apart; the dual-plane X-ray system receiver receives the attenuated X-rays that pass through the human body and forms an image; the tracking device 5 is used to obtain the joint center position of the human joint to be tracked; the host computer 6 is used to convert the joint center coordinates obtained by the tracking device 5 into the dual-plane X-ray system coordinate system, and control the movement of the dual-plane X-ray system transmitter and receiver.

[0092] This means that the transmitter and receiver can move freely. One way is to Figure 3As shown, the transmitter and receiver can be installed on the transmission shaft, and the transmission shaft is installed on the mobile platform. The mobile platform and the transmission shaft drive the transmitter and the receiver to move freely. Another way is that the transmitter and the receiver are installed at the end of the mechanical arm, and the mechanical arm drives the receiver and the transmitter to move freely. In this way, a local X-ray or a whole body X-ray of the patient in the weight-bearing position can be obtained; the double-plane X-ray system includes two transmitters and two receivers, and the two transmitters can be at any angle between 60 and 120 degrees. After the transmitter emits X-rays, it passes through the human body and forms an image on the receiver. The transmitter and the receiver can move along the vertical axis, the horizontal axis, or move freely. During the movement, between a pair of transmitters and receivers, the receiver is always guaranteed to be perpendicular to the optical axis of the transmitter and the intersection of the optical axis and the receiver is at the center of the receiver.

[0093] In this embodiment, X-ray images are collected and dynamic X-ray images of joint positions are obtained during the completion of the action. The relative relationship between the joints in each frame is obtained by aligning the joint X-ray images and the three-dimensional model in each frame, thereby obtaining the movement relationship between the bones and joints. The three-dimensional model can be realized through the three-dimensional reconstruction model and statistical shape model of the patient's CT data, that is, the two-dimensional joint X-ray image is combined with the three-dimensional model to obtain the relative relationship between the joints in each frame, so as to analyze the patient's motor function.

[0094] Embodiment 2

[0095] The present invention provides a dynamic tracking system based on a dual-plane X-ray system, wherein the dual-plane X-ray system includes a transmitter for transmitting X-rays to a human body; and a receiver for receiving X-rays attenuated after passing through a human body to form an image. The dynamic tracking system includes:

[0096] A calibration module, used for calibrating the dual-plane X-ray system and the spatial position of the tracking device;

[0097] An acquisition module, used to acquire the spatial position of a human body joint through the tracking device; (not equivalent to the tracking device)

[0098] A coordinate conversion module, used for converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system;

[0099] An adjustment module, used for adjusting the position of the dual-plane X-ray system according to the joint position and joint speed at the next moment predicted by the joint position so that the dual-plane X-ray system follows the joint movement;

[0100] The result output module is used to collect X-ray images and obtain dynamic X-ray images of human joint movement. By aligning the joint X-ray images of each frame with the three-dimensional model, the relative relationship between the joints in each frame is obtained, thereby obtaining the kinematic parameters of the joints.

[0101] The present invention can obtain dynamic images of joint movements in the human body under load-bearing position, can obtain joint kinematic parameters under a complete natural movement of the human body, and accurately evaluate the patient's joint movement function; can obtain the spatial position of the human body's joint center in real time, can ensure that the human body's joint center is in the center of the frontal / lateral X-ray image, and increase the proportion of useful information of the X-ray image in the entire X-ray image; each frame of the collected dynamic image is aligned with the three-dimensional model from 2D to 3D, so as to obtain the three-dimensional structure information and dynamic function information of the bones and joints required by doctors.

[0102] The present invention also provides a dynamic tracking device based on a dual-plane X-ray system, including a memory and a processor, wherein the memory stores computer-readable instructions, and when the processor executes the computer-readable instructions, it implements the dual-plane X-ray method based on dynamic tracking as in Embodiment 1 of the present invention.

[0103] The specific contents and implementation methods of the above-mentioned calibration module, acquisition module, coordinate conversion module, adjustment module, and result output module are as described in the first embodiment and will not be repeated here.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic tracking method based on a dual-plane X-ray system, wherein the dual-plane X-ray system comprises a transmitter for transmitting X-rays to a human body; and a receiver for receiving X-rays attenuated after passing through a human body to form an image, characterized in that: The steps include: Calibrate the dual-plane X-ray system and the tracking device spatial position; Acquiring the spatial position of the human body joints by means of the tracking device; The joint position fed back by the tracking device is converted into the coordinates of the dual-plane X-ray system, and the predicted joint position and joint speed information at the next moment are obtained to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement, including: Use Kalman filter to obtain the predicted value of the joint center state at the current moment According to the state measurement value y(t) of the joint center spatial position and velocity output by the tracking device at the current moment, the predicted value of the joint center state at the current moment is corrected To obtain the best estimate The specific implementation is as follows: Where, Q(t) is the input noise covariance matrix, R(t) is the observation noise covariance matrix; x(t) represents the estimated value of the state at time t; a i is a constant; p(t) represents the estimated position at time t, v(t) represents the estimated velocity at time t; p(t-1) represents the measured position at time t-1, v(t-1) represents the measured velocity at time t-1; P(t) represents the state error at time t; F represents the state transfer matrix; K represents the Kalman gain matrix; B represents the state control matrix; H represents the gain matrix; ui represents the control input or process noise, which is a constant; X-ray images are collected and dynamic X-ray images of human joint movement are obtained. By aligning the joint X-ray images of each frame with the three-dimensional model, the relative relationship between the joints in each frame is obtained, thereby obtaining the kinematic parameters of the joints.

2. A dynamic tracking method based on a dual-plane X-ray system as claimed in claim 1, characterized in that: The joint position and joint speed information includes: the joint center position and joint speed in the XYZ axis direction in the dual-plane X-ray system coordinate system, the Z axis direction is the vertical direction, that is, the transmission axis direction, and the XY axis direction is the horizontal direction, that is, the direction perpendicular to the Z axis.

3. A dynamic tracking method based on a dual-plane X-ray system as claimed in claim 1, characterized in that: The calibrating of the dual-plane X-ray system and the spatial position of the tracking device comprises: A correction box is provided between the field of view of the biplane X-ray system and the tracking device instrument; Capturing the spatial coordinates of the first marking body on the correction box by the dual-plane X-ray system and outputting the first coordinates; Capturing the spatial coordinates of the first marking body on the correction box by the tracking device and outputting the second coordinates; The spatial position of the first marker on the correction box is obtained and a third coordinate is output. When the third coordinate corresponds to the first coordinate and the second coordinate, a conversion matrix between the tracking device coordinate system and the dual-plane X-ray system coordinate system is obtained.

4. A dynamic tracking method based on a dual-plane X-ray system as claimed in claim 1, characterized in that: In obtaining the spatial position of the human joint by the tracking device, if the tracking device adopts a photoelectric tracking device or an electromagnetic tracking device, a second marker is set at the human joint position, and the human joint position is located by the marker to obtain the spatial position of the human joint in a moving state.

5. The dynamic tracking method based on a dual-plane X-ray system according to claim 1, characterized in that: In the step of obtaining the spatial position of the human joints by the tracking device, if the tracking device adopts a camera, the position of the human joints in the field of view is automatically located by the camera to obtain the spatial position of the human joints in the moving state.

6. A dynamic tracking method based on a dual-plane X-ray system as claimed in claim 2, characterized in that: The step of converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system, and obtaining the predicted joint position and joint velocity information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement comprises: After obtaining the estimated joint positions and joint velocities, they are converted into joint positions and joint velocities in the XYZ three-axis directions in the coordinate system of the dual-plane X-ray system through coordinate transformation; The joint position and joint speed information in the XYZ three-axis directions are sent to the motor driver to control the movement of the transmitter and the receiver.

7. A dynamic tracking method based on a dual-plane X-ray system as claimed in claim 2, characterized in that: The obtaining of predicted joint position and joint speed information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement further includes: arranging a plurality of the transmitters and a plurality of the receivers relative to each other and arranging them on a transmission shaft, wherein the transmission shaft is arranged on a mobile platform, and the mobile platform motor driver drives the transmitter and the receiver to move along the plane according to the position and speed components of the XY axes, and at the same time, according to the position and speed components in the Z-axis direction, the transmission shaft motor driver controls the transmitter and the receiver to move along the Z-axis direction.

8. A dynamic tracking method based on a dual-plane X-ray system as claimed in claim 2, characterized in that: The obtaining of predicted joint position and joint speed information at the next moment to adjust the position of the dual-plane X-ray system so that the dual-plane X-ray system follows the joint movement further includes: arranging a plurality of the transmitters and a plurality of the receivers relative to each other and arranging them at the end of a robotic arm, and the robotic arm motor driver drives the transmitters and the receivers to move freely according to the position and speed components of the XYZ axes.

9. A dynamic tracking system based on a dual-plane X-ray system, implementing a dynamic tracking method based on a dual-plane X-ray system as claimed in any one of claims 1 to 8, wherein the dual-plane X-ray system comprises an emitter for emitting X-rays to a human body; The receiver is used to receive the attenuated X-rays after passing through the human body to form an image, and is characterized in that: The dynamic tracking system comprises: A calibration module, used for calibrating the dual-plane X-ray system and the spatial position of the tracking device; An acquisition module, used for acquiring the spatial position of a human body joint through the tracking device; A coordinate conversion module, used for converting the joint position fed back by the tracking device into the coordinates of the dual-plane X-ray system; An adjustment module, used for adjusting the position of the dual-plane X-ray system according to the joint position and joint speed at the next moment predicted by the joint position so that the dual-plane X-ray system follows the joint movement; The result output module is used to collect X-ray images and obtain dynamic X-ray images of human joint movement. By aligning the joint X-ray images of each frame with the three-dimensional model, the relative relationship between the joints in each frame is obtained, thereby obtaining the kinematic parameters of the joints.

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