Method and system for registering a surgical robot coordinate system with a ct machine coordinate system

Abstract

A method and system for registering a surgical robot coordinate system and a CT machine coordinate system. The system comprises a 3D structured light camera (1) and a calibration board (2) used with a surgical robot console, a mechanical arm (4) and a CT machine. The CT machine coordinate system is registered with the mechanical arm coordinate system in the surgical robot using a 3D vision system. The 3D structured light camera (1) in the 3D vision system moves synchronously with the mechanical arm (4) and a puncture device (3) fixedly installed at the end of the mechanical arm (4). The coordinate registration process in the robot surgery is simplified. The 3D structured light camera (1) and the puncture device (3) are installed together at the end of the mechanical arm (4), so that the volume of the surgical robot equipment is reduced.

Description

Technical Field

[0001] This invention relates to the field of puncture robots, and more specifically, to a method and system for registering the coordinate system of a surgical robot with that of a CT scanner. Background Technology

[0002] During a robotic puncture procedure, the doctor diagnoses the patient and develops a surgical plan based on medical imaging equipment (such as a CT scan). The surgical robot then performs the puncture according to the doctor's plan. Only after the surgical robot's coordinate system is aligned with the coordinate system of the medical imaging equipment can the surgical robot complete the surgical procedure according to the doctor's plan.

[0003] Currently, most surgical robots use infrared binocular cameras to capture images of marker components fixed to both the robotic arm and the patient. These images are then combined with CT images of the marker components on the patient, and image recognition and spatial geometry algorithms are used to determine the coordinate registration between the robotic arm and the CT scanner. This technology and method require the marker components to be fixed to both the patient and the robotic arm, and a large infrared binocular camera to be placed at a suitable position outside the robotic arm's field of vision. The entire system is complex, inconvenient to operate, and requires extensive training for medical personnel to operate. In particular, fixing the marker components to the patient requires effective patient cooperation, which limits the widespread adoption and application of surgical robots. Summary of the Invention

[0004] The purpose of this invention is to provide a method for registering the coordinate system of a surgical robot with that of a CT scanner. This is a novel registration method. This invention only requires a high-precision, small-sized 3D structured light camera to be fixedly installed at the end of the robotic arm. Combined with a calibration plate specially designed for the 3D structured light camera, the registration of the robotic arm coordinates and the CT scanner coordinates can be completed by placing the calibration plate on the CT scanner. There is no need to fix corresponding markers on the robotic arm and the patient, nor is there a need to install a large infrared binocular camera. This simplifies the surgical robot equipment, makes it easier to use and operate, and can be widely promoted and applied to medical units of all levels.

[0005] The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner in this invention uses a 3D vision system to register the coordinate system of the CT scanner with the coordinate system of the robotic arm in the surgical robot. The 3D structured light camera in the 3D vision system moves synchronously with the robotic arm and the puncture device fixedly installed at the end of the robotic arm.

[0006] Preferably, the 3D vision system includes a 3D structured light camera mounted at the end of the robotic arm and fixed as a whole with the puncture device, and a calibration plate that can be directly placed on the CT scanner and is located within the shooting range of the 3D structured light camera.

[0007] Preferably, the method for registering the CT scanner coordinate system and the robotic arm coordinate system is characterized by performing the following steps:

[0008] 1) Move the robotic arm, which is equipped with a 3D structured light camera, to the surgical area next to the CT scanner;

[0009] 2) Place the calibration plate on the CT scanner, within the range that the 3D structured light camera can capture;

[0010] 3) Start the registration process. The robotic arm carrying the 3D structured light camera moves to multiple poses in sequence. After moving to each pose, the 3D structured camera is turned on to project multiple sets of structured light and capture photos of the calibration structure projected onto the calibration plate. The transformation parameters of the robotic arm and the photos of the calibration structure on the calibration plate are recorded by computer software for each pose. The hand-eye calibration algorithm is used to obtain the transformation relationship between the coordinate system of the calibration plate and the coordinate system of the robotic arm, which is the third transformation matrix.

[0011] 4) The robotic arm is retracted to its initial position, the calibration plate remains stationary on the CT scanner, and the CT scanner is started to scan the calibration plate; the CT image data of the four spherical calibration elements on the calibration plate are acquired, and the coordinate matrix of the center of the four spherical calibration elements relative to the calibration plate is combined to obtain the transformation relationship between the CT coordinate system and the calibration plate coordinate system, which is the fourth transformation matrix;

[0012] 5) Based on the third transformation matrix between the calibration plate coordinate system and the robotic arm coordinate system, and the fourth transformation matrix between the CT machine coordinate system and the calibration plate coordinate system, obtain the transformation relationship between the CT machine coordinate system and the robotic arm coordinate system, which is the fifth transformation matrix, and complete the coordinate registration between the CT machine coordinate system and the robotic arm coordinate system.

[0013] Preferably, step 3) is performed according to the following steps:

[0014] 3.1) The registration procedure is started. The robotic arm carrying the 3D structured light camera moves sequentially to n pre-set different poses. After moving to each pose, the transformation relationship between the calibration board coordinate system and the camera coordinate system is obtained for each pose, which is the first transformation matrix W. BC The transformation relationship between the center point of the robotic arm's end effector and the robotic arm's coordinate system is the second transformation matrix W. AT ;

[0015] 3.2) Select the first transformation matrix W corresponding to two poses (i, j). BC Second transformation matrix W AT The transformation matrix W between the camera coordinate system and the coordinate system of the center point of the robotic arm end effector is obtained according to the following equation (1). CT (ij) ;

[0016] W AT (i) W CT (ij) W BC (i) =W AT (j) W CT (ij) W BC (j) (1)

[0017] 3.3) Obtain the transformation matrix W between the calibration plate coordinate system and the robot arm coordinate system for the two poses (i, j) according to the following equation (2). AB (ij) ;

[0018] W AB (ij) = W AT (i) W CT (ij) W BC (i) =W AT (j) W CT (ij) W BC (j) (2)

[0019] 3.4) Repeat steps 3.2) and 3.3) to select the first transformation matrix W for two different poses from the n poses. BC Second transformation matrix W AT After combination, n*(n-1) / 2 transformation matrices W can be obtained. AB (ij) For n*(n-1) / 2 transformation matrices W AB (ij) The average value of the corresponding identical variables is calculated, and the average values ​​of all identical variables are combined to form the transformation relationship between the calibration plate coordinate system and the robot arm coordinate system, which is called the third transformation matrix.

[0020] Preferably, in step 3.1), after the robotic arm moves to each pose, the following steps are performed:

[0021] 3.1.1) The 3D structured light camera projects structured light onto the calibration plate, and captures images of the marked structures on the calibration plate where the structured light is projected. Computer software records the pose transformation parameters of the robotic arm and the images of the marked structures on the calibration plate. A hand-eye calibration algorithm is used to obtain the transformation relationship between the coordinate system of the calibration plate and the coordinate system of the center point of the 3D structured light camera for that pose, which is the first transformation matrix W. BC ;

[0022] 3.1.2) Based on the robot arm pose transformation parameters for each pose, obtain the pose representation of the robot arm end effector center point in the robot arm coordinate system, that is, the transformation relationship between the coordinate system of the robot arm end effector center point and the robot arm coordinate system for that pose, which is the second transformation matrix W. AT .

[0023] Preferably, the number of poses of the 3D structured light camera moving with the robotic arm in step 3) is 4-25.

[0024] Preferably, in step 3.1.1), the 3D structured light camera projects blue-violet LED light with a wavelength of 490nm onto the calibration plate in the form of 13-24 striped gratings.

[0025] Preferably, the calibration plate includes a base plate, four spherical calibration members, columnar connectors for fixing the base plate and the spherical calibration members, and locking fasteners for locking the columnar connectors and the base plate. The height of each columnar connector is distributed in an arithmetic sequence. All columnar connectors are fixedly disposed on the same side surface of the base plate. The side surface of the base plate where the columnar connectors are disposed is provided with a checkerboard pattern.

[0026] Preferably, the columnar connector includes a first connecting portion connected to the spherical calibration member and a second connecting portion connected to the substrate. The first connecting portion is provided with a cylindrical groove into which the spherical calibration member is inserted. The depth of the groove is greater than the radius of the spherical calibration member, and the inner diameter of the groove is less than or equal to the diameter of the spherical calibration member.

[0027] The system for registering the coordinate system of the surgical robot with the coordinate system of the CT scanner in this invention includes a 3D structured light camera and a calibration plate used in conjunction with the surgical robot control console, the robotic arm, and the CT scanner. The 3D structured light camera is fixedly installed together with a puncture device mounted at the end of the robotic arm and moves together with the robotic arm as the robotic arm moves.

[0028] When using the system of this invention for registration, simply push the surgical robot and robotic arm equipped with a 3D structured light camera next to the CT scanner, place the calibration plate within the range that the CT scanner can capture with the 3D structured light camera, and start the program to automatically complete the coordinate registration. The operation is simple, easy to learn, and easy to use. This greatly simplifies the operation of the surgical robot and significantly reduces the training time for medical personnel.

[0029] This invention applies a 3D structured light camera to a surgical robot, enabling rapid and accurate registration between the surgical robot's coordinate system and the CT scanner's coordinate system. The registration accuracy can reach within 1mm, providing accurate positioning and identification for the surgical robot to perform puncture surgery, thus ensuring the precision of the surgery.

[0030] Furthermore, this invention, through the use of a 3D structured light camera, greatly simplifies the coordinate registration process during robotic surgery, making it independent of the patient and easy for operators to use, significantly reducing the learning and training time for medical staff. Moreover, the 3D structured light camera, installed together with the puncture device at the end of the robotic arm, reduces the size of the surgical robot, greatly minimizing the space required in CT operating rooms, allowing conventional CT examination rooms to be fully utilized, thus enabling robotic surgery to be performed in more hospitals. Attached Figure Description

[0031] Figure 1 This is a flowchart of the method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner in this invention.

[0032] Figure 2 This is a schematic diagram of the system used in this invention for registering the coordinate system of the surgical robot with the coordinate system of the CT scanner.

[0033] Figure 3 This is a schematic diagram of the structure of the 3D structured light camera and the puncture device after assembly in this invention.

[0034] Figure 4 This is a three-dimensional structural diagram of the calibration plate in this invention.

[0035] Figure 5 This is a schematic diagram of the checkerboard structure within the calibration board substrate of this invention.

[0036] Figure 6 This is a cross-sectional view of the four columnar connectors in this invention.

[0037] Figure 7 This is a schematic diagram of the working state structure of the system in this invention.

[0038] Figure 8 This is the working principle of registration in this invention. Figure 1 .

[0039] Figure 9 This is the working principle of registration in this invention. Figure 2 .

[0040] Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention.

[0042] like Figure 1 , Figure 2 , Figure 3 , Figure 8 and Figure 9 As shown, the method for registering the coordinate system of the surgical robot and the coordinate system of the CT scanner in this invention is to use a 3D vision system to register the coordinate system of the CT scanner with the coordinate system of the robotic arm in the surgical robot. The 3D structured light camera in the 3D vision system moves synchronously with the robotic arm 4 and the puncture device 3 installed at the end of the robotic arm.

[0043] The 3D vision system for aligning the coordinate system of the surgical robot with that of the CT scanner comprises software and hardware components. The software component is integrated with the control system of the surgical robot; the specific integration and software program can be implemented by those skilled in the art after a detailed description of the method described in this invention. The hardware component includes a 3D structured light camera 1 mounted on a puncture device 3 at the end of the surgical robot's robotic arm 4, and a calibration plate 2 that can be stably placed on the CT scanner. The 3D structured light camera 1 and the puncture device 3 are fixedly mounted together via a mounting bracket 32, both mounted at the end of the robotic arm 4, and move synchronously with the robotic arm 4 as the puncture device 3 moves. The specific structure of the fixed mounting of the 3D structured light camera 1 and the puncture device 3, as well as the mounting bracket 32, is readily achievable by those skilled in the art and will not be described in detail here.

[0044] like Figure 3 As shown, the 3D structured light camera 1 of this invention can be divided into two parts, including a structured light source 30 and a DDP camera 31, which are respectively installed on both sides of the puncture device 3, so that the puncture needle 5 in the puncture device 3 is located between the structured light source 30 and the DDP camera 31. After the structured light source 30 and the DDP camera 31 are fixedly installed, the light source coverage area of ​​the structured light source 30 and the shooting area of ​​the camera 31 are exactly overlapping and located below the puncture device 3, which can better locate the puncture position. The 3D structured light camera 1 of this invention can also be... Figure 7 and Figure 9 As shown, it is directly and fixedly installed as a whole at the end of the robotic arm 4, and is set parallel (or side by side) to the puncture device 3.

[0045] like Figure 4 As shown, the calibration plate 2 includes a base plate 20, four spherical calibration members 22, four columnar connectors 21 for fixing and connecting the base plate 20 and the spherical calibration members 22, and four locking fasteners 23 for locking the columnar connectors 21 and the base plate 20.

[0046] The substrate 20 is a square ceramic substrate with a length of 160mm, a width of 140mm, and a thickness of 5mm. A through-hole 25 is provided at each of the four right-angle positions of the ceramic substrate. Marking structures 24 are evenly distributed on one side surface of the ceramic substrate 20, located precisely in the center of the four through-holes 25. The marking structures 24 are geometric shapes drawn or printed on the surface of the ceramic substrate 20, such as... Figure 5 As shown, the present invention preferably uses alternating black and white squares to form a checkerboard pattern, with the side length of the black and white squares being 8mm.

[0047] The columnar connector 21 is preferably integrally formed from polyformaldehyde thermoplastic crystalline polymer (POM). A spherical calibration component 22 is fixed above each columnar connector 21. The spherical calibration component 22 is made of a material that can produce clear images in the CT scanner without producing artifacts, and preferably an AL2O3 ceramic ball with a diameter of 20mm.

[0048] The materials used for the columnar connector 21 and the spherical calibration component 22 are such that the density of the spherical calibration component 22 is 1.5-4 times greater than that of the columnar connector 21, which can accurately and clearly identify them from CT images without producing artifacts in the CT images.

[0049] like Figure 6 As shown, the columnar connector 21 includes a first connecting portion 26 connected to the spherical calibration member 22, a second connecting portion 27 connected to the substrate 20, and a connecting post 28 for connecting the first connecting portion 26 and the second connecting portion 27. The first connecting portion 26, the second connecting portion 27, and the connecting post 28 are integrally formed from polyoxymethylene thermoplastic crystalline polymer material. The heights of the four columnar connectors 21 are all different, and the structure, shape, and dimensions of the first connecting portion 26 and the second connecting portion 27 of each columnar connector 21 are the same. The heights of the connecting posts 28 for connecting the first connecting portion 26 and the second connecting portion 27 are different, and the four connecting posts 28 are arranged in an arithmetic sequence, preferably 0mm, 20mm, 40mm, and 60mm.

[0050] The first connecting part 26 has a cylindrical groove 29 inside for the spherical calibration member 22 to sink into. The depth of the groove 29 is greater than the radius of the spherical calibration member 22, but less than 2 / 3 of the diameter of the spherical calibration member 22. In this embodiment, the depth of the groove 29 is preferably 21 mm, and the diameter is preferably 19.9-20 mm. Due to the properties of the polyoxymethylene thermoplastic crystalline polymer material, the spherical calibration member 22 is slightly stuck when it sinks into the groove 29, requiring a little force to enter the groove 29. This ensures that the center of the spherical calibration member 22 is completely in the center of the groove 29, and the spherical calibration member 22 will not rotate or move after entering the groove 29, keeping the center of the spherical calibration member 22 always in the center of the groove 29. In order to allow the spherical calibration member 22 to enter the groove 29 smoothly, a vent hole 19 is provided at the bottom of the groove 29.

[0051] Preferably, the four locking fasteners 23 are made of hard rubber support columns, which can ensure that the calibration plate 2 is stable and does not slip when placed on the CT machine.

[0052] In this invention, the dimensions of the checkerboard grid, the columnar connector 21, and the spherical calibration component 22 in the calibration plate 2, as well as their positions in the calibration plate 2, are precisely controlled. This ensures that the spherical calibration component 22 can be clearly imaged in the CT scanner without producing artifacts, while also ensuring that the spherical calibration component 22 can be stably fixed in the calibration plate, making the coordinates of the center point of the spherical calibration component 22 in the calibration plate coordinate system accurate.

[0053] like Figure 1 , Figure 7 , Figure 8 and Figure 9 As shown, the method for registering the surgical robot coordinate system and the CT scanner coordinate system in this invention is used to register the CT scanner coordinate system and the robotic arm coordinate system, and is performed according to the following steps:

[0054] 1) Move the robotic arm 4, which is fixed with the 3D structured light camera 1, to the predetermined surgical area next to the CT machine 6 and fix it. In this step, the robotic arm 4 can be pre-started and moved to the predetermined position.

[0055] 2) Place the calibration plate 2 on the CT bed of the CT machine 6 and place it within the range that the 3D structured light camera 1 can capture.

[0056] 3) Start the registration process. The robotic arm 4, carrying the 3D structured light camera 1, moves synchronously to the pre-set first pose (set within the surgical robot program) and performs the following steps:

[0057] 3.1) Turn on the structured light source 30 in the 3D structured light camera 1 to project 490nm blue-violet LED light onto the calibration board 2, forming a 20-striped grating on the marker structure 24 of the calibration board 2. The blue-violet LED light is refracted to the DDP camera 31, where the Gray code of the grating stripes is converted into real-time data. A half-precision matching algorithm is used in the software, followed by a patching algorithm to form a point cloud image. The content distance of the checkerboard grid in the marker structure 24 of the calibration board 2 (the distance from corner point to corner point) is calculated. Then, based on the true value of the marker structure 24 in the calibration board 2, deviation correction calculation is performed to obtain the transformation relationship W between the calibration board coordinate system and the camera coordinate system in the first pose. BC1 ,

[0058] The transformation relationship between the calibration plate coordinate system and the camera coordinate system is called the first transformation matrix W. BC .

[0059] The specific algorithm involved in this step is the hand-eye calibration algorithm, which is a well-known technology. The specific principles and algorithms will not be described in detail.

[0060] In this step, the projection wavelength of the blue-violet LED light can be between 450nm and 550nm, and depending on the wavelength, it can be displayed as 13-24 stripes on the calibration plate 2. In this embodiment, a wavelength of 490nm is preferred, and it is displayed as 20 stripes on the calibration plate 2 to facilitate rapid calculation by computer software.

[0061] 3.2) Based on the robot arm pose transformation parameters (coordinates x, y, z and angle θ) for each pose. x θ y θ z The pose representation of the end effector center point of the first pose robot arm in the robot arm coordinate system is obtained, that is, the transformation relationship between the coordinate system of the end effector center point of the first pose robot arm and the robot arm coordinate system, which is the second transformation matrix W. AT1 .

[0062] Specifically, it involves transforming the transformation matrix into a rotation and translation matrix, and then converting it into a 4×4 homogeneous transformation matrix W. AT :

[0063]

[0064] 4) Start the robotic arm 4 to move to the second pose, repeat step 3) above, and obtain the first transformation matrix W between the calibration plate coordinate system and the camera coordinate system in the second pose. BC2 The second transformation matrix W between the center point of the end effector of robotic arm 4 and the coordinate system of the robotic arm. AT2 ;

[0065] This process is repeated, moving the robotic arm sequentially to 4 to 10 different pre-defined poses, and obtaining the first transformation matrix W for each pose. BCi , for W BC1 W BC2 W BC3 ,…….W BC10 The second transformation matrix W ATi , is: W AT1 W AT2 W AT3 ,…….W AT10 .

[0066] 5) Obtain the transformation matrix W between the camera coordinate system and the coordinate system of the center point of the robotic arm's end effector. CT .

[0067] Specifically, from the 10 poses in step 4), select any two poses (i, j) and their first transformation matrix W. BCi W BCj Second transformation matrix W ATi W ATj The transformation relationship between the camera coordinate system and the coordinate system of the center point of the robotic arm end effector can be obtained according to the following equation (1), namely the transformation matrix W. CT (ij) .

[0068] W AT (i) W CT (ij) W BC (i) =W AT (j) W CT (ij) W BC (j) (1)

[0069] 6) Obtain the transformation matrix W between the calibration plate coordinate system and the robot arm coordinate system. AB (ij) .

[0070] The transformation relationship between the calibration plate coordinate system and the robot arm coordinate system for the two poses (i, j) is obtained according to the following equation (2), that is, the transformation matrix is ​​W. AB (ij) .

[0071] W AB (ij) =W AT (i) W CT (ij) W BC (i) =W AT(j) W CT (ij) W BC (j) (2)

[0072] 7) Repeat steps 5) and 6) to select the first transformation matrix W for two different poses from the 10 poses. BC Second transformation matrix W AT By combining them in pairs, we can obtain 10*9 / 2 = 45 transformation matrices W. AB (ij) For 45 transformation matrices W AB (ij) The average value of the corresponding identical variables is calculated, and the average values ​​of all identical variables are combined to form the transformation relationship between the calibration plate coordinate system and the robot arm coordinate system, which is called the third transformation matrix.

[0073] It should be noted that the preset 10 poses in this embodiment are selected by combining the structural dimensions of the calibration plate 2 and the feature parameters of the 3D structured light camera 1 to ensure the measurement accuracy and transformation matrix calculation accuracy. The number of poses can be between 4 and 20, depending on the structural dimensions of the calibration plate 2 and the feature parameters of the 3D structured light camera 1.

[0074] Same variable refers to the specific variable at each same position in the transformation matrix, such as u ABx u ABy u ABz wait.

[0075] 8) Control the robotic arm 4 to retract, keep the calibration plate 2 stationary on the CT machine 6, and start the CT machine 6 to perform a close scan on the calibration plate 2.

[0076] The CT influence data of the four spherical calibration elements 22 on the calibration plate 2 are obtained. This influence data includes the CT values ​​and three-dimensional CT coordinates of all pixels in the image. Using an image recognition algorithm based on CT values ​​and a sphere centering algorithm, the coordinates of the sphere centers of the four spherical calibration elements 22 in the CT coordinate system are calculated and represented by coordinate matrix B. The coordinate matrix of the centers of the four spherical calibration elements 22 on the calibration plate 2 The following equation can be obtained:

[0077]

[0078] Having obtained the coordinate matrix B, we can solve the above equation to calculate the transformation relationship from the CT coordinate system to the calibration plate coordinate system, which is called the fourth transformation matrix.

[0079] 9) Obtain the third transformation matrix W between the calibration plate coordinate system and the robotic arm coordinate system. AB The fourth transformation matrix W from the CT coordinate system to the calibration plate coordinate system BD Then, the transformation relationship between the CT machine coordinate system and the robotic arm coordinate system can be obtained according to the following calculation formula (3), which is called the fifth transformation matrix W. AD .

[0080]

[0081] The fifth transformation matrix W between the CT coordinate system and the robotic arm coordinate system is obtained. AD After that, the coordinate registration between the CT machine coordinate system and the robotic arm coordinate system was completed, thus completing the coordinate registration between the CT machine coordinate system and the surgical robot coordinate system.

[0082] In summary, this invention fixes a 3D structured light camera to the end of a robotic arm and uses a hand-eye calibration method, eliminating the need for a separate binocular camera. This effectively reduces the impact of various background light sources in the CT room on the measurement and achieves very high measurement accuracy. The theoretical measurement accuracy can reach 0.001mm, and under the conditions of the example scenario, an accuracy of 0.1mm can be achieved.

Claims

1. A method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner, characterized in that, The coordinate system of the CT scanner is registered with the coordinate system of the robotic arm in the surgical robot using a 3D vision system. The 3D structured light camera in the 3D vision system moves synchronously with the robotic arm and the puncture device fixedly mounted at the end of the robotic arm. The 3D vision system includes a 3D structured light camera mounted at the end of the robotic arm and fixed as a whole with the puncture device, and a calibration plate that can be directly placed on the CT scanner and is within the imaging range of the 3D structured light camera. The following steps are performed: 1) Move the robotic arm, which is equipped with a 3D structured light camera, to the surgical area next to the CT scanner; 2) Place the calibration plate on the CT scanner, within the range that the 3D structured light camera can capture; 3) Start the registration process. The robotic arm carrying the 3D structured light camera moves to multiple poses in sequence. After moving to each pose, the 3D structured camera is turned on to project multiple sets of structured light and capture photos of the calibration structure projected onto the calibration plate. The transformation parameters of the robotic arm and the photos of the calibration structure in the calibration plate are recorded by computer software for each pose. The hand-eye calibration algorithm is used to obtain the transformation relationship between the calibration plate coordinate system and the robotic arm coordinate system, which is the third transformation matrix. 4) The robotic arm is retracted to its initial position, the calibration plate remains stationary on the CT scanner, and the CT scanner is started to scan the calibration plate; the CT image data of the four spherical calibration elements on the calibration plate are acquired, and the coordinate matrix of the center of the four spherical calibration elements relative to the calibration plate is combined to obtain the transformation relationship between the CT scanner coordinate system and the calibration plate coordinate system, which is the fourth transformation matrix; 5) Based on the third transformation matrix between the calibration plate coordinate system and the robotic arm coordinate system, and the fourth transformation matrix between the CT machine coordinate system and the calibration plate coordinate system, obtain the transformation relationship between the CT machine coordinate system and the robotic arm coordinate system, which is the fifth transformation matrix, and complete the coordinate registration between the CT machine coordinate system and the robotic arm coordinate system.

2. The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner according to claim 1, characterized in that, In step 3), the following steps are performed: 3.1) The registration procedure is started. The robotic arm carrying the 3D structured light camera moves sequentially to n pre-set different poses. After moving to each pose, the transformation relationship between the calibration board coordinate system and the camera coordinate system is obtained for each pose, which is the first transformation matrix W. BC The transformation relationship between the center point of the robotic arm's end effector and the robotic arm's coordinate system is the second transformation matrix W. AT ; 3.2) Select the first transformation matrix W corresponding to two poses (i, j). BC Second transformation matrix W AT The transformation matrix W between the camera coordinate system and the coordinate system of the center point of the robotic arm end effector is obtained according to the following equation (1). CT (ij) ; IN AT （i） IN CT (ij) IN BC （i） =W AT （j） IN CT (ij) IN BC （j） (1) 3.3) Obtain the two transformation matrices W between the calibration plate coordinate system and the robot arm coordinate system for the two poses (i, j) according to the following equation (2). AB (ij) ; IN AB （ij） = In AT （i） IN CT (ij) IN BC （i） =W AT （j） IN CT (ij) IN BC （j） (2) 3.4) Repeat steps 3.2) and 3.3) to select the first transformation matrix W for two different poses from the n poses. BC Second transformation matrix W AT After combination, n*(n-1) / 2 transformation matrices W can be obtained. AB (ij) For n*(n-1) / 2 transformation matrices W AB (ij) The average value of the corresponding identical variables is calculated, and the average values ​​of all identical variables are combined to form the transformation relationship between the calibration plate coordinate system and the robot arm coordinate system, which is called the third transformation matrix W. AB = .

3. The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner according to claim 2, characterized in that, In step 3.1), after the robotic arm moves to each pose, it performs the following steps: 3.1.1) The 3D structured light camera projects structured light onto the calibration plate, and captures images of the marked structures on the calibration plate where the structured light is projected. Computer software records the pose transformation parameters of the robotic arm and the images of the marked structures on the calibration plate. A hand-eye calibration algorithm is used to obtain the transformation relationship between the coordinate system of the calibration plate and the coordinate system of the center point of the 3D structured light camera for that pose, which is the first transformation matrix W. BC ; 3.1.2) Based on the robot arm pose transformation parameters for each pose, obtain the pose representation of the robot arm end effector center point in the robot arm coordinate system, that is, the transformation relationship between the coordinate system of the robot arm end effector center point and the robot arm coordinate system for that pose, which is the second transformation matrix W. AT .

4. The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner according to claim 2, characterized in that, In step 3), the number of poses of the 3D structured light camera that moves with the robotic arm is an even number between 4 and 20.

5. The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner according to claim 3, characterized in that, In step 3.1.1), the 3D structured light camera projects blue-violet LED light with a wavelength of 490nm onto the calibration plate in the form of 13-24 striped gratings.

6. The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner according to any one of claims 1-5, characterized in that, The calibration plate includes a base plate, four spherical calibration members, columnar connectors for fixing the base plate and the spherical calibration members, and locking fasteners for locking the columnar connectors and the base plate. The height of each columnar connector is distributed in an arithmetic sequence. All columnar connectors are fixedly disposed on the same side surface of the base plate. The side surface of the base plate where the columnar connectors are disposed is provided with a checkerboard pattern.

7. The method for registering the coordinate system of a surgical robot with the coordinate system of a CT scanner according to claim 6, characterized in that, The columnar connector includes a first connecting portion connected to the spherical calibration member and a second connecting portion connected to the substrate. The first connecting portion is provided with a cylindrical groove into which the spherical calibration member is inserted. The depth of the groove is greater than the radius of the spherical calibration member, and the inner diameter of the groove is less than or equal to the diameter of the spherical calibration member.

8. A system for the method of registering a surgical robot coordinate system with a CT scanner coordinate system as described in any one of claims 1-7, characterized in that, It includes a surgical robot control console, a robotic arm, a 3D structured light camera used in conjunction with a CT scanner, and a calibration plate. The 3D structured light camera is fixedly installed together with a puncture device mounted at the end of the robotic arm, and moves together with the puncture device as the robotic arm moves.

Images