WO2023284368A1 - 标记点选取位置的验证方法、装置、终端设备和存储介质 - Google Patents

标记点选取位置的验证方法、装置、终端设备和存储介质 Download PDF

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WO2023284368A1
WO2023284368A1 PCT/CN2022/090080 CN2022090080W WO2023284368A1 WO 2023284368 A1 WO2023284368 A1 WO 2023284368A1 CN 2022090080 W CN2022090080 W CN 2022090080W WO 2023284368 A1 WO2023284368 A1 WO 2023284368A1
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point
error
coordinate set
position coordinates
marker
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PCT/CN2022/090080
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English (en)
French (fr)
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孟李艾俐
周越
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元化智能科技(深圳)有限公司
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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/39Markers, e.g. radio-opaque or breast lesions markers

Definitions

  • the present application relates to the technical field of image registration, and in particular to a method, device, terminal device and storage medium for verifying selected positions of marker points.
  • a step called "registration” is usually performed, the purpose of which is to fit as accurately as possible the patient's diseased part (such as the femur) with the preoperatively acquired diseased part.
  • the 3D model of the site can ensure that the doctor can complete the operation according to the operation plan.
  • the commonly used registration registration method is mainly to use a probe equipped with an infrared reflective ball to collect a certain number of biomarker points in a specific area of the diseased part during the operation, and then based on these collected biomarker points, use The registration algorithm such as nearest neighbor iteration performs multiple fittings, and finally completes the registration registration.
  • the embodiment of the present application provides a method, device, terminal device and storage medium for verifying the selected position of a marker point, which can independently verify whether the selected position of the marker point is accurate after each marker point is selected, It enables the operator to conveniently collect accurate marker points, thereby avoiding repeated registration and registration procedures.
  • the first aspect of the embodiment of the present application provides a method for verifying the selected position of a marker point, including:
  • the first coordinate set is obtained after performing coordinate transformation processing on the pre-acquired object coordinate set according to the first coordinate transformation parameter a coordinate set, the object coordinate set includes position coordinates of the plurality of specified marker points on the target object;
  • the target error parameter is calculated according to the third set of coordinates and the pre-acquired set of model coordinates, the set of model coordinates includes position coordinates corresponding to the plurality of specified marker points on the three-dimensional model of the target object, and the target The error parameter is used to measure the degree of deviation between the position coordinates included in the third coordinate set and the position coordinates included in the model coordinate set;
  • the reference error parameter is used to measure the difference between the position coordinates contained in the first coordinate set and the position coordinates contained in the model coordinate set. the degree of deviation between.
  • the target object and its 3D model are pre-registered through multiple designated marker points to obtain the result of rough registration; after that, when the operator selects a target marker point, it will enter the fine registration link , specifically adding the position coordinates of the target marker point to the marker set after the rough registration, and calculating the current overall registration error based on the marker set; finally, if the current overall registration error is less than the rough registration Accurate error means that the registration accuracy has been improved to a certain extent. At this time, it is determined that the target marker point has passed the verification, that is, the selected position of the target marker point is considered to be accurate.
  • the system can independently verify whether the selected position of the marker point is accurate, so that the operator can conveniently collect the marker point with an accurate position, thereby avoiding Perform a repeat registration registration process.
  • the second aspect of the embodiment of the present application provides a device for verifying the selected position of a marker point, including:
  • a marker acquisition module configured to acquire position coordinates of target markers other than a plurality of designated markers on the target object
  • a position coordinate adding module configured to add the position coordinates of the target marker point to the first coordinate set to obtain a second coordinate set, the first coordinate set is a pre-acquired object coordinate set according to the first coordinate transformation parameter
  • a coordinate set obtained after coordinate transformation processing is performed, the object coordinate set includes position coordinates of the plurality of specified marker points on the target object;
  • a position coordinate transformation module configured to perform coordinate transformation processing on the second coordinate set according to the first coordinate transformation parameter to obtain a third coordinate set
  • An error parameter calculation module configured to calculate target error parameters according to the third coordinate set and the pre-acquired model coordinate set, the model coordinate set including the three-dimensional model of the target object corresponding to the plurality of specified marker points position coordinates, the target error parameter is used to measure the degree of deviation between the position coordinates contained in the third coordinate set and the position coordinates contained in the model coordinate set;
  • a mark point verification module configured to determine that the target mark point has passed the verification if the target error parameter is smaller than a reference error parameter, and the reference error parameter is used to measure the relationship between the position coordinates included in the first coordinate set and the model The degree of deviation between the location coordinates contained in the coordinate set.
  • the third aspect of the embodiments of the present application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and operable on the processor, when the processor executes the computer program Realize the method for verifying the selected position of the marker point as provided in the first aspect of the embodiment of the present application.
  • the fourth aspect of the embodiment of the present application provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the method provided in the first aspect of the embodiment of the present application.
  • the verification method for the selected position of the marker is not limited to the first aspect of the embodiment of the present application.
  • the fifth aspect of the embodiment of the present application provides a computer program product, which, when the computer program product is run on the terminal device, causes the terminal device to execute the method for verifying the selected position of the marker point described in the first aspect of the embodiment of the present application.
  • Fig. 1 is the flow chart of the verification method of a kind of mark point selection position that the embodiment of the present application proposes;
  • Fig. 2 is a schematic diagram of the geometric relationship of the reference error parameters proposed in the embodiment of the present application.
  • FIG. 3 is a schematic diagram of the registration and registration process of the femur proposed in the embodiment of the present application.
  • FIG. 4 is a schematic diagram of the tibia registration and registration process proposed in the embodiment of the present application.
  • Fig. 5 is a structural diagram of a verification device for selecting a position of a marker point proposed in an embodiment of the present application
  • FIG. 6 is a schematic diagram of a terminal device proposed in an embodiment of the present application.
  • This application provides a method for verifying the selected position of a marked point.
  • it can be independently verified whether the selected position of the marked point is accurate, so that the operator can conveniently Accurate marker points are collected, thereby avoiding repeated registration and registration processes.
  • the specific implementation process and principles please refer to the method embodiments described below.
  • Fig. 1 shows a method for verifying the selected position of a marker point provided by the embodiment of the present application, including:
  • the target object and its three-dimensional model are the objects to be registered
  • the target object may be any shape or type of object
  • the three-dimensional model corresponding to the target object may be obtained in a specified manner.
  • the target object can be the real diseased part of the patient, and its 3D model can be segmented from the CT image of the diseased part collected before the operation.
  • step 101 the embodiment of the present application performs rough registration processing on the target object and its three-dimensional model in advance, and the specific implementation manner of the rough registration will be described below first.
  • One of the point sets is a set of multiple specified marker points on the target object, corresponding to the object coordinate set described herein, which includes the position coordinates of multiple specified marker points on the target object; the multiple specified marker points can be Artificially selected points that are suitable for characterizing the key parts of the shape and structure of the target object.
  • the embodiment of the present application uses these designated marking points to achieve the rough registration of the target object and its three-dimensional model. In theory, these designated marking points The larger the number, the more accurate the rough registration result will be.
  • Another point set is a set of points on the three-dimensional model of the target object corresponding to the multiple specified marker points, corresponding to the model coordinate set described herein, which includes the points on the three-dimensional model corresponding to the multiple specified marker points Position coordinates (that is, the position coordinates of the corresponding points), for example, if the target object is a cuboid, and its multiple designated marker points are the 8 corner points of the cuboid, then the model coordinate set includes the 8 corner points on the 3D model of the cuboid Position coordinates.
  • the purpose of coarse registration is to find a coordinate transformation relationship (or coordinate transformation parameters), so that the Euclidean distance between the marker points in the object coordinate set and the marker points in the model coordinate set is the shortest after conversion of the coordinate transformation relationship . That is, according to the object coordinate set and the model coordinate set, a satisfying coordinate transformation relation (namely the first coordinate transformation parameter described in this paper) can be calculated, and the coordinate transformation relation can generally be expressed as (R, t), where R Indicates the rotation transformation parameter, and t indicates the translation vector.
  • the plurality of specified marker points includes a reference marker point
  • the first coordinate transformation parameter can be calculated in the following manner:
  • a reference marker point can be selected from multiple specified marker points, and the reference marker points of the two coordinate sets can be coincident through translation.
  • the selected reference marker point may be the center point of the femoral head (for a more specific description of this part, please refer to the actual application scenario described later).
  • wi is the weight of each marker point, and the weights of all marker points can be set to be equal
  • Rf0 is the first rotation transformation parameter described herein
  • tf0 is the first translation vector described herein.
  • the obtained position coordinates and the position coordinates corresponding to the reference mark points included in the model coordinate set The difference is the translation vector t f0' mentioned above, and the first coordinate transformation parameter finally obtained is (Rf0, Tf0), which is the first rotation transformation parameter and the second translation vector T f0 mentioned above, where the second translation vector T f0 is the sum of the first translation vector t f0 and said difference t f0' .
  • the embodiment of the present application needs to use the result of the rough registration as part of the verification of the fine registration process, and the verification is mainly by checking the size of the registration error, so the first rotation transformation parameters (Rf0, Tf0 ) after that, the error parameters of the coarse registration can be further calculated as the reference error for the subsequent execution of the fine registration.
  • the error of the fine registration is required to be smaller than the reference error (the registration accuracy of the fine registration is higher than that of the rough registration Accurate registration accuracy).
  • coordinate transformation processing may be performed on the object coordinate set according to the first coordinate transformation parameter, so as to obtain the first coordinate set.
  • the c point set (first coordinate set) can be obtained.
  • the reference error parameter is used to measure the degree of deviation between the position coordinates included in the first coordinate set and the position coordinates included in the model coordinate set.
  • the reference error parameter can be calculated in the following manner:
  • the reference error parameter is used to measure the degree of deviation between the position coordinates contained in the first coordinate set and the position coordinates contained in the model coordinate set, so the center point of the position coordinates contained in the first coordinate set and the position coordinates contained in the model coordinate set can be used The distance between the center points of .
  • the reference mark points of the two coordinate sets have been fitted, that is, the reference mark points of the two coordinate sets are coincident, so the reference mark should be removed when calculating the center point coordinates of each coordinate set point.
  • the error p c is equivalent to rotating the first normal vector Ac of the plane where the first reference point deviation vector v c and the second reference point deviation vector u c are located. After an error rotation angle ⁇ c , then translate according to the first error translation vector g c . According to the geometric relationship shown in Figure 2, the following three relations can be obtained:
  • both the first error rotation angle ⁇ c and the first error translation vector g c can be calculated according to the first reference point deviation vector v c and the second reference point deviation vector uc .
  • the first coordinate transformation parameters, the first coordinate set, and the reference error parameters obtained through rough registration have all been recorded, and then the step of fine registration can be performed.
  • the position coordinates of target marker points other than the multiple specified marker points on the target object are acquired.
  • the target object is a femur with 8 designated marker points
  • the doctor can use a probe to collect a marker point at a position different from the 8 designated marker points on the surface of the femur as the target marker point.
  • coordinate transformation processing may be performed on the second coordinate set according to the first coordinate transformation parameter described above to obtain the third coordinate set.
  • the target error parameter can be calculated based on the combination of the third coordinate set and the aforementioned model coordinates.
  • the target error parameter is used to measure the degree of deviation between the position coordinates contained in the third coordinate set and the position coordinates contained in the model coordinate set. Therefore, it can be represented by the distance between the center point of the position coordinates included in the third coordinate set and the center point of the position coordinates included in the model coordinate set.
  • the target error parameter is used to measure whether the position of the selected target mark point is accurate, so as to complete the verification process of the target mark point.
  • the method for calculating the target error parameter is similar to the method for calculating the reference error parameter described above, which may specifically include:
  • the center point coordinates of other position coordinates in the third coordinate set except the position coordinates corresponding to the reference mark points are calculated.
  • the position coordinate corresponding to the reference mark point is d81
  • the coordinates of the center point of the third coordinate set can be expressed as:
  • the third center point coordinate dc1 and the position coordinate hc of the reference mark point calculate the difference between the third center point coordinate dc1 and the position coordinate hc of the reference mark point to obtain the third reference point deviation vector, namely in Represents the third datum point deviation vector.
  • the second reference point deviation vector u c for rough registration will be updated to the third reference point deviation vector
  • the corresponding error can be used express.
  • the center point coordinate a c of the model coordinate set and the position coordinate hc of the reference mark point remain unchanged, the deviation vector v c of the first reference point remains unchanged.
  • the second error rotation angle and the second error translation vector can be based on the first reference point deviation vector v c and the third reference point deviation vector calculated. Finally, rotate the second error by the angle and the second error translation vector Recorded as the target error parameter.
  • the target error parameter can be used to represent the overall registration error after adding the position coordinates of the target marker point, and the reference error parameter can represent the error of the coarse registration. Therefore, if the target error parameter is smaller than the reference error parameter, it means that the fine registration is relatively Since the coarse registration has improved the registration accuracy to a certain extent, it can be considered that the selected position of the target marker point is accurate, and then step 106 is executed. On the contrary, if the target error parameter is greater than or equal to the reference error parameter, it can be determined that the target marker point has failed the verification, that is, step 107 is executed.
  • the target error parameter is smaller than the reference error parameter, it is determined that the target mark point has passed the verification, which may include:
  • the modulus of the second error translation vector is less than or equal to the modulus of the first error translation vector and the first evaluation coefficient
  • ⁇ c represents the first error rotation angle
  • k 1 represents the first evaluation coefficient
  • g c represents the first error translation vector
  • k 2 represents the second evaluation coefficient
  • k 1 and k 2 can select values between 0 and 1 based on empirical values.
  • the verification method may also include:
  • the second error rotation angle is greater than the product of the first error rotation angle and the first evaluation coefficient, or the modulus of the second error translation vector is greater than the modulus of the first error translation vector and the second evaluation coefficient Product, that is, when the above two discriminant relations are not established at the same time, on the one hand, it can be directly determined that the target mark point has not passed the verification; on the other hand, the two normal vectors Ac and For further judgment, first use the following formula to calculate the angle between the two normal vectors
  • Angle Whether it is less than the first threshold can be used to indicate whether the error of the fine registration exceeds the upper limit of the error of the initial registration. when angle When it is less than the first threshold, it can be considered that the error of the fine registration does not exceed the upper limit of the error of the initial registration, which is equivalent to meeting the accuracy requirements of the coarse registration.
  • the error of the fine registration has exceeded or reached the upper limit of the error of the initial registration, which is equivalent to not meeting the accuracy requirements of the coarse registration, so it is determined that the target marker point has not passed the verification at this time.
  • the target error parameter is smaller than the reference error parameter, which means that the fine registration has obtained a certain degree of registration accuracy improvement compared with the coarse registration. At this time, it can be considered that the selected position of the target marker point is accurate, so it is determined that the target marker point has passed the verification .
  • the target marker point after it is determined that the target marker point is verified, it may further include:
  • the second rotation transformation parameter and the third translation vector according to the registration coordinate set and the corresponding point coordinate set, and the position coordinates contained in the registration coordinate set pass through the second rotation transformation parameter and the first translation vector.
  • the Euclidean distance between the obtained position coordinates and the position coordinates contained in the corresponding point coordinate set is the shortest
  • the registration coordinate set contains the position coordinates of the initial marker point
  • the coordinate set includes position coordinates of corresponding points of the initial marker point on the three-dimensional model
  • the updated registration coordinate set and the updated corresponding point coordinate set continue to calculate the updated second rotation transformation parameter and the updated third translation vector until the final second rotation transformation parameter and the final third translation vector are recorded, so
  • the updated set of corresponding point coordinates includes updated position coordinates of corresponding points of the initial marker point on the three-dimensional model.
  • the relevant personnel can continue to collect the next marker point from the target object, and perform the same verification process as the target marker point on the next marker point until the specified number of points on the target object is obtained.
  • Validated markers For example, if the target object is a femur, in addition to the 8 specified marker points, another 30 verified marker points can be obtained.
  • Each weight wi here can be set to the same value
  • Rf1 is the second rotation transformation parameter mentioned above
  • tf1 is the third translation vector mentioned above.
  • r represents the second threshold value
  • (Rfm, tfm) is the coordinate transformation parameter of the final record.
  • the fitting from the target object to the 3D model can be completed according to the coordinate transformation parameters (Rfm, tfm), and the fine registration process ends.
  • the target error parameter is greater than or equal to the reference error parameter, indicating that the registration accuracy of the fine registration is the same or lower than that of the coarse registration, which is caused by the inaccurate position of the selected target marker point, so it can be determined
  • the target point validation failed. For the scene of registration and registration, it means that the position of the target marker point currently collected by the doctor is not accurate. At this time, the system can output relevant instruction information to prompt the doctor to reselect the position of the target marker point.
  • the target object and its 3D model are pre-registered through multiple designated marker points to obtain the result of rough registration; after that, when the operator selects a target marker point, it will enter the fine registration link , specifically adding the position coordinates of the target marker point to the marker set of the target object after rough registration, and calculating the current overall registration error based on the marker set; finally, if the current overall registration error If the error is smaller than the coarse registration, it means that the registration accuracy has been improved to a certain extent. At this time, it is determined that the target marker point has passed the verification, that is, the selected position of the target marker point is considered to be accurate.
  • the system can independently verify whether the selected position of the marker point is accurate, so that the operator can conveniently collect the marker point with an accurate position, thereby avoiding Perform a repeat registration registration process.
  • Application Scenario 1 Registration of Femur in Registration and Registration
  • the CT image of the patient's femur is scanned, and the CT image is segmented to obtain a three-dimensional model of the patient's femur.
  • the biomarker points shown in Table 1 below are respectively obtained by the doctor in the navigation software (as the multiple designated marker points mentioned above):
  • the above 8 biomarkers are all recognized and agreed by the industry in the academic field of orthopedic medicine, and are operable. After obtaining the above 8 marker points, enter the normal preoperative planning process. Since this application does not involve the preoperative planning process, this part of the content is omitted.
  • the femoral marking points 1-7 in Table 1 are all distributed on the side of the distal end of the femur, and the marking point 8 is on the proximal end. Since the surgical approach is only on the knee joint during knee replacement surgery, and the exposed bone surface is only at the distal end of the femur, marker 8 cannot be directly obtained by selecting the bone surface with a probe. To solve this problem, the industry-accepted method is to rigidly fix the reflective ball bracket on the femur, and repeatedly shake the thigh to make the knee joint do a circular motion. This trajectory calculates the position of the center of the femoral head.
  • the doctor first exposes the operation site (distal end of the femur) through a conventional surgical approach, and then enters the registration and registration process, which includes a rough registration stage and a fine registration stage.
  • the doctor can use the needle tip of the probe equipped with a reflective ball (the real-time three-dimensional position of the needle tip is read by the navigator) to sequentially select the femoral marker points 1-7 in Table 1 on the exposed femoral surface, Then shake the patient's thigh repeatedly to make the distal end of the femur make a circular movement, and record the trajectory of the reflective ball array rigidly fixed on the femur through the navigator to calculate the marker point 8 in Table 1, which is the three-dimensional position of the center point of the femoral head .
  • the coordinate system of the 3D femur model is Cmf
  • the coordinate system of the femur in the real world is Cf.
  • the doctor uses a probe to collect a new marker point 1 (the target marker point mentioned above) on the patient's femur surface, and then the marker point 1 can be verified by steps 101-107. If the mark point 1 passes the verification, the doctor can select the next mark point 2 and perform the same verification process as mark point 1 until all mark points (for example, 30 mark points that are preset to be collected) pass the verification . If the mark point 1 fails the verification, it means that the selected position is wrong. At this time, the system can output a corresponding prompt to guide the doctor to click mark point 1 again.
  • the final coordinate transformation parameters (Rfm, tfm) can be obtained as mentioned in step 106, and the coordinate transformation parameters are used to complete the fitting from the real femur to the three-dimensional model of the femur. So far The fine registration process of the femur ends.
  • the registration method of the tibia is basically the same as that of the femur, the difference mainly lies in the selection of biomarker points.
  • doctors can obtain the biomarkers shown in Table 2 in the navigation software.
  • the following 7 biomarkers are also recognized and agreed in the orthopedic academic field and are operable. .
  • the tibial marker points 1-2 in Table 2 are distributed on the side of the distal end of the tibia, and the tibial marker points 3-7 are distributed on the side of the proximal end of the tibia. Since the surgical approach is only on the knee joint during knee replacement surgery, and the exposed bone surface is only at the proximal end of the tibia, the tibial markers 1-2 are directly selected by the doctor on the skin surface of the patient using a probe , and tibial markers 3-7 can be obtained by pointing the bone surface with a probe.
  • the subsequent registration and registration of the tibia is basically the same as the registration and registration of the femur mentioned above. It is only necessary to replace the center point of the femoral head with the center point of the ankle joint, and will not repeat it here.
  • the registration and registration process of the tibia refer to Figure 4.
  • sequence numbers of the steps in the above embodiments do not mean the order of execution, and the execution order of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application .
  • the above mainly describes a method for verifying a selected position of a marker point, and a verification device for a selected position of a marked point will be described below.
  • an embodiment of a verification device for selecting a position of a marker point in the embodiment of the present application includes:
  • a marker point acquisition module 501 configured to acquire position coordinates of target marker points other than a plurality of designated marker points on the target object;
  • a position coordinate adding module 502 configured to add the position coordinates of the target marker point to the first coordinate set to obtain a second coordinate set, the first coordinate set is the pre-acquired object coordinates according to the first coordinate transformation parameters Collecting a coordinate set obtained after coordinate transformation processing is performed, the object coordinate set includes position coordinates of the plurality of specified marker points on the target object;
  • a position coordinate transformation module 503, configured to perform coordinate transformation processing on the second coordinate set according to the first coordinate transformation parameter to obtain a third coordinate set
  • An error parameter calculation module 504 configured to calculate target error parameters according to the third set of coordinates and the pre-collected set of model coordinates, where the set of model coordinates includes the three-dimensional model of the target object and the plurality of specified marker points Corresponding position coordinates, the target error parameter is used to measure the degree of deviation between the position coordinates contained in the third coordinate set and the position coordinates contained in the model coordinate set;
  • Mark point verification module 505 configured to determine that the target mark point has passed the verification if the target error parameter is smaller than a reference error parameter, and the reference error parameter is used to measure the difference between the position coordinates contained in the first coordinate set and the The degree of deviation between the position coordinates contained in the model coordinate set.
  • the plurality of specified marker points includes a reference marker point
  • the device may further include:
  • a coordinate transformation parameter calculation module configured to calculate a first rotation transformation parameter and a first translation vector according to the object coordinate set and the model coordinate set, where the position coordinates included in the object coordinate set undergo the first rotation After the transformation parameters and the processing of the first translation vector, the Euclidean distance between the obtained position coordinates and the position coordinates included in the model coordinate set is the shortest;
  • the difference calculation module is used to calculate the position coordinates of the reference mark points contained in the object coordinate set. After the first rotation transformation parameters and the first translation vector are processed, the obtained position coordinates are different from the The difference between the position coordinates contained in the model coordinate set and the reference marker points;
  • a coordinate transformation parameter determination module configured to determine the first rotation transformation parameter and a second translation vector as the first coordinate transformation parameter, and the second translation vector is the difference between the first translation vector and the difference and.
  • the device may also include:
  • a first center point coordinate calculation module configured to calculate the first center point coordinates of other position coordinates in the model coordinate set except the position coordinates corresponding to the reference mark points;
  • the second center point coordinate calculation module is used to calculate the second center point coordinates of other position coordinates in the first coordinate set except the position coordinates corresponding to the reference mark point;
  • the first reference point deviation vector calculation module is used to calculate the difference between the first center point coordinates and the position coordinates of the reference mark point to obtain the first reference point deviation vector;
  • a second reference point deviation vector calculation module configured to calculate the difference between the second center point coordinates and the position coordinates of the reference mark point to obtain a second reference point deviation vector
  • a reference error calculation module configured to calculate a first error rotation angle and a first error translation vector based on the first reference point deviation vector and the second reference point deviation vector, taking the reference mark point as a reference, the The error between the coordinates of the second center point and the coordinates of the first center point is equivalent to rotating with the first normal vector of the plane where the first reference point deviation vector and the second reference point deviation vector are located After the first error rotation angle, then translate according to the first error translation vector;
  • a reference error determination module configured to determine the first error rotation angle and the first error translation vector as the reference error parameters.
  • error parameter calculation module may include:
  • a third center point coordinate calculation unit configured to calculate the third center point coordinates of other position coordinates in the third coordinate set except the position coordinates corresponding to the reference mark point;
  • a third reference point deviation vector calculation unit configured to calculate the difference between the coordinates of the third center point and the position coordinates of the reference mark point to obtain a third reference point deviation vector
  • a target error calculation unit configured to calculate a second error rotation angle and a second error translation vector based on the first reference point deviation vector and the third reference point deviation vector, with the reference mark point as a reference, the The error between the coordinates of the third center point and the coordinates of the first center point is equivalent to taking the second normal vector of the plane where the first reference point deviation vector and the third reference point deviation vector are located as the axis rotation After the second error rotation angle, then translate according to the second error translation vector;
  • a target error determining unit configured to determine the second error rotation angle and the second error translation vector as the target error parameters.
  • the mark verification module may include:
  • the first marking point verification unit is configured to if the second error rotation angle is less than or equal to the product of the first error rotation angle and the first evaluation coefficient, and the modulus of the second error translation vector is less than or equal to the The product of the modulus of the first error translation vector and the second evaluation coefficient determines that the target mark point has passed the verification, and both the first evaluation coefficient and the second evaluation coefficient are values between 0 and 1.
  • mark verification module may also include:
  • a normal vector included angle calculation unit configured to if the second error rotation angle is greater than the product of the first error rotation angle and the first evaluation coefficient, or the modulus of the second error translation vector is greater than the first error translation The product of the modulus of the vector and the second evaluation coefficient, then calculate the included angle between the first normal vector and the second normal vector;
  • the second marking point verification unit is configured to determine that the target marking point has passed the verification if the angle between the first normal vector and the second normal vector is smaller than the first threshold, otherwise it is determined that the target marking point has failed verify.
  • the device may also include:
  • a new marker point acquisition module configured to acquire the position coordinates of the next marker point on the target object other than the plurality of designated marker points and the target marker point;
  • An initial marker acquisition module configured to perform the same verification process as the target marker on the next marker until a specified number of verified initial markers on the target object are obtained;
  • the first corresponding point obtaining module is used to obtain the corresponding point of the initial marking point on the three-dimensional model by calculating the minimum distance from the initial marking point to the surface of the three-dimensional model;
  • the fine registration coordinate transformation parameter calculation module is used to calculate the second rotation transformation parameter and the third translation vector according to the registration coordinate set and the corresponding point coordinate set, and the position coordinates included in the registration coordinate set pass through the first After the processing of the second rotation transformation parameter and the third translation vector, the Euclidean distance between the obtained position coordinates and the position coordinates contained in the corresponding point coordinate set is the shortest, and the registration coordinate set contains the initial marker point
  • the position coordinates of the corresponding point coordinates set include the position coordinates of the corresponding points of the initial marker point on the three-dimensional model;
  • a registration coordinate set update module configured to perform coordinate transformation processing on the registration coordinate set according to the second rotation transformation parameter and the third translation vector, to obtain an updated registration coordinate set, and the updated registration coordinate set
  • the coordinate set includes the updated position coordinates of the initial marker point
  • the second corresponding point obtaining module is used to obtain the corresponding point of the updated initial marker point on the three-dimensional model by calculating the minimum distance from the updated initial marker point to the surface of the three-dimensional model ;
  • the first fine registration coordinate transformation parameter recording module is used for if the Euclidean distance between the updated position coordinates of the initial marker point and the updated position coordinates of the corresponding point of the initial marker point on the three-dimensional model is less than or equal to the second threshold, record the second rotation transformation parameter and the third translation vector;
  • the second fine registration coordinate transformation parameter recording module is used for if the Euclidean distance between the updated position coordinates of the initial marker point and the updated position coordinates of the corresponding point of the initial marker point on the three-dimensional model is greater than
  • For the second threshold according to the updated registration coordinate set and the updated corresponding point coordinate set, continue to calculate the updated second rotation transformation parameters and the updated third translation vector until the final second rotation transformation is recorded parameters and the final third translation vector, the updated set of corresponding point coordinates includes the updated position coordinates of the corresponding points of the initial marker point on the three-dimensional model.
  • the embodiment of the present application also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the verification of the selected position of any marker point as shown in Figure 1 is realized method.
  • the embodiment of the present application also provides a computer program product.
  • the computer program product is run on a terminal device, the terminal device is executed to implement any verification method for selecting a position of a marker point as shown in FIG. 1 .
  • Fig. 6 is a schematic diagram of a terminal device provided by an embodiment of the present application.
  • the terminal device 6 of this embodiment includes: a processor 60 , a memory 61 , and computer-readable instructions 62 stored in the memory 61 and operable on the processor 60 .
  • the processor 60 executes the computer-readable instructions 62, it implements the steps in the embodiment of the method for verifying the selected position of each marker above, such as steps 101 to 107 shown in FIG. 1 .
  • the processor 60 executes the computer-readable instructions 62
  • the functions of the modules/units in the above-mentioned device embodiments are realized, for example, the functions of the modules 501 to 505 shown in FIG. 5 .
  • the computer-readable instructions 62 can be divided into one or more modules/units, and the one or more modules/units are stored in the memory 61 and executed by the processor 60 to complete the application .
  • the one or more modules/units may be a series of computer program instruction segments capable of accomplishing specific functions, and the instruction segments are used to describe the execution process of the computer-readable instructions 62 in the terminal device 6 .
  • the so-called processor 60 can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), Off-the-shelf programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • a general-purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like.
  • the storage 61 may be an internal storage unit of the terminal device 6 , such as a hard disk or memory of the terminal device 6 .
  • the memory 61 can also be an external storage device of the terminal device 6, such as a plug-in hard disk equipped on the terminal device 6, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, flash memory card (Flash Card), etc. Further, the memory 61 may also include both an internal storage unit of the terminal device 6 and an external storage device.
  • the memory 61 is used to store the computer program and other programs and data required by the terminal device.
  • the memory 61 can also be used to temporarily store data that has been output or will be output.

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Abstract

本申请涉及图像配准技术领域,提出一种标记点选取位置的验证方法、装置、终端设备和存储介质。在本申请中,目标物体及其三维模型预先通过多个指定标记点执行了配准,获得粗配准的结果;之后,当操作人员选取一个目标标记点后,会进入精配准环节,具体是将该目标标记点的位置坐标添加至粗配准结束后的标记点集合中,并基于该标记点集合计算当前的整体配准误差;最后,若当前的整体配准误差小于粗配准的误差,则表示获得了一定程度的配准精度提升,此时判定该目标标记点通过验证,即认为该目标标记点的选取位置是准确的。通过这样设置,在注册配准的过程中,操作人员每选取一个标记点,系统都可以单独验证该标记点的选取位置是否准确。

Description

标记点选取位置的验证方法、装置、终端设备和存储介质
本申请要求于2021年7月16日在中国专利局提交的、申请号为202110805685.7的中国专利申请的优先权,其全部内容通过引用结合在本申请中。
技术领域
本申请涉及图像配准技术领域,尤其涉及一种标记点选取位置的验证方法、装置、终端设备和存储介质。
背景技术
在对患者进行手术的过程中,通常需要执行一个称作“注册配准”的步骤,其目的是尽可能精确地拟合患者的患病部位(例如股骨)与术前采集到的该患病部位的三维模型,以确保医生可以按照手术规划方案完成手术。
目前,常用的注册配准方法主要是由医生在术中利用装有红外反射球的探针在患病部位的特定区域采集一定数量的生物标记点,然后基于采集到的这些生物标记点,使用最近邻迭代等配准算法进行多次拟合,最终完成注册配准。
然而,使用配准算法得出的拟合结果总是存在误差的,故在完成一次注册配准后,系统软件会对整体的配准误差进行评估;若该配准误差过大,则需要重新执行注册配准的流程(即需要重新采集所有的生物标记点),这会导致患者创口的暴露时间大幅提升,增加手术风险。
技术问题
有鉴于此,本申请实施例提供了一种标记点选取位置的验证方法、装置、终端设备和存储介质,能够在每完成一个标记点的选取后,单独验证该标记点的选取位置是否准确,使得操作人员能够方便地采集到位置准确的标记点,从而避免执行重复的注册配准流程。
技术解决方案
本申请实施例的第一方面提供了一种标记点选取位置的验证方法,包括:
获取目标物体上除多个指定标记点之外的目标标记点的位置坐标;
将所述目标标记点的位置坐标添加至第一坐标集合中,得到第二坐标集合,所述第一坐标集合是按照第一坐标变换参数对预采集的物体坐标集合执行坐标变换处理后得到的坐标集合,所述物体坐标集合包含所述目标物体上所述多个指定标记点的位置坐标;
按照所述第一坐标变换参数对所述第二坐标集合执行坐标变换处理,得到第三坐标集合;
根据所述第三坐标集合和预采集的模型坐标集合计算得到目标误差参数,所述模型坐标集合包含所述目标物体的三维模型上与所述多个指定标记点对应的位置坐标,所述目标误差参数用于衡量所述第三坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,所述基准误差参数用于 衡量所述第一坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度。
在本申请实施例中,目标物体及其三维模型预先通过多个指定标记点执行了配准,获得粗配准的结果;之后,当操作人员选取一个目标标记点后,会进入精配准环节,具体是将该目标标记点的位置坐标添加至粗配准结束后的标记点集合中,并基于该标记点集合计算当前的整体配准误差;最后,若当前的整体配准误差小于粗配准的误差,则表示获得了一定程度的配准精度提升,此时判定该目标标记点通过验证,即认为该目标标记点的选取位置是准确的。通过这样设置,在注册配准的过程中,操作人员每选取一个标记点,系统都可以单独验证该标记点的选取位置是否准确,使得操作人员能够方便地采集到位置准确的标记点,从而避免执行重复的注册配准流程。
本申请实施例的第二方面提供了一种标记点选取位置的验证装置,包括:
标记点获取模块,用于获取目标物体上除多个指定标记点之外的目标标记点的位置坐标;
位置坐标添加模块,用于将所述目标标记点的位置坐标添加至第一坐标集合中,得到第二坐标集合,所述第一坐标集合是按照第一坐标变换参数对预采集的物体坐标集合执行坐标变换处理后得到的坐标集合,所述物体坐标集合包含所述目标物体上所述多个指定标记点的位置坐标;
位置坐标变换模块,用于按照所述第一坐标变换参数对所述第二坐标集合执行坐标变换处理,得到第三坐标集合;
误差参数计算模块,用于根据所述第三坐标集合和预采集的模型坐标集合计算得到目标误差参数,所述模型坐标集合包含所述目标物体的三维模型上与所述多个指定标记点对应的位置坐标,所述目标误差参数用于衡量所述第三坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
标记点验证模块,用于若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,所述基准误差参数用于衡量所述第一坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度。
本申请实施例的第三方面提供了一种终端设备,包括存储器、处理器以及存储在所述存储器中并可在所述处理器上运行的计算机程序,所述处理器执行所述计算机程序时实现如本申请实施例的第一方面提供的标记点选取位置的验证方法。
本申请实施例的第四方面提供了一种计算机可读存储介质,所述计算机可读存储介质存储有计算机程序,所述计算机程序被处理器执行时实现如本申请实施例的第一方面提供的标记点选取位置的验证方法。
本申请实施例的第五方面提供了一种计算机程序产品,当计算机程序产品在终端设备上运行时,使得终端设备执行本申请实施例的第一方面所述的标记点选取位置的验证方法。
可以理解的是,上述第二方面至第五方面的有益效果可以参见上述第一方面中的相关描述,在此不 再赘述。
附图说明
图1是本申请实施例提出的一种标记点选取位置的验证方法的流程图;
图2是本申请实施例提出的基准误差参数的几何关系示意图;
图3是本申请实施例提出的股骨的注册配准流程示意图;
图4是本申请实施例提出的胫骨的注册配准流程示意图;
图5是本申请实施例提出的一种标记点选取位置的验证装置的结构图;
图6是本申请实施例提出的一种终端设备的示意图。
本发明的实施方式
本申请提供了一种标记点选取位置的验证方法,在注册配准的过程中,能够在每完成一个标记点的选取后,单独验证该标记点的选取位置是否准确,使得操作人员能够方便地采集到位置准确的标记点,从而避免执行重复的注册配准流程,其具体的实施过程和原理请参见下文所述的方法实施例。
应当理解,本申请各个方法实施例的执行主体为各种类型的终端设备或服务器,比如手机、平板电脑、笔记本电脑、台式电脑和各类医疗设备等。
请参阅图1,示出了本申请实施例提供的一种标记点选取位置的验证方法,包括:
101、获取目标物体上除多个指定标记点之外的目标标记点的位置坐标;
在本申请实施例中,目标物体及其三维模型是待配准的对象,目标物体可以是任何形状或类型的物体,并可以采用指定方式获得该目标物体对应的三维模型。例如,在“注册配准”的应用场景中,目标物体可以是患者的真实患病部位,而其三维模型可以从术前采集到的该患病部位的CT图像中分割出来。
在执行步骤101之前,本申请实施例预先对目标物体及其三维模型执行了粗配准的处理,以下先对粗配准的具体实施方式进行说明。
在执行粗配准时,首先采集两个不同坐标系下(即目标物体所处的世界坐标系和三维模型所处的模型坐标系)的点集。其中一个点集是该目标物体上多个指定标记点的集合,对应于本文所述的物体坐标集合,其包含该目标物体上多个指定标记点的位置坐标;该多个指定标记点可以是人为选定的,适合用于表征该目标物体的形状结构的关键部位的点,本申请实施例通过这些指定标记点来实现目标物体及其三维模型的粗配准,理论上这些指定标记点的数量越多,则获得的粗配准结果越准确。另一个点集是该目标物体的三维模型上与该多个指定标记点对应的点的集合,对应于本文所述的模型坐标集合,其包含该三维模型上与该多个指定标记点对应的位置坐标(即对应点的位置坐标),例如若目标物体为一个长方体,其多个指定标记点为长方体的8个角点,则该模型坐标集合包含该长方体的三维模型上8个角点的位置坐标。
粗配准的目的是寻找一个坐标变换关系(或坐标变换参数),使得物体坐标集合中的标记点在经过 该坐标变换关系的转换后,与模型坐标集合中的标记点之间的欧式距离最短。也即,根据物体坐标集合和模型坐标集合可以计算得到一个满足条件的坐标变换关系(即本文所述的第一坐标变换参数),该坐标变换关系一般可以表示为(R,t),其中R表示旋转变换参数,t表示平移向量。
本申请的一个实施例中,所述多个指定标记点中包含一个基准标记点,第一坐标变换参数可以根据以下方式计算得到:
(1)根据所述物体坐标集合和所述模型坐标集合,计算得到第一旋转变换参数和第一平移向量,所述物体坐标集合包含的位置坐标在经过所述第一旋转变换参数和所述第一平移向量的处理后,得到的位置坐标与所述模型坐标集合包含的位置坐标之间的欧氏距离最短;
(2)计算所述物体坐标集合包含的所述基准标记点的位置坐标在经过所述第一旋转变换参数和所述第一平移向量的处理后,得到的位置坐标与所述模型坐标集合包含的与所述基准标记点对应的位置坐标之间的差值;
(3)将所述第一旋转变换参数和第二平移向量确定为所述第一坐标变换参数,所述第二平移向量为所述第一平移向量与所述差值之和。
在粗配准的时候,可以从多个指定标记点中选取一个基准标记点,且通过平移使得两个坐标集合的基准标记点重合。例如,若目标物体为股骨,则选取的基准标记点可以为股骨头中心点(关于这部分更具体的说明,可以参照后文所述的实际应用场景)。假设模型坐标集合为a={a1…a8},其表示目标物体的三维模型上的8个指定标记点的坐标;物体坐标集合为b={b1…b8},其表示目标物体上的8个指定标记点的坐标,则首先寻找坐标变换关系(Rf0,tf0),使点集b中的标记点经过(Rf0,tf0)的转换后,与点集a中的标记点的欧式距离最短,如以下公式所示:
Figure PCTCN2022090080-appb-000001
其中,wi为各个标记点的权重,可以设置所有标记点的权重均相等,Rf0即本文所述的第一旋转变换参数,tf0即本文所述的第一平移向量。
在获得坐标变换关系(Rf0,tf0)之后,相当于完成了粗配准步骤,接下来可以执行基准标记点的拟合步骤,使得两个坐标集合的基准标记点重合。同样以上述股骨头中心点为例,假设股骨头中心点在模型坐标集合中的坐标为a8,在物体坐标集合中的坐标为b8,则可以采用(Rf0,tf0)对b8进行处理,然后将得到的结果减去a8,这个差值可以表示经(Rf0,tf0)变换后a8到b8的平移向量t f0′,即
t f0′=(R f0b 8+t f0)-a 8
为了拟合基准标记点,将粗配准结果中的所有标记点全部沿平移向量t f0′进行平移,将此步骤获得 的点集记作c={c1…c8},c点集中的各个标记点满足:
c i=R f0b i+t f0+t f0′
至此,坐标变换关系更新为(Rf0,Tf0),其中T f0=t f0+t f0′
物体坐标集合包含的基准标记点的位置坐标在经过第一旋转变换参数Rf0和第一平移向量tf0的处理后,得到的位置坐标与模型坐标集合包含的与基准标记点对应的位置坐标之间的差值即上述的平移向量t f0′,最终得到的第一坐标变换参数为(Rf0,Tf0),即前文所述的第一旋转变换参数以及第二平移向量T f0,其中第二平移向量T f0是第一平移向量t f0和所述差值t f0′之和。
由于本申请实施例需要将粗配准的结果部分用作精配准流程的验证,而验证主要是通过检验配准的误差大小,故在通过粗配准获得第一旋转变换参数(Rf0,Tf0)之后,还可以进一步计算得到粗配准的误差参数,作为后续执行精配准的基准误差,通常要求精配准的误差要小于该基准误差(精配准的配准精度要高于粗配准的配准精度)。
在获得第一坐标变换参数之后,可以按照该第一坐标变换参数对物体坐标集合执行坐标变换处理,从而得到第一坐标集合。例如,前文所述的b点集(物体坐标集合)在经过第一坐标变换参数(Rf0,Tf0)的处理后,可以获得c点集(第一坐标集合)。此时,基准误差参数用于衡量第一坐标集合包含的位置坐标与模型坐标集合包含的位置坐标之间的偏差程度。
在本申请的一个实施例中,所述基准误差参数可以根据以下方式计算得到:
(1)计算所述模型坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第一中心点坐标;
(2)计算所述第一坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第二中心点坐标;
(3)计算所述第一中心点坐标与所述基准标记点的位置坐标之差,得到第一基准点偏差向量;
(4)计算所述第二中心点坐标与所述基准标记点的位置坐标之差,得到第二基准点偏差向量;
(5)根据所述第一基准点偏差向量和所述第二基准点偏差向量,计算得到第一误差旋转角度和第一误差平移向量,以所述基准标记点为基准,所述第二中心点坐标与所述第一中心点坐标之间的误差等效于以所述第一基准点偏差向量和所述第二基准点偏差向量所处平面的第一法向量为轴旋转所述第一误差旋转角度后,再按照所述第一误差平移向量平移;
(6)将所述第一误差旋转角度和所述第一误差平移向量确定为所述基准误差参数。
基准误差参数用于衡量第一坐标集合包含的位置坐标与模型坐标集合包含的位置坐标之间的偏差程度,故可以用第一坐标集合包含的位置坐标的中心点与模型坐标集合包含的位置坐标的中心点之间的 距离来表示。在之前的操作中,已经将两个坐标集合的基准标记点进行了拟合,即两个坐标集合的基准标记点是重合的,故在计算每个坐标集合的中心点坐标时应该除去基准标记点。在前文所述的例子中,模型坐标集合为a={a1…a8},其中a8表示基准标记点,那么模型坐标集合的中心点坐标可以表示为:
Figure PCTCN2022090080-appb-000002
也即,除了a8之外的其余7个指定标记点的中心点坐标。
第一坐标集合为c={c1…c8},其中c8表示基准标记点,那么第一坐标集合的中心点坐标可以表示为除了c8之外的其余7个指定标记点的中心点坐标,也即如下的表达式:
Figure PCTCN2022090080-appb-000003
在获得两个坐标集合的中心点坐标之后,误差可以用两个中心点坐标之间的差值来表示,即误差p c=c c-a c
为便于描述,将基准标记点的位置坐标记作hc,则存在关系h c=a 8=b 8
接下来,计算模型坐标集合的中心点坐标与基准标记点的位置坐标之差,得到第一基准点偏差向量,即v c=a c-h c,其中v c表示第一基准点偏差向量。
计算第一坐标集合的中心点坐标与基准标记点的位置坐标之差,得到第二基准点偏差向量,即u c=c c-h c,其中u c表示第二基准点偏差向量。
如图2所示,以基准标记点为基准,误差p c等效于以第一基准点偏差向量v c和第二基准点偏差向量u c所处平面的第一法向量Ac为轴旋转第一误差旋转角度φ c后,再按照第一误差平移向量g c平移。根据图2所示的几何关系,可以获得以下3个关系式:
A c=v c×u c
Figure PCTCN2022090080-appb-000004
Figure PCTCN2022090080-appb-000005
可见,第一误差旋转角度φ c和第一误差平移向量g c都可以根据第一基准点偏差向量v c和第二基准点偏差向量u c计算得到。最后,将第一误差旋转角度φ c和第一误差平移向量g c作为基准误差参数记录。
至此,通过粗配准获得的第一坐标变换参数、第一坐标集合以及基准误差参数已全部记录,接下来可以执行精配准的步骤。
在精配准的环节,首先获取目标物体上除该多个指定标记点之外的目标标记点的位置坐标。例如, 若目标物体为股骨,其具有8个指定标记点,则在精配准时可由医生用探针在股骨表面采集一个与该8个指定标记点不同位置的标记点,作为目标标记点。
102、将所述目标标记点的位置坐标添加至第一坐标集合中,得到第二坐标集合;
在获得目标标记点后,将其位置坐标添加至前文所述的第一坐标集合中,得到第二坐标集合。例如,假设目标标记点的位置坐标为c9,则将c9添加至第一坐标集合c={c1…c8}中,得到第二坐标集合c={c1…c9}。
103、按照第一坐标变换参数对所述第二坐标集合执行坐标变换处理,得到第三坐标集合;
为了评估新采集的目标标记点的位置选取误差,可以按照前文所述的第一坐标变换参数对第二坐标集合执行坐标变换处理,得到第三坐标集合。例如,可以采用(Rf0,Tf0)对第二坐标集合c={c1…c9}执行坐标变换处理,得到第三坐标集合,记作d1={d11…d91}。
104、根据所述第三坐标集合和模型坐标集合计算得到目标误差参数;
接着,可以根据第三坐标集合和前文所述的模型坐标结合计算得到目标误差参数,目标误差参数用于衡量第三坐标集合包含的位置坐标与模型坐标集合包含的位置坐标之间的偏差程度,故可以用第三坐标集合包含的位置坐标的中心点与模型坐标集合包含的位置坐标的中心点之间的距离来表示。本申请实施例通过目标误差参数衡量选取的目标标记点的位置是否准确,从而完成目标标记点的验证过程。
计算目标误差参数的方法与前文所述的计算基准误差参数的方法类似,具体可以包括:
(1)计算所述第三坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第三中心点坐标;
(2)计算所述第三中心点坐标与所述基准标记点的位置坐标之差,得到第三基准点偏差向量;
(3)根据所述第一基准点偏差向量和所述第三基准点偏差向量,计算得到第二误差旋转角度和第二误差平移向量,以所述基准标记点为基准,所述第三中心点坐标与所述第一中心点坐标之间的误差等效于以所述第一基准点偏差向量和所述第三基准点偏差向量所处平面的第二法向量为轴旋转所述第二误差旋转角度后,再按照所述第二误差平移向量平移;
(4)将所述第二误差旋转角度和所述第二误差平移向量确定为所述目标误差参数。
首先,计算第三坐标集合中除与基准标记点对应的位置坐标之外的其它位置坐标的中心点坐标。例如,在第三坐标集合d1={d11…d91}中,与基准标记点对应的位置坐标是d81,那么第三坐标集合的中心点坐标可以表示为:
Figure PCTCN2022090080-appb-000006
然后,计算第三中心点坐标dc1与基准标记点的位置坐标hc之差,得到第三基准点偏差向量,即
Figure PCTCN2022090080-appb-000007
其中
Figure PCTCN2022090080-appb-000008
表示第三基准点偏差向量。可见,在精配准时,通过添加目标标记点的位置坐标,会将粗配准的第二基准点偏差向量u c更新为第三基准点偏差向量
Figure PCTCN2022090080-appb-000009
对应的误差可以用
Figure PCTCN2022090080-appb-000010
表示。而由于模型坐标集合的中心点坐标a c和基准标记点的位置坐标hc未变,故第一基准点偏差向量v c保持不变。
类似的,参照图2所示的几何关系,在精配准时相当于将粗配准中的c c变更为
Figure PCTCN2022090080-appb-000011
将u c变更为
Figure PCTCN2022090080-appb-000012
以基准标记点为基准,误差
Figure PCTCN2022090080-appb-000013
等效于以第一基准点偏差向量v c和第三基准点偏差向量
Figure PCTCN2022090080-appb-000014
所处平面的第二法向量
Figure PCTCN2022090080-appb-000015
为轴旋转第二误差旋转角度
Figure PCTCN2022090080-appb-000016
后,再按照第二误差平移向量
Figure PCTCN2022090080-appb-000017
平移,即可以获得以下3个关系式:
Figure PCTCN2022090080-appb-000018
Figure PCTCN2022090080-appb-000019
Figure PCTCN2022090080-appb-000020
可见,第二误差旋转角度
Figure PCTCN2022090080-appb-000021
和第二误差平移向量
Figure PCTCN2022090080-appb-000022
都可以根据第一基准点偏差向量v c和第三基准点偏差向量
Figure PCTCN2022090080-appb-000023
计算得到。最后,将第二误差旋转角度
Figure PCTCN2022090080-appb-000024
和第二误差平移向量
Figure PCTCN2022090080-appb-000025
作为目标误差参数记录。
105、判断所述目标误差参数是否小于基准误差参数;
在获得目标误差参数之后,判断其是否小于粗配准时获取到的基准误差参数。目标误差参数可以用于表示添加目标标记点的位置坐标后的整体配准误差,基准误差参数可以表示粗配准的误差,因此,若目标误差参数小于基准误差参数,则表示精配准相较于粗配准获得了一定程度的配准精度提升,此时可以认为该目标标记点的选取位置是准确的,然后执行步骤106。反之,若目标误差参数大于或等于基准误差参数,可以判定该目标标记点验证未通过,即执行步骤107。
具体的,若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,可以包括:
若所述第二误差旋转角度小于或等于所述第一误差旋转角度与第一评价系数的乘积,且所述第二误差平移向量的模小于或等于所述第一误差平移向量的模与第二评价系数的乘积,则判定所述目标标记点通过验证,所述第一评价系数和所述第二评价系数均为0至1之间的数值。
例如,可以判断是否同时满足以下2个判别关系式:
Figure PCTCN2022090080-appb-000026
Figure PCTCN2022090080-appb-000027
其中,
Figure PCTCN2022090080-appb-000028
表示第二误差旋转角度,φ c表示第一误差旋转角度,k 1表示第一评价系数,
Figure PCTCN2022090080-appb-000029
表示第二 误差平移向量,g c表示第一误差平移向量,k 2表示第二评价系数,k 1和k 2可以根据经验值选取0至1之间的数值。
进一步的,所述验证方法还可以包括:
(1)若所述第二误差旋转角度大于所述第一误差旋转角度与第一评价系数的乘积,或者所述第二误差平移向量的模大于所述第一误差平移向量的模与第二评价系数的乘积,则计算所述第一法向量和所述第二法向量的夹角;
(2)若所述第一法向量和所述第二法向量的夹角小于第一阈值,则判定所述目标标记点通过验证,否则判定所述目标标记点未通过验证。
若所述第二误差旋转角度大于所述第一误差旋转角度与第一评价系数的乘积,或者所述第二误差平移向量的模大于所述第一误差平移向量的模与第二评价系数的乘积,即上述2个判别关系式不同时成立时,一方面可以直接判定该目标标记点未通过验证;另一方面可以通过前文所述的两个法向量Ac和
Figure PCTCN2022090080-appb-000030
进一步判断,首先采用以下公式计算两个法向量之间的夹角
Figure PCTCN2022090080-appb-000031
Figure PCTCN2022090080-appb-000032
然后,判断该夹角
Figure PCTCN2022090080-appb-000033
是否小于某个设定的第一阈值;若是,则可以判定目标标记点通过验证,否则判定目标标记点未通过验证。夹角
Figure PCTCN2022090080-appb-000034
是否小于第一阈值,可用于表示精配准的误差是否超过初配准的误差上限。当夹角
Figure PCTCN2022090080-appb-000035
小于第一阈值时,可认为精配准的误差未超过初配准的误差上限,相当于符合粗配准的精度要求,此时仍然可以判定目标标记点验证通过;而当夹角
Figure PCTCN2022090080-appb-000036
大于或等于第一阈值时,可认为精配准的误差已超过或达到初配准的误差上限,相当于不符合粗配准的精度要求,故此时判定目标标记点未通过验证。
106、判定所述目标标记点通过验证;
目标误差参数小于基准误差参数,表示精配准相较于粗配准获得了一定程度的配准精度提升,此时可以认为该目标标记点的选取位置是准确的,故判定目标标记点通过验证。
在本申请的一个实施例中,在判定所述目标标记点通过验证之后,还可以包括:
(1)获取所述目标物体上除所述多个指定标记点和所述目标标记点之外的下一个标记点的位置坐标;
(2)对所述下一个标记点执行与所述目标标记点相同的验证处理,直至获得所述目标物体上指定数量通过验证的初始标记点;
(3)通过计算所述初始标记点到所述三维模型的面的最小距离的方法,求得所述初始标记点在所 述三维模型上的对应点;
(4)根据配准坐标集合和对应点坐标集合,计算得到第二旋转变换参数和第三平移向量,所述配准坐标集合包含的位置坐标在经过所述第二旋转变换参数和所述第三平移向量的处理后,得到的位置坐标与所述对应点坐标集合包含的位置坐标之间的欧氏距离最短,所述配准坐标集合包含所述初始标记点的位置坐标,所述对应点坐标集合包含所述初始标记点在所述三维模型上的对应点的位置坐标;
(5)按照所述第二旋转变换参数和所述第三平移向量对所述配准坐标集合执行坐标变换处理,得到更新的配准坐标集合,所述更新的配准坐标集合包含更新的所述初始标记点的位置坐标;
(6)通过计算更新的所述初始标记点到所述三维模型的面的最小距离的方法,求得更新的所述初始标记点在所述三维模型上的对应点;
(7)若更新的所述初始标记点的位置坐标与更新的所述初始标记点在所述三维模型上的对应点的位置坐标之间的欧式距离小于或等于第二阈值,则记录所述第二旋转变换参数和所述第三平移向量;
(8)若更新的所述初始标记点的位置坐标与更新的所述初始标记点在所述三维模型上的对应点的位置坐标之间的欧式距离大于所述第二阈值,则根据所述更新的配准坐标集合和更新的对应点坐标集合,继续计算得到更新的第二旋转变换参数和更新的第三平移向量,直至记录最终的第二旋转变换参数和最终的第三平移向量,所述更新的对应点坐标集合包含更新的所述初始标记点在所述三维模型上的对应点的位置坐标。
在精配准的环节,需要获得多个通过验证的标记点的位置坐标,以实现拟合目标物体和三维模型的目标。因此,在判定目标标记点通过验证之后,相关人员可以继续从该目标物体上采集下一个标记点,对该下一个标记点执行与目标标记点相同的验证处理,直至获得该目标物体上指定数量通过验证的标记点。例如,若目标物体为股骨,则除8个指定标记点外,可以另外获得30个通过验证的标记点。这些通过验证的标记点称作初始标记点,接下来可以通过计算初始标记点到三维模型的面(三维模型的表面是由许多三角形组成的mesh网格)的最小距离的方法,求得每个初始标记点在三维模型上的对应点。初始标记点构成的坐标集合称作配准坐标集合,可以表示为p1={p11…pn1},其中n为初始标记点的数量;各个初始标记点在三维模型上的对应点构成的坐标集合称作对应点坐标集合,可以表示为q1={q11…qn1}。然后,寻找坐标变换关系(Rf1,tf1),使p1中的标记点经过该变换后和q1中的标记点的欧氏距离最短,即:
Figure PCTCN2022090080-appb-000037
这里的各个权重wi可以设置为相同的数值,Rf1即前文所述的第二旋转变换参数,tf1即前文所述的第三平移向量。
然后,按照(Rf1,tf1)对配准坐标集合p1={p11…pn1}执行坐标变换处理,得到更新的配准坐标集 合p2={p12…pn2},其包含更新的初始标记点的位置坐标,例如初始标记点p11更新为p12=Rf1*p11+tf1。
接着,采用同样的方法,即通过计算更新的初始标记点到三维模型的面的最小距离的方法求得每个更新的初始标记点在三维模型上的对应点。也即,求得与更新的配准坐标集合p2={p12…pn2}对应的更新的对应点坐标集合q2={q12…qn2}。判断p2和q2中各个位置坐标之间的欧式距离是否小于或等于某个设定的第二阈值;若是,则表示配准误差符合要求,此时记录下对应的坐标变换关系(Rf1,tf1)。若否,则表示配准误差不符合要求,此时循环执行相同的步骤,即寻找更新的坐标变换关系(Rf2,tf2),使p2中的标记点经过该变换后和q2中的标记点的欧氏距离最短,然后再采用(Rf2,tf2)对p2执行坐标变换处理,得到p3,求取与p3对应的q3,判断p3和q3中各个位置坐标之间的欧式距离是否小于或等于第二阈值…如此不断重复,假设经过m次变换,最终获得满足条件的pm和qm,如下公式所示:
Figure PCTCN2022090080-appb-000038
其中,r表示第二阈值,(Rfm,tfm)为最终记录的坐标变换参数。
至此,可以按照坐标变换参数(Rfm,tfm)完成从目标物体到三维模型的拟合,精配准过程结束,
107、判定所述目标标记点未通过验证。
目标误差参数大于或等于基准误差参数,表示精配准的配准精度相较于粗配准的配准精度持平或者下降,这是由于选取的目标标记点的位置不准确导致的,因此可以判定该目标标记点验证未通过。针对注册配准的场景,表示医生当前采集的目标标记点的位置不准确,此时系统可以输出相关的指示信息,提示医生重新选取目标标记点的位置。
在本申请实施例中,目标物体及其三维模型预先通过多个指定标记点执行了配准,获得粗配准的结果;之后,当操作人员选取一个目标标记点后,会进入精配准环节,具体是将该目标标记点的位置坐标添加至粗配准结束后的目标物体的标记点集合中,并基于该标记点集合计算当前的整体配准误差;最后,若当前的整体配准误差小于粗配准的误差,则表示获得了一定程度的配准精度提升,此时判定该目标标记点通过验证,即认为该目标标记点的选取位置是准确的。通过这样设置,在注册配准的过程中,操作人员每选取一个标记点,系统都可以单独验证该标记点的选取位置是否准确,使得操作人员能够方便地采集到位置准确的标记点,从而避免执行重复的注册配准流程。
为便于理解本申请提出的技术方案,以下列举2个实际的应用场景。
应用场景1:注册配准环节中股骨的配准
在对患者手术前,扫描患者股骨部位的CT图像,对该CT图像进行分割,获得患者股骨的三维模型。在股骨的三维模型上,由医生在导航软件中分别获取如下表1所示的生物标记点(作为前文所述的多个指定标记点):
表1
标记点序号 股骨
1 外上髁
2 内上髁
3 股骨远端外侧
4 股骨远端内侧
5 股骨后髁外侧
6 股骨后髁内侧
7 股骨远端中心
8 股骨头中心
以上8个生物标记点都是在骨科医学相关学术领域获得业界公认及共识的,具备可操作性。在获取上述8个标记点完毕后,进入正常的术前规划流程,由于本申请不涉及术前规划流程,故这部分内容省略。
需要说明的是,表1中的股骨标记点1-7均分布在股骨远心端一侧,标记点8则是在近心端。由于在膝关节置换手术过程中,手术入路只在膝关节上,暴露的骨面也只在股骨远心端,因此标记点8无法直接通过探针点选骨面的方式获得。针对此问题,业界认可的方式是在股骨上刚性固定反光球支架,通过反复摇晃大腿使膝关节做画圆的动作,并在这一过程中用红外线导航仪记录股骨的三维运动轨迹,并由此轨迹计算出股骨头中心的位置。
在手术过程中,医生首先通过常规手术入路使手术位置(股骨远心端)暴露,然后进入注册配准环节,该环节包括粗配准阶段和精配准阶段。
在粗配准阶段,医生可以使用装有反光球的探针(针尖的实时三维位置由导航仪读取)的针尖依次在暴露的股骨表面上点选表1中的股骨标记点1-7,然后反复摇晃患者大腿使股骨远端做出画圆动作,通过导航仪记录刚性固定在股骨上的反光球阵列的运动轨迹,以算出表1中的标记点8,即股骨头中心点的三维位置。假设股骨三维模型所在的坐标系为Cmf,真实世界股骨所在的坐标系为Cf。令a={a1…a8}为股骨CT模型上的8个标记点坐标,b={b1…b8}为真实股骨由医生用探针点选的8个标记点坐标,则粗配准的目的是寻找变换关系(Rf0,tf0),使b中的标记点经过(Rf0,tf0)转换后和a中的标记点的欧氏距离最短。在粗配准结束后,获得坐标变换关系(Rf0,tf0),接下来需要拟合两个坐标系下的股骨头中心点,从而获得新的坐标变换参数为(Rf0,Tf0),具体操作方式可以参照前文所述的相关内容。在粗配准结束后,系统还会记录相应的基准误差参数,例如前文所述的第一误差旋转角度φ c和第一误差平移向量g c
之后进入精配准阶段,医生用探针在患者股骨表面采集一个新的标记点1(前文所述的目标标记点),接下来可以采用步骤101-107的方式对该标记点1进行验证。若该标记点1通过验证,则医生可以选取 下一个标记点2,执行与标记点1相同的验证过程,直至所有标记点(例如预先设定好的需要采集的30个标记点)都通过验证。若标记点1未通过验证,表示其选取位置有误,此时系统可以输出相应的提示,指导医生重新点选标记点1。在30个标记点都通过验证后,可以采用如步骤106中提及的方式获取最终的坐标变换参数(Rfm,tfm),采用该坐标变换参数完成从真实股骨到股骨三维模型的拟合,至此股骨的精配准过程结束。
关于股骨的注册配准流程,可以参照图3。
应用场景2:注册配准环节中胫骨的配准
胫骨的配准方式与股骨的配准方式基本相同,区别主要在于生物标记点的选取。在胫骨的三维模型上,医生可以在导航软件中分别获取如下表2所示的生物标记点,以下7个生物标记点同样是在骨科医学相关学术领域获得业界公认及共识的,具备可操作性。
表2
标记点序号 胫骨
1 外髁
2 内髁
3 胫骨平台中心
4 胫骨结节
5 PCL止点中心
6 胫骨平台外侧
7 胫骨平台内侧
需要说明的是,表2中的胫骨标记点1-2分布在胫骨远心端一侧,而胫骨标记点3-7分布在胫骨近心端一侧。由于在膝关节置换手术过程中,手术入路只在膝关节上,暴露的骨面也只在胫骨近心端,因此胫骨标记点1-2是由医生使用探针直接在患者皮肤表面选取的,而胫骨标记点3-7可以通过探针点选骨面的方式获得。
之后的胫骨注册配准环节,与前文所述的股骨注册配准环节基本一致,只需将股骨头中心点替换为踝关节中心点即可,在此不再赘述。关于胫骨的注册配准流程,可以参照图4。
应理解,上述各个实施例中各步骤的序号的大小并不意味着执行顺序的先后,各过程的执行顺序应以其功能和内在逻辑确定,而不应对本申请实施例的实施过程构成任何限定。
为便于理解,以下列举几个实际的应用场景,以更好地说明本申请提出的标记点选取位置的验证方法。
上面主要描述了一种标记点选取位置的验证方法,下面将对一种标记点选取位置的验证装置进行描述。
请参阅图5,本申请实施例中一种标记点选取位置的验证装置的一个实施例包括:
标记点获取模块501,用于获取目标物体上除多个指定标记点之外的目标标记点的位置坐标;
位置坐标添加模块502,用于将所述目标标记点的位置坐标添加至第一坐标集合中,得到第二坐标集合,所述第一坐标集合是按照第一坐标变换参数对预采集的物体坐标集合执行坐标变换处理后得到的坐标集合,所述物体坐标集合包含所述目标物体上所述多个指定标记点的位置坐标;
位置坐标变换模块503,用于按照所述第一坐标变换参数对所述第二坐标集合执行坐标变换处理,得到第三坐标集合;
误差参数计算模块504,用于根据所述第三坐标集合和预采集的模型坐标集合计算得到目标误差参数,所述模型坐标集合包含所述目标物体的三维模型上与所述多个指定标记点对应的位置坐标,所述目标误差参数用于衡量所述第三坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
标记点验证模块505,用于若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,所述基准误差参数用于衡量所述第一坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度。
在本申请的一个实施例中,所述多个指定标记点中包含一个基准标记点,所述装置还可以包括:
坐标变换参数计算模块,用于根据所述物体坐标集合和所述模型坐标集合,计算得到第一旋转变换参数和第一平移向量,所述物体坐标集合包含的位置坐标在经过所述第一旋转变换参数和所述第一平移向量的处理后,得到的位置坐标与所述模型坐标集合包含的位置坐标之间的欧氏距离最短;
差值计算模块,用于计算所述物体坐标集合包含的所述基准标记点的位置坐标在经过所述第一旋转变换参数和所述第一平移向量的处理后,得到的位置坐标与所述模型坐标集合包含的与所述基准标记点对应的位置坐标之间的差值;
坐标变换参数确定模块,用于将所述第一旋转变换参数和第二平移向量确定为所述第一坐标变换参数,所述第二平移向量为所述第一平移向量与所述差值之和。
在本申请的一个实施例中,所述装置还可以包括:
第一中心点坐标计算模块,用于计算所述模型坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第一中心点坐标;
第二中心点坐标计算模块,用于计算所述第一坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第二中心点坐标;
第一基准点偏差向量计算模块,用于计算所述第一中心点坐标与所述基准标记点的位置坐标之差,得到第一基准点偏差向量;
第二基准点偏差向量计算模块,用于计算所述第二中心点坐标与所述基准标记点的位置坐标之差, 得到第二基准点偏差向量;
基准误差计算模块,用于根据所述第一基准点偏差向量和所述第二基准点偏差向量,计算得到第一误差旋转角度和第一误差平移向量,以所述基准标记点为基准,所述第二中心点坐标与所述第一中心点坐标之间的误差等效于以所述第一基准点偏差向量和所述第二基准点偏差向量所处平面的第一法向量为轴旋转所述第一误差旋转角度后,再按照所述第一误差平移向量平移;
基准误差确定模块,用于将所述第一误差旋转角度和所述第一误差平移向量确定为所述基准误差参数。
进一步的,所述误差参数计算模块可以包括:
第三中心点坐标计算单元,用于计算所述第三坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第三中心点坐标;
第三基准点偏差向量计算单元,用于计算所述第三中心点坐标与所述基准标记点的位置坐标之差,得到第三基准点偏差向量;
目标误差计算单元,用于根据所述第一基准点偏差向量和所述第三基准点偏差向量,计算得到第二误差旋转角度和第二误差平移向量,以所述基准标记点为基准,所述第三中心点坐标与所述第一中心点坐标之间的误差等效于以所述第一基准点偏差向量和所述第三基准点偏差向量所处平面的第二法向量为轴旋转所述第二误差旋转角度后,再按照所述第二误差平移向量平移;
目标误差确定单元,用于将所述第二误差旋转角度和所述第二误差平移向量确定为所述目标误差参数。
在本申请的一个实施例中,所述标记点验证模块可以包括:
第一标记点验证单元,用于若所述第二误差旋转角度小于或等于所述第一误差旋转角度与第一评价系数的乘积,且所述第二误差平移向量的模小于或等于所述第一误差平移向量的模与第二评价系数的乘积,则判定所述目标标记点通过验证,所述第一评价系数和所述第二评价系数均为0至1之间的数值。
进一步的,所述标记点验证模块还可以包括:
法向量夹角计算单元,用于若所述第二误差旋转角度大于所述第一误差旋转角度与第一评价系数的乘积,或者所述第二误差平移向量的模大于所述第一误差平移向量的模与第二评价系数的乘积,则计算所述第一法向量和所述第二法向量的夹角;
第二标记点验证单元,用于若所述第一法向量和所述第二法向量的夹角小于第一阈值,则判定所述目标标记点通过验证,否则判定所述目标标记点未通过验证。
在本申请的一个实施例中,所述装置还可以包括:
新标记点获取模块,用于获取所述目标物体上除所述多个指定标记点和所述目标标记点之外的下一个标记点的位置坐标;
初始标记点获取模块,用于对所述下一个标记点执行与所述目标标记点相同的验证处理,直至获得所述目标物体上指定数量通过验证的初始标记点;
第一对应点求取模块,用于通过计算所述初始标记点到所述三维模型的面的最小距离的方法,求得所述初始标记点在所述三维模型上的对应点;
精配准坐标变换参数计算模块,用于根据配准坐标集合和对应点坐标集合,计算得到第二旋转变换参数和第三平移向量,所述配准坐标集合包含的位置坐标在经过所述第二旋转变换参数和所述第三平移向量的处理后,得到的位置坐标与所述对应点坐标集合包含的位置坐标之间的欧氏距离最短,所述配准坐标集合包含所述初始标记点的位置坐标,所述对应点坐标集合包含所述初始标记点在所述三维模型上的对应点的位置坐标;
配准坐标集合更新模块,用于按照所述第二旋转变换参数和所述第三平移向量对所述配准坐标集合执行坐标变换处理,得到更新的配准坐标集合,所述更新的配准坐标集合包含更新的所述初始标记点的位置坐标;
第二对应点求取模块,用于通过计算更新的所述初始标记点到所述三维模型的面的最小距离的方法,求得更新的所述初始标记点在所述三维模型上的对应点;
第一精配准坐标变换参数记录模块,用于若更新的所述初始标记点的位置坐标与更新的所述初始标记点在所述三维模型上的对应点的位置坐标之间的欧式距离小于或等于第二阈值,则记录所述第二旋转变换参数和所述第三平移向量;
第二精配准坐标变换参数记录模块,用于若更新的所述初始标记点的位置坐标与更新的所述初始标记点在所述三维模型上的对应点的位置坐标之间的欧式距离大于所述第二阈值,则根据所述更新的配准坐标集合和更新的对应点坐标集合,继续计算得到更新的第二旋转变换参数和更新的第三平移向量,直至记录最终的第二旋转变换参数和最终的第三平移向量,所述更新的对应点坐标集合包含更新的所述初始标记点在所述三维模型上的对应点的位置坐标。
本申请实施例还提供一种计算机可读存储介质,所述计算机可读存储介质存储有计算机程序,所述计算机程序被处理器执行时实现如图1表示的任意一种标记点选取位置的验证方法。
本申请实施例还提供一种计算机程序产品,当该计算机程序产品在终端设备上运行时,使得终端设备执行实现如图1表示的任意一种标记点选取位置的验证方法。
图6是本申请一实施例提供的终端设备的示意图。如图6所示,该实施例的终端设备6包括:处理器60、存储器61以及存储在所述存储器61中并可在所述处理器60上运行的计算机可读指令62。所述处理器60执行所述计算机可读指令62时实现上述各个标记点选取位置的验证方法的实施例中的步骤,例如图1所示的步骤101至107。或者,所述处理器60执行所述计算机可读指令62时实现上述各装置实施例中各模块/单元的功能,例如图5所示模块501至505的功能。
所述计算机可读指令62可以被分割成一个或多个模块/单元,所述一个或者多个模块/单元被存储在所述存储器61中,并由所述处理器60执行,以完成本申请。所述一个或多个模块/单元可以是能够完成特定功能的一系列计算机程序指令段,该指令段用于描述所述计算机可读指令62在所述终端设备6中的执行过程。
所称处理器60可以是中央处理单元(Central Processing Unit,CPU),还可以是其他通用处理器、数字信号处理器(Digital Signal Processor,DSP)、专用集成电路(Application Specific Integrated Circuit,ASIC)、现成可编程门阵列(Field-Programmable Gate Array,FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
所述存储器61可以是所述终端设备6的内部存储单元,例如终端设备6的硬盘或内存。所述存储器61也可以是所述终端设备6的外部存储设备,例如所述终端设备6上配备的插接式硬盘,智能存储卡(Smart Media Card,SMC),安全数字(Secure Digital,SD)卡,闪存卡(Flash Card)等。进一步地,所述存储器61还可以既包括所述终端设备6的内部存储单元也包括外部存储设备。所述存储器61用于存储所述计算机程序以及所述终端设备所需的其他程序和数据。所述存储器61还可以用于暂时地存储已经输出或者将要输出的数据。
所属领域的技术人员可以清楚地了解到,为描述的方便和简洁,上述描述的系统,装置和单元的具体工作过程,可以参考前述方法实施例中的对应过程,在此不再赘述。
以上所述实施例仅用以说明本申请的技术方案,而非对其限制;尽管参照前述实施例对本申请进行了详细的说明,本领域的普通技术人员应当理解:其依然可以对前述各实施例所记载的技术方案进行修改,或者对其中部分技术特征进行等同替换;而这些修改或者替换,并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围,均应包含在本申请的保护范围之内。

Claims (10)

  1. 一种标记点选取位置的验证方法,其特征在于,包括:
    获取目标物体上除多个指定标记点之外的目标标记点的位置坐标;
    将所述目标标记点的位置坐标添加至第一坐标集合中,得到第二坐标集合,所述第一坐标集合是按照第一坐标变换参数对预采集的物体坐标集合执行坐标变换处理后得到的坐标集合,所述物体坐标集合包含所述目标物体上所述多个指定标记点的位置坐标;
    按照所述第一坐标变换参数对所述第二坐标集合执行坐标变换处理,得到第三坐标集合;
    根据所述第三坐标集合和预采集的模型坐标集合计算得到目标误差参数,所述模型坐标集合包含所述目标物体的三维模型上与所述多个指定标记点对应的位置坐标,所述目标误差参数用于衡量所述第三坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
    若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,所述基准误差参数用于衡量所述第一坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
    若所述目标误差参数大于或等于所述基准误差参数,则判定所述目标标记点未通过验证。
  2. 如权利要求1所述的验证方法,其特征在于,所述多个指定标记点中包含一个基准标记点,所述第一坐标变换参数根据以下方式计算得到:
    根据所述物体坐标集合和所述模型坐标集合,计算得到第一旋转变换参数和第一平移向量,所述物体坐标集合包含的位置坐标在经过所述第一旋转变换参数和所述第一平移向量的处理后,得到的位置坐标与所述模型坐标集合包含的位置坐标之间的欧氏距离最短;
    计算所述物体坐标集合包含的所述基准标记点的位置坐标在经过所述第一旋转变换参数和所述第一平移向量的处理后,得到的位置坐标与所述模型坐标集合包含的与所述基准标记点对应的位置坐标之间的差值;
    将所述第一旋转变换参数和第二平移向量确定为所述第一坐标变换参数,所述第二平移向量为所述第一平移向量与所述差值之和。
  3. 如权利要求2所述的验证方法,其特征在于,所述基准误差参数根据以下方式计算得到:
    计算所述模型坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第一中心点坐标;
    计算所述第一坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第二中心点坐标;
    计算所述第一中心点坐标与所述基准标记点的位置坐标之差,得到第一基准点偏差向量;
    计算所述第二中心点坐标与所述基准标记点的位置坐标之差,得到第二基准点偏差向量;
    根据所述第一基准点偏差向量和所述第二基准点偏差向量,计算得到第一误差旋转角度和第一误差 平移向量,以所述基准标记点为基准,所述第二中心点坐标与所述第一中心点坐标之间的误差等效于以所述第一基准点偏差向量和所述第二基准点偏差向量所处平面的第一法向量为轴旋转所述第一误差旋转角度后,再按照所述第一误差平移向量平移;
    将所述第一误差旋转角度和所述第一误差平移向量确定为所述基准误差参数。
  4. 如权利要求3所述的验证方法,其特征在于,根据所述第三坐标集合和预采集的模型坐标集合计算得到目标误差参数,包括:
    计算所述第三坐标集合中除与所述基准标记点对应的位置坐标之外的其它位置坐标的第三中心点坐标;
    计算所述第三中心点坐标与所述基准标记点的位置坐标之差,得到第三基准点偏差向量;
    根据所述第一基准点偏差向量和所述第三基准点偏差向量,计算得到第二误差旋转角度和第二误差平移向量,以所述基准标记点为基准,所述第三中心点坐标与所述第一中心点坐标之间的误差等效于以所述第一基准点偏差向量和所述第三基准点偏差向量所处平面的第二法向量为轴旋转所述第二误差旋转角度后,再按照所述第二误差平移向量平移;
    将所述第二误差旋转角度和所述第二误差平移向量确定为所述目标误差参数。
  5. 如权利要求4所述的验证方法,其特征在于,若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,包括:
    若所述第二误差旋转角度小于或等于所述第一误差旋转角度与第一评价系数的乘积,且所述第二误差平移向量的模小于或等于所述第一误差平移向量的模与第二评价系数的乘积,则判定所述目标标记点通过验证,所述第一评价系数和所述第二评价系数均为0至1之间的数值。
  6. 如权利要求5所述的验证方法,其特征在于,还包括:
    若所述第二误差旋转角度大于所述第一误差旋转角度与第一评价系数的乘积,或者所述第二误差平移向量的模大于所述第一误差平移向量的模与第二评价系数的乘积,则计算所述第一法向量和所述第二法向量的夹角;
    若所述第一法向量和所述第二法向量的夹角小于第一阈值,则判定所述目标标记点通过验证,否则判定所述目标标记点未通过验证。
  7. 如权利要求1至6中任一项所述的验证方法,其特征在于,在判定所述目标标记点通过验证之后,还包括:
    获取所述目标物体上除所述多个指定标记点和所述目标标记点之外的下一个标记点的位置坐标;
    对所述下一个标记点执行与所述目标标记点相同的验证处理,直至获得所述目标物体上指定数量通过验证的初始标记点;
    通过计算所述初始标记点到所述三维模型的面的最小距离的方法,求得所述初始标记点在所述三维 模型上的对应点;
    根据配准坐标集合和对应点坐标集合,计算得到第二旋转变换参数和第三平移向量,所述配准坐标集合包含的位置坐标在经过所述第二旋转变换参数和所述第三平移向量的处理后,得到的位置坐标与所述对应点坐标集合包含的位置坐标之间的欧氏距离最短,所述配准坐标集合包含所述初始标记点的位置坐标,所述对应点坐标集合包含所述初始标记点在所述三维模型上的对应点的位置坐标;
    按照所述第二旋转变换参数和所述第三平移向量对所述配准坐标集合执行坐标变换处理,得到更新的配准坐标集合,所述更新的配准坐标集合包含更新的所述初始标记点的位置坐标;
    通过计算更新的所述初始标记点到所述三维模型的面的最小距离的方法,求得更新的所述初始标记点在所述三维模型上的对应点;
    若更新的所述初始标记点的位置坐标与更新的所述初始标记点在所述三维模型上的对应点的位置坐标之间的欧式距离小于或等于第二阈值,则记录所述第二旋转变换参数和所述第三平移向量;
    若更新的所述初始标记点的位置坐标与更新的所述初始标记点在所述三维模型上的对应点的位置坐标之间的欧式距离大于所述第二阈值,则根据所述更新的配准坐标集合和更新的对应点坐标集合,继续计算得到更新的第二旋转变换参数和更新的第三平移向量,直至记录最终的第二旋转变换参数和最终的第三平移向量,所述更新的对应点坐标集合包含更新的所述初始标记点在所述三维模型上的对应点的位置坐标。
  8. 一种标记点选取位置的验证装置,其特征在于,包括:
    标记点获取模块,用于获取目标物体上除多个指定标记点之外的目标标记点的位置坐标;
    位置坐标添加模块,用于将所述目标标记点的位置坐标添加至第一坐标集合中,得到第二坐标集合,所述第一坐标集合是按照第一坐标变换参数对预采集的物体坐标集合执行坐标变换处理后得到的坐标集合,所述物体坐标集合包含所述目标物体上所述多个指定标记点的位置坐标;
    位置坐标变换模块,用于按照所述第一坐标变换参数对所述第二坐标集合执行坐标变换处理,得到第三坐标集合;
    误差参数计算模块,用于根据所述第三坐标集合和预采集的模型坐标集合计算得到目标误差参数,所述模型坐标集合包含所述目标物体的三维模型上与所述多个指定标记点对应的位置坐标,所述目标误差参数用于衡量所述第三坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
    第一标记点验证模块,用于若所述目标误差参数小于基准误差参数,则判定所述目标标记点通过验证,所述基准误差参数用于衡量所述第一坐标集合包含的位置坐标与所述模型坐标集合包含的位置坐标之间的偏差程度;
    第二标记点验证模块,用于若所述目标误差参数大于或等于所述基准误差参数,则判定所述目标标 记点未通过验证。
  9. 一种终端设备,包括存储器、处理器以及存储在所述存储器中并可在所述处理器上运行的计算机程序,其特征在于,所述处理器执行所述计算机程序时实现如权利要求1至7中任一项所述的标记点选取位置的验证方法。
  10. 一种计算机可读存储介质,所述计算机可读存储介质存储有计算机程序,其特征在于,所述计算机程序被处理器执行时实现如权利要求1至7中任一项所述的标记点选取位置的验证方法。
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