CN116363184A

CN116363184A - Hip joint position registration method and device, electronic equipment and storage medium

Info

Publication number: CN116363184A
Application number: CN202310615797.5A
Authority: CN
Inventors: 沈丽萍; 张巍; 王婧; 牛乾
Original assignee: Hangzhou Santan Medical Technology Co Ltd
Current assignee: Hangzhou Santan Medical Technology Co Ltd
Priority date: 2023-05-26
Filing date: 2023-05-26
Publication date: 2023-06-30
Anticipated expiration: 2043-05-26
Also published as: CN116363184B

Abstract

The embodiment of the invention provides a hip joint position registration method, a hip joint position registration device, electronic equipment and a storage medium, and relates to the technical field of image processing. The hip joint position registration method comprises the following steps: determining a first registration area on the three-dimensional model; acquiring a first candidate position in real time; transforming the first candidate position according to the first transformation relation to obtain a second candidate position; judging whether the second candidate position is positioned in the first registration area; when the second candidate position is located in the first registration area, responding to the position obtaining instruction, and obtaining the current position of the tool as the first registration position; determining a second transformation relation between the points on the target hip joint and the positions of the points on the three-dimensional model surface according to the positions of the points on the three-dimensional model surface, the first registration positions and the first transformation relation; and according to the second transformation relation, carrying out position registration on the actual position on the target hip joint. The scheme provided by the embodiment of the invention can accurately register the actual position of the hip joint.

Description

Hip joint position registration method and device, electronic equipment and storage medium

Technical Field

The present invention relates to the field of image processing technologies, and in particular, to a hip joint position registration method, a hip joint position registration device, an electronic device, and a storage medium.

Background

Hip replacement surgery is a common artificial joint replacement procedure used to reestablish normal function of the patient's hip joint. Currently, a doctor needs to plan a surgical path according to a hip CT (Computed Tomography, electronic computed tomography) image of a patient, and then a surgical robot controls a mechanical arm to move according to a registration result of the planned surgical path and an actual position of a hip joint, so as to assist the doctor in performing hip joint replacement surgery.

In the prior art, registration points for registration are required to be obtained based on a hip joint CT image and a physical hip joint, and then the hip joint is subjected to position registration according to the obtained positions of the registration points. The registration results thus obtained are of low accuracy.

Disclosure of Invention

The embodiment of the invention aims to provide a hip joint position registration method, a device, electronic equipment and a storage medium, so as to accurately register the actual position of the hip joint of a patient. The specific technical scheme is as follows:

according to a first aspect of an embodiment of the present invention, there is provided a method of hip joint position registration, the method comprising:

Determining a first registration area on a three-dimensional model, wherein the three-dimensional model is a three-dimensional model corresponding to a target hip joint;

obtaining in real time a first candidate position of a tool for acquiring a registration position on the target hip;

performing position transformation on the first candidate position according to a first transformation relation to obtain a second candidate position, wherein the first transformation relation is a transformation relation of the position between a point on the target hip joint and a point on the surface of the three-dimensional model, which is obtained in advance;

judging whether the second candidate position is positioned in the first registration area;

obtaining a current position of the tool as a first registration position in response to a position obtaining instruction when the second candidate position is located within the first registration region;

determining a new transformation relation between the point on the target hip joint and the point position of the three-dimensional model surface as a second transformation relation according to the position of each point on the three-dimensional model surface, the first registration position and the first transformation relation;

and according to the second transformation relation, transforming the actual position on the target hip joint to finish position registration.

Optionally, when the second candidate location is located within the first registration area, the method further comprises:

Obtaining a shortest distance between the second candidate location and the three-dimensional model surface;

judging whether the shortest distance is smaller than a preset error distance or not;

if yes, executing the step of responding to the position obtaining instruction to obtain the current position of the tool as a first registration position.

Optionally, the method further comprises:

obtaining a second region update location acquired by the tool acquiring the registration location within a region of the target hip joint corresponding to the first registration region;

determining a first area updating position corresponding to the second area updating position on the surface of the three-dimensional model according to the second area updating position and the first transformation relation;

and updating the first registration area according to the determined first area updating position.

Optionally, the determining, according to the positions of the points on the three-dimensional model surface and the obtained first registration position and the first transformation relation, a new transformation relation between the points on the target hip joint and the positions between the points on the three-dimensional model surface, as the second transformation relation, includes:

performing position transformation on each first registration position according to the first transformation relation to obtain a second registration position;

For each second registration position, determining a third registration position closest to the second registration position on the three-dimensional model surface according to the second registration position and the positions of all points on the three-dimensional model surface;

and determining a second transformation relation between the target hip joint and the three-dimensional model according to each first registration position and the corresponding third registration position.

Optionally, the determining the first registration area on the three-dimensional model includes:

obtaining the characterization positions of a plurality of hip joints selected by a user on the three-dimensional model, and obtaining the description information of each characterization position; determining a first registration area according to the obtained characterization position and the description information;

and/or

Obtaining a region framed by a user on the three-dimensional model; the framed area is determined to be a first registration area.

Optionally, the obtaining the current position of the tool as the first registration position includes:

the current position of the surgical probe with the reflectarray connected to the binocular camera is obtained as the first registration position.

According to a second aspect of embodiments of the present invention, there is provided a hip joint position registration device, the device comprising:

A first registration area determination module for determining a first registration area on the three-dimensional model;

a first candidate position acquisition module for acquiring in real time a first candidate position of a tool for acquiring a registration position on the target hip joint;

the second candidate position transformation module is used for carrying out position transformation on the first candidate position according to a first transformation relation to obtain a second candidate position, wherein the first transformation relation is a transformation relation of the position between a point on the target hip joint and a point on the surface of the three-dimensional model, which is obtained in advance;

the position judging module is used for judging whether the second candidate position is positioned in the first registration area or not;

a first registration position determination module for obtaining a current position of the tool as a first registration position in response to a position obtaining instruction when the second candidate position is located within the first registration region;

the second transformation relation determining module is used for determining a new transformation relation between the point on the target hip joint and the point on the three-dimensional model surface according to the position of each point on the three-dimensional model surface, the first registration position and the first transformation relation, and taking the new transformation relation as a second transformation relation;

And the target hip joint position registration module is used for transforming the actual position on the target hip joint according to the second transformation relation to finish position registration.

Optionally, the apparatus further includes:

a shortest distance obtaining module, configured to obtain a shortest distance between the second candidate position and the three-dimensional model surface;

and the shortest distance judging module is used for judging whether the shortest distance is smaller than a preset error distance, and if so, triggering the first registration position determining module.

Optionally, the apparatus further includes:

a second region update location acquisition module for acquiring a second region update location acquired by a tool acquiring a registration location within a region of the target hip joint corresponding to the first registration region;

a first area update position determining module, configured to determine a first area update position corresponding to the second area update position on the three-dimensional model surface according to the second area update position and the first transformation relationship;

and the first registration area updating module is used for updating the first registration area according to the determined first area updating position.

Optionally, the second transformation relation determining module includes:

The second registration position obtaining submodule is used for carrying out position transformation on each first registration position according to the first transformation relation to obtain a second registration position;

a third registration position determining sub-module, configured to determine, for each second registration position, a third registration position on the three-dimensional model surface closest to the second registration position according to the second registration position and a position of each point on the three-dimensional model surface;

and the second transformation relation determining submodule is used for determining a second transformation relation between the target hip joint and the three-dimensional model according to each first registration position and the corresponding third registration position.

Optionally, the first registration area determining module is specifically configured to obtain a plurality of characteristic positions of hip joints selected by a user on the three-dimensional model, and obtain description information of each characteristic position; determining a first registration area according to the obtained characterization position and the description information; and/or obtaining a region framed by a user on the three-dimensional model; the framed area is determined to be a first registration area.

Optionally, the first registration position determining module is specifically configured to obtain, as the first registration position, a current position of the surgical probe with the reflectarray connected to the binocular camera.

According to a third aspect of an embodiment of the present invention, there is provided an electronic device including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory perform communication with each other through the communication bus;

a memory for storing a computer program;

and a processor, configured to implement the hip joint position registration method according to the first aspect when executing the computer program stored in the memory.

According to a fourth aspect of embodiments of the present invention, there is provided a computer readable storage medium having stored therein a computer program which, when executed by a processor, implements the hip joint position registration method according to the first aspect described above.

The embodiment of the invention has the beneficial effects that:

the hip joint position registration scheme provided by the embodiment of the invention can determine the first registration area on the three-dimensional model and obtain the first candidate position acquired on the target hip joint by the tool for acquiring the registration position. And carrying out position transformation on the first candidate position to obtain a second candidate position. Judging whether the second candidate position is positioned in the first registration area, and determining the first candidate position corresponding to the second candidate position positioned in the first registration area as the first registration position, so that a user can be guided to acquire the position of the position which is subjected to position transformation in the first registration area as the first registration position, and the accuracy of the obtained first registration position is ensured. Because the accuracy of the obtained first registration position is high, the accuracy of the second transformation relation determined according to the first registration position is high, and the accuracy of the position registration of the target hip joint by using the second transformation relation is high. Therefore, the scheme provided by the embodiment of the invention can accurately register the actual position of the hip joint.

Of course, it is not necessary for any one product or method of practicing the invention to achieve all of the advantages set forth above at the same time.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and other embodiments may be obtained according to these drawings to those skilled in the art.

Fig. 1 is a flowchart of a first hip joint position registration method according to an embodiment of the present invention;

FIG. 2a is a schematic representation of a first registration position on a three-dimensional model corresponding to the medial aspect of an acetabular fossa on a target hip joint according to an embodiment of the invention;

FIG. 2b is a schematic representation of a first registration position on a three-dimensional model corresponding to the outside of an acetabular fossa on a target hip joint according to an embodiment of the invention;

fig. 3 is a schematic flowchart of updating a first registration area according to an embodiment of the present invention;

fig. 4 is a flowchart of a second hip joint position registration method according to an embodiment of the present invention;

fig. 5 is a schematic overall flow chart of hip joint position registration provided by an embodiment of the present invention;

Fig. 6 is a schematic structural view of a hip joint position registration device according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, those of ordinary skill in the art will be able to devise all other embodiments that are obtained based on this application and are within the scope of the present invention.

Hip replacement surgery is a common artificial joint replacement procedure. Currently, surgical robots can be used to assist doctors in performing hip replacement surgery. The surgical robot can control the mechanical arm to move according to the planned path of the doctor, so that the doctor is helped to complete the operation.

Because the position and the shape of the hip joint in the operation process are often different from those of the hip joint when the CT image of the hip joint is acquired, the operation robot can not accurately control the movement of the mechanical arm according to the operation path planned by a doctor. In view of the above, the embodiment of the invention provides a hip joint position registration method, which realizes accurate registration of the actual position of a hip joint.

The execution body of the embodiment of the present invention is described below.

The execution body of the embodiment of the invention can be an electronic device, and in particular, can be an electronic device connected with a surgical robot, such as a desktop computer and the like.

The following describes a hip joint position registration method provided by the embodiment of the present invention through specific embodiments.

Referring to fig. 1, a flow chart of a first method of hip joint position registration is provided, the method comprising the following steps S101-S107.

Step S101: a first registration area on the three-dimensional model is determined.

The three-dimensional model corresponds to a target hip joint, and the target hip joint is a patient operation side hip joint.

The first registration area is described below.

The first registration area is an area of the three-dimensional model surface and can comprise two partial areas of an inner area of the acetabular fossa and an outer area of the acetabular fossa on the three-dimensional model.

As shown by the black areas in fig. 2a and 2b, the first registration area is the area on the three-dimensional model corresponding to the medial and lateral sides of the acetabular fossa on the target hip joint. Wherein fig. 2a provides a schematic representation of a first registration position on the three-dimensional model corresponding to the medial aspect of the acetabular fossa on the target hip joint and fig. 2b provides a schematic representation of a first registration position on the three-dimensional model corresponding to the lateral aspect of the acetabular fossa on the target hip joint.

The manner in which the electronic device determines the first registration area is described below.

In a first implementation, the electronic device may obtain a plurality of characteristic positions of the hip joints selected by the user on the three-dimensional model, and obtain description information of each characteristic position; and determining a first registration area according to the obtained characterization position and the description information.

Wherein, the characteristic position of the hip joint is a position which is determined by a user according to medical knowledge and used for describing the structure of the hip joint, and the information of each characteristic position is used for representing the structure of the hip joint described by each characteristic position.

In particular, the electronic device may display the three-dimensional model on a communicatively coupled display device such that a user may view the three-dimensional model and input a representative location of his selected target hip joint to the electronic device using the input device.

Under the condition, the electronic equipment can preset the acquisition sequence of each characteristic position and the description information of each characteristic position, so that a user can input the selected characteristic position of the hip joint to the electronic equipment according to the preset sequence, and the electronic equipment determines the description information corresponding to each characteristic position according to the acquisition sequence.

In another case, the user may input descriptive information for each representative position as well, when inputting the representative position of his selected target hip joint. Thus, the electronic device can obtain the descriptive information of each characterization position and each characterization position.

In a second implementation manner, the electronic device may obtain a frame selection region selected by a user on the three-dimensional model; the selection area is determined as a first registration area.

Specifically, the electronic device may display the three-dimensional model on a communicatively coupled display device, such that a user may view the three-dimensional model, input a selected region thereof to the electronic device using the input device, and the electronic device determines the region input by the input device as the first registration region. In particular, the input device may be a mouse. A touch pad, etc. The user may use an input device such as a mouse, touch pad, or the like to determine the area selected by the user in a frame-selected manner.

In one case, the user may select an area of the three-dimensional model that corresponds to the actual exposed area of the target hip joint as the box area.

In this way, the electronic device can efficiently and accurately determine the first registration area according to the medical structural characteristics of the hip joint; the first registration area that can be actually used for registration may also be determined based on the actual exposure of the target hip joint. By the method, the efficiency and the accuracy of determining the first registration area can be improved.

In a third implementation manner, a shape parameter corresponding to a position in a first registration area on the hip joint can be preset in the electronic device, so that the electronic device can analyze and calculate the shape parameter of each position on the surface of the three-dimensional model, and determine that the position, of which the shape parameter accords with the shape parameter corresponding to the position in the preset first registration area, belongs to the first registration area, so that the first registration area is determined. For example, the preset shape parameter may be a curvature vector of an inner region and a curvature vector of an outer region of the acetabular fossa, and the electronic device may determine the first registration region including the inner region of the acetabular fossa and the outer region of the acetabular fossa by analyzing and calculating the curvature vectors of the respective positions to determine the positions belonging to the inner region of the acetabular fossa and the positions belonging to the outer region of the acetabular fossa.

Step S102: a first candidate position of a tool for acquiring a registration position on a target hip joint is obtained in real time.

Wherein the first candidate position is the position of the tool for acquiring the registration position. In one case, the optical coordinates of the position of the tool that acquired the registration position may be obtained for the electronic device.

Step S103: and carrying out position transformation on the first candidate position according to the first transformation relation to obtain a second candidate position.

The first transformation relation is a transformation relation of the position between the point on the target hip joint and the point on the surface of the three-dimensional model, which is obtained in advance. In a first implementation, the first transformation relationship may be a transformation relationship of a point on the target hip joint and a point position on the three-dimensional model surface, which is determined according to a previous registration experience. In a second implementation, the first transformation relationship may be a transformation relationship predetermined according to the positions of points planned on the three-dimensional model and the positions of the corresponding points of the points on the target hip joint.

The second candidate position is a position obtained after the first candidate position is transformed and is a position on the three-dimensional model. When the first candidate position is a coordinate in the space coordinate system, the second candidate position is a coordinate in the model coordinate system. The first candidate positions are in one-to-one correspondence with the second candidate positions.

In one case, the second candidate position is a model coordinate obtained by transforming the optical coordinate of the position of the tool for acquiring the registration position, which is obtained by the electronic device.

Step S104: it is determined whether the second candidate location is within the first registration area.

Specifically, whether the second candidate position is located within the first registration area may be determined in the following manner.

In one implementation, it may be determined whether the second candidate location is a location of a point contained in the first registration area. If yes, the second candidate position is located in the first registration area; if not, the second candidate location is located within the first registration area.

In another implementation manner, since the tool for acquiring the registration position may be a surgical probe, the tool for acquiring the registration position, that is, a straight line corresponding to the surgical probe on the three-dimensional model, may be determined according to the second candidate position and the geometry of the tool for acquiring the registration position, and whether the straight line intersects the first registration area may be determined. If yes, the second candidate position is located in the first registration area; if not, the second candidate location is located within the first registration area.

Step S105: when the second candidate position is located within the first registration area, a current position of the tool is obtained as the first registration position in response to the position obtaining instruction.

The current position of the tool is the first candidate position of the tool corresponding to the position obtaining instruction, and is the position on the target hip joint. In one case, the optical coordinates of the position of the tool that acquired the registration position may be obtained for the electronic device. The position obtaining instruction may be an instruction initiated by a user to the electronic device through a tool. For example, an acquisition button may be provided on the tool, and when the user presses the acquisition button, a position acquisition instruction is sent to the electronic device; for another example, an acquisition pedal may be provided that when depressed by a user, sends a position acquisition instruction to the electronic device.

The current position of the obtained tool is the position on the target hip joint corresponding to the first registration area, which may be referred to as the second registration area. Because the first registration area comprises two partial areas of the inner side area of the acetabular fossa and the outer side area of the acetabular fossa on the three-dimensional model, the second registration area also comprises two partial areas of the inner side area of the acetabular fossa and the outer side area of the acetabular fossa on the target hip joint.

The first registration location is the location of points on the target hip joint acquired within the second registration region, and the points are located within the second registration region. Since the target hip joint is present in real space, the first registration position is the position of these points in real space. Specifically, the first registration position may be coordinates in a spatial coordinate system corresponding to the actual space of the points.

Since there are a plurality of first registration positions, a serial number may be set to each first registration position. The sequence number may be a consecutive positive integer starting from 1. Such as 1, 2, 3 … …, etc.

Since the second registration area also includes both medial and lateral acetabular fossa regions on the target hip, the first registration location may include locations of points acquired medial and lateral to the acetabular fossa.

The first preset number may be 1, 3, 5, etc., which is not limited in the embodiment of the present invention.

The manner in which the electronic device obtains the first registration position is described below.

In a first implementation, the electronic device may obtain a current position of a surgical probe with a reflectarray coupled to a binocular camera as a first registration position. Specifically, the user may move the surgical probe tip to a position within the second registration area and press the capture button, at which time the binocular camera sends the position of the tip to the electronic device, and the electronic device determines the received position information as the first registration position.

At this time, the spatial coordinate system may be an optical coordinate system corresponding to an image acquired by the binocular camera, and the first registration position may be a coordinate of a point on the target hip joint acquired in the second registration area under the optical coordinate system.

Thus, the binocular camera can accurately obtain the first registration position by determining the position of the surgical probe tip through the specific structure of the light reflecting array.

In a second implementation, the electronic device may obtain the position of the surgical probe acquisition in connection with the camera with the depth sensor as the first registration position. Specifically, the user moves the surgical probe tip to a position in the second registration area, presses the acquisition button, the camera sends the determined position to the electronic device, and the electronic device sequentially determines the received position information as the first registration position.

In a third implementation manner, the electronic device may perform content matching on the image of the target hip joint acquired by the camera and the three-dimensional model, and determine the first registration position in the second registration area on the target hip joint according to the content matching result and by combining the image of the target hip joint.

Step S106: and determining a transformation relation between the positions of the points on the new target hip joint and the points on the three-dimensional model surface as a second transformation relation according to the positions of the points on the three-dimensional model surface, the first registration position and the first transformation relation.

The positions of the respective points of the three-dimensional model surface may be model coordinates of the respective points of the three-dimensional model surface in a model coordinate system. Such as CT coordinates of the individual points.

The three-dimensional model corresponds to the target hip joint, and it can be considered that only rigid transformation occurs between points on the three-dimensional model and points on the target hip joint. Therefore, the determined second transformation relationship can be expressed in the following form.

In one case, the determined second transformation relationship may be represented by an expression, and the expression parameters include a translation matrix and a rotation matrix, since a rigid body transformation occurs between points on the three-dimensional model and points on the target hip joint. Assuming that the coordinates of a point on the target hip joint are P, the coordinates of a point on the three-dimensional model corresponding to the point are Q, R is a first rotation matrix corresponding to the second transformation relationship, and T is a first translation matrix corresponding to the second transformation relationship, when the second transformation relationship is represented by using an expression, the expression is:

；

In another case, the determined second transformation relation may also be represented by a transformation matrix determined by a translation matrix and a rotation matrix.

Also, assuming that the coordinates of a point on the target hip joint are P, the coordinates of a point on the three-dimensional model corresponding to the point are Q, R is a first rotation matrix corresponding to the second transformation relationship, T is a first translation matrix corresponding to the second transformation relationship, and when the transformation matrix is used to represent the second transformation relationship, the transformation matrix is:

。

similarly, the first transformation relationship may also be represented by an expression or form of a transformation matrix.

An implementation of the electronic device determining the second transformation relationship is described below.

In a first implementation, the position corresponding to each first registration position may be determined from each point of the three-dimensional model surface according to the first transformation relationship, so as to determine the second transformation relationship according to the position corresponding to each first registration position and the three-dimensional model surface. The specific implementation will be further described later, and will not be described in detail here.

In a second implementation manner, the second transformation relationship may be determined according to the positions of the points on the three-dimensional model surface and the obtained transformation relationship between the first registration positions and the target after the first preset number of first registration positions are acquired. The manner in which a particular implementation is obtained with respect to a target transformation will be described further below and will not be described in detail herein.

In a third implementation, the position of the point of the position corresponding to the first registration position may be determined from the points of the three-dimensional model surface according to the first transformation relationship, and the second transformation relationship may be determined using an NDT (Normal Distributions Transform, normal distribution transformation) algorithm for the position of the point of the first registration position corresponding to the first registration position.

Step S107: and according to the second transformation relation, transforming the actual position on the target hip joint to finish position registration.

Assuming the actual position on the target hip joint is

The position corresponding to the three-dimensional model after registration is +.>

As described above for step S106, when the second transformation relationship is in the form of an expression, there are

；

When the second transformation relationship is in the form of a transformation matrix, the transformation matrix is recorded as

Thereby having

。

Thus, the electronic equipment can complete the position registration of the target hip joint according to the second transformation relation.

The actual position of the target hip joint may be a position on the target hip joint according to the particular application involved in the following. For example, after the position registration is completed, the surgical path of the surgical robot needs to be guided according to the registration result, and at this time, the actual position of the target hip joint may be the position on the target hip joint related to the surgical path of the surgical robot.

In one case, the electronic device may transform each actual position on the target hip joint, e.g., the electronic device may receive the optical coordinates of each actual position on the target hip joint acquired by the binocular camera, and transform each optical coordinate to obtain a corresponding model coordinate. In another case, the electronic device may transform the coordinates of the part of the actual position on the target hip joint, e.g. the electronic device may obtain the optical coordinates of the position on the target hip joint acquired by the position acquisition tool, and transform the obtained optical coordinates to obtain the corresponding model coordinates. The embodiment of the present invention is not limited thereto.

By applying the scheme provided by the embodiment, the first candidate position acquired by the tool for acquiring the registration position on the target hip joint can be obtained, and the first candidate position is subjected to position transformation to obtain the second candidate position. By judging whether the second candidate position is located in the first registration area or not and determining the first candidate position corresponding to the second candidate position located in the first registration area as the first registration position, a user can be guided to acquire the position of the position in the first registration area after position transformation as the first registration position, the accuracy of the obtained first registration position is ensured, and therefore the accuracy of the second transformation relation determined according to the first registration position is high, and the accuracy of position registration of the target hip joint by using the second transformation relation is high. Therefore, the scheme provided by the embodiment of the invention can accurately register the actual position of the hip joint.

In addition, because the accuracy of the obtained first registration position is high, when the first registration position is used for registration, the number of the first registration positions required for achieving the same registration accuracy is small, and the registration efficiency is improved.

Further, in an embodiment of the present invention, in the case that the second candidate position is located in the first registration area, the following steps a-B are further included before step S105.

Step A: a shortest distance between the second candidate location and the three-dimensional model surface is obtained.

The shortest distance between the second candidate position and the three-dimensional model surface may be a shortest distance between the second candidate position and the three-dimensional model surface, and the distance is a distance in a normal direction of the three-dimensional model surface. In particular, the electronic device may determine a point on the three-dimensional model surface where the normal passes through the second candidate location, thereby determining a distance between the point and the second candidate location as a shortest distance between the second candidate location and the three-dimensional model surface.

And (B) step (B): and judging whether the shortest distance is smaller than a preset error distance.

If the shortest distance is smaller than the preset error distance, the accuracy of the second candidate position can meet the registration requirement, and the accuracy of the first candidate position corresponding to the second candidate position can meet the registration requirement. At this time, step S105 is performed.

In addition, the electronic device may also prompt the user that the accuracy of the first candidate position can meet the registration requirement. For example, displaying a signal on a display device communicatively coupled thereto that satisfies the registration need suggests to the user that the accuracy of the first candidate location is capable of satisfying the registration need; for another example, issuing a warning sound signal to the user that the accuracy of the first candidate position is satisfactory for registration.

The preset error distance may be 5mm, 10mm, etc., which is not limited in the embodiment of the present invention.

Therefore, on the premise that the position of the first registration position after position transformation is ensured to be in the first registration area, the shortest distance between the position of the first registration position after position transformation and the surface of the three-dimensional model is further ensured to be smaller than a preset error distance, and the accuracy of the obtained first registration position is ensured.

Because the accuracy of the obtained first registration position is high, the number of the first registration positions required for achieving the same registration accuracy is small when the first registration position is used for registration; when the same number of first registration positions are used for registration, the success rate of meeting the required registration precision is high.

The first candidate position is taken as a first registration position, and the accuracy of the obtained first registration position can meet the registration requirement.

When the shortest distance between the second candidate position and the three-dimensional model surface is not smaller than the preset error distance, the accuracy of the second candidate position cannot meet the registration requirement, and the accuracy of the first candidate position corresponding to the second candidate position cannot meet the registration requirement. At this time, the first candidate position cannot be regarded as the first registration position.

As described above for step S105, the electronic device may obtain the position of the surgical probe acquisition in connection with the camera with the depth sensor as the first registration position. Specifically, the user will move the surgical probe tip to a position within the second registration area and press the capture button, at which time the binocular camera sends the position of the tip to the electronic device, which determines the received position information as the first registration position.

In this way, the accuracy of the obtained first registration position can be improved, and the accuracy of determining the second transformation relationship from the first registration position is high. The accuracy of the registration can be improved by performing the position registration based on the thus determined second transformation relationship.

In one embodiment of the invention, the first registration area may be updated according to the actual condition of the target hip joint. Specifically, referring to fig. 3, a schematic flowchart of updating the first registration area is provided, which may be accomplished by the following steps S301-S303.

Step S301: the means for obtaining the acquired registration positions updates the positions at the target hip joint for a second region acquired within a region corresponding to the first registration region.

The second region update location is a location of a tool that acquired the registration location. In one case, the optical coordinates of the position of the tool that acquired the registration position may be obtained for the electronic device.

Step S302: and determining a first area updating position corresponding to the second area updating position acquired on the target hip joint on the three-dimensional model surface according to the second area updating position acquired on the target hip joint and the first transformation relation.

The first area updating position is a position obtained after the second area updating position is transformed, and is a position on the three-dimensional model. When the second area update position is a coordinate in the space coordinate system, the first area update position is a coordinate in the model coordinate system. The first area updating positions are in one-to-one correspondence with the second area updating positions.

Step S303: the first registration area is updated according to the determined first area update location.

Specifically, the electronic device may use the determined update location of the first area as a boundary location of the updated first registration area, so as to determine the updated first registration area according to the boundary location, and complete updating of the first registration area.

Since the first registration area corresponds to the second registration area, which is on the target hip joint, it can be considered that steps S301-S303 update the first registration area according to the updated second registration area. The second area update position obtained in step S301 is the boundary position of the updated second registration area, and therefore, the first area update position obtained after the second area update position is subjected to the position transformation is the boundary position of the updated first registration area. In this way, the electronic device may update the first registration area according to the first area update location.

The steps S301 to S303 may be performed before step S105, i.e., before the plurality of first registration positions are obtained, or may be performed in the first registration positions are obtained, or may be performed after the plurality of first registration positions are obtained, which is not limited in the present invention.

In this way, the first registration area can be updated according to the actual condition of the target hip joint, so that the points in the first registration area can be acquired, and the accuracy of the acquired first registration position is ensured.

As described above with respect to step S106, in one embodiment of the present invention, the second transformation relationship may be determined according to the positions of the respective first registration positions corresponding to the three-dimensional model surface. In particular, referring to fig. 4, a flow chart of a second method of hip position registration is provided. In the present embodiment, the above step S106 may be implemented by the following steps S106A to S106B.

Step S106A: and carrying out position transformation on each first registration position according to the first transformation relation to obtain a second registration position.

The second registration position is a position obtained after the first registration position is transformed and is a position on the three-dimensional model. When the first registration position is a coordinate in the spatial coordinate system, the second registration position is a coordinate in the model coordinate system. The first registration positions are in one-to-one correspondence with the second registration positions.

In this case, the second registration position is a model coordinate obtained by transforming an optical coordinate of the first registration position, for example, a CT coordinate obtained by transforming an optical coordinate of the first registration position.

In one implementation, the first registration position is assumed to be the transformation matrix matrixC

The transformed second registration position is +.>

Then, the electronic device may perform a position transformation on the first registration position by the following relation:

。

step S106B: for each second registration position, determining a third registration position closest to the second registration position on the three-dimensional model surface according to the second registration position and the positions of the points on the three-dimensional model surface.

As explained for step S106A, the second registration position may be a coordinate in the model coordinate system. The positions of the points on the three-dimensional model surface can also be coordinates in a model coordinate system. In this way, a third registration position on the three-dimensional model surface closest to the second registration position can be determined by the relation between the coordinates. The second registration positions are in one-to-one correspondence with the third registration positions.

The third registration positions are model coordinates of points closest to the model coordinates obtained by transforming the optical coordinates of the first registration positions, and the points corresponding to each third registration position can be considered to be corresponding near points of the points corresponding to the second registration positions corresponding to the third registration positions.

An implementation of the electronic device to determine the third registration position is explained below.

In one implementation, for each second registration position, a distance between the position of each point on the model surface and the second registration position may be calculated, a distance closest to the second registration position is determined from the calculated distances, and a position corresponding to the distance is determined as a third registration position.

In another implementation, the third registration position may be determined using a kd-Tree (k-dimensional tree) method. Specifically, the space where the three-dimensional model is located may be divided into a plurality of subspaces, and only one extracted point on the surface of the three-dimensional model exists in each subspace. In this way, the electronic device may determine, according to the subspace corresponding to the second registration position, that the point of the three-dimensional model surface existing in the subspace is the point closest to the second registration position, and that the position of the point of the three-dimensional model surface is the third registration position.

Step S106C: and determining a second transformation relation between the target hip joint and the three-dimensional model according to each first registration position and the corresponding third registration position.

The first registration positions and the second registration positions are in one-to-one correspondence, and the second registration positions and the third registration positions are in one-to-one correspondence, so that the first registration positions and the third registration positions are in one-to-one correspondence.

In one implementation, the electronic device may determine the second transformation relationship using an SVD (Singular Value Decomposition ) method for the first registration position and the third registration position.

Specifically, the electronic device may perform position registration on the first registration position and the third registration position by using an SVD method according to the following relation, and calculate the translation matrix and the rotation matrix.

;

;

;

;

;

;

;

;

Wherein n represents the number of the determined third registration positions, and n also represents the number of the first registration positions due to the one-to-one correspondence between the first registration positions and the third registration positions; p denotes a first centroid position corresponding to the first registration position,

representing a second centroid position corresponding to the third registration position; />

Represents the i first registration position, +.>

Representing an ith third registration position;

a first centroid displacement vector representing an ith first registration position relative to the first centroid position,/->

A second centroid displacement vector representing an ith third registration position relative to the second centroid position; h is the constructed intermediate matrix,>

representing a process of singular value decomposition of the intermediate matrix, wherein U is a first decomposition matrix, and V is a second decomposition matrix; r represents the solved rotation matrix, and T represents the solved translation matrix.

Thus, the electronic device may determine the second transformation relationship based on the rotation matrix and the translation matrix obtained by the solution.

In another implementation manner, the electronic device may perform iterative computation on each first registration position and a third registration position corresponding to the first registration position based on a preset rigid transformation constraint condition and a preset transformation adjustment end condition, so as to determine the second transformation relationship. Specific implementations will be further described in the examples that follow and are not described in detail herein.

By adopting the mode, the first registration positions can be transformed by using the first transformation relation to obtain the second registration positions, and the third registration position closest to each second registration position on the surface of the three-dimensional model is determined, so that the second transformation relation is determined according to the first registration positions and the corresponding third registration positions. The second transformation relationship thus determined is further determined on the basis of the first transformation relationship, and therefore, the determined second transformation relationship is more accurate than the first transformation relationship, and the accuracy of registration can be improved by performing position registration based on the second transformation relationship.

In one embodiment of the present invention, as described in the foregoing description of step S106C, the iterative calculation may be performed on each first registration position and the third registration position corresponding to the first registration position based on the preset rigid transformation constraint condition and the preset transformation adjustment end condition, so as to determine the second transformation relationship. Specifically, in the present embodiment, the step S106C may be completed through the following steps C to E.

Step C: and determining a rotation parameter and a translation parameter which meet the preset rigid body transformation constraint condition based on the distance between the two positions in each registration position pair, and obtaining a second transformation relation between the target hip joint and the three-dimensional model, which is determined based on the rotation parameter and the translation parameter.

Wherein each registration position pair comprises: a first registration position and a third registration position closest to a second registration position corresponding to the first registration position.

Specifically, the rotation parameter may be represented by a rotation matrix, and the translation parameter may be represented by a translation matrix. Thus, as in the previous description of step S104, the second transformation relationship may be determined from the rotation matrix and the translation matrix.

The above-described preset rigid body transformation constraint may have various cases.

In one case, the preset rigid body transformation constraint condition may be: and the constraint condition that the average distance between the position after the rigid body transformation is carried out on each first registration position and the third registration position corresponding to each first registration position is minimum is adopted.

In this case, the second transformation relationship is determined by the preset rigid transformation constraint condition, so that the average distance between the position after rigid transformation of each first registration position and the third registration position corresponding to each first registration position is minimized, the second transformation relationship is accurate, and the position registration is performed based on the second transformation relationship, so that the registration accuracy can be improved.

Specifically, the rotation parameter and the translation parameter may be determined according to the following expression.

;/>

Wherein, the liquid crystal display device comprises a liquid crystal display device,

representing preset rigid body transformation constraints +.>

Representing the number of first registration positions, since the first registration positions are in one-to-one correspondence with the third registration positions,/->

Also representing the number of third registration positions; />

Representing the determined rotation parameter ∈>

Representing the determined translation parameters; />

Represents the j-th third registration position, < >>

Representing the j-th first registration position.

In another case, the preset rigid body transformation constraint condition may be: and a constraint condition that the maximum distance between the position after rigid body transformation on each first registration position and the third registration position corresponding to each first registration position is minimum.

Step D: and carrying out rigid transformation on each first registration position by adopting translation parameters and rotation parameters to obtain a new second registration position corresponding to each first registration position.

The new second registration position is obtained here in a similar manner to the previous description of step S106A, and will not be described in detail.

Step E: for each first registration position, calculating the distance between a new second registration position corresponding to the first registration position and a third registration position corresponding to the first registration position.

When the distance does not satisfy the preset transformation adjustment end condition, the process returns to step S106B.

There are various cases corresponding to the rigid body transformation constraint conditions preset in the description of the step C, and there are various cases corresponding to the preset transformation adjustment end conditions.

In one case, the preset transformation adjustment end condition is: the average distance between the new second registration position corresponding to each first registration position and the third registration position corresponding to the first registration position is smaller than a preset distance threshold.

In this case, by adjusting the second transformation relationship according to the preset transformation adjustment end condition, the average distance between the position obtained by performing rigid transformation on each first registration position and the third registration position corresponding to each first registration position is smaller than the preset distance threshold, so that the second transformation relationship is accurate, and the position registration is performed based on the second transformation relationship, thereby improving the registration accuracy.

In another case, the preset transformation adjustment end condition is: the maximum distance between the new second registration position corresponding to each first registration position and the third registration position corresponding to the first registration position is smaller than a preset distance threshold.

By the method, the second transformation relation is determined and adjusted based on the preset rigid body transformation constraint condition and the preset transformation adjustment end condition, so that the accuracy of the second transformation relation is continuously improved, and the finally determined second transformation relation is high in accuracy. In this way, the accuracy of the registration can be improved by performing the position registration based on the second transformation relationship.

In one embodiment of the present invention, as described above with respect to step S106, the second transformation relationship may be determined according to the positions of the points on the three-dimensional model surface, the obtained third registration position, and the target transformation relationship. Specifically, step S106 may be implemented by the following step S106D.

Step S106D: when the first preset number of first registration positions are obtained, determining a second transformation relation between the points on the target hip joint and the positions between the points on the three-dimensional model surface according to the positions of the points on the three-dimensional model surface, the obtained first registration positions and the target transformation relation, if the number of the obtained first registration positions does not reach the second preset number, updating the target transformation relation into the second transformation relation, and returning to execute step S105.

The initial relationship of the target transformation relationship is the first transformation relationship. The second preset number may be 15, 20, etc., which is not limited in the embodiment of the present invention.

The electronic device may display the number of acquired first registration positions on a communicatively connected display device, or may display the number of first registration positions that still need to be acquired, i.e. the difference between the second preset number and the number of acquired first registration positions. When the number of the obtained first registration positions reaches a second preset number, the electronic equipment can display reminding ending acquisition information on a display device in communication connection to remind a user to end acquisition.

In addition, in one implementation, after each update of the target transformation relationship, the electronic device may calculate an error that exists when registering the target hip joint using the target transformation relationship, and adjust the first preset number according to the calculated error. Specifically, a correspondence between the error and the first preset number may be set. For example, when the calculated error is 5mm, the first preset number is 6; when the calculated error is 4mm, the first preset number is 3.

The manner of determining the second transformation relationship will be described below.

In one case, the positions corresponding to the first registration positions may be determined from points of the three-dimensional model surface according to the target transformation relationship, so that the second transformation relationship is determined according to the positions of the first registration positions corresponding to the three-dimensional model surface.

In another case, the position of the point of the position corresponding to the first registration position may be determined from the respective points of the three-dimensional model surface according to the target transformation relationship, and the second transformation relationship may be determined using an NDT algorithm for the position of the point of the first registration position corresponding to the first registration position.

By the method, after the first preset number of first registration positions are obtained, the second transformation relationship is updated according to the target transformation relationship of the first transformation relationship as the initial relationship, and the second transformation relationship is determined as the target transformation relationship. In this way, as the number of acquired first registration positions increases, the second transformation relationship is iteratively updated, thereby improving the accuracy of the determined second transformation relationship. The accuracy of the registration can be improved by performing the position registration based on the second transformation relationship.

The overall flow of hip position registration is described below.

Referring to fig. 5, fig. 5 provides an overall flow diagram for hip joint position registration. Specifically, the following steps S501 to S512 are included.

Step S501: a three-dimensional model of the target hip joint is acquired.

Step S502: a first registration area on the three-dimensional model is determined.

Step S503: the user moves the tool that collects the registration position over the target hip joint.

Step S504: and acquiring the position of the tool for acquiring the registration position in the three-dimensional model in real time according to the first transformation relation.

Step S505: judging whether the corresponding position of the tool for collecting the registration position in the three-dimensional model is in the first registration area, if so, executing step S506; if not, step S511 is performed.

Step S506: judging whether the shortest distance between the corresponding position of the tool for collecting the registration position in the three-dimensional model and the surface of the three-dimensional model is smaller than a preset error distance.

If yes, go to step S507; if not, go to step S512.

Step S507: and reminding a user to acquire the first registration position in a second registration area corresponding to the first registration area on the target hip joint through the acousto-optic information, and acquiring the acquired first registration position.

Step S508: it is determined whether the number of first registration positions obtained in the second registration area is not less than a preset number.

If yes, go to step S509; if not, step S503 is executed.

Step S509; and determining a second transformation relation between the three-dimensional model and the target hip joint according to the first transformation relation and the first registration position.

Step S510: and according to the second transformation relation, transforming the actual position on the target hip joint.

Step S511: and moving the tool for collecting the registration positions, so that the corresponding positions of the tool for collecting the registration positions in the three-dimensional model are positioned in the first registration area, and executing step S504.

Step S512: the tool that acquired the registration position is moved close to the target hip joint and step S504 is performed.

In one case, the above step S511 may be completed by the following steps S511A to S511D.

Step S511A: and judging whether the tool for acquiring the registration position can move to a second registration area corresponding to the first registration area. If yes, go to step S511D; if not, step S511B is performed.

Step S511B: a second region update location is acquired using a tool that acquires registration locations.

Step S511C: and determining a first area updating position according to the first transformation relation and the second area updating position, and updating the first registration area based on the first area updating position.

Step S511D: and moving the tool for collecting the registration positions, so that the corresponding positions of the tool for collecting the registration positions in the three-dimensional model are positioned in the first registration area, and executing step S504.

Corresponding to the above-mentioned hip joint position registration method, the embodiment of the invention also provides a hip joint position registration device.

Referring to fig. 6, there is provided a schematic structural view of a hip joint position registration device, the device comprising:

a first registration area determining module 601, configured to determine a first registration area on the three-dimensional model;

a first candidate position acquisition module 602 for acquiring in real time a first candidate position of a tool for acquiring a registration position on the target hip;

a second candidate position transformation module 603, configured to perform a position transformation on the first candidate position according to a first transformation relationship, so as to obtain a second candidate position, where the first transformation relationship is a transformation relationship between a point on the target hip joint and a point on the three-dimensional model surface, which is obtained in advance;

a position determining module 604, configured to determine whether the second candidate position is located in the first registration area;

a first registration position determination module 605 for obtaining a current position of the tool as a first registration position in response to a position obtaining instruction when the second candidate position is located within the first registration region;

A second transformation relationship determining module 606, configured to determine, as a second transformation relationship, a transformation relationship between a new point on the target hip joint and a point on the three-dimensional model surface according to the position of each point on the three-dimensional model surface, the first registration position, and the first transformation relationship;

the target hip joint position registration module 607 is configured to transform the actual position on the target hip joint according to the second transformation relationship, so as to complete position registration.

By applying the scheme provided by the embodiment, the first candidate position acquired by the tool for acquiring the registration position on the target hip joint can be obtained, and the first candidate position is subjected to position transformation to obtain the second candidate position. By judging whether the second candidate position is located in the first registration area or not and determining the first candidate position corresponding to the second candidate position located in the first registration area as the first registration position, a user can be guided to acquire the position of the position in the first registration area after position transformation as the first registration position, the accuracy of the obtained first registration position is ensured, and therefore, the accuracy of position registration of the target hip joint according to the first registration position is high. Therefore, the scheme provided by the embodiment of the invention can accurately register the actual position of the hip joint.

In one embodiment of the invention, the apparatus further comprises:

In one embodiment of the present invention, the second transformation relationship determining module 606 includes:

In one embodiment of the present invention, the first registration area determining module 601 is specifically configured to obtain a plurality of characteristic positions of hip joints selected by a user on the three-dimensional model, and obtain description information of each characteristic position; determining a first registration area according to the obtained characterization position and the description information; and/or obtaining a region framed by a user on the three-dimensional model; the framed area is determined to be a first registration area.

In one embodiment of the present invention, the first registration position determining module 605 is specifically configured to obtain, as the first registration position, a current position of the surgical probe with the reflectarray connected to the binocular camera.

The embodiment of the present invention further provides an electronic device, as shown in fig. 7, including a processor 701, a communication interface 702, a memory 703 and a communication bus 704, where the processor 701, the communication interface 702, and the memory 703 perform communication with each other through the communication bus 704,

a memory 703 for storing a computer program;

the processor 701 is configured to implement the hip joint position registration method described in the foregoing method embodiment when executing the program stored in the memory 703.

The communication bus mentioned above for the electronic device may be a Peripheral component interconnect standard (Peripheral ComponentInterconnect, PCI) bus or an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, or the like. The communication bus may be classified as an address bus, a data bus, a control bus, or the like. For ease of illustration, the figures are shown with only one bold line, but not with only one bus or one type of bus.

The communication interface is used for communication between the electronic device and other devices.

The Memory may include random access Memory (Random Access Memory, RAM) or may include Non-Volatile Memory (NVM), such as at least one disk Memory. Optionally, the memory may also be at least one memory device located remotely from the aforementioned processor.

The processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), etc.; but also digital signal processors (DigitalSignal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

In yet another embodiment of the present invention, a computer readable storage medium is provided, in which a computer program is stored, which when executed by a processor implements the hip joint position registration method according to the foregoing method embodiment.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present invention, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), etc.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for the apparatus, electronic device and storage medium embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and references to the parts of the description of the method embodiments are only needed.

The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method of hip joint position registration, the method comprising:

2. The method of claim 1, wherein when the second candidate location is within the first registration area, the method further comprises:

3. The method according to claim 1, wherein the method further comprises:

4. The method according to claim 1, wherein determining a new transformation relationship between the positions of the points on the target hip joint and the points on the three-dimensional model surface as the second transformation relationship according to the positions of the points on the three-dimensional model surface, the first registration position and the first transformation relationship comprises:

5. The method of any of claims 1-4, wherein the determining a first registration area on the three-dimensional model comprises:

and/or

6. The method according to any one of claims 1-4, wherein said obtaining the current position of the tool as a first registration position comprises:

7. A hip joint position registration device, the device comprising:

8. The apparatus of claim 7, wherein the apparatus further comprises:

9. The apparatus of claim 7, wherein the apparatus further comprises:

10. The apparatus of claim 7, wherein the second transformation relationship determination module comprises:

11. The apparatus according to any one of claims 7-10, wherein the first registration area determination module is configured to obtain a plurality of characteristic positions of the hip joints selected by the user on the three-dimensional model, and obtain descriptive information of each characteristic position; determining a first registration area according to the obtained characterization position and the description information; and/or obtaining a region framed by a user on the three-dimensional model; the framed area is determined to be a first registration area.

12. The apparatus according to any one of claims 7-10, wherein the first registration position determining module is configured to obtain, as the first registration position, a current position of a surgical probe with a reflectarray connected to the binocular camera.

13. The electronic equipment is characterized by comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory are communicated with each other through the communication bus;

a memory for storing a computer program;

a processor for carrying out the method steps of any one of claims 1-6 when executing a computer program stored on a memory.

14. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored therein a computer program which, when executed by a processor, implements the method steps of any of claims 1-6.