Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
The technical scheme of the present application is described below by specific examples.
Referring to fig. 1, a schematic step flow diagram of a modeling method according to an embodiment of the present application is shown, which may specifically include the following steps:
s101, acquiring a first distance between a first navigation device and each reference position of a modeling object and a second distance between a second navigation device and each reference position of the modeling object, wherein the first navigation device and the second navigation device are respectively configured at different positions of the modeling object;
it should be noted that the method may be applied to a terminal device. Namely, the execution main body of the method is terminal equipment, and modeling of the modeling object is completed by the terminal equipment through collecting required data. The terminal device in this embodiment may be a device such as a mobile phone or a tablet computer, or may be other devices capable of directly communicating with the modeling object and acquiring various data of the modeling object in real time in a moving or stationary state, which is not limited in this embodiment.
The modeling object in this embodiment may also be different depending on the applicable scenario. For example, in a scenario where a vehicle such as a shared automobile needs to be modeled to achieve automatic parking of the vehicle, the modeled object may be the vehicle such as the shared automobile; alternatively, the modeling object may be a ferry, a large ship, or the like, and the specific type of the modeling object is not limited in this embodiment.
In this embodiment, in order to implement real-time, dynamic and accurate modeling of the modeling object, two navigation devices may be configured at different positions on the modeling object in advance, where the navigation devices may be two high-precision satellite navigation receivers, and are configured to receive satellite signals such as beidou, GPS, and the like.
Of course, the navigation device may be a receiver that only supports satellite signals transmitted by a certain satellite navigation system, for example, only receives satellite signals of a beidou system or only receives satellite signals of a GPS system; alternatively, the navigation device may be a receiver capable of supporting simultaneous reception of satellite signals transmitted by a plurality of satellite navigation systems, for example, a receiver capable of simultaneously receiving satellite signals of a beidou system, a GPS system, and other systems, and processing a plurality of different satellite signals, which is not limited in this embodiment.
In this embodiment, after two navigation devices are configured at different positions of the modeling object, distances between the two navigation devices and the different positions of the modeling object may be measured, respectively.
In general, to model the shape of a modeled object, this can be achieved by determining the location of various points on the contour of the modeled object. However, if the distance to the two navigation devices is measured for each point on the modeled object contour, the subsequent data throughput will be relatively large. Thus, considering the accuracy of the modeling process and the rapidity of data processing, only the distances between each reference position of the modeling object and the two navigation devices may be measured, wherein the reference positions may be the positions of the intersection point, the end point, the middle point, the bisection point, the tangent point, and the like on the contour line of the modeling object. For example, if the projected shape of the modeling object is substantially a polygon such as a quadrangle, the distances between the respective corners on the modeling object and the two navigation devices may be measured. If the projected shape of the modeled object is substantially elliptical, the distance between two endpoints on the major axis and/or two endpoints on the minor axis on the modeled object and the two navigation devices may be measured.
For example, taking an automobile as an example, a first distance between the front, rear, left and right angles of the automobile and the first navigation device and a second distance between the front, rear, left and right angles and the second navigation device can be measured, wherein the front, rear, left and right angles are reference positions required for modeling the automobile.
The first distance and the second distance may be measured when two navigation devices are configured. Because the relative positions of the two navigation devices on the modeling object are fixed in the modeling process, the data can be directly acquired for use in the subsequent modeling process by measuring the first distance and the second distance in advance and storing the first distance and the second distance, and the data processing amount in the modeling process is reduced.
S102, determining longitude and latitude information of a first position where the first navigation device is located and longitude and latitude information of a second position where the second navigation device is located;
when the modeling object is static, longitude and latitude information of the positions of the two navigation devices are fixed, and static modeling of the modeling object can be achieved based on the fixed longitude and latitude information. When the modeling object is in a motion state, longitude and latitude information of the position of the two navigation devices is continuously changed, for example, when an automobile is in a driving process, the longitude and latitude information of the two navigation devices configured on the automobile is changed in real time, and dynamic modeling of the modeling object can be realized based on the dynamically changed longitude and latitude information.
The embodiment can automatically output longitude and latitude information of the positions of the two navigation devices to the terminal device by adopting the function that the navigation device can receive satellite signals, and the terminal device can further process the longitude and latitude information.
S103, constructing a target coordinate system based on longitude and latitude information of a first position where the first navigation device is located and longitude and latitude information of a second position where the second navigation device is located;
after receiving the latitude and longitude information of the respective positions transmitted by the two navigation devices, the terminal device can construct a target coordinate system based on the latitude and longitude information of the two position points. The positions of the two navigation devices and the reference positions of the modeling object can be regarded as a coordinate point on the target coordinate system.
S104, calculating coordinate values of each reference position of the modeling object according to the target coordinate system, the first distance and the second distance;
after the target coordinate system is constructed, since the coordinate values of the positions of the two navigation devices in the target coordinate system are determined, the distances between the two positions and the reference positions of the modeling object are also determined, and the coordinate values of the reference positions in the target coordinate system can be calculated according to the geometric relationship.
And S105, modeling the modeling object by adopting the coordinate values of the reference positions.
It should be noted that, for a modeling object in a stationary state, coordinate values of each reference position are fixed, and a model shape obtained by modeling using the coordinate values can be used to determine a position where the modeling object is currently stationary. For a modeling object in a non-stationary state, the coordinate values of each reference position of the modeling object are dynamic, and a dynamic model can be established according to the dynamically changed coordinate values and used for tracking the real-time change condition of the position of the modeling object.
In the embodiment of the application, by configuring the first navigation device and the second navigation device at different positions of the modeling object, a first distance between the first navigation device and each reference position of the modeling object and a second distance between the second navigation device and each reference position of the modeling object can be obtained, longitude and latitude information of the first position where the first navigation device is located and longitude and latitude information of the second position where the second navigation device is located are determined, and then a target coordinate system is constructed based on the longitude and latitude information, so that coordinate values of each reference position of the modeling object can be calculated according to the target coordinate system and the first distance and the second distance, and modeling of the modeling object is completed by adopting the coordinate values of each reference position. According to the embodiment, the shape state and the position change condition of the modeling object in the dynamic process can be accurately and timely determined by utilizing the navigation technology, the whole data processing process is completed in the constructed plane coordinate system, and the calculation process is convenient and simple; compared with rough modeling performed by using a single device, the accuracy of the model is improved, and for modeling objects with different shapes, high-accuracy devices are not required to be configured at each reference position, so that the number of devices is reduced, and the modeling cost is reduced.
Referring to fig. 2, a schematic step flow diagram of another modeling method according to an embodiment of the present application is shown, which may specifically include the following steps:
s201, acquiring a first distance between a first navigation device and each reference position of a modeling object and a second distance between a second navigation device and each reference position of the modeling object;
the execution subject of the method can be a terminal device, and modeling of the modeling object is completed through the terminal device. For ease of understanding, the present embodiment will be described later taking a modeling object as an example of an automobile.
In this embodiment, the first navigation device and the second navigation device may be high-precision measurement devices based on Real-time kinematic (RTK) carrier phase difference technology. The RTK carrier phase difference technology is a difference method for processing the observed quantity of the carrier phases of two measuring stations in real time, and the carrier phases acquired by a reference station are sent to a user receiver to calculate the difference and calculate the coordinates. The method is a new common satellite positioning measurement method, and can obtain centimeter-level positioning accuracy in real time.
The first navigation device and the second navigation device may be respectively configured at different positions of the modeling object.
Take an automobile as an example. Referring to fig. 3, a schematic diagram of the configuration of the navigation apparatus on an automobile according to the present embodiment is shown. The automobile is orthographic projected onto the ground level, four reference positions of the automobile are respectively points A, B, C, D, and then two high-precision RTK navigation devices, namely RTKa and RTKb, can be erected above the central axis of the automobile through a GNSS antenna.
Then, a first distance and a second distance between the two RTK navigation devices and four reference positions of the car, respectively, may be measured. That is, first distances L from the first position points RTKa of the configuration RTKa shown in fig. 4 to the points A, B, C, D, respectively, are measured Aa 、L Ba 、L Ca 、L Da Measuring a second distance L from each of the second position points RTKb of the configuration RTKb to the point A, B, C, D Ab 、L Bb 、L Cb 、L Db And measuring the distance L between two navigation devices ab 。
Of course, the two navigation devices may be disposed not only on the vehicle center axis but also at other positions. On any plane, both points can define a plane. Thus, two location points of the configuration of the navigation device may be in relatively parallel positions on the roof axis.
S202, receiving first positioning data output by the first navigation equipment and second positioning data output by the second navigation equipment in real time; respectively extracting longitude and latitude information in the first positioning data and the second positioning data;
the embodiment can automatically output longitude and latitude information of the positions of the two navigation devices to the terminal device by adopting the function that the navigation device can receive satellite signals, and the terminal device can further process the longitude and latitude information.
Of course, for some GPS receivers, the data format is NMEA-0183, and the latitude and longitude data is represented in dddmm.mmmm, which needs to be converted into specific latitude and longitude, where the formula is: longitude and latitude (degree) =ddd+mm.mmmm/60.
For example, if the sentence including latitude and longitude information output by the receiver is latitude: 2308.474898, longitude: 11329.968159, the format of the longitude and latitude data is DDDMM.MMMM, wherein the latitude DDD is equal to 23, and the MMMM is equal to 08.474898; longitude DDD is equal to 113, mm.mmmm is equal to 29.968159, and is obtained by conversion according to the above formula:
longitude (degree): 113+29.968159/60= 113.4994693
Latitude (degree): 23+8.474898/60= 23.1412483
S203, determining the direction of a target coordinate system by taking the first position of the first navigation device as an origin, taking the straight line of the origin along the weft direction as an X axis and taking the straight line of the origin along the warp direction as a Y axis;
the shape of the earth is an irregular elliptic sphere with two stages of parts slightly flattened and an equator slightly bulging, and the Gaussian-Ke Lv Touying method used in the academic community can be widely expanded into a plane, but the latitude and longitude lines are not straight lines, so that the calculation formula is extremely complex.
Considering that the area of the modeling object of the present embodiment is extremely small relative to the earth, a simplified target coordinate system can be established by an approximate method when modeling.
As shown in fig. 5, a schematic diagram of the target coordinate system of the present embodiment is shown. The coordinate system may be a straight line instead of a curved line, and the X-axis is set to be a line along the weft direction, the Y-axis is set to be a line along the warp direction, and the RTK a point is set as the origin. Thus, the directions of the X axis and the Y axis of the target coordinate system can be preliminarily determined.
S204, respectively determining a first projection point of the second position of the second navigation device on the X axis and a second projection point of the second navigation device on the Y axis;
in the target coordinate system, a first projection point of the RTK b point at the second position where the second navigation device is located on the X axis and a second projection point of the RTK b point on the Y axis are the coordinate values of the RTKb point.
Namely, the distance Yb between the RTK b point and the origin along the meridian direction is the Y-axis coordinate of the RTKb point; along the weft direction, the distance Xb from the origin is the X-axis coordinate of the RTKb point.
S205, calculating the distance between the second projection point and the origin by adopting the longitude and latitude information of the first position and the longitude and latitude information of the second position, and taking the distance as a Y-axis coordinate value of the second position;
for obtaining the Y-axis coordinate of the RTKb point, that is, the distance from RTKa to Yb, an ellipse can be intercepted along the origin of the target coordinate system and the meridian where the second projection point is located, a transformation coordinate system containing the ellipse is constructed, and a first corresponding point of the first position in the transformation coordinate system and a second corresponding point of the second projection point in the transformation coordinate system are determined. Then, taking the latitude value of the first position as an included angle value between a first corresponding point in the conversion coordinate system and the X axis of the conversion coordinate system, and calculating to obtain a coordinate value of the first corresponding point in the conversion coordinate system according to a preset latitude value formula; taking the latitude value of the second position as an included angle value between a second corresponding point in the conversion coordinate system and the X axis of the conversion coordinate system, and calculating to obtain a coordinate value of the second corresponding point in the conversion coordinate system according to a preset latitude value formula; further, the distance between the second projection point and the origin in the target coordinate system can be calculated based on the coordinate value of the first corresponding point in the transformed coordinate system and the coordinate value of the second corresponding point in the transformed coordinate system.
As shown in fig. 6, is a schematic diagram of a transformation coordinate system constructed by taking out ellipses. The ellipse is obtained by cutting the ellipse along the meridian where RTKa and Yb are located. In fig. 6, the distance from RTKa to Yb is actually a length of an ellipse in the meridian section in fig. 6, and since the length of the arc is extremely short relative to the entire ellipse, and the equation for calculating the length of the ellipse is very complex, the calculation is simplified to a two-point linear distance calculation method in this embodiment.
In the transformation coordinate system shown in fig. 6, the RTKa point coordinates are set to (xa, ya). The Yb point coordinates are (X1, Y1). According to the definition of latitude: as can be seen from the angle between the normal line direction of the ellipsoidal surface (the line perpendicular to a point tangent on the curved surface) and the equatorial full-plane, in fig. 6, the angle Ba between the normal line of the RTKa point and the X-axis of the transformation coordinate system is the latitude of the RTKa point.
Using the elliptic equation:
tangential equation over elliptical RTKa points:
let the dimension of the RTKa point be Ba, then, according to the definition of the latitude and the above formula (2), it can be obtained:
simultaneous equations (1), (2) and (3) can calculate the coordinate values of the RTKa point in the transformation coordinate system of fig. 6:
the expression a in the formulas (4) and (5) represents the major half axis of the earth ellipsoid, which is 6378137 meters, the expression b represents the minor half axis of the earth ellipsoid, which is 6356752 meters, and Ba is the earth dimension value (degree) of the RTKa point.
As can be seen from FIG. 5, the latitude of Yb is equal to the latitude of the RTK b point, and the Yb point coordinates (X1, Y1) are obtained in the same way. The distance between the origin and the Yb point is calculated by using the coordinates of two points:
s206, calculating the distance between the first projection point and the origin point to serve as an X-axis coordinate value of the second position, and obtaining a target coordinate system;
as can be seen from fig. 5, the distance from the RTKa point to Xb is actually along an arc length on the latitude circle, and the latitude circle is a circle. Therefore, the target circle can be intercepted along the origin of the target coordinate system and the weft line where the first projection point is located, and a third corresponding point of the first position in the target circle and a fourth corresponding point of the first projection point in the target circle are determined; the arc length between the third corresponding point and the fourth corresponding point is calculated to be the distance between the first projection point and the origin in the target coordinate system. That is, a longitude difference between the first position and the second position is calculated, and the product of the longitude difference and the radius of the target circle, which is the X-axis coordinate value of the first projection point in the conversion coordinate system, is used as the arc length between the third corresponding point and the fourth corresponding point.
Specifically, according to an arc length formula l=r×θ, where R is a target circle radius, and θ is an angle of a central angle subtended by the arc. The radius of the latitude circle on the RTKa point is the X-axis coordinate Xa of the RTKa point in FIG. 6.θ is the difference in longitude between the RTKa and RTKb points, so the distance between the calculated origin and Xb point is: axb=xa.
Therefore, in the target coordinate system shown in fig. 5, the coordinate of the RTKb point is (aXb, aYb), and the coordinate of the RTKa point is (0, 0).
S207, calculating coordinate values of each reference position of the modeling object according to the target coordinate system, the first distance and the second distance;
in this embodiment, after the target coordinate system is constructed and the coordinate value of the first position RTKa and the coordinate value of the second position RTKb in the target coordinate system are calculated, the coordinate value of the target position in the target coordinate system can be calculated according to the coordinate value of the first position, the coordinate value of the second position, the first distance between the target position and the first position, and the second distance between the target angle and the second position, for any target position of the modeling object, in combination with the first distance and the second distance between the two position points and each angle measured in advance. The target position is any one of a plurality of reference positions.
Taking the car angle A point in FIG. 3 as an example, the distance L from A to RTK a is known Aa Distance L of A to RTKb ab Let the coordinates of point a be (X2, Y2) in conjunction with the following equations (7), (8):
coordinate values of the point a in the target coordinate system can be obtained.
Similarly, the coordinate value of the automobile angle B, C, D point can be calculated.
And S208, modeling the modeling object by adopting the coordinate values of the reference positions.
It should be noted that, although the present embodiment only takes an automobile with four reference positions as an example, the present embodiment is equally applicable to other modeling objects. For example, the ship shown in fig. 7 may employ the same method, where the distances between the six points A, B, C, D, E, F in fig. 7 and the two RTK navigation devices are determined first, and then coordinates of the six points are obtained by establishing a target coordinate system and calculating a formula of the distances between the two points, so as to establish a dynamic model.
According to the method, the simple plane coordinate system is built, the whole modeling data processing process is converted into the built plane coordinate system, the calculation process is convenient and simple, the accuracy of the model is improved, the number of devices is reduced, the modeling cost is reduced, and the method is suitable for modeling objects in various shapes.
It should be noted that, the sequence number of each step in the above embodiment does not mean the sequence of execution sequence, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.
Referring to FIG. 8, a schematic diagram of a modeling apparatus according to one embodiment of the present application is shown, and may specifically include the following modules:
an obtaining module 801, configured to obtain a first distance between a first navigation device and each reference position of a modeling object, and a second distance between a second navigation device and each reference position of the modeling object, where the first navigation device and the second navigation device are respectively configured at different positions of the modeling object;
a determining module 802, configured to determine latitude and longitude information of a first location where the first navigation device is located and a second location where the second navigation device is located;
a construction module 803, configured to construct a target coordinate system based on latitude and longitude information of a first location where the first navigation device is located and a second location where the second navigation device is located;
a calculation module 804, configured to calculate coordinate values of respective reference positions of the modeling object according to the target coordinate system, and the first distance and the second distance;
a modeling module 805, configured to model the modeling object using coordinate values of the respective reference positions.
In this embodiment of the present application, the determining module 802 may specifically include the following sub-modules:
the positioning data receiving sub-module is used for receiving the first positioning data output by the first navigation equipment and the second positioning data output by the second navigation equipment in real time;
and the longitude and latitude information extraction sub-module is used for respectively extracting longitude and latitude information in the first positioning data and the second positioning data.
In the embodiment of the present application, the building module 803 may specifically include the following sub-modules:
the coordinate system direction determining submodule is used for determining a target coordinate system direction by taking a first position where the first navigation equipment is located as an original point, taking a straight line of the original point along the weft direction as an X axis and taking a straight line of the original point along the warp direction as a Y axis;
the projection point determining submodule is used for respectively determining a first projection point of the second position of the second navigation equipment on the X axis and a second projection point of the second navigation equipment on the Y axis;
the coordinate value calculating sub-module is used for calculating the distance between the second projection point and the origin by adopting the longitude and latitude information of the first position and the longitude and latitude information of the second position, and taking the distance as a Y-axis coordinate value of the second position; and calculating the distance between the first projection point and the origin as an X-axis coordinate value of the second position to obtain a target coordinate system.
In this embodiment of the present application, the coordinate value calculating submodule may specifically include the following units:
a transformation coordinate system construction unit, configured to intercept an ellipse along an origin of the target coordinate system and a meridian where the second projection point is located, construct a transformation coordinate system including the ellipse, and determine a first corresponding point of the first position in the transformation coordinate system and a second corresponding point of the second projection point in the transformation coordinate system;
the coordinate value calculating unit is used for taking the latitude value of the first position as an included angle value between a first corresponding point in the conversion coordinate system and the X axis of the conversion coordinate system, and calculating to obtain the coordinate value of the first corresponding point in the conversion coordinate system according to a preset latitude value formula; taking the latitude value of the second position as an included angle value between a second corresponding point in the conversion coordinate system and the X axis of the conversion coordinate system, and calculating to obtain a coordinate value of the second corresponding point in the conversion coordinate system according to a preset latitude value formula; and calculating the distance between the second projection point and the original point in the target coordinate system according to the coordinate value of the first corresponding point in the conversion coordinate system and the coordinate value of the second corresponding point in the conversion coordinate system.
In this embodiment of the present application, the coordinate value calculating unit may be further configured to intercept a target circle along an origin of the target coordinate system and a weft line where the first projection point is located, determine a third corresponding point of the first position in the target circle, and a fourth corresponding point of the first projection point in the target circle; and calculating the arc length between the third corresponding point and the fourth corresponding point as the distance between the first projection point and the origin in the target coordinate system.
In this embodiment of the present application, the coordinate value calculating unit may be further configured to calculate a longitude difference between the first location and the second location, and take a product of the longitude difference and a radius of the target circle as a circular arc length between the third corresponding point and the fourth corresponding point, where the radius of the target circle is an X-axis coordinate value of the first projection point in the transformation coordinate system.
In the embodiment of the present application, the computing module 804 may specifically include the following sub-modules:
a reference position coordinate value calculating sub-module, configured to calculate, for any target position of the modeling object, a coordinate value of the target position in the target coordinate system according to the coordinate value of the first position, the coordinate value of the second position, a first distance between the target position and the first position, and a second distance between the target position and the second position, where the target position is any one of the reference positions.
For the device embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and reference should be made to the description of the method embodiments.
Referring to fig. 9, a schematic diagram of a terminal device according to an embodiment of the present application is shown. As shown in fig. 9, the terminal device 900 of the present embodiment includes: a processor 910, a memory 920 and a computer program 921 stored in said memory 920 and executable on said processor 910. The processor 910, when executing the computer program 921, implements the steps in the respective embodiments of the modeling method described above, such as steps S101 to S105 shown in fig. 1. Alternatively, the processor 910, when executing the computer program 921, implements functions of the modules/units in the above-described device embodiments, for example, functions of the modules 801 to 805 shown in fig. 8.
Illustratively, the computer program 921 may be partitioned into one or more modules/units that are stored in the memory 920 and executed by the processor 910 to complete the present application. The one or more modules/units may be a series of computer program instruction segments capable of performing a specific function, which instruction segments may be used to describe the execution of the computer program 921 in the terminal device 900. For example, the computer program 921 may be divided into an acquisition module, a determination module, a construction module, a calculation module, and a modeling module, each of which functions specifically as follows:
the system comprises an acquisition module, a modeling module and a control module, wherein the acquisition module is used for acquiring a first distance between a first navigation device and each reference position of the modeling object and a second distance between a second navigation device and each reference position of the modeling object, and the first navigation device and the second navigation device are respectively configured at different positions of the modeling object;
the determining module is used for determining longitude and latitude information of a first position where the first navigation device is located and longitude and latitude information of a second position where the second navigation device is located;
the construction module is used for constructing a target coordinate system based on longitude and latitude information of a first position where the first navigation device is located and longitude and latitude information of a second position where the second navigation device is located;
a calculation module for calculating coordinate values of respective reference positions of the modeling object according to the target coordinate system, and the first distance and the second distance;
and the modeling module is used for modeling the modeling object by adopting the coordinate values of the reference positions.
The terminal device 900 may be a computing device such as a desktop computer, a notebook computer, a palm computer, a cloud server, etc. The terminal device 900 may include, but is not limited to, a processor 910, a memory 920. It will be appreciated by those skilled in the art that fig. 9 is merely an example of a terminal device 900, and is not meant to be limiting of the terminal device 900, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the terminal device 900 may also include input and output devices, network access devices, buses, etc.
The processor 910 may be a central processing unit (Central Processing Unit, CPU), but may 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 arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 920 may be an internal storage unit of the terminal device 900, for example, a hard disk or a memory of the terminal device 900. The memory 920 may also be an external storage device of the terminal device 900, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided on the terminal device 900. Further, the memory 920 may also include both an internal storage unit and an external storage device of the terminal device 900. The memory 920 is used for storing the computer program 921 and other programs and data required for the terminal device 900. The memory 920 may also be used to temporarily store data that has been output or is to be output.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.