Axial Force Signal Processing Method and Device for Micro-Drills Used in Printed Circuit Boards

Abstract

This application is applicable to the field of signal processing technology, and provides a method and device for processing the axial force signal of a micro drill for a printed circuit board. The above-mentioned method for processing the axial force signal of a micro drill for a printed circuit board first calculates the expected frequency of the axial force signal based on the cyclic stationary algorithm. Then, the expected signal of the axial force signal is obtained according to the expected period, where the expected period is calculated based on the expected frequency. Finally, the axial force signal is filtered according to the expected signal. In the method for processing the axial force signal of a micro drill for a printed circuit board provided by the embodiments of this application, an accurate expected frequency can be obtained, and then an expected signal with a high signal-to-noise ratio can be obtained. Finally, the signal output after filtering the axial force signal by the expected signal also has the characteristic of a high signal-to-noise ratio, reducing the influence of noise signals, thereby improving the accuracy of the axial force signal.

Description

Technical Field

[0001] This application belongs to the technical field of signal processing, and particularly relates to a method and device for processing the axial force signal of a micro drill for a printed circuit board. Background Art

[0002] A printed circuit board (PCB) is an important basic component in electronic products and is regarded as the mother of electronic products. It has a very wide range of applications in daily life.

[0003] The micro-drilling process of a PCB is a semi-closed machining process, and the heat generated during the drilling process can only be released in a limited space. Due to the very poor heat dissipation ability of the epoxy glass cloth, as the drilling process progresses, the temperature of the hole will gradually increase. When reaching a certain temperature, the resin will melt and firmly adhere to the spiral groove and the cutting edge, hindering chip evacuation. Since the chips cannot be discharged smoothly, they will block in the drill hole, which is likely to cause a sharp increase in the axial force and torque of the tool during the drilling process. Once exceeding the strength limit of the micro drill, the micro drill will break, resulting in the scrapping of the entire PCB and seriously affecting the production efficiency. Therefore, during the micro-drilling process of a PCB, the drilling force is one of the key factors affecting the drilling performance.

[0004] The axial force signal of the micro drill can accurately describe the dynamic change of the drilling force during the micro-drilling process. However, the axial force signal of the micro drill is too weak and is often submerged in the noise signal, resulting in the inability to accurately analyze the axial force signal. Summary of the Invention

[0005] The embodiments of this application provide a method and device for processing the axial force signal of a micro drill for a printed circuit board, which can solve the problem that the axial force signal cannot be accurately analyzed due to the existence of noise signals.

[0006] In a first aspect, the embodiments of this application provide a method for processing the axial force signal of a micro drill for a printed circuit board, including:

[0007] Calculating the expected frequency of the axial force signal based on the cyclic stationary algorithm;

[0008] Obtaining the expected signal of the axial force signal according to the expected period; wherein, the expected period is calculated according to the expected frequency;

[0009] Filtering the axial force signal according to the expected signal.

[0010] In a possible implementation manner of the first aspect, the calculating the expected frequency of the axial force signal based on the cyclic stationary algorithm includes:

[0011] Calculating the cyclic autocorrelation function of the axial force signal;

[0012] Perform a time-frequency transformation on the cyclic autocorrelation function to obtain the power-frequency relationship of the cyclic autocorrelation function;

[0013] Extract the desired frequency based on the power-frequency relationship.

[0014] In a possible implementation manner of the first aspect, the obtaining of the desired signal of the axial force signal according to the desired period includes:

[0015] Slice the axial force signal based on the desired period to obtain a plurality of sliced signals;

[0016] Determine the desired signal according to the plurality of sliced signals.

[0017] In a possible implementation manner of the first aspect, the duration of each of the sliced signals is one or more of the desired periods, and the determining of the desired signal according to the plurality of sliced signals includes:

[0018] Calculate the average value of the plurality of sliced signals as the desired signal.

[0019] In a second aspect, an embodiment of the present application provides a signal processing device, including:

[0020] A desired frequency determination module, configured to calculate the desired frequency of the axial force signal based on a cyclic stationary algorithm;

[0021] A desired signal determination module, configured to obtain the desired signal of the axial force signal according to the desired period; wherein, the desired period is calculated according to the desired frequency; and

[0022] A filtering module, configured to filter the axial force signal according to the desired signal.

[0023] In a possible implementation manner of the second aspect, the desired frequency determination module includes:

[0024] A cyclic autocorrelation unit, configured to calculate the cyclic autocorrelation function of the axial force signal;

[0025] A time-frequency transformation unit, configured to perform a time-frequency transformation on the cyclic autocorrelation function to obtain the power-frequency relationship of the cyclic autocorrelation function; and

[0026] A desired frequency determination unit, configured to extract the desired frequency based on the power-frequency relationship.

[0027] In a possible implementation manner of the second aspect, the desired signal determination module includes:

[0028] A slicing unit, configured to slice the axial force signal based on a desired period to obtain a plurality of sliced signals;

[0029] A desired signal determining unit, configured to determine the desired signal according to the plurality of sliced signals.

[0030] In a possible implementation manner of the second aspect, the desired signal determining unit includes:

[0031] A calculation unit, configured to calculate the average value of the plurality of sliced signals as the desired signal.

[0032] In a third aspect, an embodiment of the present application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method described in any item of the first aspect is implemented.

[0033] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described in any item of the first aspect is implemented.

[0034] In a fifth aspect, an embodiment of the present application provides a computer program product. When the computer program product runs on a terminal device, the terminal device is enabled to execute the method described in any item of the first aspect above.

[0035] The beneficial effects of the embodiments of the present application compared with the prior art are as follows:

[0036] First, the desired frequency of the axial force signal is calculated based on the cyclic stationary algorithm. Then, the desired signal of the axial force signal is obtained according to the desired period, where the desired period is calculated based on the desired frequency. Finally, the axial force signal is filtered according to the desired signal. In the method for processing the axial force signal of the micro drill for a printed circuit board provided by the embodiments of the present application, an accurate desired frequency can be obtained, and then a desired signal with a high signal-to-noise ratio can be obtained. Finally, the signal output after filtering the axial force signal by the desired signal also has the characteristic of a high signal-to-noise ratio, reducing the influence of the noise signal, thereby improving the accuracy of the axial force signal.

[0037] It can be understood that the beneficial effects of the above second aspect to the fifth aspect can refer to the relevant descriptions in the first aspect above, and will not be elaborated here. Description of the Drawings

[0038] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a schematic flowchart of a method for processing the axial force signal of a micro drill for a printed circuit board provided by an embodiment of the present application;

[0040] Figure 2 It is a waveform diagram of an expected signal provided by an embodiment of the present application;

[0041] Figure 3 It is a waveform diagram of the filtered axial force signal provided by an embodiment of the present application;

[0042] Figure 4 It is a schematic structural diagram of a signal processing device provided by an embodiment of the present application.

[0043] Figure 5 It is a schematic structural diagram of a terminal device provided by an embodiment of the present application. Detailed implementation manners

[0044] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are proposed to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0045] It should be understood that when used in the specification of the present application and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0046] It should also be understood that the term " / and / " used in the specification of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0047] As used in the specification of this application and the appended claims, the term "if" may be construed, depending on the context, as "when", "once", "in response to determining", or "in response to detecting". Similarly, the phrases "if determined" or "if [the described condition or event] is detected" may be construed, depending on the context, to mean "once determined", "in response to determining", "once [the described condition or event] is detected", or "in response to detecting [the described condition or event]".

[0048] In addition, in the description of the specification of this application and the appended claims, the terms "first", "second", "third", etc. are used only for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0049] Reference to "one embodiment" or "some embodiments" or the like described in the specification of this application means that a specific feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0050] Figure 1 The flowchart of the method for processing the axial force signal of a micro drill for a printed circuit board provided by an embodiment of this application is shown. Refer to Figure 1 As shown, the method for processing the axial force signal of a micro drill for a printed circuit board includes steps S101 to S103.

[0051] Step S101, calculating the expected frequency of the axial force signal based on the cyclic stationary algorithm.

[0052] Specifically, by analyzing the axial force signal collected in the experiment, it can be known that the axial force signal after filtering out the noise signal is a typical cyclic stationary signal. Analyzing and processing the axial force signal using the cyclic stationary algorithm can obtain the expected frequency (the frequency of the expected signal).

[0053] Exemplarily, step S101 may specifically include steps S1011 to S1013.

[0054] Step S1011, calculating the cyclic autocorrelation function of the axial force signal.

[0055] Specifically, assume that the axial force signal is a stationary random signal superimposed on a cyclic stationary signal. Then the axial force signal can be expressed as:

[0056] y_n(t) = x(t) + n(t)

[0057] Wherein, y_n(t) is the axial force signal, x(t) is a cyclostationary signal (desired signal) with α as the cyclic frequency, and n(t) is a randomly generated zero-mean stationary random noise signal independent of the statistics of x(t).

[0058] Calculating the cyclic autocorrelation function of the axial force signal can obtain:

[0059]

[0060] Wherein, is the cyclic autocorrelation function of the axial force signal, is the cyclic autocorrelation function of the cyclostationary signal, is the cyclic autocorrelation function of the noise signal.

[0061] Since when α≠0 and α∈Φ, Φ is a real number, the cyclic autocorrelation function of the noise signal Thus, That is, the frequency of the cyclic autocorrelation function of the axial force signal is the same as the frequency of the cyclic autocorrelation function of the cyclostationary signal. Through the above analysis, it can be known that calculating the cyclic autocorrelation function of the axial force signal can determine the desired frequency (the frequency of the desired signal).

[0062] Step S1012: Perform a time-frequency transformation on the cyclic autocorrelation function to obtain the power-frequency relationship of the cyclic autocorrelation function.

[0063] Specifically, the cyclic autocorrelation function can be Fourier-transformed to convert the cyclic autocorrelation function from a time-domain signal to a frequency-domain signal, obtaining the power-frequency relationship of the cyclic autocorrelation function for subsequent extraction of frequency characteristics in the frequency domain.

[0064] Step S1013: Extract the desired frequency based on the power-frequency relationship.

[0065] Specifically, according to the power-frequency relationship, a spectrogram is plotted, and the maximum value in the frequency curve is selected as the desired frequency.

[0066] Step S102: Obtain the desired signal of the axial force signal according to the desired period.

[0067] Specifically, after obtaining the desired frequency through step S101, the reciprocal of the desired frequency can be taken to obtain the desired period. By the principle of period cumulative averaging (time-domain cumulative principle) of the time-domain signal, the weak signal with an obvious period in the axial force signal can be quickly and effectively extracted.

[0068] Exemplarily, step S102 may specifically include step S1021 and step S1022.

[0069] Step S1021: Slice the axial force signal based on the expected period to obtain a plurality of sliced signals.

[0070] Specifically, assume that the expected signal is s(t), and the expected signal s(t) is a time-domain signal with a determined period or a time-domain signal that can be repeatedly generated during the test detection and acquisition process. Add a Gaussian noise signal n(t) to the expected signal s(t), and the synthesized signal is the actual axial force signal x(t), then:

[0071] x(t) = s(t) + n(t)

[0072] The mean of the Gaussian noise signal n(t) is zero, and the variance is σ 2 (t). Then the signal-to-noise ratio SNR of the expected signal at time t is:

[0073] SNR = s 2 (t) / σ 2 (t)

[0074] Wherein, s 2 (t) is the variance of the expected signal.

[0075] Slice the actual axial force signal x(t) according to the expected period to obtain a plurality of sliced signals.

[0076] Step S1022: Determine the expected signal according to the plurality of sliced signals.

[0077] Specifically, the duration of each sliced signal is one or more expected periods. Then calculate the average value of the plurality of sliced signals to obtain the expected signal:

[0078]

[0079] The power of the expected signal y(t) obtained in the above formula is still s 2 (t). For each measurement and acquisition period of the test signal, the noise signal is not a correlated signal. At this time, the output noise power is:

[0080]

[0081] After superimposing and averaging the actual axial force signal x(t) according to the expected period, the power of the actual axial force signal x(t) does not change, and the power of the noise signal is reduced to 1 / N of the input. This shows that after processing the actual axial force signal x(t) by the accumulation averaging method of the time-domain signal, the signal-to-noise ratio is increased by 10log 10 NdB, and the waveform of the obtained expected signal is asFigure 2 as shown

[0082] Step S103: Filter the axial force signal according to the desired signal.

[0083] Specifically, perform Wiener filtering on the axial force signal according to the desired signal. The essence of Wiener filtering is to minimize the mean square value of the estimation error (defined as the difference between the desired response and the actual output of the filter). Use the average signal after filtering based on the time-domain accumulation principle as the desired signal of the axial force signal, and perform Wiener filtering on the axial force signal. The output signal obtained at this time not only improves the signal-to-noise ratio, but also has a better correlation between the waveform of the signal and the axial force signal. The waveform of the axial force signal after filtering is as Figure 3 as shown

[0084] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0085] Figure 4 shows a schematic structural diagram of a signal processing device provided by an embodiment of the present application. As Figure 4 shown, the signal processing device includes:[[]]

[0086] A desired frequency determination module 41, configured to calculate the desired frequency of the axial force signal based on a cyclic stationary algorithm;

[0087] A desired signal determination module 42, configured to obtain the desired signal of the axial force signal according to the desired period; wherein, the desired period is calculated according to the desired frequency; and

[0088] A filtering module 43, configured to filter the axial force signal according to the desired signal.

[0089] In an embodiment of the present application, the desired frequency determination module 41 includes:[[]]

[0090] A cyclic autocorrelation unit, configured to calculate the cyclic autocorrelation function of the axial force signal;

[0091] A time-frequency transformation unit, configured to perform time-frequency transformation on the cyclic autocorrelation function to obtain the power-frequency relationship of the cyclic autocorrelation function; and

[0092] A desired frequency determination unit, configured to extract the desired frequency based on the power-frequency relationship.

[0093] In an embodiment of the present application, the desired signal determination module 42 includes:[[]]

[0094] A slicing unit, configured to slice the axial force signal based on a desired period to obtain a plurality of sliced signals;

[0095] A desired signal determination unit, configured to determine the desired signal according to the plurality of sliced signals.

[0096] In one embodiment of the present application, the desired signal determination unit includes:

[0097] A calculation unit, configured to calculate the average value of the plurality of sliced signals as the desired signal.

[0098] It should be noted that for the information interaction, execution process, etc. between the above-mentioned devices / units, since they are based on the same concept as the method embodiment of the present application, for their specific functions and the technical effects brought, reference can be specifically made to the method embodiment part, and details will not be elaborated here.

[0099] In addition, Figure 4 The signal processing device shown can be a software unit, a hardware unit, or a unit combining software and hardware built into an existing terminal device, can also be integrated into the terminal device as an independent pendant, or can exist as an independent terminal device.

[0100] Those skilled in the art can clearly understand that for the convenience and conciseness of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments, and details will not be elaborated here.

[0101] Figure 5 This is a schematic structural diagram of a terminal device provided in an embodiment of the present application. As Figure 5 shown, the terminal device 5 in this embodiment may include: at least one processor 50 ( Figure 5 only one processor 50 is shown in Figure 1Steps S101 to S103 in the illustrated embodiment. Alternatively, when the processor 50 executes the computer program 52, the functions of each module / unit in the above-described device embodiments are implemented. For example Figure 4 the functions of the illustrated modules 41 to 43.

[0102] Exemplarily, the computer program 52 may be divided into one or more modules / units. The one or more modules / units are stored in the memory 51 and executed by the processor 50 to complete the present invention. The one or more modules / units may be a series of computer program 52 instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program 52 in the terminal device 5.

[0103] The terminal device 5 may be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art can understand that Figure 5 merely examples of the terminal device 5 are given and do not constitute a limitation on the terminal device 5. It may include more or fewer components than shown in the figure, or combine certain components, or different components. For example, it may also include input / output devices, network access devices, etc.

[0104] The so-called processor 50 may be a central processing unit (CPU), and the processor 50 may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0105] In some embodiments, the memory 51 may be an internal storage unit of the terminal device 5, such as the hard disk or memory of the terminal device 5. In some other embodiments, the memory 51 may also be an external storage device of the terminal device 5, such as a plug-in hard disk equipped on the terminal device 5, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 51 may also include both the internal storage unit and the external storage device of the terminal device 5. The memory 51 is used to store an operating system, application programs, a Boot Loader, data, and other programs, such as the program code of the computer program 52. The memory 51 may also be used to temporarily store data that has been output or is to be output.

[0106] An embodiment of the present application also provides a computer-readable storage medium storing a computer program 52, and when the computer program 52 is executed by a processor 50, the steps in the above method embodiments can be implemented.

[0107] An embodiment of the present application provides a computer program product, and when the computer program product runs on a mobile terminal, the mobile terminal can execute the steps in the above method embodiments.

[0108] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above method embodiments of the present application, the computer program 52 can be used to instruct relevant hardware to complete. The computer program 52 can be stored in a computer-readable storage medium, and when the computer program 52 is executed by the processor 50, the steps in the above method embodiments can be implemented. Among them, the computer program 52 includes computer program code, and the computer program code can be in the form of source code, object code, an executable file, or some intermediate form, etc. The computer-readable medium may at least include: any entity or device capable of carrying the computer program code to the terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk, or an optical disc, etc. In some jurisdictions, according to legislation and patent practice, the computer-readable medium may not be an electrical carrier signal and a telecommunication signal.

[0109] In the above embodiments, the descriptions of the respective embodiments each have their own emphasis. For parts not described in detail or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0110] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0111] In the embodiments provided in this application, it should be understood that the disclosed device / network device and method can be implemented in other ways. For example, the device / network device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0112] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0113] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of this application, and should all be included in the protection scope of this application.

Claims

1. A method for processing the axial force signal of a micro drill for a printed circuit board, characterized in that, it includes: Calculating the expected frequency of the axial force signal based on the cyclic stationary algorithm; Obtaining the expected signal of the axial force signal according to the expected period; wherein, the expected period is calculated according to the expected frequency; Performing Wiener filtering on the axial force signal according to the expected signal; The calculating the expected frequency of the axial force signal based on the cyclic stationary algorithm includes: Calculating the cyclic autocorrelation function of the axial force signal; Performing time-frequency transformation on the cyclic autocorrelation function to obtain the power-frequency relationship of the cyclic autocorrelation function; Extracting the expected frequency based on the power-frequency relationship; The obtaining the expected signal of the axial force signal according to the expected period includes: Slicing the axial force signal based on the expected period to obtain a plurality of sliced signals; Determining the expected signal according to the plurality of sliced signals; The duration of each sliced signal is one or more of the expected periods, and the determining the expected signal according to the plurality of sliced signals includes: Calculating the average value of the plurality of sliced signals as the expected signal.

2. A signal processing device, characterized in that, it includes: An expected frequency determination module for calculating the expected frequency of the axial force signal based on the cyclic stationary algorithm; An expected signal determination module for obtaining the expected signal of the axial force signal according to the expected period; wherein, the expected period is calculated according to the expected frequency; and A filtering module for filtering the axial force signal according to the expected signal; The expected frequency determination module includes: A cyclic autocorrelation unit for calculating the cyclic autocorrelation function of the axial force signal; A time-frequency transformation unit for performing time-frequency transformation on the cyclic autocorrelation function to obtain the power-frequency relationship of the cyclic autocorrelation function; and An expected frequency determination unit for extracting the expected frequency based on the power-frequency relationship; The expected signal determination module includes: A slicing unit for slicing the axial force signal based on the expected period to obtain a plurality of sliced signals; An expected signal determination unit for determining the expected signal according to the plurality of sliced signals; The expected signal determination unit includes: A calculation unit for calculating the average value of the plurality of sliced signals as the expected signal.

3. A terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, the method described in claim 1 is implemented.

4. A computer-readable storage medium, the computer-readable storage medium stores a computer program, characterized in that, when the computer program is executed by a processor, the method described in claim 1 is implemented.

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