A test pattern generation method and apparatus

Abstract

The application discloses a kind of test pattern generation method and device, wherein the method comprises: obtaining the line width corresponding to multiple line pairs;Wherein, line pair number is the number of line pairs needed to be determined in different positions of the original test pattern;According to each line width, generate the original test pattern containing sub-line pair;Each line pair in the original test pattern is composed of multiple sub-line pairs;Anti-distortion is carried out on the original test pattern, and the target test pattern is obtained.The method of the application improves the accuracy of anti-distortion to generate the target test pattern, and ensures that the target test pattern can be used for accurate test of the resolving power of camera module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lens testing, in particular to a test image generation method and device. BACKGROUND

[0002] The resolving power of a camera module represents the ability of the camera module to clearly reproduce the details of the photographed scene, and is an important parameter of the camera module. Currently, the resolving power of the camera module is tested by using the camera module to take a photograph of a preset TV Line Chart image, and then analyzing the photograph to determine the resolving power of the camera module. However, for a fisheye wide-angle lens, the distortion is greater than 2%, which causes the position of the image and the position of the actual object to be unsynchronized after the fisheye wide-angle lens takes a photograph of the TV Line Chart image; for example, the actual object is at a position of 0.7F in the field of view, but the corresponding position in the photograph is not at 0.7F. Therefore, the current TV Line Chart image has low precision and cannot accurately test the fisheye wide-angle lens. SUMMARY

[0003] In view of the above problems, the present application provides a test image generation method and device, which improves the precision of the anti-distortion generated target test image and ensures that the target test image can be used to accurately test the resolving power of the camera module.

[0004] In a first aspect, the present application provides the following technical solutions through an embodiment:

[0005] A test image generation method, comprising:

[0006] obtaining line widths corresponding to a plurality of line pairs; wherein the number of line pairs is the number of line pairs that need to be determined at different positions in an original test image; generating an original test image containing sub-line pairs according to each of the line widths; wherein each line pair in the original test image is composed of a plurality of sub-line pairs; and performing anti-distortion on the original test image to obtain a target test image.

[0007] Optionally, the original test image comprises a line pair image part and a frame image part; and the generating of the original test image containing sub-line pairs according to each of the line widths comprises:

[0008] generating line outlines of a plurality of line pairs according to each of the line widths; forming a closed line at a position where each of the line widths is determined in the line outline to generate a line pair image part; the closed line divides the line pair into a plurality of sub-line pairs; and generating the original test image according to the line pair image part and the frame image part.

[0009] Optionally, the original test chart comprises a line pair image part and a frame image part; and the generating the original test chart comprising sub-line pairs according to each line width comprises:

[0010] generating a sub-line pair according to each adjacent two line widths at a position where the line pair needs to be generated, to obtain a plurality of sub-line pairs; connecting each adjacent two sub-line pairs to form a closed line; generating the line pair image part according to the plurality of sub-line pairs; and generating the original test chart according to the line pair image part and the frame image part.

[0011] Optionally, the closed line is along a width direction of the line pair.

[0012] Optionally, before the generating the original test chart according to the line pair image part and the frame image part, the method further comprises:

[0013] generating a test chart frame composed of a plurality of lines to obtain the frame image part.

[0014] Optionally, the obtaining the target test chart by performing inverse distortion on the original test chart comprises:

[0015] performing inverse distortion on the original test chart according to a preset distortion parameter to obtain the target test chart; the distortion parameter represents a distortion degree of a lens to be tested.

[0016] In a second aspect, based on the same inventive concept, an embodiment of the present application provides the following technical scheme:

[0017] A test chart generation device comprises:

[0018] an acquisition module configured to acquire line widths corresponding to a plurality of line pairs; wherein the number of line pairs is the number of line pairs to be determined at different positions in an original test chart; a generation module configured to generate an original test chart comprising sub-line pairs according to each line width; wherein each line pair in the original test chart is composed of a plurality of sub-line pairs; and an inverse distortion module configured to perform inverse distortion on the original test chart to obtain a target test chart.

[0019] Optionally, the original test chart comprises a line pair image part and a frame image part; and the generation module is specifically configured to:

[0020] generate line outlines of a plurality of line pairs according to each line width; form a closed line at each position where the line width is determined on the line pair in the line outline to generate a line pair image part; the closed line divides the line pair into a plurality of sub-line pairs; and generate the original test chart according to the line pair image part and the frame image part.

[0021] In a third aspect, based on the same inventive concept, the present application provides the following technical solutions through an embodiment:

[0022] An electronic device, comprising a processor and a memory coupled to the processor, the memory storing instructions that, when executed by the processor, cause the electronic device to perform the steps of the method of any one of the first aspect.

[0023] In a fourth aspect, based on the same inventive concept, the present application provides the following technical solutions through an embodiment:

[0024] A readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the steps of the method of any one of the first aspect.

[0025] The test pattern generation method and device provided by the embodiment of the present application, by acquiring a plurality of line pair corresponding line widths; then, according to each line width, generating an original test pattern containing a sub-line pair; each line pair in the original test pattern is composed of a plurality of sub-line pairs; finally, the original test pattern is de-warped to obtain a target test pattern. Since the line pair is composed of a plurality of sub-line pairs, it is ensured that the closed line at the end of the sub-line pair can be calculated by point taking in the de-warping process, avoiding the decrease of the accuracy of the target test pattern caused by the change of the line width of the line pair after de-warping, improving the accuracy of the de-warping generated target test pattern, and ensuring that the target test pattern can be used for accurate testing of the resolving power of the camera module.

[0026] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor. In the drawings:

[0028] Figure 1 A flow chart of a test pattern generation method provided by an embodiment of the present application is shown;

[0029] Figure 2 An original test pattern in an embodiment of the present application is shown;

[0030] Figure 3 An A1 area enlarged schematic view of a line pair A of the original test pattern in an embodiment of the present application is shown;

[0031] Figure 4 Fig. 1 shows a schematic diagram of a post-fitting anti-distortion curve in an embodiment of the present application;

[0032] Figure 5 Fig. 2 shows a schematic diagram of an anti-distortion processing principle in an embodiment of the present application;

[0033] Figure 6 Fig. 3 shows a target test chart in an embodiment of the present application;

[0034] Figure 7 Fig. 4 shows a schematic diagram of a test effect of a camera module based on the target test chart in an embodiment of the present application;

[0035] Figure 8 Fig. 5 shows a functional module structure schematic diagram of a test chart generation device in an embodiment of the present application. DETAILED DESCRIPTION

[0036] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0037] The test chart generation method and device provided in the present application can be implemented based on existing drawing software, for example, CAD (Autodesk Computer Aided Design), PS (Photoshop) image making software, etc., without limitation. In the following specific embodiments, implementation based on CAD software will be taken as an example for description. The method and device of the present application can be used to accurately generate a test chart for testing a camera module; for example, to generate a TV Line Chart for a fisheye wide-angle lens. In the process of generating a test chart, higher precision of the test chart can be effectively ensured, and the precision loss in the test chart transformation process can be avoided, so that the resolving power of the fisheye wide-angle lens can be accurately tested. The method and device of the present application will be described and explained in detail through specific embodiments.

[0038] Referring to Fig. 1, a flowchart of a test chart generation method according to an embodiment of the present application is shown; the test chart generation method comprises the following steps: Figure 1

[0039] Step S10: obtaining line widths corresponding to a plurality of line pairs; wherein the number of line pairs is the number of line pairs to be determined at different positions in the original test chart;

[0040] ​Step S20: generating a raw test chart containing sub-line pairs according to each line width; wherein each line pair in the raw test chart is composed of a plurality of sub-line pairs;

[0041] Step S30: performing inverse warping on the raw test chart to obtain a target test chart.

[0042] In this embodiment, through the above steps S10-S30, when generating the raw test chart before inverse warping, a plurality of sub-line pairs are used to constitute a complete line pair, so that a closed line different from the extension direction of the line pair can be formed between the lines of each sub-line pair; in the point taking operation in the inverse warping process, the closed line can be taken for calculation, avoiding the decrease of the accuracy of the target test chart caused by the change of the line width of the line pair after inverse warping, improving the accuracy of the target test chart generated by inverse warping, and ensuring that the target test chart can be used for accurate testing of the resolving power of the camera module. The steps of the method of this embodiment will be described and explained respectively.

[0043] Step S10: obtaining line widths corresponding to a plurality of line pairs; wherein the number of line pairs is the number of line pairs to be determined at different positions in the raw test chart.

[0044] In step S10, the number of line pairs is the number of line pairs at different positions in the test chart or the target test chart. A line pair includes a line and a gap; the number of line pairs can be determined according to different camera modules to be tested, for example, provided by the downstream demander. The way to obtain the line width is as follows:

[0045] First, the length and width of the photosensitive chip are obtained according to the size of the photosensitive chip of the camera module to be tested. Because the size of each pixel on the photosensitive chip is known in production, the length of the photosensitive chip can be obtained based on the number of pixels in the length direction and the length of a single pixel; the width of the photosensitive chip can be obtained based on the number of pixels in the width direction and the width of a single pixel. Then, according to the number of line pairs defined at different positions, the line width of the line pair at the position can be calculated; for the line width at the first position in the width direction, for the line width at the second position in the length direction,

[0046] For example, please refer to Figure 2 , Figure 2 The figure shows the raw test chart before inverse warping, wherein line pair A represents the line pair contained in region A; wherein position 18 represents that the total number of line pairs that can be generated in the length direction corresponding to this position is 1800, position 19 represents that the total number of line pairs that can be generated in the length direction corresponding to this position is 1900, position 20 represents that the total number of line pairs that can be generated in the length direction corresponding to this position is 2000, and position 21 represents that the total number of line pairs that can be generated in the length direction corresponding to this position is 2100, and so on.

[0047] Step S20: generating a raw test chart containing sub-line pairs according to each line width; wherein each line pair in the raw test chart is composed of a plurality of sub-line pairs.

[0048] In step S20, please continue to refer to Figure 2 , draw the line pair image part c1 and the frame image part c2 of the raw test chart respectively, the line pair image part c1 mainly contains the first positioning mark c11 and the line pair (such as the line pair A and the line pair B marked in Figure 2 ).

[0049] The first positioning mark c11 is used for positioning the field of view position, which can be generated by using a conventional method. As for the line pair image part c1, at least two implementation manners are provided in the embodiment:

[0050] The first manner is: first, generate a plurality of line contours of line pairs according to each line width; different positions in a line pair have different line widths. Then, form a closed line a11 at each position of the line width on the line contour of the line pair to generate the line pair image part c1; wherein the closed line a11 divides the line pair into a plurality of sub-line pairs, so that each line in the line pair is composed of a plurality of wedge-shaped sub-line pairs, as shown in Figure 3 , Figure 3 is Figure 2 the enlarged schematic view of A1 of the line pair A in . Finally, generate the raw test chart according to the line pair image part c1 and the frame image part c2.

[0051] Figure 3 The second manner is: first, generate a plurality of sub-line pairs according to each adjacent two line widths at the positions where the line pairs need to be generated; generate all the sub-line pairs in the length direction and the width direction of the raw test chart according to the above manner; form a closed line a11 at the connection of the line contours of each adjacent two sub-line pairs, so that the adjacent two sub-line pairs remain independent, so that each line contour in the line pair is composed of a plurality of wedge-shaped sub-line pairs, as shown in . The position of the closed line a11 is the position of the calculated line width. Generate the line pair image part c1 according to the plurality of sub-line pairs; in actual execution, all the directly connected sub-line pairs among the plurality of sub-line pairs can jointly constitute a line pair of a region, such as the line pair A. Finally, generate the raw test chart according to the line pair image part c1 and the frame image part c2.

[0052] In the two implementation manners above, the line profile after being filled can form a line pair. The generated closed line a11 can close the end of the line pair, and the specific direction is not limited. In this embodiment, the direction of the closed line a11 can be determined as along the width direction of the corresponding line pair. In this way, the width of the line pair can be ensured to be more stable during the inverse distortion processing.

[0053] Regarding the frame image part c2, it includes a second positioning mark c21 and a test chart frame c22, as shown in Figure 2 The second positioning mark c21 is used to position the field of view edge.

[0054] In this embodiment, the test chart frame can be generated as a continuous line segment; or the test chart frame can be generated as a test chart frame composed of multiple line segments, so as to obtain the frame image part c2. In the inverse distortion processing, the inverse distortion processing of the adjacent two line segments of the frame image part c2 composed of multiple line segments does not affect each other, which can effectively improve the accuracy of the inverse distortion processing and ensure the accuracy of the field of view edge after the inverse distortion processing.

[0055] Step S30: performing inverse distortion on the original test chart to obtain a target test chart.

[0056] In step S30, the processing manner can be specifically as follows: performing inverse distortion on the original test chart according to a preset distortion parameter to obtain a target test chart; the distortion parameter represents the distortion degree of the lens to be tested. The distortion parameter is preset, which can be provided by a demander or determined by a generation enterprise based on the specific production needs of the camera module. Taking an example for description, an exemplary distortion parameter of a camera module provided in this embodiment is shown in Table 1 as follows:

[0057] Table 1: Distortion parameter

[0058]

[0059]

[0060] Then, the actual image height and the ideal image height are fitted as an inverse distortion curve, and the relationship curve is derived: in this embodiment, a sextic curve is selected to be fitted and derived, as shown in Figure 4 That is:

[0061] y = 0.0934x 6 - 0.7742x 5 + 2.477x 4 - 3.6377x 3 + 2.4612x 2 + 0.3965x + 0.018

[0062] Finally, the original coordinates on the original test image are input into the anti-distortion curve to output the target coordinates after anti-distortion, such as Figure 5 After completing the transformation of all coordinate points, the target test image can be obtained, as shown in Figure 6 As shown. In the anti-distortion conversion process, all the coordinate points on the closed line a11 are anti-distorted, which can ensure that the line width of the line pair is effectively controlled during the anti-distortion process, and the line width accuracy does not decrease. When the target test chart obtained by the method of this embodiment is used to test the resolution of the wide-angle fisheye camera module, it can be guaranteed that the accurate line pair for testing is obtained after the field of view imaging is distorted, and the line width of the line pair is also accurate. The test effect is as shown in FIG. Figure 7 shown.

[0063] Furthermore, if the closed line a11 is not used to segment and close the line pairs, and the original test image is formed according to the existing technical solution, and then the anti-distortion image is obtained by anti-distortion processing, the line width of the middle line pairs cannot be guaranteed. For example, among the 2000-2600 line pairs (positions 20 to 26), only the line width of the line pairs at positions 20 and 26 can be guaranteed, and the line width of the line pairs at positions 21 and 25 and therebetween cannot be guaranteed; due to the large span of the image, the span of the distortion parameters in the middle is large, and the accuracy cannot be guaranteed.

[0064] In summary, the test pattern generation method provided in this embodiment obtains the line widths corresponding to multiple line pairs; then, based on each line width, generates an original test pattern containing sub-line pairs; each line pair in the original test pattern is composed of multiple sub-line pairs; finally, the original test pattern is dedistorted to obtain a target test pattern. Because the line pairs are composed of multiple sub-line pairs, the closed lines at the ends of the sub-line pairs can be calculated using points during the dedistortion process, avoiding changes in the line pair widths after dedistortion that may cause a decrease in the accuracy of the target test pattern. This improves the accuracy of the target test pattern generated by dedistortion and ensures that the target test pattern can be used to accurately test the resolution of the camera module.

[0065] See also Figure 8 Based on the same inventive concept, another embodiment of the present application further provides a test pattern generating device 300, comprising:

[0066] An acquisition module 301 is used to acquire line widths corresponding to a plurality of line pair numbers;

[0067] A generating module 302 generates an original test pattern including sub-line pairs according to each of the line widths; wherein each line pair in the original test pattern is composed of a plurality of the sub-line pairs;

[0068] The dedistortion module 303 is configured to dedistort the original test image to obtain a target test image.

[0069] As an optional implementation, the original test chart comprises a line pair image part and a frame image part; the generating module 302 is specifically configured to:

[0070] generate a plurality of line contours of line pairs according to each of the line widths; form a closed line in each of the line contours where the position of the line width is determined, and generate a line pair image part; the closed line divides the line pair into a plurality of the sub-line pairs; and generate the original test chart according to the line pair image part and the frame image part.

[0071] As an optional implementation, the original test chart comprises a line pair image part and a frame image part; the generating module 302 is specifically configured to:

[0072] generate a plurality of the sub-line pairs according to each of the line widths at positions where the line pair needs to be generated; form a closed line at a connection between line contours of each of the two connected sub-line pairs; generate the line pair image part according to the plurality of the sub-line pairs; and generate the original test chart according to the line pair image part and the frame image part.

[0073] As an optional implementation, the closed line is along a width direction of the line pair.

[0074] As an optional implementation, the generating module 302 is further configured to, before generating the original test chart according to the line pair image part and the frame image part:

[0075] generate a test chart frame composed of a plurality of line segments, and obtain the frame image part.

[0076] As an optional implementation, the anti-distortion module 303 is specifically configured to:

[0077] perform anti-distortion on the original test chart according to a preset distortion parameter, and obtain a target test chart; the distortion parameter represents a distortion degree of a lens to be tested.

[0078] It should be noted that the test chart generating device 300 provided in the embodiments of the present application has the same specific implementation and technical effects as the foregoing method embodiments, and for brevity of description, the part not mentioned in the device embodiment can be referred to the corresponding content in the foregoing method embodiments.

[0079] Based on the same inventive concept, another embodiment of the present application further provides an electronic device, comprising a processor and a memory coupled to the processor, the memory storing instructions which, when executed by the processor, cause the electronic device to perform the steps of the method of any one of the preceding method embodiments. It should be noted that the electronic device provided by the embodiment of the present application, when the instructions are executed by the processor, the specific implementation of each step and the technical effects generated are the same as those of the preceding method embodiments. For brief description, the part not mentioned in the device embodiment can be referred to the corresponding content in the preceding method embodiments.

[0080] Based on the same inventive concept, another embodiment of the present application further provides a readable storage medium having a computer program stored thereon, characterized in that the program, when executed by a processor, implements the steps of the method of any one of the preceding method embodiments. It should be noted that the readable storage medium provided by the embodiment of the present application, when the program is executed by the processor, the specific implementation of each step and the technical effects generated are the same as those of the preceding method embodiments. For brief description, the part not mentioned in the device embodiment can be referred to the corresponding content in the preceding method embodiments.

[0081] The term "and / or", appearing herein, merely describes association relationships of associated objects, and means that three relationships can exist, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects; the word "comprises" does not exclude the existence of elements or steps not listed in the claims. The word "one" or "an" before an element does not exclude the existence of multiple such elements. The present application can be implemented by means of hardware including a plurality of different elements and by means of a properly programmed computer. In a unit claim in which a plurality of devices are listed, a plurality of these devices can be embodied by means of one and the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words can be interpreted as names.

[0082] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0083] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0084] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0085] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0086] While the preferred embodiments of the application have been described, additional variations and modifications can be made to the embodiments by those of skill in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, the attached claims are intended to embrace all such variations and modifications as fall within the scope of the present application.

[0087] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A test pattern generation method characterized by, The method comprises the following steps: acquiring line widths corresponding to a plurality of line pair numbers; wherein the line pair number is the number of line pairs to be determined at different positions in an original test chart; generating an original test chart containing sub-line pairs according to each line width; wherein each line pair in the original test chart is composed of a plurality of sub-line pairs; performing inverse distortion on the original test chart to obtain a target test chart; the original test chart comprises a line pair image part and a frame image part; the step of generating an original test chart containing sub-line pairs according to each line width comprises: generating line contours of a plurality of line pairs according to each line width; forming a closed line at each position in the line contour where the line width is determined to generate a line pair image part; the closed line divides the line pair into a plurality of sub-line pairs; different positions in a line pair have different line widths; generating the original test chart according to the line pair image part and the frame image part.

2. The method of claim 1, wherein, The closed line is arranged along the width direction of the line pair.

3. The method according to claim 1 or 2, characterized in that, Before the step of generating the original test chart according to the line pair image part and the frame image part, the method further comprises: generating a test chart frame composed of a plurality of line segments to obtain the frame image part.

4. The method of claim 1, wherein, The step of performing inverse distortion on the original test chart to obtain a target test chart comprises: performing inverse distortion on the original test chart according to a preset distortion parameter to obtain a target test chart; the distortion parameter represents the distortion degree of a lens to be tested.

5. A test pattern generation apparatus characterized by comprising: The method comprises the following steps: an acquisition module is configured to acquire line widths corresponding to a plurality of line pair numbers; wherein the line pair number is the number of line pairs to be determined at different positions in an original test chart; a generation module is configured to generate an original test chart containing sub-line pairs according to each line width; wherein each line pair in the original test chart is composed of a plurality of sub-line pairs; the original test chart comprises a line pair image part and a frame image part; the generation module is specifically configured to: generate line contours of a plurality of line pairs according to each line width; form a closed line at each position in the line contour where the line width is determined to generate a line pair image part; the closed line divides the line pair into a plurality of sub-line pairs; different positions in a line pair have different line widths; generate the original test chart according to the line pair image part and the frame image part. an inverse distortion module is configured to perform inverse distortion on the original test chart to obtain a target test chart.

6. An electronic device, comprising: The electronic device comprises a processor and a memory; the memory is coupled to the processor; the memory stores instructions; when the instructions are executed by the processor, the electronic device performs the steps of the method in any one of claims 1-4.

7. A readable storage medium, having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the steps of the method in any one of claims 1-4.

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