A navigation optimization method and system for mobile robots

Abstract

This invention discloses a navigation optimization method and system for mobile robots. Based on the navigation target coordinates set on the mobile robot and the robot's starting coordinates, a global movement path is obtained for the mobile robot to move from the starting coordinates to the navigation target coordinates, along with a corresponding local movement path. If the local movement path matches the global path, it is saved as a temporary local movement path. The last coordinate point on the temporary local movement path is deleted, and the temporary local movement path after the deletion is updated as a new local movement path. The mobile robot moves according to the speed calculated from the new local movement path. By deleting the last coordinate point on the local movement path, the problem of the robot being unable to accurately approach the target point due to obstacles occupying the navigation target coordinates is solved, thus achieving greater flexibility in mobile robot navigation.

Description

Technical Field

[0001] This invention relates to the field of mobile robot navigation application technology, and in particular to a navigation optimization method and navigation optimization system for mobile robots. Background Technology

[0002] Path planning is a type of navigation application for mobile robots, which can provide a collision-free path for a mobile robot from a starting point to an ending point.

[0003] In existing technologies, path planning for mobile robots requires knowledge of the robot's current location and the navigation target point to generate a navigation route. If, during navigation, the target point is obstructed or inaccessible to the robot, the robot will issue an empty navigation route, causing it to stop in place. Alternatively, the robot may follow the issued navigation route but fail to reach the target point due to its occupancy, causing it to stop near the target point or move aimlessly in the vicinity. These issues highlight the shortcomings of mobile robots in terms of intelligence. Summary of the Invention

[0004] The purpose of this invention is to provide a navigation optimization method and system for mobile robots, which enables the mobile robot to navigate and move infinitely close to the target point when the target point is occupied.

[0005] To achieve the above objectives, the technical solutions of the present invention are as follows:

[0006] A navigation optimization method for a mobile robot includes the following steps:

[0007] S1: Obtain the global map of the current environment and the starting coordinates of the mobile robot determined based on the global map of the current environment;

[0008] S2: Set the navigation target coordinates of the mobile robot, and have the mobile robot save them;

[0009] S3: Based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot, obtain the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates, and obtain the corresponding local movement path based on the global movement path;

[0010] S4: Determine if there are any obstacles covering the local movement path; the obstacle is located at the endpoint;

[0011] If so, the current local movement path is saved as a temporary local movement path, the last coordinate point on the temporary local movement path is deleted, and the temporary local movement path after deleting the coordinate point is updated as the new local movement path. The mobile robot moves at the speed calculated according to the new local movement path.

[0012] Furthermore, after saving the current local movement path as a temporary local movement path, deleting the last coordinate point on the temporary local movement path, and updating the temporary local movement path as the new local movement path, the method further includes:

[0013] If there are still obstacles covering the new local movement path, then the new local movement path will be used as a temporary local movement path. The last coordinate point on the current temporary local movement path will be deleted, and the temporary local movement path after the current coordinate point is deleted will be updated as the new local movement path.

[0014] Furthermore, the step of obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates and the corresponding local movement path based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot includes:

[0015] After obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates, the global movement path is smoothed. The smoothing process involves interpolating two adjacent coordinate points in the global movement path to add them as a new coordinate point to the global movement path.

[0016] Furthermore, after determining whether there are obstacles covering the local movement path, step S5 is also included:

[0017] Determine whether the distance between the mobile robot's current position and the navigation target point is less than a preset distance;

[0018] If so, the mobile robot navigation movement ends.

[0019] Furthermore, the mobile robot moves at a speed calculated according to the new local movement path, specifically including:

[0020] The mobile robot samples the direction of movement for a new local movement path and obtains the movement speed corresponding to different directions of movement;

[0021] The mobile robot performs trajectory deduction based on the movement speed corresponding to different running directions to obtain running trajectories corresponding to different running directions, and evaluates and filters them according to a first rule; the first rule is the obstacle avoidance capability of the robot's current position and running trajectory.

[0022] The optimal running trajectory is applied to the mobile robot, and the moving speed corresponding to the optimal running trajectory is taken as the moving speed of the mobile robot.

[0023] As a preferred embodiment of the present invention, a navigation optimization system for a mobile robot is provided, comprising:

[0024] The first acquisition unit is used to acquire the global map of the current environment and the starting coordinates of the mobile robot determined based on the global map of the current environment.

[0025] The first setting unit is used to set the navigation target coordinates of the mobile robot, and the mobile robot saves them.

[0026] The second acquisition unit is used to acquire the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot, and to acquire the corresponding local movement path based on the global movement path.

[0027] The first determination unit is used to determine whether there is an obstacle covering the local movement path; the obstacle is located at the endpoint.

[0028] The first processing unit is used to save the current local movement path as a temporary local movement path if the condition is met, delete the last coordinate point on the temporary local movement path, and update the temporary local movement path after deleting the coordinate point as the new local movement path. The mobile robot moves according to the speed calculated by the new local movement path.

[0029] Furthermore, the navigation optimization system also includes:

[0030] The second processing unit is used to, if there are still obstacles covering the new local movement path, treat the new local movement path as a temporary local movement path, continue to delete the last coordinate point on the current temporary local movement path, and update the temporary local movement path after the current deleted coordinate point as the new local movement path.

[0031] Furthermore, the second acquisition unit includes:

[0032] The first calculation module is used to smooth the global movement path after obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates. The smoothing process is to interpolate two adjacent coordinate points in the global movement path and add them as a new coordinate point in the global movement path.

[0033] As a preferred embodiment of the present invention, a terminal device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0034] As a preferred embodiment of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, implements the steps of the method described above.

[0035] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the navigation optimization method of the present invention;

[0037] Figure 2 This is a flowchart illustrating the navigation optimization method of the present invention;

[0038] Figure 3 This is a schematic block diagram of the navigation optimization system of the present invention;

[0039] Figure 4 This is a schematic block diagram of the navigation optimization system of the present invention;

[0040] Figure 5 This is a schematic block diagram of the navigation optimization system of the present invention;

[0041] Figure 6 This is a schematic block diagram of a terminal device according to the present invention. Detailed Implementation

[0042] To better illustrate the present invention, the invention will now be described in further detail with reference to the accompanying drawings.

[0043] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0044] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0045] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0046] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0047] In existing technologies, path planning for mobile robots requires knowledge of the robot's current location and the navigation target point to generate a navigation route. If, during navigation, the target point is obstructed or inaccessible to the robot, the robot will issue an empty navigation route, causing it to stop in place. Alternatively, the robot may follow the issued navigation route but fail to reach the target point due to its occupancy, causing it to stop near the target point or move aimlessly in the vicinity. These issues highlight the shortcomings of mobile robots in terms of intelligence.

[0048] Therefore, the technical problem that this invention actually solves is how to optimize the navigation target position of a mobile robot.

[0049] This invention is applied in the field of navigation application technology for mobile robots. In this embodiment, the route planning mentioned includes a global movement path and a local movement path. The global movement path determines the route of the mobile robot from the starting point to the destination, while the local movement path determines the obstacle avoidance capability of the mobile robot.

[0050] As an exemplary example in this embodiment, such as Figure 1 As shown, a navigation optimization method for a mobile robot includes the following steps:

[0051] S1: Obtain the global map of the current environment and the starting coordinates of the mobile robot determined based on the global map of the current environment;

[0052] The global map represents the activity area of ​​the mobile robot, marking information such as the origin of coordinates, obstacles, and activity range. The global map is a grid map, a mesh graphic composed of a series of square grids, marking information about the indoor environment. The grid map records the position of the grid with the horizontal (X-coordinate) and vertical (Y-coordinate). In addition, in the grid map, a specific horizontal and vertical coordinate is used as the starting coordinates of the mobile robot, that is, the starting point of the mobile robot's movement.

[0053] S2: Set the navigation target coordinates of the mobile robot, and have the mobile robot save them;

[0054] Based on the coordinate system determined by the global map, the navigation target coordinates are manually input into the mobile robot, and these navigation target coordinates are stored and recorded by the memory integrated in the mobile robot itself.

[0055] Furthermore, once the mobile robot has moved from the starting coordinates to the navigation target coordinates, the recorded navigation target coordinates are removed from the mobile robot's memory to avoid interfering with the mobile robot's next movement and navigation.

[0056] S3: Based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot, obtain the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates, and obtain the corresponding local movement path based on the global movement path;

[0057] When the mobile robot receives a navigation target, it lays out a global movement path based on the starting coordinates and the starting and ending positions indicated by the navigation target coordinates. For example, it uses the Dijkstra algorithm to search for a global movement path. In this embodiment, the global movement path avoids the inaccessible positions between the starting and ending positions to serve as the optimal movement route for the mobile robot.

[0058] Furthermore, after obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates, the global movement path is smoothed. The smoothing process involves interpolating two adjacent coordinate points in the global movement path to add them as a new coordinate point to the global movement path.

[0059] The purpose of smoothing is to make the mobile robot's movement path smooth.

[0060] Furthermore, the smoothing process involves interpolating the coordinates of two adjacent points in the global movement path. This interpolation calculation is as follows:

[0061] Obtain all coordinate points generated on the global movement path. Calculate the average value of the coordinate points on each global movement path and the coordinate points on the next global movement path. Add the coordinate points obtained above to the global movement path. The global movement path with the added coordinate points becomes the actual movement path of the mobile robot.

[0062] In this context, the method for obtaining the added coordinate points is as follows: for example, if the coordinate point M(,) on the global movement path is set, and the coordinate point N(,) on the next global path relative to the current coordinate point is set, then the coordinates of the added coordinate point between point M and point N are ((+) / 2, (+) / 2).

[0063] S4: Determine if there are obstacles covering the local movement path;

[0064] If so, the current local movement path is saved as a temporary local movement path, the last coordinate point on the temporary local movement path is deleted, and the temporary local movement path after deleting the coordinate point is updated as the new local movement path. The mobile robot moves at the speed calculated according to the new local movement path.

[0065] It should be noted in advance that if it is determined that there are no obstacles covering the local movement path, the mobile robot will move at the starting and ending positions indicated by the global movement path, and at the speed calculated by the local movement path.

[0066] In step S4, if the global movement path includes coordinate points (A, B, C, ..., X, Y, Z), that is, the local movement path is the path between coordinate points A and B, the path between B and C, ..., the path between X and Y, and the path between Y and Z, and there is an obstacle covering the local movement path in the global movement path, according to the above-mentioned navigation path of the mobile robot, there is no untravelable position, that is, the obstacle is blocking the mobile robot's progress. It can be understood that the obstacle is located at the end position and covers the end position, making it impossible for the mobile robot to reach the target position. From the above, it can be understood that the obstacle covers several coordinates in the global movement path, or the obstacle covers several local movement paths. The last coordinate point on the temporary local movement path is deleted, that is, the last segment of the temporary local movement path is deleted, and the current temporary local movement path is used as the new local movement path. The mobile robot moves according to the speed calculated by the new local movement path.

[0067] In another scenario, if the newly generated local movement path is still covered by obstacles, then this new local movement path is used as a temporary local movement path. The last coordinate point on the current temporary local movement path is then deleted, and the temporary local movement path after the current coordinate point is deleted is updated as the new local movement path.

[0068] In addition, the mobile robot keeps the global map updated in real time. If an obstacle on the navigation target coordinates is removed, the mobile robot will return to step S2 to continue the execution of the step.

[0069] On the other hand, the mobile robot moves at a speed calculated according to the new local movement path, specifically including:

[0070] The mobile robot samples the direction of movement for a new local movement path and obtains the movement speed corresponding to different directions of movement;

[0071] The mobile robot performs trajectory deduction based on the movement speed corresponding to different running directions to obtain running trajectories corresponding to different running directions, and evaluates and filters them according to the first rule;

[0072] The optimal running trajectory is applied to the mobile robot, and the moving speed corresponding to the optimal running trajectory is taken as the moving speed of the mobile robot.

[0073] Specifically, the mobile robot samples the running direction of the new local movement path to obtain multiple different running directions. Each point in the running direction has a corresponding linear velocity and angular velocity, and their linear velocities and angular velocities are different. Then, the running trajectory corresponding to the running direction is deduced based on the running direction. For example, the running trajectory of the mobile robot in a running direction and the corresponding linear velocity and angular velocity for a time period is simulated as A1. After the end of the time period, the running trajectory in the same running direction is simulated for another time period as A2. The new local movement path is divided into multiple time periods. Combining the above, and setting the number of time periods as N, the running trajectory in a running direction on the new local movement path can be simulated as (A1, A2, ..., AN). Correspondingly, different running directions can simulate different running trajectories. Continuing according to the first rule, in this embodiment, the first rule can be the obstacle avoidance capability of the robot's current position and running trajectory, so the final running trajectory can be selected and applied to the mobile robot. The mobile robot moves at the running speed corresponding to the running trajectory.

[0074] S5, determine whether the distance between the current position of the mobile robot and the navigation target point is less than the preset distance;

[0075] The preset distance is input manually and is adjustable by the operator. It is used to determine when the robot should stop moving after each movement, i.e., when the robot's navigation movement ends.

[0076] In addition, such as Figures 1 to 2As shown, when the mobile robot is moving, if the navigation target coordinates are covered by an obstacle, and the mobile robot moves to the vicinity of the navigation target coordinates, the navigation movement of the mobile robot ends when the distance between the current position of the mobile robot and the navigation target point is less than a preset distance.

[0077] If the distance between the current position of the mobile robot and the navigation target point is greater than the preset distance, then return to step S2 above and execute the steps in sequence.

[0078] The mobile robot moves at a speed calculated according to the new local movement path, specifically including:

[0079] The mobile robot samples the direction of movement for a new local movement path and obtains the movement speed corresponding to different directions of movement;

[0080] Based on the movement speed corresponding to different directions of movement, evaluate them according to the first rule;

[0081] The optimal running direction is applied to the mobile robot, and this optimal running direction is used as the first moving speed.

[0082] As a preferred embodiment of the present invention, a navigation optimization system for a mobile robot is provided, such as... Figure 3 As shown, it includes:

[0083] The first acquisition unit 21 is used to acquire the global map of the current environment and the starting coordinates of the mobile robot determined based on the global map of the current environment.

[0084] The first setting unit 22 is used to set the navigation target coordinates of the mobile robot, and the mobile robot saves them.

[0085] The second acquisition unit 23 is used to acquire the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates and the corresponding local movement path based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot.

[0086] The first judgment unit 24 is used to determine whether there is an obstacle covering the local movement path; the obstacle is located at the end point;

[0087] The first processing unit 241 is configured to, if so, save the current local movement path as a temporary local movement path, delete the last coordinate point on the temporary local movement path, and update the temporary local movement path after deleting the coordinate point as a new local movement path, and the mobile robot moves according to the speed calculated by the new local movement path.

[0088] Furthermore, the navigation optimization system also includes:

[0089] The second processing unit 242 is used to, if there are still obstacles covering the new local movement path, take the new local movement path as a temporary local movement path, continue to delete the last coordinate point on the current temporary local movement path, and update the temporary local movement path after the current deleted coordinate point as the new local movement path.

[0090] Furthermore, such as Figure 4 As shown, the second acquisition unit 24 includes:

[0091] The first calculation module 240 is used to smooth the global movement path after obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates. The smoothing process is to interpolate two adjacent coordinate points in the global movement path and add them as a new coordinate point in the global movement path.

[0092] Furthermore, the navigation optimization system also includes:

[0093] The second judgment unit 25 is used to determine whether the distance between the current position of the mobile robot and the navigation target point is less than a preset distance;

[0094] The third processing unit 26 is used to terminate the navigation movement of the mobile robot if the condition is met.

[0095] As a preferred embodiment of the present invention, a terminal device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0096] As a preferred embodiment of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method described above.

[0097] The terminal device 120 may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor 1200 and a memory 1201. Those skilled in the art will understand that... Figure 5 This is merely an example of terminal device 120 and does not constitute a limitation on the terminal device. It may include more or fewer components than shown, or combine certain components, or different components. For example, the terminal device may also include input / output devices, network access devices, buses, etc.

[0098] The processor referred to can be a Central Processing Unit (CPU), or 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. A general-purpose processor can be a microprocessor or any conventional processor.

[0099] The memory 1201 can be an internal storage unit of the terminal device 120, such as a hard disk or memory of the terminal device 120. The memory 1201 can also be an external storage device of the terminal device 120, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on the terminal device 120.

[0100] Furthermore, the memory 1201 may include both internal storage units of the terminal device 120 and external storage devices. The memory 1201 is used to store the computer program and other programs and data required by the terminal device.

[0101] The memory 1201 can also be used to temporarily store data that has been output or will be output.

[0102] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A navigation optimization method for a mobile robot, characterized in that, Includes the following steps: S1: Obtain the global map of the current environment and the starting coordinates of the mobile robot determined based on the global map of the current environment; S2: Set the navigation target coordinates of the mobile robot, and have the mobile robot save them; S3: Based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot, obtain the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates, and obtain the corresponding local movement path based on the global movement path; S4: Determine if there are any obstacles covering the local movement path; the obstacles are located at the endpoint. If so, the current local movement path is saved as a temporary local movement path, the last coordinate point on the temporary local movement path is deleted, and the temporary local movement path after deleting the coordinate point is updated as the new local movement path. The mobile robot moves according to the speed calculated by the new local movement path. If there are still obstacles covering the new local movement path, then the new local movement path will be used as a temporary local movement path. The last coordinate point on the current temporary local movement path will be deleted, and the temporary local movement path after the current deleted coordinate point will be updated as the new local movement path. After determining whether there are obstacles covering the local movement path, step S5 is also included: Determine whether the distance between the current position of the mobile robot and the navigation target point is less than a preset distance; If so, the mobile robot's navigation movement ends; If the distance between the current position of the mobile robot and the navigation target point is greater than the preset distance, then return to step S2 above and execute the steps in sequence.

2. The navigation optimization method for a mobile robot according to claim 1, characterized in that, The step of obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates and the corresponding local movement path based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot includes: After obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates, the global movement path is smoothed. The smoothing process involves interpolating two adjacent coordinate points in the global movement path to add them as a new coordinate point to the global movement path.

3. The navigation optimization method for a mobile robot according to claim 1, characterized in that, The mobile robot moves at a speed calculated according to the new local movement path, specifically including: The mobile robot samples the direction of movement for a new local movement path and obtains the movement speed corresponding to different directions of movement; The mobile robot performs trajectory deduction based on the movement speed corresponding to different running directions to obtain running trajectories corresponding to different running directions, and evaluates and filters them according to a first rule; the first rule is the obstacle avoidance capability of the robot's current position and running trajectory. The optimal running trajectory is applied to the mobile robot, and the moving speed corresponding to the optimal running trajectory is taken as the moving speed of the mobile robot.

4. A navigation optimization system for a mobile robot, characterized in that, The system is used to implement the navigation optimization method for a mobile robot as described in any one of claims 1-3, and the system includes: The first acquisition unit is used to acquire the global map of the current environment and the starting coordinates of the mobile robot determined based on the global map of the current environment. The first setting unit is used to set the navigation target coordinates of the mobile robot, and the mobile robot saves them. The second acquisition unit is used to acquire the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates based on the navigation target coordinates set on the mobile robot and the starting coordinates of the mobile robot, and to acquire the corresponding local movement path based on the global movement path. The first determination unit is used to determine whether there is an obstacle covering the local movement path; the obstacle is located at the endpoint. The first processing unit is used to, if so, save the current local movement path as a temporary local movement path, delete the last coordinate point on the temporary local movement path, and update the temporary local movement path after deleting the coordinate point as a new local movement path. The mobile robot moves according to the speed calculated by the new local movement path. The second processing unit is used to, if there are still obstacles covering the new local movement path, take the new local movement path as a temporary local movement path, continue to delete the last coordinate point on the current temporary local movement path, and update the temporary local movement path after the current deleted coordinate point as the new local movement path. The second judgment unit is used to determine whether the distance between the current position of the mobile robot and the navigation target point is less than a preset distance; The third processing unit is used to indicate if the mobile robot's navigation movement has ended.

5. The navigation optimization system for a mobile robot according to claim 4, characterized in that, The second acquisition unit includes: The first calculation module is used to smooth the global movement path after obtaining the global movement path of the mobile robot from the starting coordinates to the navigation target coordinates. The smoothing process is to interpolate two adjacent coordinate points in the global movement path and add them as a new coordinate point in the global movement path.

6. A terminal device, comprising 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, it implements the steps of the method as described in any one of claims 1 to 3.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 3.

Images