Method and device for cooperative surveying based on unmanned aerial vehicle group

Abstract

The application discloses a method based on cooperative surveying and mapping of a UAV group, which is divided into two parts of offline planning and online planning. Before taking off, a task is pre-assigned, and after taking off, the online planning function is triggered according to a sudden situation for dynamic adjustment. In the case of cooperative surveying and mapping of the UAV group, the application provides an efficient dynamic planning method, and in the case of no ground center node coordination, the UAV group can efficiently complete the surveying and mapping task in a harsh environment through mutual communication.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of surveying and mapping path planning. In the case of unmanned aerial vehicle group marshalling for cooperative surveying and mapping, a kind of efficient dynamic planning method is provided, especially a method, device, storage medium and computer program product based on unmanned aerial vehicle group cooperative surveying and mapping. BACKGROUND

[0002] Compared with traditional terrain mapping and image aerial photography methods, unmanned aerial vehicle surveying and mapping can save huge time and cost. Data collection work that may have taken days or weeks can be completed in a few hours, and modeling analysis can be quickly completed. Unmanned aerial vehicle surveying and mapping specialization brings great value to companies in various industries.

[0003] Currently, unmanned aerial vehicles are usually manually controlled by operators on site or use software to plan flights to complete single or multiple flights. Such operation mode has large workload and high operation difficulty when large-scale surveying and mapping is performed. Software planning also generally requires unified scheduling by a ground command center. In many outdoor spaces, such conditions are not available, such as limited channels or poor communication channels with serious interference. Moreover, due to the uncertainty of natural conditions in the wild, high-altitude air flow is unstable, and local air flow is abnormal, so there is a certain failure rate of unmanned aerial vehicles during flight. Therefore, multiple unmanned aerial vehicles need to be coordinated to complete a surveying and mapping task

[0004] In many special cases, there is no mature solution in the industry, and the following methods are generally used:

[0005] 1. Multiple unmanned aerial vehicles form a cluster to cooperatively complete a surveying and mapping task in a fixed area. The boundary of the area is clear, and there is general geographic information. However, due to outdated or various other reasons, the original data only contains general geographic information, such as the approximate positions of mountains, rivers, and lakes. However, the conditions of ground objects, vegetation, roads, and temporary buildings are unknown.

[0006] 2. The communication between the ground command station and the unmanned aerial vehicle is poor or severely interfered. After the unmanned aerial vehicle takes off, the ground command station cannot continue to communicate and command the unmanned aerial vehicle.

[0007] 3. The weather condition is uncertain, resulting in a high failure rate of unmanned aerial vehicles. For example, after a group of four unmanned aerial vehicles completes a surveying and mapping task, only two may be able to return, and the most complete surveying and mapping information needs to be obtained.

[0008] The existing solution generally uses the method of unified coordination and scheduling of unmanned aerial vehicles by the ground station or manual control by the operator within the visible range. In the case where the ground and airborne communication channels cannot be effectively guaranteed at all times, this method cannot effectively control and coordinate the unmanned aerial vehicles

[0009] The existing scheme generally does not consider error tolerance, that is, if the unmanned aerial vehicle fails during the surveying and mapping, the entire surveying and mapping task fails, and needs to be re-performed, so that the timeliness of the surveying and mapping task cannot be guaranteed, and if the poor surveying and mapping environment cannot be improved, the surveying and mapping task cannot be completed

[0010] The existing scheduling method is generally lack of flexibility, and is a static scheduling method, and cannot dynamically plan according to actual conditions, so that efficiency and accuracy are balanced reasonably under actual conditions. SUMMARY

[0011] In view of the defects in the prior art, the application provides a method for cooperative surveying and mapping based on a group of unmanned aerial vehicles, which can solve the problems that the current general scheme cannot solve, and can enable the group of unmanned aerial vehicles to efficiently and cooperatively complete the surveying and mapping task under pre-formation, and has high tolerance to faults. In the case that part of the unmanned aerial vehicles fail during the task and cannot continue to fly or communicate, the normal surveying and mapping is still ensured.

[0012] In order to achieve the above effect, the method for cooperative surveying and mapping based on a group of unmanned aerial vehicles provided by the application comprises:

[0013] Step 1, grouping the unmanned aerial vehicles by offline loading, each group being an independent system, to realize a networking system of the unmanned aerial vehicles;

[0014] Step 2, setting information including unmanned aerial vehicle grouping information, surveying and mapping task information, and surveying and mapping area geographic information;

[0015] Step 3, using a hierarchical structure to unitize the networking system, setting corresponding numbers for each independent system, confirming a master unit planning system, and other systems being sub-systems;

[0016] Step 4, setting an operation mode, the master unit planning system performing offline planning to obtain a cooperative task, formulating a specific behavior motion planning through a planning module, and distributing to each sub-system, the master unit planning system obtaining environmental information from the outside world and state information from each sub-system;

[0017] Step 5, each sub-system and the master unit planning system maintain a heartbeat link, when the master unit planning system stops working, each sub-system maintains the previous planning, and each motion behavior is tested in sequence according to the number from small to large, and accepts the test link from other sub-systems.

[0018] Preferably, the number is not elected, and the smallest or largest number is preferably set as the master unit, and the number of each unit is preset.

[0019] Preferably, the above-mentioned master control unit planning system includes a master control unit, a master control unit planning module, and a master control unit knowledge domain.

[0020] Preferably, the above subsystem includes an execution unit, an execution unit planning module, and an execution unit knowledge domain.

[0021] Preferably, the knowledge domain of the aforementioned master control unit is mainly a collaboration domain used to describe the collaboration rules of each subsystem.

[0022] Preferably, the above method further includes:

[0023] For a subsystem, if none of the subsystems with numbers smaller than its own cannot be linked, then the subsystem itself is upgraded to a master control unit planning system. If there are subsystems with numbers smaller than its own that respond and link, then the subsystem with the smallest number is configured as the new master control unit planning system.

[0024] Preferably, the target area of ​​the above grouping is divided into N parts, and each drone is responsible for completing the N+M adjacent parts, where M is a preset value.

[0025] An apparatus for implementing the above-described method of collaborative mapping based on UAV swarms includes:

[0026] The grouping preset module is used to pre-set the drones by loading them offline, so that each group is an independent system and the drone networking system is realized.

[0027] The task setting module includes setting information such as UAV formation information, surveying and mapping task information, and geographic information of the surveying and mapping area.

[0028] The modular programming module adopts a hierarchical structure to modularize the network system, assigns corresponding numbers to each independent system, confirms the main control unit planning system, and other systems are subsystems;

[0029] The operation mode setting module is used to set the operation mode. The main control unit planning system performs offline planning, obtains collaborative tasks, formulates specific behavioral motion plans through the planning module, and distributes them to each subsystem. The main control unit planning system obtains environmental information from the outside world and status information from each subsystem.

[0030] The system link module is used to maintain a heartbeat link between each subsystem and the main control unit planning system. When the main control unit planning system stops working, each subsystem first maintains its previous plan and performs its own operation behavior, and performs test links in order of number from smallest to largest, and accepts test links from other subsystems.

[0031] The system replanning module is used to determine if any subsystems with numbers smaller than its own cannot be linked. If so, the system is upgraded to a master control unit planning system. If any subsystems with numbers smaller than its own respond and link, the subsystem with the smallest number is configured as the new master control unit planning system.

[0032] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the above-described method.

[0033] A computer program product includes a computer program / instructions that, when executed by a processor, implement the steps of the above-described method.

[0034] This invention provides an efficient dynamic planning method for collaborative mapping in the context of UAV swarms. Without the need for coordination from a ground-based central node, the UAV swarms can communicate with each other to efficiently complete mapping tasks in harsh environments. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of an embodiment of the present invention based on UAV swarm collaborative mapping is shown;

[0037] Figure 2 A schematic diagram of another embodiment of the present invention based on UAV swarm collaborative mapping is shown;

[0038] Figure 3 A schematic diagram of the planning system architecture of the main control unit of the device based on UAV swarm collaborative mapping of the present invention is shown. Detailed Implementation

[0039] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0041] like Figure 1 As shown, this invention provides an embodiment of a method for collaborative mapping based on unmanned aerial vehicle (UAV) swarms, comprising:

[0042] S1. By pre-setting the drones through offline loading, each drone is grouped into an independent system, thus realizing the drone networking system;

[0043] S2. The settings include UAV formation information, surveying and mapping task information, and geographic information of the surveying and mapping area.

[0044] S3. The network system is modularized using a hierarchical structure. Each independent system is assigned a corresponding number. The main control unit is confirmed as the planning system, and other systems are subsystems.

[0045] S4. Set the work mode. The main control unit planning system performs offline planning, obtains collaborative tasks, formulates specific behavioral motion plans through the planning module, and distributes them to each subsystem. The main control unit planning system obtains environmental information from the outside world and status information from each subsystem.

[0046] S5. Each subsystem and the main control unit planning system maintain a heartbeat link. When the main control unit planning system stops working, each subsystem first maintains its previous plan and performs its own movement behavior, and performs test links in order of number from smallest to largest, and accepts test links from other subsystems.

[0047] In some embodiments, the numbering is not generated by election, and it is generally preferred that the smallest or largest number is set as the main control unit, and the number of each unit is preset.

[0048] In some embodiments, the master control unit planning system includes a master control unit, a master control unit planning module, and a master control unit knowledge domain.

[0049] In some embodiments, the subsystem includes an execution unit, an execution unit planning module, and an execution unit knowledge domain.

[0050] In some embodiments, the knowledge domain of the master control unit is mainly a collaboration domain used to describe the collaboration rules of each subsystem.

[0051] like Figure 2 As shown, this invention provides an embodiment of a method for collaborative mapping based on unmanned aerial vehicle (UAV) swarms, comprising:

[0052] S1. By pre-setting the drones through offline loading, each drone is grouped into an independent system, thus realizing the drone networking system;

[0053] S2. The settings include UAV formation information, surveying and mapping task information, and geographic information of the surveying and mapping area.

[0054] S3. The network system is modularized using a hierarchical structure. Each independent system is assigned a corresponding number. The main control unit is confirmed as the planning system, and other systems are subsystems.

[0055] S4. Set the work mode. The main control unit planning system performs offline planning, obtains collaborative tasks, formulates specific behavioral motion plans through the planning module, and distributes them to each subsystem. The main control unit planning system obtains environmental information from the outside world and status information from each subsystem.

[0056] S5. Each subsystem and the main control unit planning system maintain a heartbeat link. When the main control unit planning system stops working, each subsystem first maintains its previous plan and performs its own movement behavior. The subsystem performs test links in order of increasing number and accepts test links from other subsystems.

[0057] S6. For a subsystem, if none of the subsystems with numbers smaller than its own can be linked, then the subsystem itself is upgraded to a master control unit planning system. If there are subsystems with numbers smaller than its own that respond and link, then the subsystem with the smallest number is configured as the new master control unit planning system.

[0058] In some embodiments, the target area of ​​the group is divided into N parts, and each drone is responsible for completing the N+M adjacent parts, where M is a preset value.

[0059] The present invention also provides an apparatus for collaborative mapping based on a swarm of unmanned aerial vehicles (UAVs), comprising:

[0060] The grouping preset module is used to pre-set the drones by loading them offline, so that each group is an independent system and the drone networking system is realized.

[0061] The task setting module includes setting information such as UAV formation information, surveying and mapping task information, and geographic information of the surveying and mapping area.

[0062] The modular programming module adopts a hierarchical structure to modularize the network system, assigns corresponding numbers to each independent system, confirms the main control unit planning system, and other systems are subsystems;

[0063] The operation mode setting module is used to set the operation mode. The main control unit planning system performs offline planning, obtains collaborative tasks, formulates specific behavioral motion plans through the planning module, and distributes them to each subsystem. The main control unit planning system obtains environmental information from the outside world and status information from each subsystem.

[0064] The system link module is used to maintain a heartbeat link between each subsystem and the main control unit planning system. When the main control unit planning system stops working, each subsystem first maintains its previous plan and performs its own operation behavior, and performs test links in order of number from smallest to largest, and accepts test links from other subsystems.

[0065] The system replanning module is used to determine if any subsystems with numbers smaller than its own cannot be linked. If so, the system is upgraded to a master control unit planning system. If any subsystems with numbers smaller than its own respond and link, the subsystem with the smallest number is configured as the new master control unit planning system.

[0066] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0067] The present invention also provides a computer program product, including a computer program / instructions, characterized in that the computer program / instructions, when executed by a processor, implement the steps of the above-described method.

[0068] like Figure 3 As shown, this invention provides an embodiment of a master control unit planning system for a device based on UAV swarm collaborative mapping. The system includes multiple aircraft units, each comprising a flight controller, a path controller, a path planner, a master control unit control system, a sensing system, and a preset task knowledge base. The master control unit control system is connected to the path planner, the intra-group synchronization system, the sensing system, and the preset task knowledge base. The path planner is connected to the flight controller via the path controller. Different aircraft units are connected through their respective intra-group synchronization systems.

[0069] This invention also provides an embodiment of a method for collaborative mapping based on UAV swarms. Through offline loading and task pre-setting, the grouping of each UAV needs to be pre-defined before takeoff. For example, group A contains N UAVs, numbered 1-N, and its task is to map area S. The area boundary and original geographic information of S are saved on each UAV. In this way, each UAV knows its group's task, the total number of UAVs in the group, and the communication address of each UAV.

[0070] In some embodiments, the groups are organized as follows: groups are independent, and each group is considered an independent system. A hierarchical structure is adopted to ensure that the entire system is suitable for unified leadership while meeting the needs of flexibility and speed. The unit with the smallest number is the master control unit, and the number of each unit is preset and does not require election. Two working modes are established according to the hierarchical structure: the master control unit is responsible for the pre-planning offline. It first obtains the collaborative task, obtains the specific behavior and movement plan through the planner, and distributes it to the execution units of each subsystem. The relevant knowledge domain is mainly the negotiation domain used to describe the negotiation rules of each subsystem. The master control unit obtains environmental information from the outside world and status information from each subsystem. It also maintains a heartbeat link with the master control unit. When the master control unit stops working, each subsystem first maintains its previous plan, performs its own movement behavior, and tests the link from the group list in ascending order of number, and accepts test links from other units. If no system with a smaller number can link, then it is promoted to master control unit. If a system with a smaller number responds to the link, then the one with the smallest number is considered the new master control unit.

[0071] In some embodiments, when the heartbeat connection of the master control unit is normal, the subsystem does not connect to other systems, thus saving communication link resources.

[0072] In some embodiments, the target area of ​​a group is divided into N parts, and each drone is responsible for completing the N+M adjacent parts, where M is a preset value. The larger M is, the more areas are covered by each other, and the better the fault tolerance rate is in the event of a drone failure, but the timeliness of the task will be reduced.

[0073] Compared with existing technologies, this invention provides an efficient dynamic planning method for collaborative mapping in the case of UAV swarms. Without the need for coordination from a ground-based central node, the UAV swarms can communicate with each other to efficiently complete mapping tasks in harsh environments.

[0074] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0075] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0076] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0077] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0078] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0080] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0081] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0082] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0083] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0085] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for collaborative mapping based on UAV swarms, characterized in that... The method includes: Step 1: Pre-configure the drones by offline loading, grouping each group into an independent system to realize the drone networking system; the target area of ​​the group is divided into N parts, and each drone is responsible for completing the N+M adjacent parts, where M is a preset value; Step 2: Set information including UAV formation information, surveying task information, and geographic information of the surveying area; Step 3: The network system is modularized using a hierarchical structure. Each independent system is assigned a corresponding number, and the main control unit is confirmed as the planning system, while other systems are subsystems. The numbering is not generated by election, and the smallest or largest number is generally preferred as the main control unit. The numbering of each unit is preset. Step 4: Set the work mode. The main control unit planning system performs offline planning, obtains collaborative tasks, formulates specific behavioral motion plans through the planning module, and distributes them to each subsystem. The main control unit planning system obtains environmental information from the outside world and status information from each subsystem. Step 5: Each subsystem and the main control unit planning system maintain a heartbeat link. When the main control unit planning system stops working, each subsystem first maintains its previous plan and performs its own movement behavior, and conducts test links in order of number from smallest to largest, and accepts test links from other subsystems. Step Six: For subsystems, if none of the subsystems with numbers smaller than their own can connect, then the subsystem upgrades to the main control unit planning system. If a subsystem with a smaller number responds to the connection, then the subsystem with the smallest number is configured as the new main control unit planning system. The system linking module is used to maintain a heartbeat link between each subsystem and the main control unit planning system. When the main control unit planning system stops working, each subsystem maintains its previous plan and continues its own behavior, testing the connection in ascending order of its number, and accepting test connections from other subsystems. The system replanning module is used to determine if any subsystem with a smaller number than its own can connect, then the subsystem upgrades to the main control unit planning system. If a subsystem with a smaller number responds to the connection, then the subsystem with the smallest number is configured as the new main control unit planning system.

2. The method for collaborative mapping based on UAV swarms according to claim 1, characterized in that, The master control unit planning system includes a master control unit, a master control unit planning module, and a master control unit knowledge domain.

3. The method for collaborative mapping based on UAV swarms according to claim 2, characterized in that, The subsystem includes an execution unit, an execution unit planning module, and an execution unit knowledge domain.

4. The method for collaborative mapping based on UAV swarms according to claim 3, characterized in that, The knowledge domain of the main control unit is primarily a collaboration domain used to describe the collaboration rules of each subsystem.

5. An apparatus for implementing the method of collaborative mapping based on UAV swarms as described in claims 1-4, comprising: The grouping preset module is used to pre-set the drones by loading them offline, so that each group is an independent system and the drone networking system is realized. The target area of ​​the group is divided into N parts, and each drone is responsible for completing the N+M adjacent parts, where M is a preset value; The task setting module includes setting information such as UAV formation information, surveying and mapping task information, and geographic information of the surveying and mapping area. The modular programming module adopts a hierarchical structure to modularize the network system. Each independent system is assigned a corresponding number, and the main control unit is identified as the planning system, while other systems are subsystems. The numbering is not generated by election, and the system with the smallest or largest number is selected as the main control unit. The numbering of each unit is preset. The operation mode setting module is used to set the operation mode. The main control unit planning system performs offline planning, obtains collaborative tasks, formulates specific behavioral motion plans through the planning module, and distributes them to each subsystem. The main control unit planning system obtains environmental information from the outside world and status information from each subsystem. The system link module is used to maintain a heartbeat link between each subsystem and the main control unit planning system. When the main control unit planning system stops working, each subsystem first maintains its previous plan and performs its own operation behavior, and performs test links in order of number from smallest to largest, and accepts test links from other subsystems. The system replanning module is used to determine if any subsystems with numbers smaller than its own cannot be linked. If so, the system is upgraded to a master control unit planning system. If any subsystems with numbers smaller than its own respond and link, the subsystem with the smallest number is configured as the new master control unit planning system.

6. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method according to any one of claims 1-4.

7. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1-4.

Images