Estimation device

Abstract

An estimation device (10) comprises a control unit (11) that: acquires target pipeline information indicating the degree of corrosion on the inside of a target pipeline and the quantity of water accumulated therein; applies the degree of corrosion on the inside of the target pipeline and the quantity of the water accumulated therein, which are indicated by the target pipeline information, to a function in which the degree of corrosion on the inside of an embedded pipeline and the quantity of water accumulated therein are associated with the degree of corrosion on the outside of the embedded pipeline; and thereby estimates the degree of corrosion on the outside of the target pipeline.

Description

estimation device

[0001] The present disclosure relates to an estimation device.

[0002] Many underground conduits, such as those used to protect communication cables, are made of steel. As corrosion of the steel progresses, holes will form in the conduit, so periodic inspections of the exterior of the conduit for corrosion are required. For example, Non-Patent Document 1 discloses inspection methods such as visual inspection or non-destructive inspection of the exterior surface of the conduit. For example, Non-Patent Document 2 discloses another inspection method, which involves measuring soil parameters such as resistivity to evaluate the corrosivity of the soil surrounding a buried conduit.

[0003] Kanagawa Prefecture, Industrial Safety Division, Safety and Disaster Prevention Bureau, "Technical Materials for Inspection of External Corrosion of High-Pressure Gas Pipes," pp. 1-32, March 2007. JFE Techno Research Corporation, "Corrosion Survey of Buried Objects and Corrosive Evaluation of Surrounding Soil," [online], [Retrieved April 4, 2024], Internet<URL:https: / / www.jfe-tec.co.jp / download / pdf / 3E3J-009-00.pdf>

[0004] Conventional techniques are inefficient because they require excavation of the ground to inspect the outside of the pipeline for corrosion.

[0005] In view of the above circumstances, an object of the present disclosure is to enable efficient estimation of corrosion on the outside of a pipeline buried underground.

[0006] An estimation device according to one embodiment includes a control unit that acquires target pipeline information indicating the degree of corrosion and amount of accumulated water inside the target pipeline, and applies the degree of corrosion and amount of accumulated water inside the target pipeline indicated in the acquired target pipeline information to a function that correlates the degree of corrosion and amount of accumulated water inside the buried pipeline with the degree of corrosion outside the buried pipeline, thereby estimating the degree of corrosion outside the target pipeline.

[0007] According to the present disclosure, it is possible to efficiently estimate the corrosion on the outside of underground pipelines.

[0008] Fig. 1 is a block diagram showing the configuration of an estimation system. Fig. 2 is a flowchart showing an example of the operation of the estimation system. Fig. 3 is a diagram showing an example of a database of buried pipelines. Fig. 4 is a diagram for explaining a function read out by the estimation device. Fig. 4 is a flowchart showing an example of the operation of the estimation system according to a modified example. Fig. 5 is a diagram for explaining weights set for each anticorrosion construction according to a modified example. Fig. 6 is a diagram for explaining a weighted function generated by the estimation device according to a modified example.

[0009] An embodiment will be described below with reference to the drawings.

[0010] In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0011] The configuration of an estimation system 1 according to this embodiment will be described with reference to FIG.

[0012] The estimation system 1 includes an estimation device 10 and a measurement device 20 .

[0013] The estimation device 10 is a general-purpose computer such as a PC, a server computer such as a cloud server, or a dedicated computer. "PC" is an abbreviation for personal computer. The estimation device 10 may also be a mobile device such as a mobile phone, a smartphone, or a tablet.

[0014] The measuring device 20 is a device that measures the degree of corrosion inside the target pipeline P. In this embodiment, the measuring device 20 is a pipe camera that photographs the inside of the target pipeline P. The measuring device 20 is capable of transmitting the photographed images to the estimation device 10 via the network 30. The measuring device 20 is inserted into the target pipeline P from inside a manhole to which the target pipeline P is connected by, for example, a worker performing maintenance and inspection work on the target pipeline P, and photographs the inner surface of the target pipeline P.

[0015] The estimation device 10 and the measurement device 20 can communicate with each other via a network 30, either wired or wirelessly. The network 30 may include, for example, the Internet, at least one WAN, at least one MAN, or any combination thereof. "WAN" is an abbreviation for wide area network. "MAN" is an abbreviation for metropolitan area network. The network 30 may include at least one wireless network, at least one optical network, or any combination thereof. The wireless network may be, for example, an ad hoc network, a cellular network, a wireless LAN, a satellite communication network, or a terrestrial microwave network. "LAN" is an abbreviation for local area network.

[0016] An overview of this embodiment will be described with reference to Figure 1. An estimation device 10 acquires target pipeline information indicating the degree of corrosion and the amount of accumulated water inside a target pipeline P. The estimation device 10 estimates the degree of corrosion on the outside of the target pipeline P by applying the degree of corrosion and the amount of accumulated water inside the target pipeline P indicated in the acquired target pipeline information to a function that associates the degree of corrosion and the amount of accumulated water inside the buried pipeline with the degree of corrosion on the outside of the buried pipeline.

[0017] Buried pipelines include pipelines used to protect power cables or communication cables. The target pipeline P is a buried pipeline for which the degree of external corrosion is to be estimated. Accumulated water may exist inside the target pipeline P due to misalignment or cracks in the target pipeline P, loose joints in the target pipeline P, or the intrusion of groundwater such as rainwater through a manhole connected to the target pipeline P. The estimation device 10 acquires information indicating the degree of corrosion based on an image of the inside of the target pipeline P captured by the measurement device 20. The function is generated based on the correlation between the amount of accumulated water and the degree of corrosion inside the buried pipeline measured in past inspection work and the degree of corrosion outside the buried pipeline. As described below, the estimation device 10 estimates the degree of external corrosion of the target pipeline P by applying the amount of accumulated water inside the target pipeline P and the degree of corrosion inside the target pipeline P to the function. As described above, according to this embodiment, it is possible to easily estimate not only the degree of corrosion on the inside of the target pipeline P, but also the degree of corrosion on the outside of the target pipeline P, which is difficult to inspect. Furthermore, according to this embodiment, the degree of corrosion can be estimated without the need to excavate the ground, etc., which makes it possible to improve the efficiency of maintenance and management of the target pipeline P. Therefore, it is possible to simply and efficiently estimate the corrosion on the outside of a pipeline buried underground.

[0018] The configuration of an estimation device 10 according to this embodiment will be described with reference to Fig. 1. The estimation device 10 includes a control unit 11, a storage unit 12, a communication unit 13, and an input / output unit 14.

[0019] The control unit 11 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination thereof. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for specific processing. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. An example of the programmable circuit is an FPGA. "FPGA" is an abbreviation for field-programmable gate array. An example of the dedicated circuit is an ASIC. "ASIC" is an abbreviation for application specific integrated circuit. The control unit 11 executes processing related to the operation of the estimation device 10 while controlling each part of the estimation device 10.

[0020] The storage unit 12 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, a RAM, a ROM, or a flash memory. "RAM" is an abbreviation for random access memory. "ROM" is an abbreviation for read only memory. RAM is, for example, an SRAM or a DRAM. "SRAM" is an abbreviation for static random access memory. "DRAM" is an abbreviation for dynamic random access memory. ROM is, for example, an EEPROM. "EEPROM" is an abbreviation for electrically erasable programmable read only memory. Flash memory is, for example, an SSD. "SSD" is an abbreviation for solid-state drive. Magnetic memory is, for example, an HDD. "HDD" is an abbreviation for hard disk drive. The storage unit 12 functions, for example, as a main storage device, an auxiliary storage device, or a cache memory. The storage unit 12 stores information used in the operation of the estimation device 10 and information obtained by the operation of the estimation device 10 .

[0021] The communication unit 13 includes at least one communication module. The communication module is, for example, a module compatible with a wired LAN communication standard such as Ethernet (registered trademark), a wireless LAN communication standard such as IEEE 802.11, or a mobile communication standard such as LTE, 4G standard, or 5G standard. "IEEE" is an abbreviation for Institute of Electrical and Electronics Engineers. "LTE" is an abbreviation for Long Term Evolution. "4G" is an abbreviation for 4th generation. "5G" is an abbreviation for 5th generation. The communication unit 13 receives information used in the operation of the estimation device 10 and transmits information obtained by the operation of the estimation device 10.

[0022] The input / output unit 14 includes at least one input / output device. The input / output device includes a touch screen integrated with a display. The input / output unit 14 accepts an operation to input information used in the operation of the estimation device 10 and outputs information obtained by the operation of the estimation device 10. The input / output unit 14 may be connected to the estimation device 10 as an external input / output device instead of being provided in the estimation device 10. Any connection method, such as a Universal Serial Bus (USB), can be used. The input / output unit 14 may not be integrated, but may be composed of separate input and output units. In this case, the input unit includes at least one input device, such as a physical key or a microphone. The output unit includes at least one output device, such as a display or a speaker.

[0023] The functions of the estimation device 10 are realized by executing a program according to this embodiment on a processor serving as the control unit 11. That is, the functions of the estimation device 10 are realized by software. The program causes a computer to execute the operations of the estimation device 10, thereby causing the computer to function as the estimation device 10. That is, the computer functions as the estimation device 10 by executing the operations of the estimation device 10 in accordance with the program.

[0024] The program can be stored on a non-transitory computer-readable medium. Examples of the non-transitory computer-readable medium include flash memory, magnetic recording devices, optical disks, magneto-optical recording media, and ROMs. The program can be distributed by selling, transferring, or lending portable media such as SD cards, DVDs, or CD-ROMs that store the program. "SD" is an abbreviation for Secure Digital. "DVD" is an abbreviation for digital versatile disc. "CD-ROM" is an abbreviation for compact disc read only memory. The program can also be distributed by storing it in the storage of a server and transferring it from the server to another computer. The program can also be provided as a program product.

[0025] A computer temporarily stores a program stored on a portable medium or transferred from a server in its main storage device. The computer then reads the program stored in the main storage device with its processor and executes processing in accordance with the read program. The computer may also read the program directly from the portable medium and execute processing in accordance with the program. The computer may also execute processing in accordance with the received program each time a program is transferred from the server to the computer. Processing may also be executed using a so-called ASP-type service that realizes functions simply by issuing execution instructions and obtaining results, without transferring the program from the server to the computer. "ASP" is an abbreviation for application service provider. A program is information used for processing by a computer and includes something equivalent to a program. For example, data that is not a direct instruction to a computer but has properties that define computer processing falls under the category of "something equivalent to a program."

[0026] Some or all of the functions of the estimation device 10 may be implemented by a programmable circuit or a dedicated circuit as the control unit 11. In other words, some or all of the functions of the estimation device 10 may be implemented by hardware.

[0027] An example of the operation of the estimation system 1 will be described with reference to Fig. 2. Of the operations described below, the operation of the estimation device 10 corresponds to the method according to this embodiment.

[0028] In step S101, the measuring device 20 transmits an image of the inside of the target pipeline P to the estimation device 10. The image transmitted by the measuring device 20 may be one image, or multiple images captured at multiple imaging positions. The multiple imaging positions include, for example, both end positions of the target pipeline P that connect to a manhole. The image may include identification information that identifies the target pipeline P.

[0029] In step S102 , the control unit 11 of the estimation device 10 receives an image from the measurement device 20 via the communication unit 13 .

[0030] In step S103, the control unit 11 analyzes the image received in S102 using any image analysis technology to determine the degree of corrosion inside the target pipeline P, and acquires information indicating the degree of corrosion as part of the target pipeline information. The degree of corrosion is, for example, the proportion of the area of ​​the corroded areas to the area of ​​the inside of the target pipeline P reflected in the image. The degree of corrosion may be a discrete number ranging from 0 to 10 corresponding to the proportion. If the control unit 11 receives multiple images from the measuring device 20, the degree of corrosion may be the average or median of the proportion of the area of ​​the corroded areas in each of the multiple images.

[0031] In step S104, the control unit 11 acquires information indicating the amount of accumulated water inside the target pipeline P as another part of the target pipeline information. Specifically, the control unit 11 searches a database constructed in the memory unit 12, which records the amount of accumulated water for each buried pipeline. The database may be constructed in an external server device with which the control unit 11 can communicate via the communication unit 13. The database is updated each time an inspection work on a buried pipeline is performed. The control unit 11 extracts information indicating the amount of accumulated water in the target pipeline P from the database. When searching the database, the control unit 11 may use identification information contained in the image received in S102 as a search key, or may use similar identification information based on a user input received via the input / output unit 14 as a search key.

[0032] The control unit 11 may determine the amount of accumulated water by analyzing the image received in S102 using any image analysis technology, and obtain information indicating the amount of accumulated water as another part of the target pipeline information.

[0033] The control unit 11 records the degree of corrosion indicated by the target pipeline information acquired in S103 in the database and updates the database, which makes it possible to use the database to acquire nearby pipeline information, as will be described below in S106.

[0034] The amount of accumulated water for each buried pipeline recorded in the database is a graded scale such as "none," "very little," "little," "medium," or "large," or a discrete value ranging from 0 to 10. The amount of accumulated water in this embodiment includes values ​​measured inside the buried pipeline at different times using a water level meter or the like and a representative value of the values ​​at those different times. The representative value may be an average value, a median value, or the like. The amount of accumulated water may also be accumulated water data for manholes connected to both ends of the buried pipeline. In this case, the accumulated water data is measured, for example, using a water level meter or the like during manhole inspection work and recorded in the database for the corresponding buried pipeline. In this way, the control unit 11 can use the accumulated water data for the manholes at both ends of the buried pipeline as the amount of accumulated water.

[0035] FIG. 3 is a diagram showing an example of a database. While FIG. 3 shows the database in a table format, the format is not limited to this. The database records, for each of buried pipelines A through N, the amount of accumulated water measured at the most recent measurement time t1 and the previous measurement time t2, a representative value of the amount of accumulated water measured at the two measurement times t1 and t2, the watershed to which the buried pipeline belongs, and the degree of corrosion inside the buried pipeline. The watershed includes the watershed of a lake, a river, or the like. For example, the amount of accumulated water for buried pipeline A was "medium" at the most recent measurement time t1 and "none" at the previous measurement time t2, and the representative value of the amount of accumulated water was "small."

[0036] By recording the watershed to which the buried pipeline belongs in the database, the database can be used to obtain nearby pipeline information, as will be described in S106 below.

[0037] In this embodiment, buried pipelines for which the amount of accumulated water at time t1 and time t2 is "none" include not only pipelines whose insides are completely dry, but also water pipes whose insides are always full of water. Buried pipeline B in the database of FIG. 3 is a water pipe. Even for buried pipelines or water pipes whose insides are completely dry, corrosion on the outside is expected. In such cases, as described below in S105 to S108, the control unit 11 estimates the degree of corrosion on the outside of the target pipeline P by using representative values ​​of the degree of corrosion and amount of accumulated water on the inside of a nearby buried pipeline that belongs to the same watershed as the target pipeline P.

[0038] As shown in S103 and S104, the control unit 11 acquires target pipeline information indicating the degree of corrosion inside the target pipeline P and the amount of accumulated water.

[0039] In step S105, the control unit 11 determines whether the amount of accumulated water indicated by the target pipeline information acquired in step S104 is less than a predetermined value. In this embodiment, the control unit 11 determines whether both the amount of accumulated water at time t1 and the amount of accumulated water at time t2 are less than a predetermined value. If it is determined that both amounts of accumulated water are less than the predetermined value, the operation of the estimation system 1 proceeds to step S106. If it is determined that the amount of accumulated water at at least one of time t1 and time t2 is equal to or greater than the predetermined value, the operation of the estimation system 1 proceeds to step S107. The predetermined value may be set in advance and stored in the memory unit 12.

[0040] In step S105, instead of determining whether the amount of accumulated water at time t1 and the amount of accumulated water at time t2 are both less than a predetermined value, the control unit 11 may determine whether the target pipeline P is experiencing temporal dry-lacquering repetition. Specifically, the control unit 11 compares the difference between the amount of accumulated water at time t1 and the amount of accumulated water at time t2, and determines that the target pipeline P is experiencing temporal dry-lacquering repetition if the difference is equal to or greater than a first threshold, i.e., if there is a certain fluctuation in the amount of accumulated water. The control unit 11 determines that the target pipeline P is not experiencing dry-lacquering repetition if there is no fluctuation and both the amount of accumulated water at time t1 and the amount of accumulated water at time t2 are less than a second threshold. The first threshold and the second threshold may be preset and stored in the memory unit 12. If the control unit 11 determines that the target pipeline P is experiencing dry-lacquering repetition, it may determine that the amount of accumulated water is equal to or greater than a predetermined value. If the control unit 11 determines that there is no dry-lacquering repetition, it may determine that the amount of accumulated water is less than the predetermined value.

[0041] In step S106, the control unit 11 acquires nearby pipeline information indicating the degree of corrosion and the amount of accumulated water inside nearby pipelines located in the same watershed as the target pipeline P. Specifically, the control unit 11 first identifies the watershed to which the target pipeline P belongs, as recorded in the database of FIG. 3 . The control unit 11 further identifies, from the database, buried pipelines that belong to the same watershed as the identified one as nearby pipelines. The control unit 11 extracts information indicating the degree of corrosion and the amount of accumulated water inside the nearby pipelines, and acquires this information as nearby pipeline information.

[0042] When there are multiple buried pipelines belonging to the same watershed, the control unit 11 may identify the buried pipeline located closest to the position of the target pipeline P as the nearby pipeline. In this case, the control unit 11 identifies the nearby pipeline by referring to map information indicating the positions of each buried pipeline, which is stored in advance in the memory unit 12.

[0043] In step S107, the control unit 11 acquires a function that associates the degree of corrosion and the amount of accumulated water inside the buried pipeline with the degree of corrosion outside the buried pipeline. In this embodiment, the control unit 11 reads and acquires the function from the storage unit 12.

[0044] The function according to this embodiment is a linear function in which the degree of corrosion on the inside of a buried pipeline is proportional to the degree of corrosion on the outside. The slope of the function, which represents the proportional relationship between the degree of corrosion on the inside and the degree of corrosion on the outside, changes depending on the amount of accumulated water. The larger the value of the amount of accumulated water, the steeper the slope of the function. In other words, the degree of corrosion on the outside corresponds to the degree of corrosion on the inside. In this embodiment, functions for each level of accumulated water amount are stored in advance in the memory unit 12. Specifically, functions having slopes for the accumulated water amounts of "very little," "little," "medium," and "large" are stored in the memory unit 12. The control unit 11 reads from the memory unit 12 a function corresponding to the representative value of the accumulated water amount indicated by the target pipeline information acquired in S104 or the representative value of the accumulated water amount indicated by the nearby pipeline information acquired in S106. Without being limited to this, the control unit 11 may acquire a function by generating a function each time by applying a coefficient corresponding to the slope of the representative value of the accumulated water volume indicated by the target pipeline information acquired in S104 or the representative value of the accumulated water volume indicated by the nearby pipeline information acquired in S106.

[0045] FIG. 4 is a graph showing an example of a function read by the control unit 11. In FIG. 4, circles represent plots of the degree of external corrosion versus the degree of internal corrosion for buried pipelines whose representative accumulated water volume is "large," and function F1 is a function generated based on the plot using linear approximation or the like. In FIG. 4, squares represent plots of the degree of external corrosion versus the degree of internal corrosion for buried pipelines whose representative accumulated water volume is "small," and function F2 is a function generated based on the plot using linear approximation or the like. Referring to FIG. 4, it can be seen that function F1 has a steeper slope than function F2, indicating that buried pipelines with a large amount of accumulated water tend to have a greater degree of external corrosion than buried pipelines with a small amount of accumulated water.

[0046] In step S108, the control unit 11 inputs the degree of corrosion on the inside of the target pipeline P indicated by the target pipeline information acquired in S103, or the degree of corrosion on the inside of the nearby pipeline indicated by the nearby pipeline information acquired in S106, into the function acquired in S107 as the degree of corrosion on the inside of the target pipeline P. In this way, the control unit 11 estimates the degree of corrosion on the outside of the target pipeline P.

[0047] As shown in S107 and S108, the control unit 11 applies the degree of corrosion and the amount of accumulated water on the inside of the target pipeline P indicated by the target pipeline information to a function that correlates the degree of corrosion and the amount of accumulated water on the inside of the buried pipeline with the degree of corrosion on the outside of the buried pipeline, thereby estimating the degree of corrosion on the outside of the target pipeline P. The control unit 11 estimates the degree of corrosion on the outside of the target pipeline P to a larger value as the degree of corrosion or the amount of accumulated water on the inside of the target pipeline P indicated by the target pipeline information increases.

[0048] As described above, even for a target pipeline P where the amount of accumulated water is less than a predetermined value, for example, where the amount of accumulated water is "very small," external corrosion is expected. In this case, if the amount of accumulated water is directly used to estimate the degree of external corrosion of the target pipeline P, the degree of external corrosion may be estimated to be lower than the actual degree. On the other hand, buried pipelines installed in the same watershed are buried in soil with similar corrosive properties, and are likely to have similar degrees of external corrosion. Therefore, as shown in S105 to S108, for a target pipeline P where the amount of accumulated water is determined to be less than a predetermined value, the degree of external corrosion of the target pipeline P can be more accurately estimated by using the degree of internal corrosion and the amount of accumulated water of nearby pipelines instead.

[0049] In step S109, the control unit 11 outputs information indicating the estimated degree of corrosion on the outside of the target pipeline P via the input / output unit 14. The control unit 11 may output the information by transmitting the information to a user's terminal device. Thereafter, the operation of the estimation system 1 ends.

[0050] A specific example of the operation of the estimation system 1 described above will be described. In step S101, the measuring device 20 transmits an image, and in step S102, the control unit 11 of the estimation device 10 receives the image. In step S103, the control unit 11 acquires a portion of the target pipeline information indicating a corrosion level of "3" on the inside of the target pipeline P. In this specific example, the target pipeline P is assumed to be buried pipeline C. Therefore, in step S104, the control unit 11 references the database of FIG. 3 and acquires, as another portion of the target pipeline information, a representative value of the accumulated water volume of buried pipeline C, "very small," as information indicating the accumulated water volume of the target pipeline P. In step S105, in this specific example, the predetermined value is assumed to be set to "small." Because the accumulated water volume indicated by the target pipeline information is "very small," which is less than "small," the operation of the estimation system 1 proceeds to step S106. In this specific example, the catchment area of ​​buried pipeline C, which is the target pipeline P, is assumed to be "X," and the catchment area of ​​buried pipeline A is also assumed to be "X." Therefore, in step S106, the control unit 11 identifies buried pipeline A as a nearby pipeline. The control unit 11 extracts the degree of corrosion of the inside of buried pipeline A, "4," and the representative value of the accumulated water volume, "small," and acquires these as nearby pipeline information. In step S107, the control unit 11 reads out, from the storage unit 12, a function F2 corresponding to the representative value of the accumulated water volume, "small," indicated in the nearby pipeline information. In step S108, the control unit 11 inputs the degree of corrosion of the inside of the nearby pipeline, "4," indicated in the nearby pipeline information, into function F2 as the degree of corrosion of the inside of the target pipeline P. In this case, it is assumed that the degree of corrosion of the outside of the target pipeline P is estimated to be "2" by function F2. In step S109, the control unit 11 outputs information indicating the degree of corrosion of the outside, "2," via the input / output unit 14.

[0051] The following additional notes are provided regarding the above-described embodiments.

[0052] (Supplementary Item 1) An estimation device comprising a control unit that acquires target pipeline information indicating the degree of corrosion and amount of accumulated water inside the target pipeline, and estimates the degree of corrosion on the outside of the target pipeline by applying the degree of corrosion and amount of accumulated water inside the target pipeline indicated by the acquired target pipeline information to a function that associates the degree of corrosion and amount of accumulated water inside the buried pipeline with the degree of corrosion on the outside of the buried pipeline. (Supplementary Item 2) The estimation device described in Supplementary Item 1, wherein the control unit estimates the degree of corrosion on the outside of the target pipeline to a larger value as the degree of corrosion on the inside of the target pipeline or the amount of accumulated water indicated by the target pipeline information increases. (Supplementary Item 3) When the amount of accumulated water inside the target pipeline indicated by the target pipeline information is less than a predetermined value, the control unit acquires nearby pipeline information indicating the degree of corrosion and amount of accumulated water inside nearby pipelines located in the same watershed as the target pipeline, and applies the degree of corrosion and amount of accumulated water inside the nearby pipeline indicated by the acquired nearby pipeline information to the function as the degree of corrosion and amount of accumulated water inside the target pipeline, thereby estimating the degree of corrosion outside the target pipeline. (Supplementary Item 3) The control unit acquires nearby pipeline information indicating the degree of corrosion and amount of accumulated water inside the nearby pipelines located in the same watershed as the target pipeline when the amount of accumulated water inside the target pipeline indicated by the target pipeline information is less than a predetermined value, and applies the degree of corrosion and amount of accumulated water inside the nearby pipelines indicated by the acquired nearby pipeline information to the function to estimate the degree of corrosion outside the target pipeline. (Appendix 4) The control unit acquires corrosion prevention construction information indicating the corrosion prevention construction performed on the target pipeline, generates a weighted function by weighting the function based on the degree of corrosion on the outside of the buried pipeline in accordance with the corrosion prevention construction indicated by the corrosion prevention construction information, and applies the degree of corrosion and amount of accumulated water on the inside of the target pipeline indicated by the target pipeline information to the weighted function, in an estimation device described in any one of appendixes 1 to 3.

[0053] The present disclosure is not limited to the above-described embodiments. For example, two or more blocks shown in the block diagram may be integrated, or one block may be divided. Two or more steps shown in the flowchart may be executed in parallel or in a different order, instead of being executed in chronological order as described, depending on the processing capabilities of the device executing each step, or as needed. Other modifications are possible within the scope of the present disclosure.

[0054] As a modified example of the present disclosure, the control unit 11 of the estimation device 10 may weight the acquired function according to the corrosion prevention work performed on the target pipeline P to generate a weighted function, and use the weighted function to estimate the degree of corrosion on the outside of the target pipeline P.

[0055] Fig. 5 is a diagram showing the operation of the estimation device 10 according to this modification. Steps S201 to S207 in Fig. 5 are the same as steps S101 to S107 described above, and therefore a description thereof will be omitted.

[0056] In step S208, the control unit 11 acquires anticorrosion work information indicating the anticorrosion work performed on the target pipeline P. The anticorrosion work is performed using a predetermined material on the outside of the target pipeline P, such as asphalt jute, coating, or zinc plating. For example, the anticorrosion work is also recorded for each buried pipeline in the database of FIG. 3 , and the control unit 11 may extract anticorrosion work information indicating the anticorrosion work performed on the target pipeline P from the database. However, the control unit 11 may also acquire anticorrosion work information based on user input received via the input / output unit 14.

[0057] In step S209, the control unit 11 generates a weighted function by weighting the degree of external corrosion of the function acquired in S207 in accordance with the anticorrosion work performed on the target pipeline P indicated by the anticorrosion work information. Specifically, the control unit 11 reads information indicating the weight set for each anticorrosion work, which is pre-stored in the memory unit 12. FIG. 6 is a diagram showing an example of this information. While FIG. 6 shows this information in a table format, the format is not limited thereto. The weight may be a value derived by an inspection of the degree of external corrosion of the buried pipeline on which anticorrosion work has been performed, or may be a value estimated from a resistance value measured using an electrochemical method, the useful life of the buried pipeline, or the like.

[0058] FIG. 7 is a graph showing an example of a function read by the control unit 11 and a weighted function generated by weighting the function read by the control unit 11. As in FIG. 4, the circles in FIG. 6 indicate plots of the degree of external corrosion relative to the degree of internal corrosion for buried pipelines with a representative value of "high" accumulated water volume, and function F1 is a function generated from this plot. Referring to FIG. 6, it can be seen that the weighted function F3 generated by weighting has a smaller slope than function F1, i.e., the weighted function F3 has a lower degree of external corrosion relative to the degree of internal corrosion than function F1. Thus, the higher the corrosion protection effect of the corrosion protection work, the smaller the slope of the generated weighted function. Therefore, in S210, it is possible to estimate the degree of external corrosion of the target pipeline P taking into account the corrosion protection effect.

[0059] The control unit 11 may further acquire age information indicating the number of years the target pipeline P has been installed, and may generate a modified weighted function by further weighting the degree of corrosion on the outside of the pipeline using the function F1 acquired in S207 or the weighted function F3 generated in S209 in Fig. 5 according to the number of years the pipeline has been installed. In this case, the control unit 11 estimates the degree of corrosion on the outside of the target pipeline P using the modified weighted function.

[0060] For example, the number of years of installation may be registered for each buried pipeline in the database of Fig. 3, and the control unit 11 may extract age information indicating the number of years of installation of the target pipeline P. However, this is not limiting, and the control unit 11 may obtain age information based on a user input received via the input / output unit 14. The control unit 11 reads information indicating weights set for each number of years of installation, which is stored in advance in the storage unit 12, and generates a modified weighted function according to the read information.

[0061] The control unit 11 generates a modified weighting function with a steeper slope the longer the installation age. That is, the control unit 11 generates a modified weighting function in which the degree of external corrosion relative to the degree of internal corrosion increases the longer the installation age. By applying the degree of internal corrosion of the target pipeline P to the modified weighting function, it becomes possible to estimate the degree of external corrosion of the target pipeline P taking into account the installation age in S210.

[0062] In step S210, the control unit 11 applies the degree of corrosion on the inside of the target pipeline P indicated by the target pipeline information acquired in S203, or the degree of corrosion on the inside of the nearby pipeline indicated by the nearby pipeline information acquired in S206, as the degree of corrosion on the inside of the target pipeline P to the weighted function or modified weighted function generated in S209. In this way, the control unit 11 estimates the degree of corrosion on the outside of the target pipeline P.

[0063] Step S211 is the same as step S109 described above, and therefore a description thereof will be omitted.

[0064] A specific example of the operation of the estimation system 1 according to the above-described modified example will be described. Steps S201 to S207 are assumed to be similar to the specific example of steps S101 to S107 of the above-described embodiment. In step S208, it is assumed that the corrosion prevention construction information acquired by the control unit 11 indicates asphalt jute. In this case, in step S209, the control unit 11 refers to the information in FIG. 6 and calculates the weight W of the asphalt jute. ｃａ The control unit 11 applies weighting to the function F1 acquired in S206 using the weighting factor F1 to generate a weighted function F3. In step S210, the control unit 11 inputs the degree of corrosion on the inside of the nearby pipeline indicated by the nearby pipeline information acquired in S206 into the generated weighted function F3 as the degree of corrosion on the inside of the target pipeline P. In this case, it is assumed that the degree of corrosion on the outside of the target pipeline P is estimated to be "1" by the weighted function F3. In step S211, the control unit 11 outputs information indicating the degree of corrosion on the outside of the target pipeline P via the input / output unit 14.

[0065] As a modified example of the present disclosure, the control unit 11 of the estimation device 10 may receive information indicating the depth of corrosion inside the target pipeline P from the measurement device 20 or a terminal device used by a worker performing maintenance and inspection work, in addition to or instead of the above-mentioned image, and acquire the information as information indicating the degree of corrosion. The degree of corrosion in this modified example is a value obtained by directly measuring the depth of corrosion inside the target pipeline P using a method using a measurement gauge or a non-destructive method such as ultrasound. The depth of corrosion inside the target pipeline P may be the maximum value, average value, median value, or the like of the depth of corrosion measured at each of multiple positions on the target pipeline P.

[0066] In this modification, the degree of corrosion on the outside of the target pipeline P estimated by the function acquired by the control unit 11 in the above-described S107, S207, or S209 includes the depth of corrosion on the outside of the target pipeline P. According to this modification, it is possible to estimate the depth of corrosion on the outside of the target pipeline P based on the depth of corrosion on the inside of the target pipeline P directly measured by the measurement device 20.

[0067] REFERENCE SIGNS LIST 1 Estimation system 10 Estimation device 11 Control unit 12 Storage unit 13 Communication unit 14 Input / output unit 20 Measurement device 30 Network

Claims

1. An estimation device comprising a control unit that acquires target pipeline information indicating the degree of corrosion and amount of accumulated water inside the target pipeline, and estimates the degree of corrosion on the outside of the target pipeline by applying the degree of corrosion and amount of accumulated water inside the target pipeline indicated in the acquired target pipeline information to a function that relates the degree of corrosion and amount of accumulated water inside the buried pipeline to the degree of corrosion on the outside of the buried pipeline.

2. The estimation device of claim 1, wherein the control unit estimates the degree of corrosion on the outside of the target pipeline to a larger value the greater the degree of corrosion or amount of accumulated water on the inside of the target pipeline indicated by the target pipeline information.

3. The estimation device described in claim 1 or 2, wherein, when the amount of accumulated water inside the target pipeline indicated by the target pipeline information is less than a predetermined value, the control unit acquires nearby pipeline information indicating the degree of corrosion and amount of accumulated water inside nearby pipelines located in the same watershed as the target pipeline, and applies the degree of corrosion and amount of accumulated water inside the nearby pipelines indicated by the acquired nearby pipeline information to the function as the degree of corrosion and amount of accumulated water inside the target pipeline, thereby estimating the degree of corrosion outside the target pipeline.

4. The estimation device described in claim 1 or 2, wherein the control unit acquires corrosion prevention construction information indicating the corrosion prevention construction performed on the target pipeline, generates a weighted function by weighting the function based on the degree of corrosion on the outside of the buried pipeline in accordance with the corrosion prevention construction indicated by the corrosion prevention construction information, and applies the degree of corrosion and amount of accumulated water on the inside of the target pipeline indicated by the target pipeline information to the weighted function, thereby estimating the degree of corrosion on the outside of the target pipeline.

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