WO2021001922A1 - Corrosion damage evaluation method, corrosion damage evaluation program, and corrosion damage evaluation device - Google Patents

Abstract

Provided is a corrosion damage evaluation method for evaluating corrosion damage on a pipe that has corroded from an initial shape, the corrosion damage evaluation method comprising: an acquisition step for acquiring an image including a corroded pipe, an extraction step for extracting a corroded cross-sectional shape of the corroded pipe from the image acquired in the acquisition step, a creation step for creating an initial cross-sectional shape of the initial shape of the pipe from the corroded cross-sectional shape extracted in the extraction step, and an evaluation step for evaluating corrosion damage by comparing the corroded cross-sectional shape extracted in the extraction step and the initial cross-sectional shape created in the creation step.

Description

Corrosion damage evaluation method, corrosion damage evaluation program and corrosion damage evaluation equipment

The present invention relates to methods, programs and devices for assessing corrosion damage to pipes.

As a technique for evaluating damage caused by corrosion of pipes, radiation is transmitted through the target pipe to take a radiation transmission photograph, and the shade of the obtained image is compared with the shade of the image in the initial state prepared in advance to corrode. A method for detecting a portion is known (for example, Patent Document 1).

JP-A-4-09696

When the corrosion damage is evaluated by the method described in Patent Document 1, in order to detect and quantify the corroded part, the initial stage before the pipe corrodes, such as the pipe having the same shape or the measurement data based on the past results. Shape data is required. Therefore, when it is difficult to obtain data in the initial state such as pipes collected from the market, there is a problem that the corrosion damage evaluation cannot be performed or the evaluation result with sufficient accuracy cannot be obtained.

The present invention solves the above-mentioned problems, and a corrosion damage evaluation method, a corrosion damage evaluation program, and a corrosion damage evaluation program capable of evaluating corrosion damage of a pipe even when information on the initial shape of the pipe cannot be obtained in advance. It is an object of the present invention to provide a corrosion damage evaluation device.

The corrosion damage evaluation method of the present invention is a corrosion damage evaluation method for evaluating corrosion damage of a pipe that has been corroded from the initial shape, and is corroded from an acquisition step of acquiring an image including the corroded pipe and an image acquired in the acquisition step. Created by the extraction step to extract the corroded cross-sectional shape of the pipe, the creation step to create the initial cross-sectional shape of the pipe in the initial shape from the corroded cross-sectional shape extracted in the extraction step, and the corroded cross-sectional shape extracted in the extraction step and the creation step. It is provided with an evaluation step for evaluating corrosion damage by comparing with the initial cross-sectional shape.

The corrosion damage evaluation program of the present invention causes a computer to execute the above corrosion damage evaluation method.

The corrosion damage evaluation device of the present invention is a corrosion damage evaluation device that evaluates corrosion damage of a pipe corroded from the initial shape, and is corroded from an acquisition unit that acquires an image including the corroded pipe and an image acquired by the acquisition unit. An extraction unit that extracts the corrosive cross-sectional shape of the pipe, a creation unit that creates the initial cross-sectional shape of the pipe in the initial shape from the corrosive cross-sectional shape extracted by the extraction unit, and a corrosive cross-sectional shape extracted by the extraction unit and a creation unit are created. It is provided with a corrosion damage evaluation unit for evaluating corrosion damage by comparing it with the initial cross-sectional shape.

According to the present invention, it is possible to quantitatively evaluate the corrosion damage of a corroded pipe without requiring the pipe data in the initial state before the pipe is corroded.

It is a block diagram which shows the schematic structure of the corrosion damage evaluation apparatus in Embodiment 1. FIG. It is a functional block diagram of the information processing apparatus in Embodiment 1. FIG. It is a flowchart of the corrosion damage evaluation method of a pipe in Embodiment 1. This is an example of a cross-sectional image of a pipe acquired from a storage unit. This is an example of a cross-sectional image that has undergone binarization processing. It is an example of the image of the extracted piping part. This is an example of an image of the extracted cavity. It is a flowchart of the method of creating an initial outer surface shape in Embodiment 1. It is an example of the image of the extracted corroded part. This is an example of an image of a pipe portion extracted from a cross-sectional image of a pipe having a groove on the inner surface. It is a flowchart of the corrosion damage evaluation method of a pipe in Embodiment 2. It is a figure explaining the method of making the shape for estimation in Embodiment 2. It is a figure explaining the method of making the shape for estimation in the modification of Embodiment 2. It is a figure explaining the method of making the shape for estimation in the modification of Embodiment 2. It is a flowchart of the corrosion damage evaluation method of a pipe in Embodiment 3. It is an example of the image of the extracted piping part. It is a flowchart of the method of creating an initial inner surface shape in Embodiment 3. It is an example of the image of the extracted corroded part.

Embodiment 1.
FIG. 1 is a block diagram showing a schematic configuration of the corrosion damage evaluation device 100 according to the first embodiment. The corrosion damage evaluation device 100 evaluates the corrosion damage of a pipe that has been corroded from the initial shape. The corrosion damage evaluation device 100 of this embodiment is an arbitrary computer such as a PC, a smartphone or a tablet PC. As shown in FIG. 1, the corrosion damage evaluation device 100 includes an operation unit 1, an input unit 2, a communication unit 3, an information processing unit 4, a storage unit 5, and an output unit 6. The operation unit 1, the input unit 2, the communication unit 3, the information processing unit 4, the storage unit 5, and the output unit 6 are connected to each other by a data bus.

The operation unit 1 is a keyboard or mouse that receives an input of an instruction from the user of the corrosion damage evaluation device 100. The input unit 2 is an input port that reads data of a cross-sectional image to be evaluated by the corrosion damage evaluation device 100 from a recording medium or the like and stores it in the storage unit 5. The communication unit 3 is a communication interface for exchanging various information with the Internet or a local area network.

The information processing unit 4 executes the corrosion damage evaluation program stored in the storage unit 5 and implements the corrosion damage evaluation method. The information processing unit 4 is, for example, an MPU (Micro-processing unit). The information processing unit 4 may be an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a circuit having other arithmetic functions.

The storage unit 5 stores a cross-sectional image of the pipe to be evaluated, a corrosion damage evaluation program executed by the information processing unit 4, various data used for executing the corrosion damage evaluation program, and the like. The storage unit 5 is a RAM (RandomAccessMemory), a ROM (Read-OnlyMemory), an HDD (HardDiskDrive), an SSD (SolidStateDrive), or the like. The corrosion damage evaluation program may be read from the recording medium by the input unit 2 and stored in the storage unit 5. Alternatively, the corrosion damage evaluation program may be downloaded from the Internet or a local area network by the communication unit 3 and stored in the storage unit 5.

The output unit 6 is a display that displays various information such as the corrosion damage evaluation result by the information processing unit 4. The hardware constituting the corrosion damage evaluation device 100 is general and is not limited to the example of the embodiment.

The corrosion damage evaluation method of the present embodiment will be described. The corrosion damage evaluation method of the present embodiment evaluates, for example, the corrosion damage on the outer surface of the refrigerant pipe of the outdoor unit for an air conditioner. The outdoor unit of the air conditioner is equipped with a heat exchanger. The heat exchanger is composed of refrigerant pipes or fins made of a metal such as aluminum or copper. Further, since the outdoor unit is installed in an environment exposed to wind and rain and the outside air, corrosion of the metal material in the heat exchanger is likely to proceed. If the outer surface of the refrigerant pipe of the heat exchanger is corroded, holes may be formed in the pipe, which may lead to problems such as refrigerant leakage. Therefore, in evaluating the corrosion resistance of the outdoor unit, it is important to evaluate the corrosion damage on the outer surface of the pipe.

Before implementing the corrosion damage evaluation method, the refrigerant piping where corrosion has progressed is first recovered. As a method of recovering the refrigerant piping, if a defect occurs in a product sold in the market, the distributor will replace the outdoor unit and recover the defective product, or a verification test (field test, field test) at the time of product development. Hereinafter referred to as "FT"), there is a method of collecting the FT machine installed for several years later.

After the refrigerant pipe that has been corroded is recovered, a cross-sectional image of the recovered refrigerant pipe is taken. The purpose of the corrosion damage evaluation of the refrigerant pipe is, for example, to prevent the pipe from being perforated. Therefore, by taking a cross-sectional image of the refrigerant pipe, it is possible to confirm the state of corrosion damage in the internal direction of the pipe connected to the hole in the pipe. As a method of taking a cross-sectional image of the refrigerant pipe, the refrigerant pipe is cut, embedded in an embedding resin such as epoxy resin, the cross-sectional portion is polished with a grinder, and then the cross section is used with an optical microscope. There is a method of taking an image. Alternatively, there is a method of taking a radiation transmission photograph using radiation and obtaining a cross-sectional image by non-destruction, as typified by an X-ray CT scan. The method for taking a cross-sectional image of the refrigerant pipe is not limited to the above, and other known methods can be used. The photographed cross-sectional image is stored in the recording medium and stored in the storage unit 5 via the input unit 2. Alternatively, the captured cross-sectional image may be transmitted via the Internet or a local area network and stored in the storage unit 5 via the communication unit 3.

FIG. 2 is a functional block diagram of the information processing unit 4 in the first embodiment. As shown in FIG. 2, the information processing unit 4 includes an acquisition unit 41, an extraction unit 42, a creation unit 43, and a corrosion damage evaluation unit 44 as functional units realized by executing a corrosion damage evaluation program. Has. In another embodiment, the acquisition unit 41, the extraction unit 42, the creation unit 43, and the corrosion damage evaluation unit 44 may be realized by individual hardware.

The acquisition unit 41 acquires an image including a corroded pipe. Specifically, the acquisition unit 41 acquires the cross-sectional image 200 of the pipe to be evaluated from the storage unit 5 in response to the operation of the operation unit 1 and outputs it to the extraction unit 42. The extraction unit 42 extracts the corroded cross-sectional shape of the corroded pipe from the image acquired by the acquisition unit 41. Specifically, the extraction unit 42 identifies and extracts the pipe unit 21, the inner surface shape 210 of the pipe unit 21, and the outer surface shape 211 from the cross-sectional image 200 of the pipe (FIG. 6). The creating unit 43 creates the initial cross-sectional shape of the pipe in the initial shape from the corroded cross-sectional shape extracted by the extracting unit 42. Specifically, the creating unit 43 enlarges the inner surface shape 210 of the piping unit 21 extracted by the extracting unit 42 to create the initial outer surface shape 211A of the piping unit 21 (FIG. 9). The corrosion damage evaluation unit 44 compares the corrosion cross-sectional shape extracted by the extraction unit 42 with the initial cross-sectional shape created by the preparation unit 43 to evaluate the corrosion damage. Specifically, the corrosion damage evaluation unit 44 quantitatively evaluates the corrosion damage of the pipe by comparing the outer surface shape 211 extracted by the extraction unit 42 with the initial outer surface shape 211A created by the preparation unit 43. Then, the evaluation result is output from the output unit 6.

FIG. 3 is a flowchart of the corrosion damage evaluation method for piping according to the first embodiment. The corrosion damage evaluation method shown in FIG. 3 is carried out by the information processing unit 4 executing the corrosion damage evaluation processing program. Each step of the corrosion damage evaluation method shown in FIG. 3 corresponds to each step of the corrosion damage evaluation processing program. As shown in FIG. 3, the information processing unit 4 first acquires a cross-sectional image 200 of the pipe to be evaluated from the storage unit 5 by the acquisition unit 41 (S1). FIG. 4 is an example of a cross-sectional image 200 of the pipe acquired from the storage unit 5.

After acquiring the cross-sectional image 200 of the pipe to be evaluated, the information processing unit 4 extracts the piping unit 21 from the acquired cross-sectional image 200 by the extraction unit 42 of the information processing unit 4 (S2). Specifically, the information processing unit 4 first obtains the brightness value of the cross-sectional image 200, and performs binarization processing using a predetermined threshold value. Then, the information processing unit 4 identifies the region where the brightness value is "0" from the background unit 22. FIG. 5 is an example of a cross-sectional image 200 that has undergone binarization processing. In the cross-sectional image 200 of FIG. 5, the background portion 22 is shown by diagonal lines. Subsequently, the information processing unit 4 calculates the area of the area other than the background unit 22, that is, the area of each area having the luminance value "1". In FIG. 5, the area without diagonal lines is the area other than the background portion 22. In the example of FIG. 5, there are three areas other than the background portion 22, and the areas of each are calculated. Then, the information processing unit 4 identifies the area having the largest area as the piping unit 21 among the areas other than the background unit 22. The information processing unit 4 extracts the identified piping unit 21 to create an image 201, and stores it in the storage unit 5. FIG. 6 is an example of the image 201 of the extracted piping unit 21.

After extracting the piping unit 21 from the acquired cross-sectional image 200, the information processing unit 4 extracts the inner surface shape 210 of the piping unit 21 by the extraction unit 42 (S3). Specifically, the information processing unit 4 calculates the area of each region that is not in contact with the outer edge of the cross-sectional image 200 from the regions identified as the background portion 22 in step S2. Then, the information processing unit 4 identifies the region having the largest area among the regions as the cavity portion 22a. Then, the information processing unit 4 extracts the identified cavity portion 22a and creates an image 202. FIG. 7 is an example of the image 202 of the extracted cavity 22a. In FIG. 7, the cavity 22a is shaded. The information processing unit 4 further performs image processing of boundary detection on the created image 202 to acquire a boundary portion, extracts the acquired boundary portion as the inner surface shape 210 of the piping unit 21, and stores it in the storage unit 5.

Further, the information processing unit 4 extracts the outer surface shape 211 of the piping unit 21 by the extraction unit 42 (S4). Specifically, in step S2, the information processing unit 4 acquires a boundary portion by performing boundary detection image processing on the extracted image 201 of the piping unit 21. Then, the information processing unit 4 extracts the boundary portion farthest from the center of the image 201 from the acquired boundary portions as the outer surface shape 211 of the piping portion 21 and stores it in the storage unit 5. As the image processing for boundary detection in the information processing unit 4, a known method of detecting the boundary based on the brightness of the image 201 or 202 can be used. The order in which the inner surface shape 210 and the outer surface shape 211 of the piping portion 21 are extracted is arbitrary, and these may be performed in parallel.

After extracting the inner surface shape 210 of the piping unit 21, the information processing unit 4 creates the initial outer surface shape 211A of the piping unit 21 from the inner surface shape 210 of the piping unit 21 extracted in step S3 by the creating unit 43. S5). The initial outer surface shape 211A is the outer surface shape in the initial state before the pipe is corroded. In the case of the refrigerant piping provided in the heat exchanger of the outdoor unit for air conditioners, the inside of the piping is filled with non-corrosive refrigerant gas such as CFCs, so the inner surface of the piping does not corrode. .. Therefore, the change in the inner surface of the pipe is smaller than the change due to the corrosion of the outer surface. Further, the shape of the inner surface and the shape of the outer surface of the pipe are substantially the same. Therefore, the shape of the outer surface of the pipe before corrosion can be estimated from the shape of the inner surface of the pipe with less corrosion.

FIG. 8 is a flowchart of a method for creating the initial outer surface shape 211A in the first embodiment. As shown in FIG. 8, the information processing unit 4 first sets the center A of the inner surface shape 210 by the creation unit 43 using the image 201 of the piping unit 21 extracted in step S2 (S51). Specifically, the information processing unit 4 sets the center of the approximated circle or ellipse as the center A when the inner surface shape 210 of the piping unit 21 can be approximated by a circle or an ellipse, and sets the geometric center of the image 201 when it cannot be approximated. Let it be the center A.

After setting the center A of the inner surface shape 210, the information processing unit 4 creates a provisional shape centered on the center A and including the outer surface shape 211 by the creation unit 43 (S52). Specifically, the information processing unit 4 enlarges the inner surface shape 210 while maintaining the center A. Then, when all the brightness values on the enlarged inner surface shape 210 become 0, it is determined that the outer surface shape 211 of the piping unit 21 is included, and the information processing unit 4 ends the expansion. Then, the enlarged inner surface shape 210 at this time is set as a provisional shape. Then, the information processing unit 4 stores the created provisional shape and the center A when the provisional shape is created in the storage unit 5 (S53).

After creating the provisional shape, the information processing unit 4 creates a comparative shape when the center is moved to the center B by the creating unit 43. Specifically, the information processing unit 4 sets the center B of the inner surface shape 210 of the piping unit 21 by the creating unit 43 (S54). The center B is a new point different from the center A, and the information processing unit 4 selects a point in the vicinity of the center A as the center B. Then, the information processing unit 4 creates a comparative shape centered on the center B and including the outer surface shape 211 (S55). Specifically, the information processing unit 4 enlarges the inner surface shape 210 while maintaining the center B. Then, when all the luminance values on the enlarged inner surface shape 210 become 0, it is determined that the outer surface shape 211 of the piping portion 21 is included, and the expansion is completed. Then, the enlarged inner surface shape 210 at this time is used as the comparative shape. Then, the information processing unit 4 stores the created comparison shape and the center B when the comparison shape is created in the storage unit 5 (S56).

After storing the comparative shape, the information processing unit 4 calculates and compares the area of the provisional shape stored in the storage unit 5 and the area of the comparative shape by the creating unit 43 (S57). When the area of the comparative shape is smaller than the area of the provisional shape (S57: YES), the information processing unit 4 stores the center B and the comparative shape in the storage unit 5 as a new center A and the provisional shape (S58). As a result, the center A stored in the storage unit 5 and the provisional shape are updated. Then, the information processing unit 4 returns to step S54, and the subsequent processing is repeated. In this way, the information processing unit 4 searches for the optimum center of the inner surface shape 210 by repeatedly comparing the comparative shape created by changing the position of the center A with the provisional shape. When the area of the comparative shape is equal to or larger than the area of the provisional shape (S57: NO), the information processing unit 4 stores the provisional shape as the initial outer surface shape 211A in the storage unit 5 (S59). As a result, the initial outer surface shape 211A of the piping portion 21 before corrosion is created.

Returning to FIG. 3, in the following step S6, the information processing unit 4 has the outer surface shape 211 of the piping unit 21 extracted in step S4 by the corrosion damage evaluation unit 44 and the initial stage of the piping unit 21 created in step S5. The region between the outer surface shape 211A and the corroded portion 23 is extracted (S6). The information processing unit 4 creates an image 203 of the extracted corroded portion 23 and stores it in the storage unit 5. FIG. 9 is an example of the image 203 of the extracted corroded portion 23. In FIG. 9, the corroded portion 23 is shaded. Here, the information processing unit 4 may display the image 203 of the corroded portion 23 shown in FIG. 9 on the output unit 6. Thereby, the corroded portion of the pipe can be clarified.

After extracting the corroded portion 23, the information processing unit 4 quantitatively evaluates the corrosion damage of the piping portion 21 by the corrosion damage evaluation unit 44 (S7). Specifically, the corrosion damage evaluation unit 44 first calculates the area of the corrosion portion 23 extracted in step S6. Then, the information processing unit 4 evaluates the degree of corrosion damage based on the size of the calculated area of the corroded portion 23. Specifically, it is determined that the larger the area of the corroded portion 23, the greater the degree of corrosion damage. Then, the information processing unit 4 outputs the evaluation result from the output unit 6 (S8), and ends the corrosion damage evaluation method. For example, the information processing unit 4 may display the degree of corrosion damage on the output unit 6 as a numerical value or a sentence as an evaluation result. Alternatively, the information processing unit 4 compares the calculated area of the corroded portion 23 with a predetermined threshold value, and if the area of the corroded portion 23 is less than the threshold value, "no problem", and if it is more than the threshold value, "problem". May be output from the output unit 6.

As described above, in the present embodiment, the shape of the pipe in the initial state is created from the cross-sectional image of the pipe to be evaluated, and the corroded portion is quantitatively evaluated. As a result, even when information on the initial state of the piping cannot be obtained, such as when evaluating the corrosion damage of a product recovered from the market, the corrosion damage evaluation can be easily performed. Further, by estimating the initial state from the inner surface shape of the pipe having less corrosion and creating the initial outer surface shape 211A, it is possible to evaluate the corrosion damage without lowering the accuracy. Further, by extracting and using the inner surface shape 210 and the outer surface shape 211 of the pipe from the cross-sectional image 200 of the pipe to be evaluated, it is possible to improve the estimation of the initial outer surface shape 211A and the specific accuracy of the corroded portion 23.

Embodiment 2.
The second embodiment will be described. The second embodiment is different from the first embodiment in that the estimation shape 220 is used instead of the inner surface shape 210 when the initial outer surface shape is created. The configuration of the corrosion damage evaluation device 100 is the same as that of the first embodiment.

For the purpose of improving the performance of the heat exchanger, a groove may be provided on the inner surface of the refrigerant pipe provided in the heat exchanger of the outdoor unit for the air conditioner. FIG. 10 is an example of image 201 of the pipe portion 21 extracted from a cross-sectional image of a pipe having a groove on the inner surface. In FIG. 10, a groove 24 is provided on the inner surface of the piping portion 21 indicated by the diagonal line. When the groove 24 is provided on the inner surface of the piping portion 21, the inner surface shape 210 of the piping portion 21 cannot be used as it is for creating the initial outer surface shape 211A. Therefore, in the corrosion damage evaluation method of the present embodiment, the estimation shape 220 for creating the initial outer surface shape 211A is created from the inner surface shape 210 of the piping portion 21, and the initial outer surface shape 211A is created by using the estimation shape 220. create.

FIG. 11 is a flowchart showing a method for evaluating corrosion damage to piping according to the second embodiment. As shown in FIG. 11, steps S1 to S4 of the corrosion damage evaluation method of the present embodiment are the same as those of the first embodiment. Then, before creating the initial outer surface shape 211A of the piping unit 21 in step S5, the information processing unit 4 creates the estimation shape 220 by the creating unit 43 (S10).

FIG. 12 is a diagram illustrating a method of creating the estimation shape 220 in the second embodiment. As shown in FIG. 12, the information processing unit 4 obtains an approximate ellipse from the inner surface shape 210 of the piping unit 21 extracted in step S3 by using the least squares method by image processing. Then, the information processing unit 4 stores the obtained approximate ellipse as the estimation shape 220 in the storage unit 5. Then, in the creation of the initial outer surface shape 211A in step S5, the information processing unit 4 creates a provisional shape and a comparative shape from the estimation shape 220 instead of the extracted inner surface shape 210 of the piping unit 21.

As described above, according to the present embodiment, even when the inner surface of the piping portion 21 has irregularities such as grooves 24, the initial state can be appropriately estimated and the initial outer surface shape 211A can be created. As a result, even if the information on the initial state cannot be obtained, the corrosion damage evaluation can be easily performed, and the deterioration of the accuracy of the corrosion damage evaluation can be suppressed.

Note that the method of creating the estimation shape 220 in the present embodiment is not limited to the example of FIG. 13 and 14 are diagrams illustrating a method of creating the estimation shape 220 in the modified example of the second embodiment. As shown in FIGS. 13 and 14, the information processing unit 4 acquires a plurality of representative points P in a portion of the inner surface shape 210 other than the groove 24, and connects the plurality of representative points P by spline complementation to form an estimation shape. 220 may be created. As shown in FIG. 13, the representative point P is a method in which the intermediate point of each curved portion other than the groove 24 in the inner surface shape 210 is set as the representative point P, or as shown in FIG. 14, every constant angle from the center of the inner surface shape 210. It can be obtained by a method in which a point on the inner surface shape 210 of the above is set as a representative point P.

Embodiment 3.
The third embodiment will be described. The third embodiment is different from the first embodiment in that the corrosion damage on the inner surface of the pipe is evaluated. The configuration of the corrosion damage evaluation device 100 is the same as that of the first embodiment.

The water heater for hot water supply or heating is equipped with a heat exchanger. The heat exchanger is composed of water pipes or fins made of a metal such as aluminum or copper. Since tap water or groundwater at the place of use flows through the water pipe of the water heater, the inner surface of the water pipe may be damaged by the ionic component dissolved in the water. If corrosion progresses on the inner surface of the water pipe of the heat exchanger, the pipe may be perforated, which may lead to problems such as water leakage. Therefore, in evaluating the corrosion resistance of water heaters, it is important to evaluate the corrosion damage on the inner surface of the pipe.

Before implementing the corrosion damage evaluation method, the water pipe that has been corroded is first collected. As a method of collecting water pipes, if a problem occurs with a product sold in the market, the distributor will replace the water heater and collect the defective product, or the FT installed for FT at the time of product development. There is a way to collect the machine after a few years.

Next, a cross-sectional image of the collected water pipe is taken. The purpose of the corrosion damage evaluation of water pipes is to prevent holes in the pipes. Therefore, by taking a cross-sectional image of the water pipe, it is possible to confirm the state of corrosion damage in the outward direction of the pipe connected to the hole in the pipe. As a method of taking a cross-sectional image of a water pipe, the water pipe is cut, embedded in an embedding resin typified by epoxy resin, the cross-sectional portion is polished with a grinder, and then the cross-section is taken using an optical microscope. There is a method of taking an image. Alternatively, there is a method of taking a radiation transmission photograph using radiation and obtaining a cross-sectional image by non-destruction, as typified by an X-ray CT scan. The method for taking a cross-sectional image of the water pipe is not limited to the above, and other known methods can be used. The photographed cross-sectional image is stored in the recording medium and stored in the storage unit 5 via the input unit 2. Alternatively, the captured cross-sectional image may be transmitted via the Internet or a local area network and stored in the storage unit 5 via the communication unit 3.

FIG. 15 is a flowchart of the method for evaluating corrosion damage to piping according to the third embodiment. The corrosion damage evaluation method shown in FIG. 15 is carried out by the information processing unit 4 executing the corrosion damage evaluation processing program. Each step of the corrosion damage evaluation method shown in FIG. 15 corresponds to each step of the corrosion damage evaluation processing program. In the corrosion damage evaluation method, first, steps S1 to S4 similar to those in the first embodiment are carried out. Specifically, the information processing unit 4 acquires the cross-sectional image 200 of the pipe to be evaluated from the storage unit 5 (S1), extracts the piping unit 21 (S2), and stores it in the storage unit 5. FIG. 16 is an example of the image 201 of the extracted piping unit 21. Subsequently, the information processing unit 4 extracts the inner surface shape 210 and the outer surface shape 211 of the piping unit 21 (S3 and S4).

Then, the information processing unit 4 creates the initial inner surface shape 210A of the piping unit 21 from the outer surface shape 211 of the piping unit 21 extracted in step S4 by the creating unit 43 (S20). The initial inner surface shape 210A is the inner surface shape in the initial state before the pipe is corroded. In the case of a water pipe provided in a heat exchanger of a water heater, corrosion hardly progresses because water does not come into contact with the outer surface of the pipe. Therefore, the change in the outer surface of the pipe is smaller than the change due to the corrosion of the inner surface. Further, the shape of the inner surface and the shape of the outer surface of the pipe are substantially the same. Therefore, the shape of the inner surface of the pipe before corrosion can be estimated from the shape of the outer surface of the pipe with less corrosion.

FIG. 17 is a flowchart of a method for creating the initial inner surface shape 210A in the third embodiment. As shown in FIG. 17, first, the information processing unit 4 sets the center A of the outer surface shape 211 by the creation unit 43 using the image 201 (FIG. 16) of the piping unit 21 extracted in step S2 (FIG. 17). S201). Specifically, the information processing unit 4 sets the center of the approximated circle or ellipse as the center A when the outer surface shape 211 of the piping unit 21 can be approximated by a circle or an ellipse, and sets the geometric center of the image 201 when it cannot be approximated. Let it be the center A.

Then, the information processing unit 4 creates a provisional shape included in the inner surface shape 210 with the center A as the center (S202). Specifically, the information processing unit 4 reduces the outer surface shape 211 while maintaining the center A. Then, when all the luminance values on the reduced outer surface shape 211 become 0, the information processing unit 4 determines that the inner surface shape 210 of the piping unit 21 is included, and ends the reduction. Then, the reduced outer surface shape 211 at this time is set as a provisional shape. Then, the information processing unit 4 records the created provisional shape and the center A when the provisional shape is created in the storage unit 5 (S203).

Subsequently, the information processing unit 4 creates a comparative shape when the center is moved to the center B by the creation unit 43. Specifically, the information processing unit 4 sets the center B of the outer surface shape 211 of the piping unit 21 by the creating unit 43 (S204). The center B is a new point different from the center A, and a point in the vicinity of the center A is selected as the center B. Then, the information processing unit 4 creates a comparative shape included in the inner surface shape 210 with the center B as the center (S205). Specifically, the information processing unit 4 reduces the outer surface shape 211 while maintaining the center B. Then, when all the luminance values on the reduced outer surface shape 211 become 0, the information processing unit 4 determines that the inner surface shape 210 of the piping unit 21 is included, and ends the reduction. Then, the information processing unit 4 uses the reduced outer surface shape 211 at this time as a comparative shape. Then, the information processing unit 4 records the created comparison shape and the center B when the comparison shape is created in the storage unit 5 (S206).

Subsequently, the information processing unit 4 calculates and compares the area of the provisional shape and the area of the comparative shape stored in the storage unit 5 by the creating unit 43 (S207). Then, when the area of the comparative shape is larger than the area of the provisional shape (S207: YES), the information processing unit 4 stores the center B and the comparative shape in the storage unit 5 as a new center A and the provisional shape (S207: YES). S208). As a result, the center A stored in the storage unit 5 and the provisional shape are updated. Then, the process returns to step S204, and the subsequent processing is repeated. In this way, the information processing unit 4 searches for the optimum center of the outer surface shape 211 by repeatedly comparing the comparative shape created by changing the position of the center A with the provisional shape. Then, when the area of the comparative shape is equal to or less than the area of the provisional shape (S207: NO), the information processing unit 4 stores the provisional shape as the initial inner surface shape 210A in the storage unit 5 (S209). As a result, the initial inner surface shape 210A of the piping portion 21 before corrosion is created.

Returning to FIG. 15, in the following step S21, the information processing unit 4 has the inner surface shape 210 of the piping unit 21 extracted in step S3 by the corrosion damage evaluation unit 44 and the initial stage of the piping unit 21 created in step S20. The region between the inner surface shape 210A and the corroded portion 23 is extracted (S21). The information processing unit 4 creates an image 203 of the extracted corroded portion 23 and stores it in the storage unit 5. FIG. 18 is an example of the image 203 of the extracted corroded portion 23. In FIG. 18, the corroded portion 23 is shaded. Here, the information processing unit 4 may display the image 203 of the corroded portion 23 shown in FIG. 18 on the output unit 6. Thereby, the corroded portion of the pipe can be clarified.

Subsequently, the information processing unit 4 quantitatively evaluates the corrosion damage of the piping unit 21 by the corrosion damage evaluation unit 44 (S22). Specifically, the information processing unit 4 first calculates the area of the corroded portion 23 extracted in step S21. Then, the information processing unit 4 evaluates the degree of corrosion damage based on the size of the calculated area of the corroded portion 23. Specifically, it is determined that the larger the area of the corroded portion 23, the greater the degree of corrosion damage. Then, the information processing unit 4 outputs the evaluation result from the output unit 6 (S22), and ends the corrosion damage evaluation method. For example, as an evaluation result, the degree of corrosion damage is displayed in the output unit 6 as a numerical value or a sentence. Alternatively, the information processing unit 4 compares the calculated area of the corroded portion 23 with a predetermined threshold value, and if the area of the corroded portion 23 is less than the threshold value, "no problem", and if it is more than the threshold value, "problem". May be output from the output unit 6.

As described above, even in this embodiment, even when the information on the initial state of the piping cannot be obtained, such as when the corrosion of the product recovered from the market is evaluated, the corrosion damage can be easily evaluated. Further, by estimating the initial state from the outer surface of the water pipe having less corrosion and creating the initial inner surface shape 210A, it is possible to evaluate the corrosion damage without lowering the accuracy.

The above is the description of the embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist of the present invention. For example, in the above embodiment, the corrosion damage evaluation method has been described as being carried out by a single corrosion damage evaluation device 100, but is not limited thereto. For example, the corrosion damage evaluation method may be carried out by a plurality of corrosion damage evaluation devices 100, or by a single device or a plurality of devices other than the corrosion damage evaluation device. Further, in the above embodiment, the corrosion damage evaluation program has been described as a program that is stored in advance in the storage unit 5 of the corrosion damage evaluation device 100 and executed by the information processing unit 4, but is not limited thereto. Absent. For example, the corrosion damage assessment program may be stored in a recording medium and distributed, or may be downloaded via the Internet.

Further, in the above embodiment, the initial shape of the inner surface or the outer surface is obtained from the shape of the inner surface or the outer surface of the pipe, but the present invention is not limited to this. For example, the initial cross-sectional shape of the inner surface, outer surface, or other part of the pipe before corrosion is obtained from the shape of a part, one or more points, or a part other than the inner surface or the outer surface of the pipe. May be good.

Further, in the method for evaluating the corrosion damage of the pipes of the first and second embodiments, the extraction of the outer surface shape in step S4 of FIGS. 3 and 11 may be omitted. In this case, the corroded portion can be specified by comparing the piping portion extracted in step S2 with the initial outer surface shape. Similarly, in the method for evaluating corrosion damage to a pipe according to the third embodiment, extraction of the inner surface shape in step S3 of FIG. 15 may be omitted.

Further, in the method of creating the initial outer surface shape 211A of the first embodiment, steps S54 to S58 of FIG. 8 may be omitted to simplify the process. Similarly, in the method of creating the initial inner surface shape 210A of the third embodiment, steps S204 to S208 of FIG. 17 may be omitted to simplify the process. Further, in the third embodiment, when the outer surface shape 211 is provided with a groove, an estimation shape for creating the initial inner surface shape 210A is created by using the method described in the second embodiment. May be good.

1 operation part, 2 input part, 3 communication part, 4 information processing part, 5 storage part, 6 output part, 21 piping part, 22 background part, 22a cavity part, 23 corroded part, 24 groove, 41 acquisition part, 42 extraction Part, 43 Creation part, 44 Corrosion damage evaluation part, 100 Corrosion damage evaluation device, 200 Cross section image, 201, 202, 203 Image, 210 Inner surface shape, 210A Initial inner surface shape, 211 Outer surface shape, 211A Initial outer surface shape, 220 For estimation shape.

Claims (11)

In the corrosion damage evaluation method that evaluates the corrosion damage of pipes that have corroded from the initial shape,
The acquisition step of acquiring an image including the corroded pipe and
An extraction step of extracting the corroded cross-sectional shape of the corroded pipe from the image acquired in the acquisition step, and
From the corrosion cross-sectional shape extracted in the extraction step, a creation step of creating an initial cross-sectional shape of the pipe in the initial shape, and
An evaluation step in which the corrosion damage evaluation is performed by comparing the corrosion cross-sectional shape extracted in the extraction step with the initial cross-sectional shape created in the preparation step, and
Corrosion damage evaluation method. The corroded cross-sectional shape includes the inner surface shape and the outer surface shape of the corroded pipe.
The initial cross-sectional shape is an initial inner surface shape or an initial outer surface shape.
The corrosion damage evaluation method according to claim 1, wherein the evaluation step compares the initial inner surface shape with the inner surface shape, or the initial outer surface shape with the outer surface shape. The creation step
The corrosion according to claim 2, further comprising a step of expanding the inner surface shape to create a provisional shape including the outer surface shape while maintaining the center of the inner surface shape, and making the provisional shape the initial outer surface shape. Damage assessment method. The creation step
The third aspect of claim 3 further comprises a step of changing the position of the center to create a comparative shape, and when the area of the comparative shape is smaller than the area of the provisional shape, the comparative shape is made into the initial outer surface shape. Corrosion damage evaluation method. The creation step
The second aspect of claim 2, further comprising a step of reducing the outer surface shape to create a provisional shape included in the inner surface shape while maintaining the center of the outer surface shape, and making the provisional shape the initial inner surface shape. Corrosion damage evaluation method. The creation step
The fifth aspect of claim 5, further comprising a step of changing the position of the center to create a comparative shape, and when the area of the comparative shape is larger than the area of the provisional shape, the comparative shape is made into the initial outer surface shape. Corrosion damage evaluation method. The creation step further includes a step of creating an estimation shape for creating the initial cross-sectional shape from the corroded cross-sectional shape.
The corrosion damage evaluation method according to any one of claims 1 to 6, wherein the preparation step is to prepare the initial cross-sectional shape from the estimation shape. The creation step
The corrosion damage evaluation method according to claim 7, wherein an approximate ellipse is obtained from the corrosion cross-sectional shape by using the least squares method, and the obtained approximate ellipse is used as the estimation shape. The creation step
The corrosion damage evaluation method according to claim 7, wherein a plurality of representative points on the corrosion cross-sectional shape are acquired, and the acquired plurality of representative points are connected by spline interpolation to obtain the estimation shape. A corrosion damage evaluation program that causes a computer to execute the corrosion damage evaluation method according to any one of claims 1 to 9. In a corrosion damage evaluation device that evaluates corrosion damage of pipes that have corroded from the initial shape
An acquisition unit that acquires an image including the corroded pipe, and
An extraction unit that extracts the corroded cross-sectional shape of the corroded pipe from the image acquired by the acquisition unit,
A creation unit that creates an initial cross-sectional shape of the pipe in the initial shape from the corroded cross-sectional shape extracted by the extraction unit, and a creation unit.
A corrosion damage evaluation unit that evaluates the corrosion damage by comparing the corrosion cross-sectional shape extracted by the extraction unit with the initial cross-sectional shape created by the preparation unit.
Corrosion damage evaluation device equipped with.

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