JP7438176B2 - Method and device for measuring the number of pipes - Google Patents

Description

The present invention relates to a number measuring method and a number measuring device for accurately measuring the number of multiple pipes stacked in a rack so that their longitudinal directions are horizontal.

ERW steel pipes (also referred to as electric resistance welded steel pipes, ERW steel pipes) are manufactured by forming a thin plate unwound from a coil into a tubular shape using rolls on a tube manufacturing line, and forming the ends of the thin plate into a tubular shape. Manufactured by electrical resistance welding. This electric resistance welding uses an induction coil to which high-frequency power is applied to generate an eddy current at the edge of a thin plate, and the edges of the thin plate heated (induction heated) by this eddy current are pressed together with a roll. It is.
Then, in the pipe making line, the long steel pipe after welding is cut into predetermined lengths required for the product.

Steel pipes cut on a pipe-making line are transported horizontally, their end faces are chamfered, their surfaces inspected, and then they fall naturally into racks and are loaded so that their longitudinal directions are horizontal. Specifically, a sling whose position can be varied in the vertical direction is installed in the rack, and the steel pipes are loaded on this sling. By changing the position of the sling vertically depending on the number of steel pipes loaded in the rack (positioning it upwards when the number is small and moving it downwards as the number increases), it is possible to prevent the steel pipes from falling by themselves. Prevents scratches from occurring.

The steel pipes loaded in the rack are transported outside the rack by a crane, coated with anti-rust oil, and then shipped in a state in which a predetermined number (scheduled number) of steel pipes are tied together.
In order to reduce the number of times steel pipes are transported by a crane and increase work efficiency, it is desirable that the number of steel pipes transported at one time be as large as possible, so it is determined near the maximum transport capacity of the crane. For this reason, the number of steel pipes loaded in a rack is large; for example, in the case of small diameter steel pipes (about 10 mm to 60 mm in outer diameter), several hundred pipes are loaded in a rack. Hundreds of steel pipes are then transported by crane out of the rack, bundled, and shipped.

Here, before shipping, it is necessary to inspect whether the number of steel pipes to be bundled matches the planned number. However, it is difficult for inspectors to manually count the number of hundreds of steel pipes loaded in a rack.

For example, Patent Documents 1 and 2 propose a method of automatically measuring the number of bundled steel pipes. However, as described in Patent Documents 1 and 2, in the method of automatically measuring the number of steel pipes after bundling, the cross-sectional shape of the bundle of steel pipes after bundling is generally hexagonal. Since it is difficult to bundle hundreds of steel pipes such as the small-diameter steel pipes mentioned above so that the bundle has a hexagonal cross-sectional shape, the methods described in Patent Documents 1 and 2 are used. Therefore, it is not realistic to measure the number of steel pipes after they are bundled.
In addition, if the number of bundled steel pipes does not match the planned number, it is necessary to untie the bundle and re-bind the correct number of steel pipes, so especially when bundling a large number of steel pipes, It is desirable to measure the number of steel pipes before bundling in order to eliminate the hassle of unbundling and re-bundling.
Therefore, it is desired to automatically measure the number of steel pipes loaded in a rack before bundling.

Although methods for automatically measuring the number of steel pipes are proposed in Patent Documents 3 and 4, these methods do not allow automatic measurement of the number of steel pipes loaded in a rack.

In the above explanation, the pipes are ERW steel pipes as an example, but the pipes are not necessarily limited to this, and it is possible to accurately measure the number of pipes loaded in a rack. desired.

Japanese Patent Application Publication No. 2013-239105 Japanese Patent Application Publication No. 2013-246749 Japanese Patent Application Publication No. 10-269337 Japanese Patent Application Publication No. 2015-43124

The present invention has been made in order to solve the problems of the prior art as described above, and is a method for accurately measuring the number of multiple pipes loaded in a rack so that the longitudinal direction is horizontal. An object of the present invention is to provide a measuring method and a number measuring device.

In order to solve the above problem, the present inventors conducted extensive studies and focused on applying a pattern matching (template matching) method. Specifically, a captured image was generated by capturing the end face of a bundle of tubes to be measured, which is made up of multiple tubes to be measured, and the image was created based on this captured image and the nominal outer diameter and nominal wall thickness of the tubes to be measured. Pattern matching is performed with the template image to calculate the matching rate of a plurality of pixel areas constituting the captured image with the template image, and the number of pixel areas for which this matching rate is greater than or equal to a predetermined threshold is calculated for the pipe bundle to be measured. We investigated a method of calculating the number of pipes to be measured in the structure.
However, if the above threshold is set too high, some pipes will not be counted and the calculated number will be less than the actual number (in other words, undetected). If the setting is too low, gaps between the measured pipes where no pipes actually exist will be counted as measured pipes, and the calculated number will be higher than the actual number (i.e., over-detection). ), and it is difficult to manually set appropriate thresholds.

Therefore, as a result of further intensive study, the present inventors determined that the vertical dimensions of the bundle of tubes to be measured (out of the plurality of loaded tubes to be measured, the uppermost tube to be measured and the lowermost tube to be measured) The vertical distance from the measurement tube) to the lateral dimension of the bundle of measurement tubes (the distance between the measurement tube located on the leftmost side and the measurement tube located on the rightmost side among the multiple measurement tubes loaded). It has been found that there is a good correlation between the aspect ratio of the pipe bundle to be measured divided by the distance in the left-right direction) and the matching rate of the pixel area corresponding to the pipe to be measured in the captured image. Therefore, it has been found that by determining the threshold value based on the aspect ratio of the pipe bundle to be measured, the number of the plurality of pipes to be measured constituting the bundle of pipes to be measured can be appropriately calculated.

The present invention was completed based on the above findings of the present inventors.
That is, in order to solve the above-mentioned problems, the present invention provides a method for measuring the number of a plurality of pipes to be measured loaded in a rack so that the longitudinal direction is horizontal, the method comprising: a captured image generation step of generating a captured image by capturing an end face of a bundle of tubes to be measured; a template image created based on the nominal outer diameter and nominal wall thickness of the tube to be measured; A pattern matching step of performing pattern matching on the generated captured image to calculate a matching rate of a plurality of pixel regions constituting the captured image with the template image, and determining the vertical dimension of the pipe bundle to be measured. A threshold value is determined based on the aspect ratio of the pipe bundle to be measured divided by the horizontal dimension, and among the plurality of pixel areas, pixels for which the matching rate calculated in the pattern matching step is equal to or higher than the threshold value. A method for measuring the number of pipes is provided, comprising: a number calculation step of calculating the number of regions as the number of the plurality of pipes to be measured constituting the bundle of pipes to be measured.

According to the present invention, in the number calculation process, a threshold value is determined based on the aspect ratio of the pipe bundle to be measured, and the matching rate calculated in the pattern matching process is determined among the plurality of pixel areas that constitute the captured image. Since the number of pixel areas that are equal to or greater than the threshold value is calculated as the number of multiple pipes to be measured that constitute the bundle of pipes to be measured, as the present inventors have found, it is possible to appropriately calculate the number of pipes to be measured. be.

In the present invention, the aspect ratio of the pipe bundle to be measured can also be calculated by image processing the captured image generated in the captured image generation step.
However, according to the findings of the present inventors, there is a good correlation between the aspect ratio of the tube bundle placed in the rack and the nominal outer diameter of the tube. Therefore, without having to calculate the aspect ratio of the pipe bundle to be measured each time by image processing the captured image, if the above correlation is applied to the nominal outer diameter of the pipe to be measured, which can be known in advance, the aspect ratio of the pipe bundle to be measured can be calculated. It is possible to estimate the ratio.
That is, in the present invention, preferably, the tube bundle is composed of a plurality of tubes placed in the rack so that the longitudinal direction is horizontal, and the plurality of tubes have different nominal outer diameters. further comprising a first relationship calculation step of calculating in advance a first relationship between the aspect ratio of the tube bundle and the nominal outer diameter of the tubes using the tube bundle, and in the number calculation step, the Using the nominal outer diameter of the measurement pipe and the first relationship calculated in the first relationship calculation step, estimate the aspect ratio of the pipe bundle to be measured, and based on the estimated aspect ratio of the bundle of pipes to be measured. determining the threshold;
According to the preferred method described above, if the first relationship (correlation between the aspect ratio of the tube bundle placed in the rack and the nominal outside diameter of the tube) is calculated in advance, the aspect ratio of the tube bundle to be measured can be adjusted to that value. There is no need to perform image processing and calculation each time, the threshold value can be determined efficiently, and the number of pipes to be measured can be calculated efficiently.

As described above, according to the findings of the present inventors, there is a good correlation between the aspect ratio of the tube bundle to be measured and the matching rate of the pixel area corresponding to the tube to be measured in the captured image. Specifically, for example, there is a good correlation between the parameter calculated by dividing the aspect ratio of a tube bundle placed in a rack by the wall thickness of the tube and the matching rate of the pixel area corresponding to the tube in the captured image. have a relationship
Therefore, in the present invention, preferably, the tube bundle is composed of a plurality of tubes placed in the rack so that the longitudinal direction is horizontal, and the tube bundle has a nominal outer diameter and a nominal wall thickness of the plurality of tubes. A second relationship in which a second relationship is calculated in advance between a parameter calculated by dividing the aspect ratio of the tube bundle by the wall thickness of the tube and the coincidence rate using a plurality of the tube bundles having different thicknesses. further comprising a calculation step, in the number calculation step, the evaluation target parameter calculated by dividing the aspect ratio of the pipe bundle to be measured by the wall thickness of the pipe to be measured, and the parameter calculated in the second relationship calculation step. The threshold value is determined using the second relationship.
According to the above preferred method, if the second relationship (the correlation between the coincidence rate and the parameter calculated by dividing the aspect ratio of the tube bundle by the wall thickness of the tube) is calculated in advance, Using the evaluation target parameter calculated by dividing the ratio by the wall thickness of the pipe to be measured and the second relationship, the threshold value can be appropriately determined, and the number of pipes to be measured can be calculated with high accuracy. .

In the above preferred method, it is also possible to use the nominal wall thickness as the wall thickness of the tube when calculating the parameters in the second relationship calculating step.
However, in the case where the tube is an electric resistance welded steel tube, the end face is chamfered, so the wall thickness of the tube in the captured image is considered to be smaller than the nominal wall thickness. Therefore, in order to calculate the second relationship with good accuracy (high correlation coefficient), it is preferable to use the wall thickness after chamfering.
That is, in the above preferred method, when calculating the parameters in the second relationship calculating step, the wall thickness of the pipe after chamfering, which is the value obtained by subtracting the amount of wall thinning due to chamfering from the nominal wall thickness of the pipe, is used as the wall thickness of the pipe. When calculating the evaluation target parameter in the number calculation step using the wall thickness, the wall thickness of the measured pipe is a chamfer that is a value obtained by subtracting the amount of wall thinning due to chamfering from the nominal wall thickness of the measured pipe. It is more preferable to use the rear wall thickness.
Note that the amount of thinning means the length of the portion that is inclined with respect to the end surface (cut surface) due to chamfering of the end surface (inner surface side and outer surface side) after cutting the pipe.

In addition, in the above-mentioned preferred method, in order to obtain a more appropriate threshold value, it is necessary to consider variations in the matching rate depending on the positions of the plurality of pixel regions that make up the captured image and the calculation error of the matching rate in the second relationship. It is preferable to take this into consideration and correct the determined threshold value.
That is, in the above-mentioned preferred method, in the second relationship calculation step, variations in the matching rate depending on the positions of the plurality of pixel regions forming the captured image and a calculation error in the matching rate in the second relationship are determined. In the number calculation step, the threshold value determined using the evaluation target parameter and the second relationship is corrected based on the correction amount, and the matching rate is It is more preferable to calculate the number of pixel regions in which is equal to or greater than the corrected threshold value as the number of the plurality of pipes to be measured constituting the bundle of pipes to be measured.

The present invention is particularly effective when the tube bundle to be measured is installed in the rack and loaded on a sling whose position can be varied in the vertical direction.

Further, the present invention is particularly effective when the pipe to be measured is an electric resistance welded steel pipe.

Further, in order to solve the above problems, the present invention provides an apparatus for measuring the number of a plurality of pipes to be measured loaded in a rack so that the longitudinal direction thereof is horizontal, the plurality of pipes to be measured being an imaging means for capturing an end face of a bundle of pipes to be measured and generating a captured image; and arithmetic processing for calculating the number of the plurality of pipes to be measured using the captured image generated by the imaging means. means, the arithmetic processing means pattern-matching a template image created based on the nominal outer diameter and nominal wall thickness of the tube to be measured and the captured image generated by the imaging means, a pattern matching step of calculating a matching rate of a plurality of pixel regions constituting the captured image with the template image; and an aspect ratio of the pipe bundle to be measured, which is obtained by dividing the vertical dimension of the pipe bundle to be measured by the horizontal dimension of the pipe bundle to be measured. A threshold value is determined based on the number of pixel regions in which the matching rate calculated in the pattern matching step is equal to or greater than the threshold value among the plurality of pixel regions to form the measured pipe bundle. A number calculation step of calculating the number of the plurality of pipes to be measured is also provided.

According to the present invention, it is possible to accurately measure the number of multiple pipes loaded in a rack so that the longitudinal direction is horizontal.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the schematic structure of the number measuring device based on one Embodiment of this invention. 2 is a diagram showing an example of a captured image generated by the imaging means 1 shown in FIG. 1. FIG. FIG. 2 is a flow diagram showing a schematic procedure of a method for measuring the number of pieces according to an embodiment of the present invention. 4 is a diagram showing an example of a first relationship calculated in the first relationship calculation step ST11 shown in FIG. 3. FIG. FIG. 4 is an explanatory diagram illustrating a method of calculating a coincidence rate used to calculate a second relationship in the second relationship calculation step ST12 shown in FIG. 3. FIG. 4 is an explanatory diagram schematically illustrating an example of a matching rate calculation position used to calculate the second relationship in the second relationship calculation step ST12 shown in FIG. 3. FIG. It is a figure which shows an example of the 2nd relationship calculated in 2nd relationship calculation process ST12 shown in FIG. It is a figure which shows the other example of the 2nd relationship calculated in 2nd relationship calculation process ST12. A diagram showing an example of the relationship between the parameter calculated by dividing the aspect ratio VH _rate of the tube bundle PB' by the post-chamfering wall thickness T1 of the tube P' and the total error σ, which is calculated in the second relationship calculation step ST12. It is. FIG. 8B is an explanatory diagram illustrating a procedure for determining the threshold value Th' before correction using the second relationship shown in FIG. 8(b).

Hereinafter, with appropriate reference to the accompanying drawings, a description will be given of a pipe number measuring device according to an embodiment of the present invention and a method for measuring the number of pipes using the same, taking as an example the case where the pipe to be measured is an electric resistance welded steel pipe. explain.

FIG. 1 is a diagram schematically showing a schematic configuration of a number measuring device according to an embodiment of the present invention. FIG. 1(a) is a plan view of the number measuring device. FIG. 1(b) is a front view illustrating the installation location of the number measuring device. In FIG. 1(a), illustration of the surface inspection table is omitted. In FIG. 1(b), illustration of the number measuring device is omitted. The X direction shown in FIG. 1 is a horizontal direction perpendicular to the longitudinal direction of the tube to be measured, the Y direction is the vertical direction, and the Z direction is the longitudinal direction of the tube to be measured. The same applies to other figures. It should be noted that the dimensions, scale, and shapes of the components shown in FIG. 1 may differ from the actual ones. The same applies to other figures.
As shown in FIG. 1, the number measuring device 100 according to the present embodiment measures a plurality of pipes P to be measured loaded in a rack R having a U-shaped cross section so that the longitudinal direction (Z direction) is horizontal. This is a device that measures the number of pieces. As shown in FIG. 1(a), the number counting device 100 includes an imaging means 1 and an arithmetic processing means 2. Moreover, the number measuring device 100 according to this embodiment further includes an illumination means 3 and a control means 4.

As shown in FIG. 1(b), the end face of the measured pipe P of this embodiment is chamfered by a chamfering machine (not shown), and then transported horizontally on a surface inspection table T (in the X direction perpendicular to the longitudinal direction). The surface is inspected while being transported (transferred to The tube P to be measured whose surface inspection has been completed naturally falls from the end of the surface inspection table T and is loaded into the rack R. Since the end of the rack R in the X direction is open, the imaging field of the imaging means 1 is not obstructed by the rack R, and the imaging means 1 can image the end surface of the tube P to be measured.
Inside the rack R, a sling S made of a band-shaped resin is installed. In this embodiment, a plurality of slings S (three in the example shown in FIG. 1A) are arranged in the Z direction. The tube to be measured P is loaded onto this sling S. The position of the sling S can be changed in the vertical direction. Specifically, one end of the sling S in the X direction is fixed, and the other end is connected to a motor drive mechanism (not shown), and by driving the motor drive mechanism, the sling S is positioned in the rack R. The length of the part is variable. If the length of this sling S is extended, the position of the sling S (the intermediate position of the sling S in the (intermediate position) fluctuates upward. When the number of pipes P to be measured loaded in the rack R is small, the sling S is positioned upward, and as the number increases, it is positioned downward, thereby preventing the occurrence of flaws in the pipes P to be measured when falling naturally. are doing.

The imaging means 1 images the end face of a bundle of measurement tubes PB made up of a plurality of measurement tubes P to generate a captured image. The imaging means 1 directly faces the end face of the tube bundle PB to be measured (that is, the line of sight of the imaging means 1 is in the Z direction), and its line of sight passes near the center of the rack R in the X direction and passes through the vicinity of the center of the rack R in the Y direction. It is arranged so as to pass near both ends of the sling S in the X direction. The imaging magnification of the imaging means 1 (the magnification of the lens system included in the imaging means 1) is set so that the entire end face of the tube bundle PB to be measured falls within the imaging field of view. As the imaging device of the imaging means 1, CMOS or CCD is used.

The illumination means 3 is arranged to face the end surface of the tube bundle PB to be measured and to illuminate the end surface of the tube bundle PB to be measured. As the illumination means 3, a known light source such as a halogen lamp is used. In the example shown in FIG. 1(a), a pair of illumination means 3 are arranged side by side in the X direction with the imaging means 1 in between; however, the illumination means 3 are not limited to this, and the illuminance of the end face of the tube bundle PB to be measured is made as uniform as possible. It is only necessary to set an appropriate number and the inclination of the optical axis so that

The control means 4 is electrically connected to the imaging means 1 and the illumination means 3 and has a function of controlling the operations of the imaging means 1 and the illumination means 3. Specifically, for example, the control means 4 is provided with a switch to start the operation, and when the inspector presses this switch, a control signal to start the operation is sent to both the imaging means 1 and the illumination means 3. be done. Thereby, the illumination means 3 illuminates the end face of the pipe bundle PB to be measured, and at the same time, the imaging means 1 images the end face of the pipe bundle PB to be measured to generate a captured image. In the generated captured image, the pixel area corresponding to the end face of the tube bundle PB to be measured is brighter than other pixel areas.

FIG. 2 is a diagram showing an example of a captured image generated by the imaging means 1 (specifically, a part of the captured image, in which a pixel region where the end face of the pipe bundle PB to be measured exists is cut out). . FIG. 2(a) is a captured image of a bundle of measured tubes PB composed of 500 measured tubes P with a nominal outer diameter OD0=10 mm and a nominal wall thickness T0=1.5 mm. FIG. 2(b) is a captured image of a bundle of measured tubes PB composed of 250 measured tubes P with a nominal outer diameter OD0=17.3 mm and a nominal wall thickness T0=2.96 mm. FIG. 2(c) is a captured image of a bundle of measured tubes PB composed of 250 measured tubes P with a nominal outer diameter OD0=22.2 mm and a nominal wall thickness T0=2.58 mm. In addition, in FIG. 2, "□" and numbers are displayed inside the approximately circular pixel area corresponding to the pipe to be measured P, but this is because the pipe to be measured is As a result of counting P (specifically, the numbers displayed in FIG. 2 mean the coincidence rate (%) of each tube P' when similar captured images are used in the second relationship calculation step ST12 described later) , the matching rate of each pixel area A1 to A5 is calculated using the matching rate of each tube P' existing in the pixel area A1 to A5), and the matching rate of each pixel area A1 to A5 is calculated using the matching rate of each tube P' existing in the pixel area A1 to A5). do not.
In the captured image shown in FIG. 2(a), the vertical dimension V of the bundle of measured tubes PB (out of the plurality of loaded measured tubes P, the uppermost measured tube P and the lowermost measured tube P) The distance from the measured pipe P in the vertical direction (Y direction) to the measured pipe bundle PB is determined by the horizontal dimension H of the measured pipe bundle PB (the measured pipe P located on the leftmost side among the plurality of measured pipes P loaded). The aspect ratio VH _rate (=V/H) of the measured pipe bundle PB divided by the distance in the left-right direction (X direction) from the rightmost pipe P to be measured was 0.35. In the captured image shown in FIG. 2(b), the aspect ratio VH _rate of the measured pipe bundle PB is 0.4, and in the captured image shown in FIG. 2(c), the aspect ratio VH _rate of the measured pipe bundle PB is: It was 0.59.
In this way, it was found that the larger the nominal outer diameter OD0 of the pipes to be measured P, the larger the aspect ratio VH _rate of the bundle of pipes to be measured PB.

A captured image generated by the imaging device 1 is input to the arithmetic processing device 2 via the control device 4 . Then, the arithmetic processing means 2 uses this captured image to calculate the number of the plurality of pipes P to be measured by executing a pattern matching step ST3 and a number calculation step ST4, which will be described later. The arithmetic processing means 2 is composed of, for example, a computer in which a program for executing each step ST3 and ST4 is installed.

In addition, although this embodiment demonstrated the structure in which the number measuring device 100 was provided with the illumination means 3, this invention is not necessarily limited to this. Depending on the installation environment of the number measuring device 100, a configuration without the illumination means 3 may be adopted as long as a captured image is generated in which the pixel area corresponding to the end face of the tube bundle PB to be measured is brighter than other pixel areas. It is possible.
Further, in this embodiment, the configuration in which the number counting device 100 includes the control means 4 has been described, but the present invention is not necessarily limited to this. For example, it is also possible to employ a configuration in which the imaging means 1 and the illumination means 3 are constantly operated without providing the control means 4. In this case, the imaging means 1 is directly connected to the arithmetic processing means 2, and the captured image generated by the imaging means 1 is directly input to the arithmetic processing means 2.

Hereinafter, a method for measuring the number of pieces using the number measuring device 100 having the above configuration will be explained.
FIG. 3 is a flowchart showing a schematic procedure of a number counting method according to an embodiment of the present invention.
As shown in FIG. 3, the number counting method according to the present embodiment includes a preparation step ST1 including a first relationship calculation step ST11 and a second relationship calculation step ST12, a captured image generation step ST2, a pattern matching step ST3, It has a number calculation step ST4. Each step ST1 to ST4 will be explained in order below.

<Preparation process ST1>
In the preparation step ST1, prior to measuring the number of the plurality of measured pipes P constituting the measured pipe bundle PB, a first relationship is calculated in advance using a pipe bundle PB' different from the measured pipe bundle PB. (first relationship calculation step ST11), and calculates a second relationship (second relationship calculation step ST12).

[First relationship calculation step ST11]
In the first relationship calculation step ST11, the tube bundle PB' is composed of a plurality of tubes P' placed in the rack R so that the longitudinal direction (Z direction) is horizontal, similar to the tube bundle PB to be measured. Using a plurality of tube bundles PB' in which the plurality of tubes P' have different nominal outer diameters OD0, each end face of the tube bundle PB' is imaged by the imaging means 1 to generate a captured image. That is, a captured image of the end face of a tube bundle PB' that is composed of a plurality of tubes P' having a certain nominal outer diameter OD0 is generated, and a captured image is generated of the end face of a tube bundle PB' that is composed of a plurality of tubes P' that has a different nominal outer diameter OD0. A captured image of the end face of the tube bundle PB' is generated. This is repeated for the number of different nominal outer diameters OD0. As a result, a plurality of captured images are generated according to the number of different nominal outer diameters OD0.
Note that by generating a captured image of the end face of another tube bundle PB' that is composed of another plurality of tubes P' having the same nominal outer diameter OD0 (i.e., a plurality of captured images corresponding to the same nominal outer diameter OD0). ) and use this in conjunction with calculating the first relationship.
Then, based on the plurality of generated captured images, a first relationship, which is the relationship between the aspect ratio VH _rate of the tube bundle PB' and the nominal outer diameter OD0 of the tube P', is calculated.

FIG. 4 is a diagram showing an example of the first relationship calculated in the first relationship calculation step ST11. In FIG. 4, the points plotted with "○" are the aspect ratio VH rate of the tube bundle PB' calculated based on the captured images corresponding to each nominal outer diameter OD0, with the horizontal axis coordinate being the nominal outer diameter OD0 of the tube _P '. is the data point with the vertical axis coordinate. The straight line indicated by a dotted line in FIG. 4 is an approximate straight line calculated by the least squares method using each data point. This approximate straight line is set as the first relationship and is stored in the arithmetic processing means 2. As can be seen from FIG. 4, as the nominal outer diameter OD0 of the tube P' increases, the aspect ratio VH _rate of the tube bundle PB' also increases.
Note that in this embodiment, an approximate straight line calculated by the least squares method using each data point is calculated as the first relationship, but the present invention is not limited to this. An approximation calculation method other than the least squares method may be used, or an approximate curve such as a quadratic function may be calculated as the first relationship.

[Second relationship calculation step ST12]
In the second relationship calculation step ST12, the tube bundle PB' is composed of a plurality of tubes P' placed in the rack R so that the longitudinal direction (Z direction) is horizontal, similar to the tube bundle PB to be measured. Using a plurality of tube bundles PB' in which the plurality of tubes P' have different nominal outer diameters OD0 and nominal wall thicknesses T0, the imaging means 1 images the end faces of the tube bundles PB' to generate captured images. That is, a captured image of the end face of a tube bundle PB' composed of a plurality of tubes P' having a certain nominal outer diameter OD0 and a nominal wall thickness T0 is generated, and a captured image is generated of the end face of a tube bundle PB' that has a certain nominal outer diameter OD0 and a nominal wall thickness T0. A captured image of the end face of a tube bundle PB' made up of a plurality of tubes P' having a diameter is generated. This process is repeated for the number of different nominal outer diameters OD0 and nominal wall thicknesses T0. As a result, a plurality of captured images corresponding to the number of different nominal outer diameters OD0 and different nominal wall thicknesses T0 are generated.
Note that by generating a captured image of the end face of another tube bundle PB' that is composed of another plurality of tubes P' having the same nominal outer diameter OD0 and nominal wall thickness T0 (that is, the same nominal outer diameter OD0 and nominal wall thickness T0), A plurality of captured images corresponding to the wall thickness T0 may be generated) and used in conjunction with calculating the second relationship. Further, if the plurality of captured images used in the first relationship calculation step ST11 include captured images corresponding to different nominal wall thicknesses T0, the plurality of captured images used in the first relationship calculation step ST11 can be used as they are. It is also possible to use it in the two-relation calculation step ST12.
Then, based on the generated plurality of captured images, a parameter calculated by dividing the aspect ratio VH _rate of the tube bundle PB by the wall thickness of the tube P and a matching rate (relative to the template image of the plurality of pixel regions constituting the captured image) are calculated. A second relationship is calculated, which is the relationship with the match rate).

The method for calculating the matching rate will be explained below.
FIG. 5 is an explanatory diagram illustrating a method for calculating the matching rate used to calculate the second relationship.
FIG. 5A is a diagram schematically showing a binarized image obtained by binarizing a captured image. Ideally, in a binarized image, the pixel area corresponding to the end face of the tube P' extracted by binarization will be white (pixel value of 255 in the case of 8 bits), and pixels other than the end face of the tube P' will be white. The area is black (in the case of 8 bits, the pixel value is 0).
FIG. 5(b) is a diagram schematically showing a template image. The template image T _IMG is created based on the nominal outer diameter OD0 and nominal wall thickness T0 of the pipe P'. Specifically, the template image T _IMG includes a perfect circle having an outer diameter corresponding to the nominal outer diameter OD0 (outer diameter obtained by multiplying the nominal outer diameter OD0 by the imaging magnification of the imaging means 1), and a perfect circle having an outer diameter corresponding to the nominal outer diameter OD0 - the nominal outer diameter OD0 A pixel area located between a perfect circle having an outer diameter corresponding to the wall thickness T0×2 (nominal outer diameter OD0 - outer diameter obtained by multiplying the nominal wall thickness T0×2 by the imaging magnification of the imaging means 1) is white ( In the case of 8 bits, the pixel value is 255), and the other pixel areas are black (in the case of 8 bits, the pixel value is 0).
Then, pattern matching (template matching) is performed between the template image T _IMG shown in FIG. 5(b) and the binarized image shown in FIG. Calculate the matching rate for the image T _IMG . Specifically, the template image _TIMG is sequentially scanned on the binarized image in the X direction and the Y direction at a predetermined pitch (for example, 1 pixel pitch), and the pixel of the binarized image where the template image _TIMG is located is The rate at which the positions of white pixels in the template image _TIMG and the positions of white pixels in the pixel area of the binarized image match in the area is calculated as a matching rate. That is, assuming that the total number of white pixels in the template image _TIMG is M and the number of matching pixels is N, the matching rate is calculated by the following equation (1).
Match rate = N/M x 100 [%] ... (1)

For example, as shown in FIG. 5(c), when the template image T _IMG is located on the pixel area PA1 of the binarized image (see FIG. 5(a)), the pixel area PA1 of the binarized image is Since there are only pixels, there are no white pixels in the pixel area PA1 of the binarized image that match the white pixels of the template image _TIMG . Therefore, the matching rate is 0%.
On the other hand, as shown in FIG. 5(d), when the template image T _IMG is located on the pixel area PA2 of the binarized image (see FIG. 5(a)), Since the position of the white pixel and the position of the white pixel in the template image _TIMG completely match, the matching rate is 100%. However, in reality, the end surface of the tube P' may not be a perfect circle, or the pixel area corresponding to the end surface of the tube P' in the binarized image may not be a perfect circle, depending on the setting of the binarization threshold. Because it is not a circle, the matching rate is never 100% and is usually less than 100%.

The calculation of the matching rate by pattern matching described above can be performed using a program for executing a pattern matching step ST3, which will be described later, executed by the arithmetic processing means 2.
In addition, in this embodiment, the case where pattern matching is performed after binarizing the captured image has been described as an example, but the present invention is not necessarily limited to this, and the captured image (shaded image) can be used as is. It is also possible to perform pattern matching. Regarding pattern matching, since various known techniques can be applied, further detailed explanation will be omitted in this specification.

In the second relationship calculation step ST12, as described above, a second relationship is calculated between the parameter calculated by dividing the aspect ratio VH _rate of the tube bundle PB' by the wall thickness of the tube P' and the coincidence rate. do.
FIG. 6 is an explanatory diagram schematically illustrating an example of a matching rate calculation position used to calculate the second relationship. In FIG. 6, a broken line PE schematically represents the outer edge shape of the tube bundle PB'. As shown in FIG. 6, when calculating the second relationship in this embodiment, in the binarized image, the matching rate in pixel areas A1 and A2 located on the upper left and right sides of the tube bundle PB', and the The matching rates in the pixel areas A3 to A5 located at the center in the left-right direction (X direction) are used. Each of the pixel regions A1 to A5 includes pixel regions corresponding to the end faces of a plurality of (10 in this embodiment) tubes P'. Then, the matching rate of the pixel regions corresponding to each of the 10 tubes P' is calculated for each of the pixel regions A1 to A5. That is, the highest matching rate when the template image _TIMG is located near the pixel area corresponding to each of the ten tubes P' is calculated as the matching rate of the pixel area corresponding to each tube P'. Then, the average value of the matching rates of the pixel areas corresponding to each of these 10 tubes P' is calculated as the matching rate of each pixel area A1 to A5. Furthermore, the average value of the matching rates of each pixel area A1 to A5 is used as the matching rate for calculating the second relationship.

FIG. 7 is a diagram showing an example of the second relationship calculated in the second relationship calculation step ST12. Specifically, the second relationship shown in FIG. 7 is calculated by using the nominal wall thickness T0 as the wall thickness of the pipe P' and dividing the aspect ratio VH _rate of the tube bundle PB' by the nominal wall thickness T0 of the pipe P'. This is the relationship between the parameters calculated and the matching rate calculated by the procedure described with reference to FIGS. 5 and 6.
In FIG. 7, the points plotted with "○" are the horizontal axis coordinates of the parameters calculated by dividing the aspect ratio VH _rate of the tube bundle PB' by the nominal wall thickness T0 of the tube P', and the vertical axis coordinates the coincidence rate. is the data point. The straight line indicated by a dotted line in FIG. 7 is an approximate straight line calculated by the least squares method using each data point. This approximate straight line is taken as a second relationship, and if this second relationship is used, this second relationship is stored in the arithmetic processing means 2. As can be seen from FIG. 7, the larger the parameter, the smaller the matching rate.

In the example shown in FIG. 7, a parameter calculated by dividing the aspect ratio VH _rate of the tube bundle PB' by the nominal wall thickness T0 of the tube P' is used. As the thickness, it is also possible to use the wall thickness T1 after chamfering (that is, T1=T0-the amount of wall thinning), which is the value obtained by subtracting the wall thinning amount due to chamfering from the nominal wall thickness T0 of the pipe P'.

FIG. 8 is a diagram showing another example of the second relationship calculated in the second relationship calculation step ST12. FIG. 8A is a diagram showing an example of the relationship between the nominal wall thickness T0 and the wall thickness T1 after chamfering. The relationship shown in FIG. 8(a) can be derived by setting the chamfering machine that performs chamfering. It is also possible to derive it by comparing the captured image generated by capturing the end face of the tube bundle PB' with the imaging means 1 and the template image _TIMG . FIG. 8(b) is a diagram showing the second relationship calculated in the second relationship calculation step ST12 when the wall thickness after chamfering T1 is used. Specifically, FIG. 8(b) uses the same data points used to calculate the second relationship shown in FIG. 7 and also uses the relationship shown in FIG. The nominal wall thickness T0, which constitutes the parameters shown on the horizontal axis, is replaced by the wall thickness T1 after chamfering.
In FIG. 8(b), the points plotted with "○" are the horizontal axis coordinates of the parameter calculated by dividing the aspect ratio VH _rate of the tube bundle PB' by the wall thickness T1 after chamfering of the tube P', and the coincidence rate is the data point with the vertical axis coordinate. The straight line indicated by a dotted line in FIG. 8(b) is an approximate straight line calculated by the least squares method using each data point. This approximate straight line is taken as a second relationship, and when this second relationship is used, this second relationship is stored in the arithmetic processing means 2. Further, the relationship between the nominal wall thickness T0 and the wall thickness T1 after chamfering as shown in FIG. 8(a) is also stored in the arithmetic processing means 2.
As can be seen from FIG. 8, similar to FIG. 7, the larger the parameter, the smaller the matching rate. Furthermore, as can be seen by comparing FIG. 8 and FIG. 7, the second relationship shown in FIG. 8 is more accurate (has a higher correlation coefficient) and can be calculated. Therefore, it is preferable to use the second relationship calculated using the wall thickness T1 after chamfering as shown in FIG. 8 as the second relationship. In the following description, an example will be described in which the second relationship calculated using the wall thickness T1 after chamfering, as shown in FIG. 8, is used.

In addition, in this embodiment, in both cases of FIG. 7 and FIG. 8, an approximate straight line calculated by the least squares method using each data point is calculated as the second relationship, but the present invention is not limited to this. isn't it. An approximation calculation method other than the least squares method may be used, or an approximate curve such as a quadratic function may be calculated as the second relationship.

As can be seen from FIGS. 7 and 8, the larger the parameter, the smaller the matching rate. In other words, the greater the aspect ratio VH _rate of the tube bundle PB', the smaller the coincidence rate. As can be seen from the above-mentioned FIG. 4, the larger the nominal outer diameter OD0 of the pipe P', the larger the aspect ratio VH _rate of the tube bundle PB'. It can be said that it will be. Possible reasons for this are as follows.
As the nominal outer diameter OD0 of the pipe P' increases, the area of the end surface of the pipe P' also increases. For this reason, after cutting or chamfering the pipe P', the distribution of surface roughness and the perpendicularity to the pipe axis tend to become uneven over the entire circumference of the end face of the pipe P'. For this reason, the brightness (pixel value) of the pixel area corresponding to the end surface of the tube P' in the captured image tends to be non-uniform, and when binarized, the pixel area corresponding to the end surface of the tube P' is more likely to be One of the reasons is thought to be that the sample size is small.
In addition, when the tube bundle PB' is composed of several hundred tubes P', the end faces of the tubes P' located below the tube bundle PB' are deformed into ellipses due to the weight of the tubes P'. . One of the reasons is that the larger the nominal outer diameter OD0 of the pipe P', the greater the weight of the pipe P', so the larger the nominal outer diameter OD0 of the pipe P', the greater the degree of deformation into an ellipse. it is conceivable that.

In addition, in the second relationship calculation step ST12 of this embodiment, in addition to calculating the second relationship, a correction amount to be used in the number calculation step ST4, which will be described later, is determined.
Specifically, in the second relationship calculation step ST12, variations in the matching rate depending on the positions of a plurality of pixel regions constituting the captured image (binarized image) and calculation errors in the matching rate in the second relationship are calculated. Taking this into account, determine the amount of correction.
In this embodiment, the variation in the matching rate depending on the position of a plurality of pixel areas is determined by considering the matching rate of the pixel areas A1 to A5 shown in FIG. 1) and the standard deviation of the matching rates of pixel areas A1 to A5 (pixels corresponding to each of the 10 tubes P' present in each pixel area A1 to A5). Consider the variation σ2 in the standard deviation of the region matching rate. Furthermore, as an error in calculating the matching rate in the second relationship, consider the distance σ3 in the vertical axis direction between the data points plotted with “◯” shown in FIG. 8(b) and the second relationship (straight line shown by a dotted line).
Then, the total error σ is calculated based on the following equation (2).
σ=(σ1 ² +σ2 ² +σ3 ² ) ^1/2 ...(2)

FIG. 9 is a diagram showing an example of the relationship between the parameter calculated by dividing the aspect ratio VH _rate of the tube bundle PB' by the wall thickness T1 after chamfering of the tube P' and the total error σ calculated as described above. It is. Specifically, FIG. 9 shows the results of calculating the total error σ for the same data points as shown in FIG. 8(b).
As shown in FIG. 9, the total error σ shows a substantially constant value regardless of the parameter values, and in the example shown in FIG. 9, it was about 4% at maximum. Therefore, in the example shown in FIG. 9, the correction amount is determined to be, for example, three times (3σ) the total error σ of 4%, which is a constant value, regardless of the value of the parameter.
Note that the present invention is not necessarily limited to this, and similarly to the first relationship and the second relationship, the relationship between the parameters and the total error σ is approximated by the method of least squares, etc., and this relationship is used to calculate the relationship for each parameter. It is also possible to determine the amount of correction.
The determined correction amount is stored in the arithmetic processing means 2.

In the number measuring method according to the present embodiment, after performing the preparation step ST1 (first relationship calculation step ST11, second relationship calculation step ST12) described above in advance, In order to measure the number of tubes P, a captured image generation step ST2, a pattern matching step ST3, and a number calculation step ST4 are performed.
In the present embodiment, an example is given in which the second relationship calculation step ST12 is executed after the first relationship calculation step ST11, but the present invention is not limited to this, and the second relationship calculation step ST12 is executed. After that, it is also possible to execute the first relationship calculation step ST11.
In the present embodiment, before executing the captured image generation step ST2, the arithmetic processing means 2 includes the nominal outer diameter OD0, the nominal wall thickness T0, and the measured tubes constituting the measured tube bundle PB. The planned number of P is input and stored.

<Captured image generation step ST2>
In the captured image generation step ST2, the imaging means 1 images the end face of a bundle of measured tubes PB composed of a plurality of measured tubes P loaded in a rack R so that the longitudinal direction (Z direction) is horizontal. Then, a captured image is generated. The generated captured image is input to the arithmetic processing means 2.

<Pattern matching process ST3>
In the pattern matching step ST3, the calculation processing means 2 creates a template image _TIMG based on the nominal outer diameter OD0 and the nominal wall thickness T0 of the tube to be measured P. Then, the arithmetic processing means 2 performs pattern matching (template matching) between the template image T _IMG and the captured image generated in the captured image generation step ST2, and performs pattern matching (template matching) on the template image T _IMG of the plurality of pixel regions constituting the captured image. Calculate the match rate. In the pattern matching step ST3, the template image T _IMG is moved in the X direction on all pixel regions constituting the captured image or on all pixel regions where the end face of the pipe bundle PB to be measured may exist in the captured image. and sequentially scan in the Y direction and calculate the matching rate.
The specific procedure for calculating the matching rate by pattern matching is the same as that described with reference to FIG. 5 for the second relationship calculation step ST12, so the description will be omitted here.

<Number calculation process ST4>
In the number calculation step ST4, the calculation processing means 2 determines the threshold value Th based on the aspect ratio VH _rate of the pipe bundle to be measured PB, which is obtained by dividing the vertical dimension V of the pipe bundle to be measured PB by the horizontal dimension H of the pipe bundle to be measured PB. do.
Specifically, first, the calculation processing means 2 uses the nominal outer diameter OD0 of the pipe to be measured P and the first relationship calculated in the first relationship calculation step ST11 to calculate the aspect ratio VH _rate of the pipe bundle to be measured PB. Estimate. Specifically, for example, when the value of the nominal outer diameter OD0 of the pipe to be measured P is input on the horizontal axis shown in FIG. 4, the value on the vertical axis calculated from the first relationship is Estimated as the ratio VH _rate .
However, the present invention is not limited to this, and it is also possible to calculate by image processing the captured image generated in the captured image generation step ST2 without using the first relationship. In this case, it is possible to omit the first relationship calculation step ST11 described above.

Next, the calculation processing means 2 uses the nominal outer diameter OD0 of the measured pipe P and the relationship between the nominal wall thickness T0 and the post-chamfered wall thickness T1 as shown in FIG. The wall thickness T1 of P after chamfering is calculated.
Then, the calculation processing means 2 calculates the evaluation target parameter by dividing the estimated aspect ratio VH _rate of the pipe bundle PB to be measured by the wall thickness (thickness T1 after chamfering) of the pipe to be measured PB. Then, the arithmetic processing means 2 determines the threshold value Th using this evaluation target parameter and the second relationship calculated in the second relationship calculation step ST12.
Specifically, for example, when the evaluation target parameter is input on the horizontal axis shown in FIG. 8(b), the value on the vertical axis calculated from the second relationship is determined as the threshold value Th' before correction. .
FIG. 10 is an explanatory diagram illustrating a procedure for determining the threshold value Th' before correction using the second relationship shown in FIG. 8(b). As shown in FIG. 10, for example, when the evaluation parameter is 0.55, the threshold value Th' before correction is determined to be 60%.

Next, the arithmetic processing means 2 corrects the threshold value determined as described above (threshold value Th' before correction) based on the correction amount (3σ) determined in the second relationship calculation step ST12. do. Specifically, when the correction amount is 3σ = 12% and the threshold value Th' before correction is 60%, the threshold value before correction is set so that the number of measured pipes P does not go undetected. 48% obtained by subtracting the correction amount 3σ from Th' is determined as the threshold value (threshold value after correction) Th.

Finally, the arithmetic processing means 2 calculates the number of pixel regions for which the matching rate is equal to or higher than the threshold value Th among the plurality of pixel regions constituting the captured image, for the plurality of to-be-measured tubes constituting the to-be-measured tube bundle PB. Calculate as the number of P.
Note that the arithmetic processing means 2 of this embodiment compares the calculated number of pipes P to be measured with the planned number of pipes P inputted in advance, and outputs an alarm if the two do not match. It is configured as follows. This makes it possible to alert the inspector.

表１に示すように、本実施形態に係る本数計測方法によれば、いずれの被計測管束ＰＢについても、演算処理手段２によって自動的に適切なしきい値Ｔｈが決定され、一致率がこのしきい値Ｔｈ以上の画素領域の数を被計測管束ＰＢの被計測管Ｐの本数として算出することで、実本数と完全に一致する計測結果が得られた。 Table 1 shows an example of the results of applying the number measuring method according to the present embodiment described above to a bundle of measured pipes PB composed of pipes P having six different nominal outer diameters OD0 and nominal wall thicknesses T0. Shown below.

As shown in Table 1, according to the number counting method according to the present embodiment, for any pipe bundle PB to be measured, an appropriate threshold Th is automatically determined by the calculation processing means 2, and the matching rate is By calculating the number of pixel regions equal to or greater than the threshold Th as the number of measured pipes P in the measured pipe bundle PB, a measurement result that completely matched the actual number of pipes was obtained.

DESCRIPTION OF SYMBOLS 1... Imaging means 2... Arithmetic processing means 3... Illumination means 4... Control means 100... Number measuring device P... Pipe to be measured PB... Tube bundle to be measured R... rack

Claims (8)

A method for measuring the number of multiple pipes to be measured loaded in a rack so that the longitudinal direction is horizontal, the method comprising:
a captured image generation step of generating a captured image by capturing an end face of a bundle of tubes to be measured made up of the plurality of tubes to be measured;
A template image created based on the nominal outer diameter and nominal wall thickness of the tube to be measured and the captured image generated in the captured image generation step are pattern-matched to determine the size of the plurality of pixel regions constituting the captured image. a pattern matching step of calculating a matching rate for the template image;
A threshold value is determined based on the aspect ratio of the pipe bundle to be measured, which is obtained by dividing the vertical dimension of the pipe bundle to be measured by the horizontal dimension of the pipe bundle to be measured; a number calculation step of calculating the number of pixel regions in which the matching rate is equal to or higher than the threshold value as the number of the plurality of pipes to be measured constituting the bundle of pipes to be measured;
A method for measuring the number of tubes. The tube bundle is made up of a plurality of tubes placed in the rack so that the longitudinal direction is horizontal, and the tube bundle is made up of a plurality of tubes having different nominal outer diameters. further comprising a first relationship calculating step of calculating in advance a first relationship that is a relationship between the aspect ratio of and the nominal outer diameter of the pipe,
In the number calculation step, the aspect ratio of the pipe bundle to be measured is estimated using the nominal outer diameter of the pipe to be measured and the first relationship calculated in the first relationship calculation step, and the aspect ratio of the bundle of pipes to be measured is estimated. determining the threshold based on the aspect ratio of the measurement tube bundle;
2. The method for measuring the number of tubes according to claim 1. A tube bundle composed of a plurality of tubes placed in the rack so that the longitudinal direction is horizontal, the plurality of tube bundles having different nominal outer diameters and nominal wall thicknesses. further comprising a second relationship calculation step of calculating in advance a second relationship that is a relationship between a parameter calculated by dividing the aspect ratio of the tube bundle by the wall thickness of the tube and the coincidence rate,
In the number calculation step, the evaluation target parameter is calculated by dividing the aspect ratio of the pipe bundle to be measured by the wall thickness of the pipe to be measured, and the second relationship calculated in the second relationship calculation step is used. , determining the threshold;
3. The method for measuring the number of tubes according to claim 1 or 2. When calculating the parameters in the second relationship calculation step, the wall thickness after chamfering, which is the value obtained by subtracting the amount of wall thinning due to chamfering from the nominal wall thickness of the pipe, is used as the wall thickness of the pipe,
When calculating the evaluation target parameter in the number calculation step, the wall thickness after chamfering, which is the value obtained by subtracting the amount of wall thinning due to chamfering from the nominal wall thickness of the measuring tube, is used as the wall thickness of the measuring tube. ,
4. The method for measuring the number of tubes according to claim 3. In the second relationship calculation step, a correction amount is calculated in consideration of variations in the coincidence rate depending on the positions of the plurality of pixel regions constituting the captured image and a calculation error of the coincidence rate in the second relationship. decide,
In the number calculation step, the threshold determined using the evaluation target parameter and the second relationship is corrected based on the correction amount, and the pixel for which the matching rate is equal to or higher than the corrected threshold calculating the number of regions as the number of the plurality of pipes to be measured constituting the bundle of pipes to be measured;
The method for measuring the number of tubes according to claim 3 or 4, characterized in that: The tube bundle to be measured is installed in the rack and is loaded on a sling whose position can be varied in the vertical direction.
The method for measuring the number of tubes according to any one of claims 1 to 5. the pipe to be measured is an electric resistance welded steel pipe;
The method for measuring the number of tubes according to any one of claims 1 to 6. A device for measuring the number of multiple pipes to be measured loaded in a rack so that the longitudinal direction is horizontal,
an imaging means for generating a captured image by imaging an end face of a bundle of tubes to be measured, which is composed of the plurality of tubes to be measured;
arithmetic processing means for calculating the number of the plurality of pipes to be measured using the captured image generated by the imaging means;
The arithmetic processing means is
A template image created based on the nominal outer diameter and nominal wall thickness of the tube to be measured and the captured image generated by the imaging means are pattern-matched to determine the image of the plurality of pixel regions constituting the captured image. a pattern matching step of calculating a matching rate for the template image;
A threshold value is determined based on the aspect ratio of the pipe bundle to be measured, which is obtained by dividing the vertical dimension of the pipe bundle to be measured by the horizontal dimension of the pipe bundle to be measured; a number calculation step of calculating the number of pixel regions in which the matching rate is equal to or higher than the threshold value as the number of the plurality of pipes to be measured constituting the bundle of pipes to be measured;
A tube number measuring device characterized by the following.

Images