JP2012242233A - Pipe inner surface inspection method and pipe inner surface inspection device - Google Patents
Pipe inner surface inspection method and pipe inner surface inspection device Download PDFInfo
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Abstract
Description
本発明は、管内面検査方法、及び管内面検査装置に関する。特に、管内面のきずの検出精度の良い管内面検査方法、及び管内検査装置に関する。 The present invention relates to a pipe inner surface inspection method and a pipe inner surface inspection apparatus. In particular, the present invention relates to a pipe inner surface inspection method and an in-pipe inspection apparatus with good detection accuracy of flaws on the pipe inner surface.
従来より、鋼管の外側から内面に照明光を出射し、内面のきずを目視検査することが一般的である。
しかしながら、照明の位置によって内面の周方向に明るい領域と暗い領域ができる。また、周方向の明るさの変動が少ないように照明を配置しても、鋼管の管軸方向で明るさに大きな変動が生じる。
このように、明るさに大きな変動が生じると、きずの位置によってはきずが見難くなり、きずを見落とす虞がある。
また、鋼管の径が小さい場合や、きずが管軸方向の奥の方にある場合には、きずを斜めから見るので、きずを正面から見た場合と見え方が異なり、きずであるか否かの判別が難しい場合がある。
また、内面には汚れ等もあり、きずの検出精度は検査員の能力に大きく依存している。
従って、検査員の能力や鋼管の径等によっては、きずの検出精度に変動が生じ、きずを見逃す虞がある。
Conventionally, it is common to emit illumination light from the outside to the inside of a steel pipe and visually inspect the flaws on the inside.
However, a bright area and a dark area are formed in the circumferential direction of the inner surface depending on the position of illumination. Moreover, even if the illumination is arranged so that there is little variation in the brightness in the circumferential direction, a great variation in the brightness occurs in the tube axis direction of the steel pipe.
As described above, when the brightness varies greatly, it becomes difficult to see the flaw depending on the position of the flaw, and the flaw may be overlooked.
Also, when the diameter of the steel pipe is small or when the flaw is in the back of the pipe axis direction, the flaw is viewed from an oblique direction. It may be difficult to determine whether.
In addition, the inner surface is also contaminated, and the detection accuracy of flaws depends greatly on the ability of the inspector.
Therefore, the flaw detection accuracy varies depending on the ability of the inspector, the diameter of the steel pipe, etc., and there is a risk of missing the flaw.
また、鋼板の表面に線状レーザ光を照射し、遅延積分型撮像手段によって鋼板の表面を撮像し、光切断画像を出力することにより、鋼板の表面のきずを検出する方法が知られている(例えば、特許文献1参照)。しかしながら、鋼管の径が小さい場合には、鋼管内に撮像手段を入れられないので、この方法によってきずを検出することは難しい。また、きずの凹凸が小さい場合や、きずと周囲との色の濃淡差が小さい場合には、この方法によってきずを検出することが難しい。
また、渦流探傷又は漏洩磁束探傷と画像による探傷とを組み合わせて表面のきずを検出する方法が知られている(例えば、特許文献2参照)。しかしながら、この方法では、渦流探傷又は漏洩磁束探傷と画像による探傷との両方を行わなければならず、手間とコストがかかる。
Also known is a method of detecting flaws on the surface of a steel sheet by irradiating the surface of the steel sheet with a linear laser beam, imaging the surface of the steel sheet with a delay integration type imaging means, and outputting a light cut image. (For example, refer to Patent Document 1). However, when the diameter of the steel pipe is small, it is difficult to detect flaws by this method because the imaging means cannot be put in the steel pipe. In addition, when the unevenness of the flaw is small or when the difference in color density between the flaw and the surrounding is small, it is difficult to detect the flaw by this method.
Also, a method for detecting flaws on the surface by combining eddy current flaw detection or leakage magnetic flaw detection and flaw detection using an image is known (for example, see Patent Document 2). However, in this method, both eddy current testing or leakage magnetic flux testing and image testing must be performed, which is laborious and expensive.
本発明は、斯かる従来技術の問題を解決するためになされたものであり、管内面のきずの検出精度が高く、かつ、手間とコストがかからない管内面検査方法、及び管内検査装置を提供することを課題とする。 The present invention has been made to solve the problems of the prior art, and provides a pipe inner surface inspection method and an in-pipe inspection apparatus that are highly accurate in detecting defects on the inner surface of the pipe and that do not require labor and cost. This is the issue.
前記課題を解決するため、本発明の発明者らは鋭意検討した結果、下記の(1)乃至(4)の知見を得た。
(1)環状照明を管の端面に対向させ、環状照明の中心軸と管の管軸とを略一致させることにより、管の内面の周方向の明るさの変動を少なくすることができる。
(2)撮像手段で管の内面を管軸方向から撮像すると、その内面画像は、環状照明に近い位置ほど内面の濃度が低く、環状照明から遠い位置ほど濃度が高くなり、管軸方向に濃度の変動が生じる。そこで、内面画像を、径方向に複数の環状領域に分割し、環状領域毎にきず候補を判別する濃度の基準範囲を設けることにより、管軸方向での濃度の変動がきず候補の検出精度に与える影響を小さくできる。
(3)きず候補を含む環状領域を、管の径方向から見た場合の環状領域に変換することにより、きずの正確な形状が分かるので、きずの検出精度がよくなる。
(4)管の内面画像を構成するすべての環状領域を、管の径方向から見た場合の環状領域に変換しようとすると、データの処理量が多くなるので、コストと手間がかかる。そこで、きず候補を含む環状領域だけを管の径方向から見た場合の環状領域に変換することによりコストと手間を低減できる。
In order to solve the above problems, the inventors of the present invention have made extensive studies and as a result, obtained the following findings (1) to (4).
(1) By making the annular illumination face the end face of the tube and making the central axis of the annular illumination substantially coincide with the tube axis of the tube, fluctuations in the circumferential brightness of the inner surface of the tube can be reduced.
(2) When the inner surface of the tube is imaged from the tube axis direction by the imaging means, the inner surface image has a lower inner surface concentration as it is closer to the annular illumination, and a higher concentration at a position farther from the annular illumination, and the concentration in the tube axis direction. Fluctuations occur. Therefore, the inner surface image is divided into a plurality of annular regions in the radial direction, and a density reference range for discriminating defect candidates is provided for each annular region, so that density fluctuations in the tube axis direction are not affected by defect detection accuracy. The effect on it can be reduced.
(3) By converting an annular region including a defect candidate into an annular region when viewed from the radial direction of the pipe, the exact shape of the defect can be known, so that the detection accuracy of the defect is improved.
(4) If all the annular regions constituting the inner surface image of the tube are converted to the annular region when viewed from the radial direction of the tube, the amount of data processing increases, which requires cost and labor. Therefore, cost and labor can be reduced by converting only the annular region including the flaw candidate into the annular region when viewed from the radial direction of the pipe.
本発明は、本発明者らが得た上記の知見に基づき完成されたものである。すなわち、環状照明を管のいずれか一方の端面に対向させると共に該環状照明の中心軸と該管の管軸とを略一致させ、該環状照明の照明光を該管の内面に向けて出射し、かつ、撮像手段を該いずれか一方の端面に対向させると共に該撮像手段の光軸と該管の管軸とを略一致させ、該管の端面及び内面を該撮像手段で撮像する撮像ステップと、前記撮像ステップで撮像した画像から、前記いずれか一方の端面の内周縁に該当する位置からいずれか他方の端面の内周縁に該当する位置までの内面画像を抽出し、該内面画像を径方向に複数の環状領域に分割する分割ステップと、前記分割ステップによって分割した前記環状領域毎に濃度の基準範囲を設け、濃度が該基準範囲から外れた画素群をきず候補画素群として抽出する1次判別ステップと、前記1次判別ステップにより抽出した前記きず候補画素群を含む所定の画素領域の画素の濃度から前記環状領域毎に定めた所定の濃度を減算し、濃度を減算された該画素領域を管内面の径方向から見た場合の画素領域に変換し、変換した画素領域からきずの有無を判別する2次判別ステップとを備えたことを特徴とする管内面検査方法を提供する。 The present invention has been completed based on the above findings obtained by the present inventors. That is, the annular illumination is made to face one of the end faces of the tube, the center axis of the annular illumination and the tube axis of the tube are substantially coincided, and the illumination light of the annular illumination is emitted toward the inner surface of the tube. And an imaging step in which the imaging means is made to face either one of the end surfaces, the optical axis of the imaging means and the tube axis of the tube are substantially matched, and the end surface and the inner surface of the tube are imaged by the imaging means; And extracting an inner surface image from a position corresponding to the inner peripheral edge of one of the end faces to a position corresponding to the inner peripheral edge of the other end face from the image captured in the imaging step, A division step for dividing the annular region into a plurality of annular regions, and a density reference range for each of the annular regions divided by the division step, and a pixel group whose density deviates from the reference range is extracted as a candidate pixel group. A determination step; The predetermined density determined for each of the annular areas is subtracted from the density of the pixels in the predetermined pixel area including the flaw candidate pixel group extracted in the primary discrimination step, and the pixel area on which the density has been subtracted is There is provided a tube inner surface inspection method characterized by comprising a secondary determination step of converting into a pixel area when viewed from the radial direction and determining the presence or absence of a flaw from the converted pixel area.
ここで、環状照明とは、光源が環状に形成された、あるいは、複数の光源が環状に配置された照明を意味する。具体的には、例えば、LEDや電球等の複数の光源が環状に配置された照明や、環状の蛍光灯等の照明を例示できる。
上記の分割ステップにおいて、環状領域の分割数は、内面画像の濃度の変動幅に拘わらずに一定の数に決めておいてもよいし、また、内面画像の濃度の変動幅が大きい場合には分割数を多くし、小さい場合には少なくするようにしてもよい。
1次判別ステップにおける環状領域毎の濃度の基準範囲は、例えば、それぞれの環状領域の濃度の代表値に基づいて決めればよい。代表値としては、最高濃度、最低濃度及び平均濃度等があげられる。
2次判別ステップにおける減算する濃度は、それぞれの環状領域の濃度の代表値に基づいて決めればよい。代表値としては、最高濃度、最低濃度及び平均濃度等があげられる。具体的には、例えば、減算する濃度は、それぞれの環状領域の平均濃度としてもよい。また、減算する濃度は、その画素領域が属する環状領域の平均濃度とせずに、その環状領域の最低濃度としてもよい。
そして、それぞれの環状領域毎に定めた濃度を減算するとき、減算される画素領域が複数の環状領域に跨っている場合には、減算される画素領域全体に亘って同一の濃度を減算するのでなく、減算される画素領域を構成する各画素が属しているそれぞれの環状領域毎に定めた濃度を減算する。
Here, the annular illumination means illumination in which a light source is formed in an annular shape or a plurality of light sources are arranged in an annular shape. Specifically, for example, illumination in which a plurality of light sources such as LEDs and light bulbs are annularly arranged, and illumination such as an annular fluorescent lamp can be exemplified.
In the above division step, the number of divisions of the annular region may be determined to be a constant number regardless of the fluctuation range of the density of the inner surface image, or when the fluctuation range of the density of the inner surface image is large. The number of divisions may be increased, and may be decreased when it is small.
The reference range of the density for each annular region in the primary determination step may be determined based on, for example, the representative value of the density of each annular region. Representative values include maximum density, minimum density, and average density.
The density to be subtracted in the secondary discrimination step may be determined based on the representative value of the density of each annular region. Representative values include maximum density, minimum density, and average density. Specifically, for example, the concentration to be subtracted may be the average concentration of each annular region. Further, the density to be subtracted may not be the average density of the annular area to which the pixel area belongs, but may be the lowest density of the annular area.
When subtracting the density determined for each annular area, if the pixel area to be subtracted straddles a plurality of annular areas, the same density is subtracted over the entire pixel area to be subtracted. Instead, the density determined for each annular region to which each pixel constituting the subtracted pixel region belongs is subtracted.
本発明によれば、環状照明の中心軸と管の管軸とを略一致させるので、内面画像の濃度の周方向の変動を少なくすることができる。
また、きず候補画素群を抽出する濃度の基準範囲を定め、基準範囲から外れた画素群をきず候補画素群とするので、抽出する基準が一定になりきずの見逃しを少なくすることができる。
上記のように環状照明の中心軸と管の管軸とを略一致させても、撮像した内面画像は、環状照明に近い位置ほど内面の濃度が低く、環状照明から遠い位置ほど濃度が高くなるように、管軸方向に濃度の変動が生じる。そこで、本発明では、内面画像を径方向に複数の環状領域に分割し、環状領域毎にきず候補画素群の濃度の基準範囲を定める。例えば、環状照明に近い位置の環状領域では基準範囲の濃度を低くし、環状照明から遠い位置の環状領域では基準範囲の濃度を高くする。このように、濃度の管軸方向の変動に応じて環状領域毎のきず候補画素群の濃度の基準範囲を定めることにより、管の内面における管軸方向の位置による明るさの変動に拘わらずに、きず候補画素群の抽出を同等の精度で行うことができる。
According to the present invention, since the central axis of the annular illumination and the tube axis of the tube are substantially coincided with each other, fluctuations in the circumferential direction of the density of the inner surface image can be reduced.
Further, since the reference range of the density for extracting the defect candidate pixel group is defined and the pixel group outside the reference range is set as the defect candidate pixel group, the reference to be extracted becomes constant, and the missing of the defect can be reduced.
Even if the central axis of the annular illumination and the tube axis of the tube are substantially coincided as described above, the imaged inner surface image has a lower inner surface concentration as it is closer to the annular illumination, and a higher concentration as it is farther from the annular illumination. As described above, the concentration varies in the tube axis direction. Therefore, in the present invention, the inner surface image is divided into a plurality of annular regions in the radial direction, and a reference range of the density of the candidate pixel group is determined for each annular region. For example, the density of the reference range is lowered in the annular area near the annular illumination, and the density of the reference range is increased in the annular area far from the annular illumination. In this way, by setting the reference range of the density of the flaw candidate pixel group for each annular region in accordance with the fluctuation of the density in the tube axis direction, regardless of the brightness fluctuation due to the position in the pipe axis direction on the inner surface of the pipe. Therefore, the flaw candidate pixel group can be extracted with the same accuracy.
第2判別ステップにおいて、環状領域毎に定めた濃度を減算するが、例えば、環状領域毎の平均濃度を減算すれば、減算された後のそれぞれの環状領域の濃度を同等の濃度レベルにすることができる。それぞれの環状領域の濃度レベルが同等になることによりきずの見え方が同等になり、環状領域間でのきずの検出精度のバラツキを小さくすることができる。特に、管軸方向に延びて複数の環状領域に跨っているきず候補画素群は、管軸方向での濃度のバラツキが小さくなるので、見易くなり検出精度がよくなる。
そして、第2判別ステップにおいて、きず候補画素群を含んだ画素領域を管内面の径方向から見た場合の画素領域に変換するので、きずの正確な形状が分かり、きず候補画素群とされた画素群からきずを精度良く検出することができる。このことにより、きずでないものをきずと判別する誤りを少なくすることができる。
特に、第2判別ステップにおけるきずの有無の判別を人が行うようにすれば、きず画素領域が領域内での濃度差を維持したまま管内面の径方向から見た場合の画素領域に変換され、目視の場合と同様の状態になるので、きずの検出精度が良くなる。
In the second determination step, the density determined for each annular area is subtracted. For example, if the average density for each annular area is subtracted, the density of each annular area after the subtraction is set to an equivalent density level. Can do. By making the density levels of the respective annular regions equal, the appearance of the flaws becomes equal, and variations in flaw detection accuracy between the annular regions can be reduced. In particular, a flaw candidate pixel group extending in the tube axis direction and straddling a plurality of annular regions has less variation in density in the tube axis direction, so that it is easy to see and detection accuracy is improved.
In the second determination step, the pixel area including the flaw candidate pixel group is converted into a pixel area when viewed from the radial direction of the inner surface of the tube, so that the exact shape of the flaw is known and the flaw candidate pixel group is obtained. A flaw can be detected from the pixel group with high accuracy. As a result, it is possible to reduce errors in determining what is not a flaw as a flaw.
In particular, if the person determines whether or not there is a flaw in the second discrimination step, the flaw pixel area is converted into a pixel area when viewed from the radial direction of the tube inner surface while maintaining the density difference in the area. Since it becomes the same state as in the case of visual observation, the flaw detection accuracy is improved.
本発明で、第2判別ステップを行わずに、第1判別ステップだけできずを検出するようにすると、きずでないものをきずと判別する虞が高くなり、きずの検出精度が悪くなる。
また、第1判別ステップを行わずに、第2判別ステップだけを行おうとすると、管の内面の全ての領域の内面画像を、管の径方向から見た場合の内面画像に変換しなければならず、データの処理量が多くなるので、コストと手間がかかる。
従って、本発明のように、第1判別ステップと第2判別ステップとを組み合わせて行うことにより、コストと手間をかけずにきずの検出精度を良くすることができる。
In the present invention, if only the first determination step cannot be detected without performing the second determination step, there is a high possibility that a non-flaw is determined as a defect, and the detection accuracy of the defect is deteriorated.
Further, if only the second determination step is performed without performing the first determination step, the inner surface image of the entire area of the inner surface of the tube must be converted into an inner surface image when viewed from the radial direction of the tube. In addition, since the amount of data processing increases, cost and labor are required.
Therefore, as in the present invention, by combining the first determination step and the second determination step, it is possible to improve the flaw detection accuracy without cost and effort.
また、前記課題を解決するため、本発明は、管のいずれか一方の端面と対向し、照明光を該管の内面に向けて出射する環状照明と、前記いずれか一方の端面と対向し、前記管の端面及び内面を撮像する撮像手段と、前記撮像手段が撮像した前記管の画像からきず候補画素群を抽出し表示するきず候補表示手段とを備え、前記環状照明は、その中心軸が前記管の管軸と略一致するように配置され、前記撮像手段は、その光軸が前記管の管軸と略一致するように配置され、前記きず候補表示手段は、前記撮像手段が撮像した前記管の端面及び内面の画像から、前記いずれか一方の端面の内周縁に該当する位置からいずれか他方の端面の内周縁に該当する位置までの内面画像を抽出し、該内面画像を径方向に複数の環状領域に分割し、該環状領域毎に濃度の基準範囲を設け、濃度が該基準範囲から外れた画素群をきず候補画素群として抽出し、該きず候補画素群を含む所定の画素領域の画素の濃度から該環状領域毎に定めた所定の濃度を減算し、濃度を減算された該画素領域を管内面の径方向から見た場合の画素領域に変換して表示することを特徴とする管内面検査装置を提供する。 In order to solve the above-mentioned problem, the present invention is opposed to any one end surface of the tube, and is opposed to any one of the end surfaces, annular illumination for emitting illumination light toward the inner surface of the tube, Imaging means for imaging an end face and an inner surface of the tube, and defect candidate display means for extracting and displaying a defect candidate pixel group from an image of the tube imaged by the imaging means, and the annular illumination has a central axis The tube is arranged so as to substantially coincide with the tube axis of the tube, the imaging means is arranged so that its optical axis substantially coincides with the tube axis of the tube, and the flaw candidate display means is imaged by the imaging means. An inner surface image from a position corresponding to the inner peripheral edge of either one of the end surfaces to a position corresponding to the inner peripheral edge of the other end surface is extracted from the images of the end surface and the inner surface of the tube, and the inner surface image is radially Divided into a plurality of annular regions, and A density reference range is provided, a pixel group whose density deviates from the reference range is extracted as a defect pixel group, and a predetermined pixel area is determined for each annular area from the density of pixels in a predetermined pixel area including the defect candidate pixel group. The tube inner surface inspection apparatus is characterized in that the pixel area from which the density is subtracted is converted into a pixel region when viewed from the radial direction of the tube inner surface.
好ましくは、管内面検査装置は、前記いずれか一方の端面と当接可能であり、かつ、該いずれか一方の端面に当接したときに、前記環状照明から該管の内面に向けて出射された照明光を通過させる当接板と、前記撮像手段、前記環状照明及び前記当接板が取り付けられた固定枠とを備え、前記撮像手段と前記当接板とは、該撮像手段の光軸と該当接板とが垂直になるように前記固定枠に固定され、前記環状照明は、前記撮像手段と前記当接板との間を該撮像手段の光軸と平行に移動可能なように取り付けられる。 Preferably, the tube inner surface inspection device is capable of abutting against any one of the end surfaces, and is emitted from the annular illumination toward the inner surface of the tube when abutting against any one of the end surfaces. A contact plate through which the illumination light passes, and a fixed frame to which the imaging means, the annular illumination, and the contact plate are attached. The imaging means and the contact plate are optical axes of the imaging means. And the corresponding illumination plate are fixed to the fixed frame so that they are perpendicular to each other, and the annular illumination is mounted so as to be movable between the imaging means and the contact plate in parallel with the optical axis of the imaging means. It is done.
当接板が、環状照明から管の内面に出射された照明光を通過させるので、管の端面を当接板に当接させた状態で、管の端面と内面とを撮像することができる。
ここで、当接板は、例えば、ガラスや樹脂等の透明な素材からなる板や、網目構造を有した金属や樹脂等からなる板である。また、管の内径よりも大きく、かつ、管の外径よりも小さい径の孔を有した板であって、孔の周囲に管の端面を当接させるようにしたものでもよい。
Since the abutment plate allows the illumination light emitted from the annular illumination to the inner surface of the tube to pass through, it is possible to image the end surface and the inner surface of the tube with the end surface of the tube abutting against the abutment plate.
Here, the contact plate is, for example, a plate made of a transparent material such as glass or resin, or a plate made of metal or resin having a mesh structure. Further, it may be a plate having a hole having a diameter larger than the inner diameter of the tube and smaller than the outer diameter of the tube so that the end surface of the tube is brought into contact with the periphery of the hole.
管の内面を撮像するにあたっては、管の内面が管軸方向全長に亘って明るく照らされることが望ましい。そのために、環状照明は、照明光を内面の管軸方向全長に亘って照らすことができる位置であって、かつ、出来るだけ管の端面に近い位置が好ましい。
一方、管軸方向に延びた内面を撮像するには被写界深度を深くしなければならないので、撮像手段は、レンズの倍率を考慮して撮像出来る距離の範囲内で当接板から離れた位置が好ましい。
このように、環状照明の好ましい位置と、撮像手段の好ましい位置とは独立した関係なので、環状照明と撮像手段とが一体として位置が決まる構成であると、それぞれの適切な位置を得ることができないので、きずの検出が難しくなる。
そこで、上記の好ましい管内面検査装置のように、環状照明が撮像手段とは別個に移動できるようにすることにより、撮像条件を最適にすることができる。また、環状照明が、撮像手段の光軸と平行に移動するので、環状照明を移動させても内面画像の濃度の周方向での均一性を維持することができる。
When imaging the inner surface of the tube, it is desirable that the inner surface of the tube is brightly illuminated over the entire length in the tube axis direction. Therefore, the annular illumination is preferably a position where the illumination light can be illuminated over the entire length of the inner surface in the tube axis direction and as close to the end surface of the tube as possible.
On the other hand, in order to image the inner surface extending in the tube axis direction, the depth of field must be increased, so that the imaging means is separated from the contact plate within the range of the distance that can be imaged in consideration of the magnification of the lens. Position is preferred.
As described above, since the preferred position of the annular illumination and the preferred position of the imaging means are independent of each other, the appropriate positions cannot be obtained if the annular illumination and the imaging means are determined as a unit. Therefore, it becomes difficult to detect flaws.
Therefore, the imaging conditions can be optimized by allowing the annular illumination to move separately from the imaging means, as in the preferred tube inner surface inspection apparatus described above. Further, since the annular illumination moves in parallel with the optical axis of the image pickup means, the uniformity of the density of the inner surface image in the circumferential direction can be maintained even if the annular illumination is moved.
固定枠を用いることにより、管の内径や長さが同一である複数の管の内面検査を行う場合、管の端面に当接板を当接させれば撮像手段と当接板との間の距離、及び環状照明と当接板との間の距離が一定なので、管の検査を順次行っても撮像条件の調整に手間がかからない。 By using a fixed frame, when performing inner surface inspection of a plurality of tubes having the same tube inner diameter and length, if the abutment plate is brought into contact with the end surface of the tube, there is no gap between the imaging means and the abutment plate. Since the distance and the distance between the annular illumination and the abutting plate are constant, it does not take time to adjust the imaging conditions even if the tubes are sequentially inspected.
本発明によれば、手間とコストをかけずに管内面のきずの検出精度が高くすることができる。 According to the present invention, it is possible to increase the accuracy of detection of flaws on the inner surface of a pipe without labor and cost.
以下、添付図面を適宜参照しつつ、本発明の実施形態に係る管内面検査方法について説明する。
図1は、本実施形態に係る管内面検査方法に用いる管内面検査装置の一例を説明する構成図である。
管内面検査装置1は、鋼管2に照明光を出射する環状照明3と、鋼管2を撮像するカメラ(撮像手段)4と、きず候補画素群を表示するきず候補表示手段5とを備えている。
環状照明3は、環状照明3の中心軸32と鋼管2の管軸22とが略一致するように鋼管2の端面21に対向して配置されている。
環状照明3は、例えば、環状に成形された合成樹脂などの基材に複数のLED31が周方向に等間隔に取り付けられた構成である。LED31は、環状照明3の中心軸側に向いており、環状照明3の中心軸32に対して傾斜して照明光を出射する。
カメラ4は、カメラ4の光軸41と鋼管2の管軸22とが略一致するように、鋼管2の端面21に対向して配置されている。
カメラ4は、例えば、CCDカメラであり、撮像した画像データをきず候補表示手段5に送信する。
きず候補表示手段5は、パーソナルコンピュータ(以下、適宜PCという)51と、PC51にインストールされてきず候補画素群を検出し、きず候補画素群を含む画素領域をPC51のモニターに表示するためのプログラムとを備える。
管内面検査装置1は、好ましくは、鋼管2の端面21に当接する当接板6と、当接板6等が取り付けられる固定枠7とを備えている。固定枠7には、環状照明3、カメラ4及び当接板6が取り付けられている。
以下に、管内面検査装置1が、当接板6と、固定枠7とを備えている場合を例として説明する。
当接板6は、例えば、透明な樹脂からなっている。
固定枠7は、カメラ4を取り付けられるカメラ取付板71と、カメラ取付板71と当接板6とを連結する複数本の平行なガイド棒73を具備している。ガイド棒73は、カメラ取付板71に対して垂直になるように構成されている。
当接板6は、ガイド棒73に垂直に固定されている。
カメラ取付板71は、中心部分にカメラ4を取り付けられる孔を具備している。
カメラ取付板71は、ガイド棒73に沿って移動できるような構成になっている。具体的には、例えば、カメラ取付板71は、複数のガイド棒73を貫通させる複数の貫通孔を具備しており、貫通したガイド棒73をねじによって固定されている。カメラ取付板71をガイド棒73に沿って移動することによりカメラ取付板71と当接板6との距離を変えることができ、これにより、カメラ4と当接板6との距離を変えることができる。
Hereinafter, a pipe inner surface inspection method according to an embodiment of the present invention will be described with reference to the accompanying drawings as appropriate.
FIG. 1 is a configuration diagram illustrating an example of a pipe inner surface inspection apparatus used in the pipe inner surface inspection method according to the present embodiment.
The pipe inner surface inspection apparatus 1 includes an annular illumination 3 that emits illumination light to the steel pipe 2, a camera (imaging means) 4 that images the steel pipe 2, and a flaw candidate display means 5 that displays a flaw candidate pixel group. .
The annular illumination 3 is disposed so as to face the end surface 21 of the steel pipe 2 so that the central axis 32 of the annular illumination 3 and the tube axis 22 of the steel pipe 2 substantially coincide with each other.
The annular illumination 3 has, for example, a configuration in which a plurality of LEDs 31 are attached at equal intervals in the circumferential direction on a base material such as a synthetic resin formed in an annular shape. The LED 31 faces the central axis side of the annular illumination 3 and emits illumination light inclined with respect to the central axis 32 of the annular illumination 3.
The camera 4 is disposed so as to face the end surface 21 of the steel pipe 2 so that the optical axis 41 of the camera 4 and the pipe axis 22 of the steel pipe 2 substantially coincide.
The camera 4 is a CCD camera, for example, and transmits the captured image data to the candidate display means 5.
The flaw candidate display means 5 is a personal computer (hereinafter referred to as PC as appropriate) 51 and a program for detecting a candidate pixel group that is not installed in the PC 51 and displaying a pixel area including the flaw candidate pixel group on the monitor of the PC 51. With.
The pipe inner surface inspection apparatus 1 preferably includes a contact plate 6 that contacts the end surface 21 of the steel pipe 2 and a fixed frame 7 to which the contact plate 6 and the like are attached. An annular illumination 3, a camera 4 and a contact plate 6 are attached to the fixed frame 7.
Hereinafter, a case where the pipe inner surface inspection apparatus 1 includes the contact plate 6 and the fixed frame 7 will be described as an example.
The contact plate 6 is made of, for example, a transparent resin.
The fixed frame 7 includes a camera mounting plate 71 to which the camera 4 is mounted, and a plurality of parallel guide bars 73 that connect the camera mounting plate 71 and the contact plate 6. The guide rod 73 is configured to be perpendicular to the camera mounting plate 71.
The contact plate 6 is fixed vertically to the guide rod 73.
The camera mounting plate 71 has a hole for mounting the camera 4 at the center.
The camera mounting plate 71 is configured to be movable along the guide rod 73. Specifically, for example, the camera mounting plate 71 includes a plurality of through holes through which the plurality of guide rods 73 penetrate, and the penetrating guide rod 73 is fixed with screws. By moving the camera mounting plate 71 along the guide rod 73, the distance between the camera mounting plate 71 and the contact plate 6 can be changed, and thereby the distance between the camera 4 and the contact plate 6 can be changed. it can.
環状照明3は、複数のガイド棒73を貫通させる複数の貫通孔を具備しており、貫通孔にガイド棒73を貫通させることによって固定枠7に取り付けられている。
環状照明3は、その中心軸32がガイド棒73と平行になるように形成されており、ガイド棒73と平行に移動することができる。
カメラ4は、その光軸41が環状照明3の中心軸32と略一致するようにカメラ取付板71に取り付けられている。
The annular illumination 3 includes a plurality of through holes that allow the plurality of guide bars 73 to pass through, and is attached to the fixed frame 7 by allowing the guide bars 73 to pass through the through holes.
The annular illumination 3 is formed so that its central axis 32 is parallel to the guide rod 73, and can move in parallel to the guide rod 73.
The camera 4 is attached to the camera mounting plate 71 so that the optical axis 41 thereof substantially coincides with the central axis 32 of the annular illumination 3.
当接板6が、環状照明3から鋼管2の内面23に出射された照明光を通過させるので、鋼管2の端面21を当接板6に当接させた状態で、鋼管2の端面21と内面23とを撮像することができる。
環状照明3がカメラ4とは別個に移動できるようにすることにより、撮像条件を最適にすることができる。また、環状照明3が、カメラ4の光軸と平行に移動するので、環状照明3を移動させても内面画像の濃度の周方向での均一性を維持することができる。
固定枠7を用いることにより、鋼管2の内径や長さが同一である複数の鋼管2の内面検査を行う場合、鋼管2の端面21に当接板6を当接させればカメラ4と当接板6との間の距離、及び環状照明3と当接板6との間の距離が一定なので、鋼管2の検査を順次行っても撮像条件の調整に手間がかからない。
Since the abutment plate 6 allows the illumination light emitted from the annular illumination 3 to the inner surface 23 of the steel pipe 2 to pass through, the end surface 21 of the steel pipe 2 and the end surface 21 of the steel pipe 2 are in contact with the abutment plate 6. The inner surface 23 can be imaged.
By allowing the annular illumination 3 to move separately from the camera 4, the imaging conditions can be optimized. Further, since the annular illumination 3 moves in parallel with the optical axis of the camera 4, evenness of the inner surface image density can be maintained even if the annular illumination 3 is moved.
When the inner surface of a plurality of steel pipes 2 having the same inner diameter and length of the steel pipe 2 is to be inspected by using the fixed frame 7, the abutment plate 6 is brought into contact with the end face 21 of the steel pipe 2 so Since the distance between the contact plate 6 and the distance between the annular illumination 3 and the contact plate 6 are constant, it is not time-consuming to adjust the imaging conditions even if the steel pipe 2 is inspected sequentially.
次に、上述した管内面検査装置1を用いた管内面検査方法について説明する。
最初に、次の撮像ステップが行われる。
環状照明3を鋼管2のいずれか一方の端面21に対向させると共に環状照明3の中心軸32と鋼管2の管軸22とを略一致させ、環状照明3の照明光を鋼管2の内面に向けて出射し、かつ、カメラ4を該いずれか一方の端面21に対向させると共にカメラ4の光軸41と鋼管2の管軸22とを略一致させ、鋼管2の端面21及び内面をカメラ4で撮像する(撮像ステップ)。
本実施形態では、既に環状照明3が、その中心軸32が鋼管2の管軸22と略一致するように鋼管2の端面21に対向して配置され、カメラ4が、その光軸41が鋼管2の管軸22と略一致するように鋼管2の端面21に対向して配置されているので、撮像ステップは、例えば、次のように行われる。
環状照明3をガイド棒73に沿って移動させ、環状照明3の照明光が、鋼管2の内面全体に出射されるようにする。このとき、例えば、環状照明3から出射された照明光が、鋼管2の端面21の内周縁の位置において、内面への入射角度αが略80°になるようにするとよい。
続いて、カメラ取付板71をガイド棒73に沿ってスライドさせ、カメラ4を撮像位置に移動させる。そして、カメラ4によって、鋼管2の端面21と内面23とを撮像する。
環状照明3の中心軸と鋼管2の管軸とが略一致しているので、内面画像の濃度の周方向の変動を少なくすることができる。
Next, a pipe inner surface inspection method using the above-described pipe inner surface inspection apparatus 1 will be described.
First, the next imaging step is performed.
The annular illumination 3 is made to face one of the end faces 21 of the steel pipe 2 and the central axis 32 of the annular illumination 3 and the tube axis 22 of the steel pipe 2 are substantially aligned so that the illumination light of the annular illumination 3 is directed to the inner surface of the steel pipe 2. The optical axis 41 of the camera 4 and the tube axis 22 of the steel pipe 2 are substantially aligned with each other, and the end face 21 and the inner surface of the steel pipe 2 are aligned with the camera 4. Imaging is performed (imaging step).
In the present embodiment, the annular illumination 3 is already arranged so as to face the end surface 21 of the steel pipe 2 so that the central axis 32 substantially coincides with the pipe axis 22 of the steel pipe 2, and the camera 4 has an optical axis 41 of the steel pipe. Since it arrange | positions facing the end surface 21 of the steel pipe 2 so that it may correspond with the 2 pipe axis 22 substantially, an imaging step is performed as follows, for example.
The annular illumination 3 is moved along the guide rod 73 so that the illumination light of the annular illumination 3 is emitted to the entire inner surface of the steel pipe 2. At this time, for example, the illumination light emitted from the annular illumination 3 may have an incident angle α on the inner surface of the end surface 21 of the steel pipe 2 of approximately 80 °.
Subsequently, the camera mounting plate 71 is slid along the guide rod 73 to move the camera 4 to the imaging position. And the end surface 21 and the inner surface 23 of the steel pipe 2 are imaged by the camera 4.
Since the central axis of the annular illumination 3 and the tube axis of the steel pipe 2 are substantially coincident with each other, fluctuations in the circumferential direction of the density of the inner surface image can be reduced.
次に、撮像ステップで撮像した画像から、カメラ4がある側(以下、手前側という)の鋼管2の端面21の内周縁に該当する位置から、手前側とは反対側(以下、奥側という)の鋼管2の端面21の内周縁に該当する位置までの内面画像を抽出し、抽出した内面画像を径方向に複数の環状領域に分割する(分割ステップ)。
分割ステップは、例えば、次のように行われる。
図2は、内面画像の抽出方法を説明する図である。図2(a)は、鋼管2の端面21と内面23との撮像画像であり、図2(b)は、図2(a)の撮像画像を二値化した撮像画像であり、図2(c)は撮像画像から抽出した手前側端面の外周縁及び内周縁と、奥側端面の内周縁の模式図である。図2(a)、(b)においては、当接板6が網目構造の樹脂板であり、当接板6の網線が画像の中心を通る縦方向及び横方向に映っている。
カメラ4は、撮像した内面画像の画像データをきず候補表示手段5に送る。そして、きず候補表示手段5は、インストールされたプログラムに従って、内面画像(図2(a)参照)に二値化処理等を行い(図2(b)参照)、端面21の外周縁C1と内周縁C2を抽出する。端面21に照明光を出射しているので、端面21の箇所は濃度が低くなる。一方、端面21の外側や内側は、端面21よりも濃度が高くなるので端面21との間に濃度の境界ができる。きず候補表示手段5は、その濃度の境界を外周縁C1及び内周縁C2として抽出する。同様にして、奥側の鋼管2の端面21の内周縁C3を抽出する(図2(c)参照)。
そして、きず候補表示手段5は、インストールされたプログラムに従って、奥側の内周縁C3と手前側の内周縁C2で囲まれた領域を内面画像として抽出する。
Next, from the image captured in the imaging step, from the position corresponding to the inner peripheral edge of the end surface 21 of the steel pipe 2 on the side where the camera 4 is located (hereinafter referred to as the near side), the side opposite to the near side (hereinafter referred to as the back side). The inner surface image up to a position corresponding to the inner peripheral edge of the end surface 21 of the steel pipe 2 is extracted, and the extracted inner surface image is divided into a plurality of annular regions in the radial direction (division step).
The dividing step is performed as follows, for example.
FIG. 2 is a diagram for explaining an inner surface image extraction method. 2A is a captured image of the end surface 21 and the inner surface 23 of the steel pipe 2, and FIG. 2B is a captured image obtained by binarizing the captured image of FIG. 2A. (c) is a schematic diagram of the outer periphery and inner periphery of the front side end surface extracted from the captured image, and the inner periphery of the back side end surface. 2A and 2B, the contact plate 6 is a resin plate having a mesh structure, and the mesh line of the contact plate 6 is shown in the vertical direction and the horizontal direction passing through the center of the image.
The camera 4 sends the image data of the captured inner surface image to the flaw candidate display means 5. Then, the flaw candidate display means 5 performs binarization processing or the like on the inner surface image (see FIG. 2A) according to the installed program (see FIG. 2B), and the outer peripheral edge C1 and the inner edge of the end surface 21 The peripheral edge C2 is extracted. Since the illumination light is emitted to the end face 21, the density of the portion of the end face 21 is low. On the other hand, since the density is higher on the outer side and the inner side of the end face 21 than on the end face 21, there is a density boundary with the end face 21. The flaw candidate display means 5 extracts the density boundaries as the outer peripheral edge C1 and the inner peripheral edge C2. Similarly, the inner peripheral edge C3 of the end surface 21 of the steel pipe 2 on the back side is extracted (see FIG. 2 (c)).
Then, the flaw candidate display means 5 extracts a region surrounded by the inner peripheral edge C3 on the back side and the inner peripheral edge C2 on the near side as an inner surface image in accordance with the installed program.
図3は、内面画像の濃度分布を測定する方法を説明する図である。図3(a)は、鋼管の中心位置を示す図であり、図3(b)は、濃度分布を測定する測定線を示す図である。
きず候補表示手段5は、インストールされたプログラムに従って、手前側の外周縁C1が囲む領域の重心を算出し、算出した重心の位置を管軸の位置G(以下、画像での管軸の位置を、適宜、中心位置という)とする(図3(a)参照)。
続いて、きず候補表示手段5は、インストールされたプログラムに従って、中心位置Gから手前側の内周縁C2までの濃度分布を、中心位置Gから手前側の内周縁C2に向けた直線に沿って測定する。中心位置Gから手前側の内周縁C2に向ける直線は、円周方向に予め設定された角度ピッチで設けられる。本実施形態では、角度ピッチを90°とし、中心位置Gから4方向に延ばした測定線D1、D2、D3、D4上の濃度分布が測定される(図3(b)参照)。
FIG. 3 is a diagram for explaining a method for measuring the density distribution of the inner surface image. Fig.3 (a) is a figure which shows the center position of a steel pipe, FIG.3 (b) is a figure which shows the measurement line which measures density | concentration distribution.
The flaw candidate display means 5 calculates the center of gravity of the area surrounded by the outer periphery C1 on the near side in accordance with the installed program, and calculates the position of the calculated center of gravity as the tube axis position G (hereinafter, the position of the tube axis in the image). (Referred to as the center position as appropriate) (see FIG. 3A).
Subsequently, the flaw candidate display means 5 measures the density distribution from the center position G to the front inner periphery C2 along a straight line from the center position G to the front inner periphery C2 according to the installed program. To do. Straight lines from the center position G toward the inner peripheral edge C2 on the near side are provided at an angular pitch set in advance in the circumferential direction. In the present embodiment, the density distribution on the measurement lines D1, D2, D3, and D4 extending in four directions from the center position G with an angular pitch of 90 ° is measured (see FIG. 3B).
続いて、測定線D1、D2、D3、D4における内周縁C2から中心位置Gへの同一距離での平均濃度が算出される。そして、平均濃度の変動範囲が予め設定された一定の濃度幅で分割される。
本実施形態では、濃度が明るさという指標に換算されて、平均濃度の変動範囲が分割される。内面23で最も明るい箇所が明るさ100%となり、撮像した箇所の内で最も暗い箇所が明るさ0%となるように撮像画像の濃度が換算される。そして、明るさ100%を基準として10%毎に内面画像を分割する基準値が4個設けられる。つまり、明るさ90%、80%、70%、60%が基準値とされる。
図4は、平均濃度の変動範囲を分割する方法を説明する図である。
図4の横軸は内周縁C2からの距離を示し、縦軸は明るさを示す。図4には、測定線D1、D2、D3、D4での明るさの平均の分布を示す線が示されている。
そして、明るさの平均の分布を示す線が、4個の基準値を示す線と交差する点が求められ、それぞれの交差する点の内周縁C2からの距離が求められる。求められた内周縁C2からの距離が内面画像を分割する位置になる。図4に示す例では、内周縁C2からの距離が、a、b、c、dのところで内面画像は複数の環状領域に分割される。
Subsequently, the average density at the same distance from the inner peripheral edge C2 to the center position G in the measurement lines D1, D2, D3, and D4 is calculated. Then, the fluctuation range of the average density is divided by a predetermined density range.
In this embodiment, the density is converted into an index called brightness, and the fluctuation range of the average density is divided. The density of the captured image is converted so that the brightest portion on the inner surface 23 has a brightness of 100% and the darkest portion of the captured portions has a brightness of 0%. Then, four reference values for dividing the inner surface image every 10% with respect to 100% brightness are provided. That is, the reference values are 90%, 80%, 70%, and 60% brightness.
FIG. 4 is a diagram for explaining a method of dividing the fluctuation range of the average density.
The horizontal axis in FIG. 4 indicates the distance from the inner peripheral edge C2, and the vertical axis indicates the brightness. FIG. 4 shows lines indicating the average distribution of brightness at the measurement lines D1, D2, D3, and D4.
Then, a point where the line indicating the average distribution of brightness intersects with the lines indicating the four reference values is obtained, and the distance from the inner peripheral edge C2 of each intersecting point is obtained. The obtained distance from the inner peripheral edge C2 is a position for dividing the inner surface image. In the example shown in FIG. 4, the inner surface image is divided into a plurality of annular regions at distances a, b, c, and d from the inner peripheral edge C2.
図5は、内面画像を複数の環状領域に分割する方法を示す図である。
きず候補表示手段5は、インストールされたプログラムに従って、測定線D1〜D4上で、内周縁C2から距離a、b、c、dの位置を求める。そして、きず候補表示手段5は、測定線D1〜D4のそれぞれの線で、内周縁C2から距離がaである4箇所を求め、求めた4箇所に最も近い円を最小二乗法で求める。同様にして、内周縁C2から距離がb、c、dの場合の円を最小二乗法で求める。そして、求めた円で内面画を複数の環状領域に分割する。
FIG. 5 is a diagram illustrating a method of dividing the inner surface image into a plurality of annular regions.
The flaw candidate display means 5 obtains the positions of the distances a, b, c, and d from the inner peripheral edge C2 on the measurement lines D1 to D4 according to the installed program. And the flaw candidate display means 5 calculates | requires four places whose distance is a from the inner periphery C2 by each line of the measurement lines D1-D4, and calculates | requires the circle nearest to the calculated | required four places by the least squares method. Similarly, a circle when the distance from the inner peripheral edge C2 is b, c, d is obtained by the least square method. Then, the inner face image is divided into a plurality of annular regions by the obtained circle.
続いて、きず候補表示手段5は、インストールされたプログラムに従って、分割ステップによって分割した環状領域毎に濃度の基準範囲を設け、濃度がその基準範囲から外れた画素群をきず候補画素群として抽出する(1次判別ステップ)。
濃度の基準範囲は、例えば、環状領域毎の濃度の代表値に基づいてきず候補表示手段5が設定するようにすればよい。代表値としては、最高濃度、最低濃度及び平均濃度等があげられる。
本実施形態では、環状領域毎の明るさの平均の−5%から+5%とした。
そして、きず候補表示手段5は、基準範囲を超えた画素群をきず候補画素群として抽出する。
このように、濃度の管軸方向の変動に応じて環状領域毎のきず候補画素群の濃度の基準範囲を定めることにより、鋼管2の内面23における管軸方向の位置による明るさの変動に拘わらずに、きず候補画素群の抽出を同等の精度で行うことができる。
Subsequently, the defect candidate display means 5 provides a density reference range for each annular area divided by the dividing step in accordance with the installed program, and extracts a pixel group whose density deviates from the reference range as a candidate pixel group. (Primary discrimination step).
The density reference range may be set by the candidate display means 5 without being based on the representative density value for each annular region, for example. Representative values include maximum density, minimum density, and average density.
In the present embodiment, the average brightness of each annular region is set to -5% to + 5%.
Then, the flaw candidate display means 5 extracts a pixel group that exceeds the reference range as a flaw candidate pixel group.
In this way, by determining the reference range of the density of the flaw candidate pixel group for each annular region in accordance with the fluctuation of the density in the tube axis direction, regardless of the brightness fluctuation due to the position in the pipe axis direction on the inner surface 23 of the steel pipe 2. In addition, the defect candidate pixel group can be extracted with the same accuracy.
続いて、1次判別ステップにより抽出したきず候補画素群を含む所定の画素領域の画素の濃度から環状領域毎に定めた濃度を減算し、濃度を減算された画素領域を管内面の径方向から見た場合の画素領域に変換し、変換した画素領域からきずの有無を判別する(2次判別ステップ)。
2次判別ステップは、例えば、次のように行われる。
図6は、きず候補画素群を含んだ画素領域を内面画像から選定する方法を説明する図である。図6(a)は、きず候補画素群を含んだ画素領域を選定する4点をプロットした状態を示す図であり、図6(c)は、きず候補画素群を含んだ画素領域を線で囲んだ状態を示す図である。
きず候補表示手段5は、インストールされたプログラムに従って、PC51のモニターに内面画像を表示し、抽出したきず候補画素群をマーキングして表示したり、その位置の座標を表示すること等によってきず候補画素群を識別できるようにする。そして、オペレータは、きず候補画素群を含んだ画素領域(以下、きず画素領域という)を内面画像から選定する。選定は、例えば、オペレータが、きず候補画素群を映されたPC51のモニター上で、きず候補画素群を囲む4点(P1〜P4)をプロットする(図6(a)参照)。きず候補表示手段5は、インストールされたプログラムに従って、中心位置Gから見て4点の内で、周方向に互いに最も離れた2点を選定し(図6(a)の例では、点P1とP2)、中心位置Gから、それぞれの2点を通る直線M1、M2を描く(図6(b)参照)。また、きず候補表示手段5は、インストールされたプログラムに従って、4点が属する環状領域の内で、最も中心位置に近い環状領域の内側の境界線と、最も中心位置から離れた環状領域の外側の境界線とを選定する(図6(b)の例では、境界線M3とM4)。そして、2本の直線M1、M2と、2本の境界線M3、M4に囲まれた領域がきず画素領域とされる。
Subsequently, the density determined for each annular area is subtracted from the density of the pixel in the predetermined pixel area including the flaw candidate pixel group extracted by the primary discrimination step, and the pixel area from which the density has been subtracted is determined from the radial direction of the tube inner surface. The pixel region is converted into a pixel region when viewed, and the presence or absence of a flaw is determined from the converted pixel region (secondary determination step).
The secondary determination step is performed as follows, for example.
FIG. 6 is a diagram for explaining a method of selecting a pixel region including a flaw candidate pixel group from the inner surface image. FIG. 6A is a diagram illustrating a state in which four points for selecting a pixel region including a flaw candidate pixel group are plotted, and FIG. 6C illustrates a pixel region including a flaw candidate pixel group with a line. It is a figure which shows the state enclosed.
The flaw candidate display means 5 displays the inner surface image on the monitor of the PC 51 according to the installed program, displays the extracted flaw candidate pixel group by marking, displays the coordinates of the position, etc. Be able to identify groups. Then, the operator selects a pixel area including the flaw candidate pixel group (hereinafter referred to as a flaw pixel area) from the inner surface image. For example, the operator plots four points (P1 to P4) surrounding the flaw candidate pixel group on the monitor of the PC 51 on which the flaw candidate pixel group is shown (see FIG. 6A). The flaw candidate display means 5 selects two points that are farthest from each other in the circumferential direction among the four points when viewed from the center position G according to the installed program (in the example of FIG. P2) From the center position G, straight lines M1 and M2 passing through the two points are drawn (see FIG. 6B). Further, the flaw candidate display means 5 is arranged in accordance with the installed program, and within the annular area to which the four points belong, the inner boundary line of the annular area closest to the center position and the outer side of the annular area farthest from the center position A boundary line is selected (in the example of FIG. 6B, boundary lines M3 and M4). A region surrounded by the two straight lines M1 and M2 and the two boundary lines M3 and M4 is a defect pixel region.
続いて、きず候補表示手段5は、インストールされたプログラムに従って、きず画素領域から環状領域毎に設定された濃度を減算し、濃度を減算されたきず画素領域をPC51のモニターに表示する。減算する濃度は、例えば、環状領域毎の濃度の代表値に基づくように設定しておけばよい。代表値としては、最高濃度、最低濃度及び平均濃度等があげられる。
本実施形態では、内面画像全体から環状領域毎の平均濃度が減算される。
図7は、きず画素領域から環状領域毎に設定された濃度が減算される状態を示す図である。図7(a)は、濃度を減算される前の内面画像であり、図7(b)は、減算する濃度を示す図であり、図7(c)は、設定された濃度が減算された後の内面画像である。
環状領域毎の平均濃度が減算されるので、減算された後のそれぞれの環状領域の濃度を同等の濃度レベルにすることができる。減算した場合に、濃度の値が負になる画素のためにきず候補画素群が見難くなるときは、適当な濃度の値を加算すればよい。それぞれの環状領域の濃度レベルが同等になることによりきずの見え方が同等になり、環状領域間でのきずの検出精度のバラツキを小さくすることができる。特に、管軸方向に延びて複数の環状領域に跨っているきず候補画素群は、管軸方向での濃度のバラツキが小さくなるので、見易くなり検出精度がよくなる。
Subsequently, the flaw candidate display means 5 subtracts the density set for each annular area from the flaw pixel area according to the installed program, and displays the flaw pixel area from which the density has been subtracted on the monitor of the PC 51. The density to be subtracted may be set based on, for example, a representative value of density for each annular region. Representative values include maximum density, minimum density, and average density.
In the present embodiment, the average density for each annular region is subtracted from the entire inner surface image.
FIG. 7 is a diagram illustrating a state in which the density set for each annular region is subtracted from the flaw pixel region. FIG. 7A is an inner surface image before the density is subtracted, FIG. 7B is a diagram showing the density to be subtracted, and FIG. 7C is a diagram in which the set density is subtracted. It is a back inner surface image.
Since the average density for each annular area is subtracted, the density of each annular area after the subtraction can be set to an equivalent density level. If the candidate pixel group becomes difficult to see because of the pixel having a negative density value after subtraction, an appropriate density value may be added. By making the density levels of the respective annular regions equal, the appearance of the flaws becomes equal, and variations in flaw detection accuracy between the annular regions can be reduced. In particular, a flaw candidate pixel group extending in the tube axis direction and straddling a plurality of annular regions has less variation in density in the tube axis direction, so that it is easy to see and detection accuracy is improved.
次に、きず候補表示手段5は、インストールされたプログラムに従って、濃度を減算されたきず画素領域を管内面の径方向から見た場合のきず画素領域に変換し、PC51のモニターに表示する。この変換は、カメラ4ときず画素領域の位置関係に基づいて幾何学的に行なわれる。変換は、例えば、次のように行われる。
図8は、きず画素領域を扇形から矩形に変換方法を説明する図である。図8(a)は、変換前の座標を示す図であり、図8(b)は、変換後の座標を示す図である。
最初にきず画素領域を扇形から矩形に変換する。例として、図8(a)に示すような頂点K1、K2、K3、K4を有するきず画素領域Kを矩形に変換する方法を説明する。
内面画像の中心位置GをXY座標の原点とする。頂点K1、K2は中心位置Gよりそれぞれ距離r離れており、頂点K3、K4は中心位置Gよりそれぞれ距離R離れている。
そして、中心位置Gと頂点K1を通る直線上に頂点K3があり、中心位置G及び頂点K1を通る直線と、Y軸とが成す角度はθである。同様に、中心位置Gと頂点K2を通る直線上に頂点K4があり、中心位置G及び頂点K2を通る直線と、Y軸とが成す角度はθである。
そして、きず画素領域Kの円弧形状を直線形状にし、頂点K1から頂点K2までの距離と、頂点K3から頂点K4までの距離を同じにした矩形に変換するには、図8に示すように、変換後のそれぞれの頂点の座標を、K1(−R・sinθ,−r)、K2(R・sinθ,−r)、K3(−R・sinθ,−R)、K4(R・sinθ,−R)とすればよい。頂点以外の各画素についても、中心位置Gからの距離と、中心位置Gと結んだ直線がY軸と成す角度から、同様に変換すればよい。
Next, the flaw candidate display means 5 converts the flaw pixel area from which the density has been subtracted into a flaw pixel area when viewed from the radial direction of the inner surface of the tube according to the installed program, and displays it on the monitor of the PC 51. This conversion is performed geometrically based not only on the camera 4 but also on the positional relationship of the pixel areas. The conversion is performed as follows, for example.
FIG. 8 is a diagram for explaining a method of converting a flaw pixel area from a sector shape to a rectangle. FIG. 8A is a diagram illustrating coordinates before conversion, and FIG. 8B is a diagram illustrating coordinates after conversion.
First, the flaw pixel area is converted from a fan shape to a rectangle. As an example, a method for converting a flaw pixel region K having vertices K1, K2, K3, and K4 as shown in FIG.
The center position G of the inner surface image is set as the origin of the XY coordinates. The vertices K1 and K2 are separated from the center position G by a distance r, and the vertices K3 and K4 are separated from the center position G by a distance R.
The vertex K3 is on a straight line passing through the center position G and the vertex K1, and the angle formed between the straight line passing through the center position G and the vertex K1 and the Y axis is θ. Similarly, there is a vertex K4 on a straight line passing through the center position G and the vertex K2, and the angle formed between the straight line passing through the center position G and the vertex K2 and the Y axis is θ.
Then, in order to change the arc shape of the flaw pixel region K into a linear shape and convert the distance from the vertex K1 to the vertex K2 into the rectangle having the same distance from the vertex K3 to the vertex K4, as shown in FIG. The coordinates of the respective vertices after conversion are represented by K1 (−R · sin θ, −r), K2 (R · sin θ, −r), K3 (−R · sin θ, −R), K4 (R · sin θ, −R). )And it is sufficient. Each pixel other than the vertex may be similarly converted from the distance from the center position G and the angle formed by the straight line connected to the center position G and the Y axis.
続いて、きず候補表示手段5は、インストールされたプログラムに従って、矩形に変換されたきず画素領域の管軸方向の長さを変換し、PC51のモニターに表示する。
内面画像では、管軸方向に同じ長さのきずでも手前側にあるきずは長く見え、奥側にあるきずは短く見えるので、管軸方向の位置に拘わらずに同じ長さに見えるように、矩形に変換されたきず画素領域を変換する。
図9は、管軸方向の長さの変換方法を説明する図である。図9(a)は、内面を撮像している状態を示す模式図であり、図9(b)は、図9(a)の模式図でのLとR’の関係を示す図であり、図9(c)は、図9(a)の模式図でのLとr’の関係を示す図であり、図9(d)は、変換後の座標を示す図である。
線分K01は、きず画素領域Kに対応する内面の領域である(以下、対応内面領域という)。きず画素領域Kと、この図9との対応関係を見ると、きず画素領域Kの中心位置G、点K5、K6に図9の点G’、K5’、K6’が対応する。
管軸からK5’までの距離r’は、内面画像での中心位置Gから頂点K5までの距離rに、実際の寸法と内面画像とでの寸法の比率を掛けたものである。
同様に、管軸からK6’までの距離R’は、内面画像での中心位置Gから頂点K6までの距離Rに、実際の寸法と内面画像とでの寸法の比率を掛けたものである。
実際の寸法と内面画像とでの寸法の比率は、例えば、鋼管2の内径IDと、撮像画像での鋼管2の内径の寸法から算出すればよい。
図中のそれぞれの記号の内容は、次の通りである。
ID:鋼管の内径
L:カメラ4から端面21までの距離
Y:端面21から対応内面領域K01の手前側の端までの距離
Z:端面21から対応内面領域K01の奥側の端までの距離
ここで、LとR’の関係を見ると、図9(b)から、
L:R’=Y:(ID/2−R’)なので、Y=L(ID/2−R’)/R’となる。
また、Lとr’の関係を見ると、図9(c)から、
L:r’=Z:(ID/2−r’)なので、Z=L(ID/2−r’)/r’となる。
そして、きず画素領域Kに対応する対応内面領域K01を鋼管2の内面23の径方向から見た場合の長さQは
Q=Z−Y=L(ID/2−r’)/r’−L(ID/2−R’)/R’となる。
L、ID、r’、R’の値が既知なので算出することができる。
また、きず画素領域Kの管軸方向の長さを、きず画素領域Kを管内面の径方向から見た場合の長さに変換するには、きず画素領域Kの管軸方向の長さに、
(Z−Y)/(R’−r’)を掛ければよい。
従って、矩形に変換されたきず画素領域Kの管軸方向の長さを、管内面の径方向から見た場合の長さに変換するには、頂点KI、K2、K3、K4の座標を次のように変換する。
KI:(−R・sinθ,−r)
K2:(R・sinθ,−r)
K3:(−R・sinθ,−R(Z−Y)/(R’−r’))
K4:(R・sinθ,−R(Z−Y)/(R’−r’))
頂点以外の各画素についても、同様に変換すればよい。
図10は、きず画素領域を、管内面の径方向から見た場合の画素領域に変換する各段階の写真である。図10(a)は、濃度を減算された後のきず画素領域であり、図10(b)は、矩形に変換された後のきず画素領域であり、図10(c)は、管軸方向の長さを変換された後のきず画素領域である。
オペレータは、PC51のモニターに表示された変換後のきず画素領域から、きず候補画素群がきずであるか否かの判別を行う。
このように、きず候補画素群を含んだきず画素領域が領域内での濃度差を維持したまま管内面の径方向から見た場合のきず画素領域に変換され、目視の場合と同様の状態になるので、きずの正確な形状が分かり、きず候補画素群からきずを精度良く検出することができる。このことにより、きずでないものをきずと判別する誤りを少なくすることができる。
なお、PC51のモニターに表示された変換後のきず画素領域から、きず候補画素群がきずであるか否かの判別を、きず候補表示手段5が、きず候補画素群の濃度、長さ、幅、及び形状等に基づいて行うようにしてもよい。
このように、本実施形態の管内面検査方法により、手間とコストをかけずに管内面のきずの検出精度が高くすることができる。
Subsequently, the flaw candidate display means 5 converts the length in the tube axis direction of the flaw pixel area converted into a rectangle according to the installed program, and displays it on the monitor of the PC 51.
In the inner surface image, even if the flaw is the same length in the tube axis direction, the flaw on the near side looks long and the flaw on the back side looks short, so that it looks the same length regardless of the position in the tube axis direction. The flaw pixel area converted into a rectangle is converted.
FIG. 9 is a diagram for explaining a method of converting the length in the tube axis direction. FIG. 9A is a schematic diagram illustrating a state in which the inner surface is being imaged, and FIG. 9B is a diagram illustrating a relationship between L and R ′ in the schematic diagram of FIG. FIG. 9C is a diagram showing the relationship between L and r ′ in the schematic diagram of FIG. 9A, and FIG. 9D is a diagram showing the coordinates after conversion.
A line segment K01 is an inner surface region corresponding to the flaw pixel region K (hereinafter referred to as a corresponding inner surface region). Looking at the correspondence between the flaw pixel area K and FIG. 9, the points G ′, K5 ′, and K6 ′ in FIG. 9 correspond to the center position G and the points K5 and K6 of the flaw pixel area K.
The distance r ′ from the tube axis to K5 ′ is obtained by multiplying the distance r from the center position G to the vertex K5 in the inner surface image by the ratio of the actual dimension and the dimension in the inner surface image.
Similarly, the distance R ′ from the tube axis to K6 ′ is obtained by multiplying the distance R from the center position G to the vertex K6 in the inner surface image by the ratio of the actual dimension to the dimension in the inner surface image.
What is necessary is just to calculate the ratio of the dimension in an actual dimension and an inner surface image from the internal diameter ID of the steel pipe 2, and the dimension of the internal diameter of the steel pipe 2 in a captured image, for example.
The contents of each symbol in the figure are as follows.
ID: inner diameter L of the steel pipe L: distance from the camera 4 to the end face 21 Y: distance from the end face 21 to the front end of the corresponding inner surface area K01 Z: distance from the end face 21 to the inner end of the corresponding inner face area K01 here Then, looking at the relationship between L and R ′, from FIG.
Since L: R ′ = Y: (ID / 2−R ′), Y = L (ID / 2−R ′) / R ′.
Also, looking at the relationship between L and r ′, from FIG.
Since L: r ′ = Z: (ID / 2−r ′), Z = L (ID / 2−r ′) / r ′.
The length Q when the corresponding inner surface region K01 corresponding to the flaw pixel region K is viewed from the radial direction of the inner surface 23 of the steel pipe 2 is Q = Z−Y = L (ID / 2−r ′) / r′−. L (ID / 2−R ′) / R ′.
Since the values of L, ID, r ′, and R ′ are known, they can be calculated.
In order to convert the length of the flaw pixel region K in the tube axis direction into the length when the flaw pixel region K is viewed from the radial direction of the tube inner surface, the length of the flaw pixel region K in the tube axis direction is changed. ,
(ZY) / (R'-r ') may be multiplied.
Therefore, in order to convert the length in the tube axis direction of the flaw pixel region K converted into the rectangle into the length when viewed from the radial direction of the tube inner surface, the coordinates of the vertices KI, K2, K3, and K4 are set as follows. Convert as follows.
KI: (−R · sin θ, −r)
K2: (R · sin θ, −r)
K3: (−R · sin θ, −R (ZY) / (R′−r ′))
K4: (R · sin θ, −R (ZY) / (R′−r ′))
Similar conversion may be performed for each pixel other than the vertex.
FIG. 10 is a photograph of each stage in which the flaw pixel area is converted into a pixel area when viewed from the radial direction of the inner surface of the tube. FIG. 10A shows a flaw pixel region after the density is subtracted, FIG. 10B shows a flaw pixel region after conversion into a rectangle, and FIG. 10C shows the tube axis direction. It is a flaw pixel area after the length of is converted.
The operator determines whether or not the flaw candidate pixel group is a flaw from the flaw pixel area after conversion displayed on the monitor of the PC 51.
In this way, the flaw pixel area including the flaw candidate pixel group is converted into a flaw pixel area when viewed from the radial direction of the inner surface of the tube while maintaining the density difference in the area, and the state is the same as in the case of visual observation. Therefore, the exact shape of the flaw can be known, and the flaw can be detected with high accuracy from the flaw candidate pixel group. As a result, it is possible to reduce errors in determining what is not a flaw as a flaw.
Note that the flaw candidate display means 5 determines whether the flaw candidate pixel group is flawed from the flaw pixel area after conversion displayed on the monitor of the PC 51. The flaw candidate display means 5 determines the density, length, and width of the flaw candidate pixel group. And based on the shape and the like.
As described above, the tube inner surface inspection method according to the present embodiment can increase the accuracy of detection of flaws on the tube inner surface without labor and cost.
1・・・管内面検査装置
2・・・鋼管(管)
21・・・端面
22・・・管軸
23・・・内面
3・・・環状照明
32・・・中心軸
4・・・カメラ(撮像手段)
41・・・光軸
5・・・きず候補表示手段
6・・・当接板
7・・・固定枠
DESCRIPTION OF SYMBOLS 1 ... Pipe inner surface inspection apparatus 2 ... Steel pipe (pipe)
21 ... End face 22 ... Tube axis 23 ... Inner surface 3 ... Annular illumination 32 ... Center axis 4 ... Camera (imaging means)
41 ... optical axis 5 ... flaw candidate display means 6 ... contact plate 7 ... fixed frame
Claims (3)
前記撮像ステップで撮像した画像から、前記いずれか一方の端面の内周縁に該当する位置からいずれか他方の端面の内周縁に該当する位置までの内面画像を抽出し、該内面画像を径方向に複数の環状領域に分割する分割ステップと、
前記分割ステップによって分割した前記環状領域毎に濃度の基準範囲を設け、濃度が該基準範囲から外れた画素群をきず候補画素群として抽出する1次判別ステップと、
前記1次判別ステップにより抽出した前記きず候補画素群を含む所定の画素領域の画素の濃度から前記環状領域毎に定めた所定の濃度を減算し、濃度を減算された該画素領域を管内面の径方向から見た場合の画素領域に変換し、変換した画素領域からきずの有無を判別する2次判別ステップとを備えたことを特徴とする管内面検査方法。 The annular illumination is opposed to one of the end faces of the tube, the central axis of the annular illumination and the tube axis of the tube are substantially aligned, and the illumination light of the annular illumination is emitted toward the inner surface of the tube; and An imaging step in which the imaging means is opposed to any one of the end faces, the optical axis of the imaging means and the tube axis of the tube are substantially coincided, and the end face and the inner surface of the tube are imaged by the imaging means;
From the image captured in the imaging step, an inner surface image is extracted from a position corresponding to the inner peripheral edge of either one of the end surfaces to a position corresponding to the inner peripheral edge of the other end surface, and the inner surface image is extracted in the radial direction. A dividing step of dividing into a plurality of annular regions;
A primary determination step in which a density reference range is provided for each of the annular regions divided by the division step, and a pixel group whose density deviates from the reference range is extracted as a candidate pixel group;
A predetermined density determined for each of the annular areas is subtracted from the density of the pixels in the predetermined pixel area including the flaw candidate pixel group extracted in the primary determination step, and the pixel area subtracted from the density is set on the inner surface of the tube. A tube inner surface inspection method comprising: a secondary determination step of converting into a pixel region when viewed from the radial direction and determining the presence or absence of a flaw from the converted pixel region.
前記いずれか一方の端面と対向し、前記管の端面及び内面を撮像する撮像手段と、
前記撮像手段が撮像した前記管の画像からきず候補画素群を抽出し表示するきず候補表示手段とを備え、
前記環状照明は、その中心軸が前記管の管軸と略一致するように配置され、
前記撮像手段は、その光軸が前記管の管軸と略一致するように配置され、
前記きず候補表示手段は、前記撮像手段が撮像した前記管の端面及び内面の画像から、前記いずれか一方の端面の内周縁に該当する位置からいずれか他方の端面の内周縁に該当する位置までの内面画像を抽出し、該内面画像を径方向に複数の環状領域に分割し、該環状領域毎に濃度の基準範囲を設け、濃度が該基準範囲から外れた画素群をきず候補画素群として抽出し、該きず候補画素群を含む所定の画素領域の画素の濃度から該環状領域毎に定めた所定の濃度を減算し、濃度を減算された該画素領域を管内面の径方向から見た場合の画素領域に変換して表示することを特徴とする管内面検査装置。 An annular illumination that faces one of the end faces of the tube and emits illumination light toward the inner surface of the tube;
An imaging means for imaging the end surface and the inner surface of the tube opposite to the one end surface;
Flaw candidate display means for extracting and displaying a flaw candidate pixel group from the tube image picked up by the image pickup means,
The annular illumination is arranged such that its central axis substantially coincides with the tube axis of the tube,
The imaging means is arranged so that its optical axis substantially coincides with the tube axis of the tube,
The flaw candidate display means, from the image of the end face and the inner face of the tube imaged by the imaging means, from the position corresponding to the inner peripheral edge of the one end face to the position corresponding to the inner peripheral edge of the other end face The inner surface image is extracted, the inner surface image is divided into a plurality of annular regions in the radial direction, a reference range of density is provided for each annular region, and a pixel group whose density is out of the reference range is used as a candidate pixel group. Extracted, subtracted a predetermined density determined for each annular area from the density of pixels in a predetermined pixel area including the flaw candidate pixel group, and viewed the pixel area from which the density was subtracted from the radial direction of the tube inner surface An apparatus for inspecting a tube inner surface, which is converted into a pixel area and displayed.
前記撮像手段、前記環状照明及び前記当接板が取り付けられた固定枠とを備え、
前記撮像手段と前記当接板とは、該撮像手段の光軸と該当接板とが垂直になるように前記固定枠に固定され、
前記環状照明は、前記撮像手段と前記当接板との間を該撮像手段の光軸と平行に移動可能なように取り付けられていることを特徴とする請求項2に記載の管内面検査装置。 An abutment plate that can abut against any one of the end faces and allows illumination light emitted from the annular illumination toward the inner surface of the tube to pass through when abutting against either one of the end faces. When,
The imaging means, the annular illumination, and a fixed frame to which the contact plate is attached,
The imaging means and the contact plate are fixed to the fixed frame so that the optical axis of the imaging means and the corresponding contact plate are perpendicular to each other,
3. The tube inner surface inspection apparatus according to claim 2, wherein the annular illumination is mounted so as to be movable between the imaging unit and the contact plate in parallel with the optical axis of the imaging unit. .
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Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2017142219A (en) * | 2016-02-13 | 2017-08-17 | 国立大学法人徳島大学 | Image inspection device, image inspection program, recording medium readable by computer and recording apparatus |
JP2018112454A (en) * | 2017-01-11 | 2018-07-19 | 株式会社アセット・ウィッツ | Inner surface automatic inspection device of pipe material and automatic inspection method of pipe inner surface |
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0989789A (en) * | 1995-09-20 | 1997-04-04 | Denso Corp | Tube-inside defect inspection apparatus |
JP2003168103A (en) * | 2001-11-30 | 2003-06-13 | Seiko Epson Corp | Method and device for detecting line defect of picture, and method for correcting image data |
JP2005134294A (en) * | 2003-10-31 | 2005-05-26 | Daido Steel Co Ltd | Method and apparatus for inspecting shape of cylindrical part |
JP2005189113A (en) * | 2003-12-25 | 2005-07-14 | Jfe Steel Kk | Surface inspecting device and surface inspection method |
JP2011089826A (en) * | 2009-10-21 | 2011-05-06 | Aisin Seiki Co Ltd | Internal surface defect inspection apparatus of screw hole or hole |
-
2011
- 2011-05-19 JP JP2011112305A patent/JP5692647B2/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0989789A (en) * | 1995-09-20 | 1997-04-04 | Denso Corp | Tube-inside defect inspection apparatus |
JP2003168103A (en) * | 2001-11-30 | 2003-06-13 | Seiko Epson Corp | Method and device for detecting line defect of picture, and method for correcting image data |
JP2005134294A (en) * | 2003-10-31 | 2005-05-26 | Daido Steel Co Ltd | Method and apparatus for inspecting shape of cylindrical part |
JP2005189113A (en) * | 2003-12-25 | 2005-07-14 | Jfe Steel Kk | Surface inspecting device and surface inspection method |
JP2011089826A (en) * | 2009-10-21 | 2011-05-06 | Aisin Seiki Co Ltd | Internal surface defect inspection apparatus of screw hole or hole |
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JP7161905B2 (en) | 2018-10-15 | 2022-10-27 | アルテミラ株式会社 | Can lid inspection machine and camera position adjustment method |
JP2020063918A (en) * | 2018-10-15 | 2020-04-23 | 昭和アルミニウム缶株式会社 | Can-top inspection machine, camera position adjustment method, and camera positioning fixture |
WO2020079987A1 (en) * | 2018-10-15 | 2020-04-23 | 昭和アルミニウム缶株式会社 | Can lid inspector, camera position adjustment method, and camera positioning tool |
US11898964B2 (en) | 2018-10-15 | 2024-02-13 | Showa Aluminum Can Corporation | Can lid inspection device, camera position adjustment method, and camera positioning jig |
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JP7396160B2 (en) | 2020-03-26 | 2023-12-12 | 富士通株式会社 | Inspection equipment, inspection program and inspection method |
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