JPH06288934A - Method for detecting edge defect of hot-rolled sheet steel - Google Patents
Method for detecting edge defect of hot-rolled sheet steelInfo
- Publication number
- JPH06288934A JPH06288934A JP5078365A JP7836593A JPH06288934A JP H06288934 A JPH06288934 A JP H06288934A JP 5078365 A JP5078365 A JP 5078365A JP 7836593 A JP7836593 A JP 7836593A JP H06288934 A JPH06288934 A JP H06288934A
- Authority
- JP
- Japan
- Prior art keywords
- edge
- luminance level
- line
- threshold
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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- Length Measuring Devices By Optical Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Image Processing (AREA)
- Image Analysis (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、撮像手段を用いた熱延
板のエッジ欠陥の検出方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an edge defect in a hot rolled sheet using an image pickup means.
【０００２】[0002]
【従来の技術】近年、薄板鋼板の表面品位に対する要求
が高くなり、また製造ラインの高速化のため、製造プロ
セスのより早い時期において、鋼板エッジ部の欠陥を正
確に且つ高速で判定する必要がある。2. Description of the Related Art In recent years, there has been an increasing demand for the surface quality of thin steel sheets, and in order to speed up the production line, it is necessary to accurately and rapidly determine defects in the edge portions of the steel sheet at an earlier stage of the production process. is there.
【０００３】このため、従来の検査員の目視による欠陥
検出は採用が困難になり、例えば被測定物のエッジを測
定するラインセンサを設け、このラインセンサに入光す
る光量（ラインセンサ内の受光素子数）から鋼板のエッ
ジ位置を求める方法や、また、実開平２−１４０３０８
号公報に開示されたように、鋼板のエッジを検出する２
個のラインセンサを設け、これによってパスラインが変
動した場合にもエッジ位置の高精度な検出を可能にして
いる。For this reason, it becomes difficult to employ the conventional defect detection by the inspector visually. For example, a line sensor for measuring the edge of the object to be measured is provided, and the amount of light incident on the line sensor (light reception within the line sensor). The method of obtaining the edge position of the steel sheet from the number of elements)
Detecting the edge of a steel plate as disclosed in Japanese Patent Publication No. 2
By providing individual line sensors, this makes it possible to detect the edge position with high accuracy even when the pass line changes.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、ライン
センサを用いたエッジ検出方法を、熱延板のエッジ検出
に用いた場合、鋼板からの輻射熱による投光器の寿命低
下、クーラント水による投光器の遮光、自発光体と異な
る波長の投射、自発光体の形状不良（凹凸）等による外
乱が大きく、その適用は困難である。However, when the edge detection method using the line sensor is used to detect the edge of the hot rolled sheet, the life of the projector is shortened by the radiant heat from the steel sheet, the projector is blocked by the coolant water, and It is difficult to apply because the disturbance caused by the projection of the wavelength different from that of the light emitting body, the shape defect (irregularity) of the self-luminous body, etc.
【０００５】本発明において解決すべき課題は、自発光
鋼板のエッジ欠陥検出に好適に使用でき、正確かつ迅速
にエッジ欠陥が判定可能な手段を提供することにある。An object to be solved in the present invention is to provide a means which can be suitably used for detecting edge defects of a self-luminous steel sheet and which can accurately and quickly determine edge defects.
【０００６】[0006]
【課題を解決するための手段】本発明の熱延板のエッジ
欠陥の検出方法は、上記課題を解決するために、自発光
鋼板の発光部と非発光部をそれぞれ任意の画素に分割し
て影像し、あらかじめ定めた２値化のしきい値と比較し
て基準エッジを求め、次に板進行方向の２ライン目のエ
ッジを求めるに当たり、前記の基準エッジから少なくと
も１画素を除いた非発光部の輝度レベルで前記しきい値
を補正し、この補正後のしきい値により２ライン目のエ
ッジを検出し、以降各ライン毎に前記の操作を繰り返し
求められたエッジ位置から欠陥を検出することを特徴と
する。In order to solve the above-mentioned problems, a method for detecting an edge defect of a hot-rolled sheet according to the present invention divides a light-emitting portion and a non-light-emitting portion of a self-luminous steel sheet into arbitrary pixels. When the image is imaged and the reference edge is obtained by comparing it with a predetermined binarization threshold value, and then the edge of the second line in the plate traveling direction is obtained, at least one pixel is removed from the reference edge to cause no light emission. The threshold value is corrected by the brightness level of the part, the edge of the second line is detected by the corrected threshold value, and the defect is detected from the edge position obtained by repeating the above operation for each line thereafter. It is characterized by
【０００７】また、ここで、しきい値の補正に使用した
非発光部を、走査の起点とすることができる。Further, the non-light emitting portion used for correcting the threshold value can be used as the starting point of scanning.
【０００８】[0008]
【作用】図３に示すように、正常なエッジ部は輝度レベ
ルがなだらかに減少しているので、低いしきい値が必要
である。しかし同図エッジ欠陥部は、輝度レベルが急激
に減少しているが、その近傍は発光部からの散乱光、つ
まり低い輝度レベルが存在する。この場合、低いしきい
値のままでは、この散乱光をエッジとして誤認してしま
う。そこで、非発光部に存在する散乱光の輝度レベルで
しきい値を補正することにより、散乱光の影響範囲から
分別する。ここでエッジ欠陥部は急激に輝度レベルが減
少しているので、しきい値が高くても問題はない。As shown in FIG. 3, the normal edge portion has a gradual decrease in the brightness level, so that a low threshold value is required. However, although the brightness level of the edge defect portion in the figure sharply decreases, scattered light from the light emitting portion, that is, a low brightness level exists in the vicinity thereof. In this case, if the threshold value remains low, the scattered light will be mistaken as an edge. Therefore, by correcting the threshold value with the brightness level of scattered light existing in the non-light emitting portion, the influence range of scattered light is separated. Here, since the edge defect portion has a sharp decrease in luminance level, there is no problem even if the threshold value is high.
【０００９】補正の対象とする画素は、エッジを検出し
た位置での発光部輝度レベルの影響を無くすため、前ラ
インエッジから少なくとも１画素を除いた非発光部を使
用する。この補正用の画素は、エッジ欠陥部における散
乱光の影響範囲のみを演算領域にする必要から５個程度
が好ましい。As a pixel to be corrected, in order to eliminate the influence of the luminance level of the light emitting portion at the position where the edge is detected, the non-light emitting portion except at least one pixel from the front line edge is used. About five pixels for this correction are preferable because it is necessary to set only the influence range of the scattered light in the edge defect portion as the calculation area.
【００１０】また、しきい値の補正に使用した非発光部
を、走査の起点とすることによって無駄な部分の走査が
不要となり、検出効率を上げることができる。Further, by using the non-light emitting portion used for the correction of the threshold value as the scanning starting point, it is not necessary to scan an unnecessary portion, and the detection efficiency can be improved.
【００１１】[0011]
【実施例】図１は本発明を実施するためのシステム構成
図である。1 is a system configuration diagram for implementing the present invention.
【００１２】同図において、１は自発光の熱延板、２は
圧延ロールで、圧延ロール２に挟まれた自発光鋼板１の
上部位置には、自発光鋼板１のエッジ部を撮像する高速
シャッタカメラ３が配置されている。また、４はこの画
像情報を処理するＣＰＵ、５は工程管理用のプロセスコ
ントローラで、これら画像処理ＣＰＵ４及びプロセスコ
ントローラ５は、統括ＣＰＵ６に接続されている。In the figure, 1 is a self-luminous hot-rolled sheet, 2 is a rolling roll, and at the upper position of the self-luminous steel plate 1 sandwiched between the rolling rolls 2, a high speed for imaging the edge portion of the self-luminous steel plate 1 A shutter camera 3 is arranged. Further, 4 is a CPU for processing this image information, 5 is a process controller for process control, and these image processing CPU 4 and process controller 5 are connected to a general CPU 6.
【００１３】次いで、図２〜図５を参照して上記装置を
用いた熱延板のエッジ欠陥検出方法について説明する。Next, a method for detecting an edge defect in a hot-rolled sheet using the above apparatus will be described with reference to FIGS.
【００１４】ここで、図２はカメラ３によって撮像され
た鋼板のエッジ欠陥部、図３はエッジ欠陥部の輝度レベ
ルを示す図、図４は検出方法を説明するためのエッジ部
の模式図、図５はエッジ欠陥検出方法のフローチャート
をそれぞれ示す。Here, FIG. 2 is an edge defect portion of a steel plate imaged by the camera 3, FIG. 3 is a diagram showing a luminance level of the edge defect portion, FIG. 4 is a schematic view of the edge portion for explaining the detection method, FIG. 5 shows a flowchart of the edge defect detecting method.
【００１５】先ず熱延板の輝度レベルによりカメラ絞り
量に補正をかけ、鋼板のエッジ部輝度レベルを２５６階
調に分割して撮像する。First, the camera aperture amount is corrected according to the brightness level of the hot-rolled sheet, and the edge part brightness level of the steel sheet is divided into 256 gradations for imaging.
【００１６】次いで、予め撮像された無欠陥部の輝度レ
ベルに基づいて、鋼板部分の輝度のしきい値Ａを設定
し、撮像データを図４の左端の暗部から走査して、最初
に表れる輝度レベルＡ階調以上の画素Ｘ9 を、鋼板のＹ
1 ラインにおけるエッジ部と判定する。Then, the threshold value A of the brightness of the steel plate portion is set on the basis of the brightness level of the defect-free portion imaged in advance, and the imaging data is scanned from the dark portion at the left end of FIG. Pixel X 9 with level A gradation or higher is set to Y on the steel plate.
Judge as an edge part on one line.
【００１７】次いで２列めのＹ2 の走査に当り、検知エ
ッジ画素Ｘ9 から暗部方向に２画素外れた位置から５画
素、すなわち、Ｙ1 の画素Ｘ2 〜Ｘ6 の輝度レベルの平
均値Ｂを、当初のしきい値Ａに加算して補正しきい値Ｃ
を設定する。Next, when scanning the second row of Y 2 , five pixels from the position two pixels away from the detected edge pixel X 9 in the dark direction, that is, the average value of the luminance levels of the pixels X 2 to X 6 of Y 1. B is added to the original threshold value A to obtain a correction threshold value C
To set.
【００１８】次いで補正に使用した左端の画素Ｘ2 の位
置をＹ2 のＸ方向の走査の起点として、暗部方向から走
査する。その際操作起点の画素Ｘ2 の輝度レベルが、修
正しきい値Ｃよりも小さい場合、画素Ｘ2 は鋼板以外の
部分であり、さらに図の右方向に操作され、しきい値Ｃ
に達した部位Ｘ9 をエッジ部と判定する。また、図４と
異なり操作起点の画素Ｘ2 の輝度が仮にしきい値Ｃより
も大きい場合には、画素Ｘ2 は鋼板部分を示すこととな
り、左方向に操作して鋼板のエッジを判定する。なお図
４中、１０はエッジ検索領域、１１は散乱光影響範囲、
１２は鋼板自発光部を示す。Next, the position of the leftmost pixel X 2 used for the correction is used as the starting point of the scanning of Y 2 in the X direction, and scanning is performed from the dark direction. At that time, when the luminance level of the pixel X 2 at the operation starting point is smaller than the correction threshold value C, the pixel X 2 is a portion other than the steel plate, and is further operated in the right direction in the drawing to set the threshold value C.
It is determined that the portion X 9 that has reached the position is the edge portion. Further, unlike FIG. 4, when the luminance of the pixel X 2 at the operation starting point is larger than the threshold value C, the pixel X 2 indicates the steel plate portion, and the pixel is operated leftward to determine the edge of the steel plate. . In FIG. 4, 10 is an edge search region, 11 is a scattered light influence range,
Reference numeral 12 denotes a steel plate self-luminous portion.
【００１９】このような手順でＹ256 まで操作し、各走
査線毎のエッジ位置重回帰線とその線から凹量を演算し
て耳割れ部を判定する。In this procedure, operations up to Y 256 are performed, and the edge position multiple regression line for each scanning line and the concave amount are calculated from the line to determine the cracked portion.
【００２０】このエッジ欠陥の検出方法を、鋼板温度１
０００℃、ライン速度９００ｍ／分の薄板ラインに適用
し、その結果と実測値とを対応させたところ、耳割れの
有無は１００％検出でき、深さは±５ｍｍ以内の精度で
検出することができた。This edge defect detection method is applied to steel plate temperature 1
When applied to a thin plate line at 000 ° C. and a line speed of 900 m / min, and correlating the result with the actual measurement value, the presence or absence of ear cracks can be detected 100%, and the depth can be detected within an accuracy of ± 5 mm. did it.
【００２１】なお上記実施では、開口幅の広い場合につ
いて述べたが、耳割れが鋭利な深さの場合には、Ｙ方向
画素列毎に処理し、長手方向全ての輝度レベル平均値と
各画素輝度レベルを比較し、低輝度レベルの画素位置を
耳割れ起点とするがよい。In the above embodiment, the case where the opening width is wide has been described. However, when the ear crack has a sharp depth, it is processed for each pixel row in the Y direction, and the average luminance level in all the longitudinal directions and each pixel. It is preferable to compare the brightness levels and use the pixel position of the low brightness level as the ear crack starting point.
【００２２】[0022]
【発明の効果】本発明によって以下の効果を奏すること
ができる。According to the present invention, the following effects can be obtained.
【００２３】（１）特に、自発光鋼板のエッジ欠陥検出
に好適に使用でき、鋼板通板中に、耳割れの位置、深
さ、幅がリアルタイムにて、且つ正確に判定可能であ
る。(1) In particular, it can be suitably used for detecting edge defects of a self-luminous steel plate, and the position, depth, and width of the edge crack can be accurately determined in real time during the passage of the steel plate.
【００２４】（２）（１）の情報に基づき、耳割れ不良
時には、操業に対し早期アクションを可能となる。(2) Based on the information of (1), it is possible to take an early action for the operation when the ear cracking is defective.
【００２５】（３）本発明の方法により得られた耳割れ
の情報をもって、耳割れ発生原因の解析データとするこ
とができる。(3) The ear crack information obtained by the method of the present invention can be used as analysis data of the cause of the ear crack.
【００２６】（４）エッジ欠陥の正確な検出が可能とな
り、後工程におけるトリム代等の決定に有効利用でき
る。(4) The edge defect can be accurately detected and can be effectively used for determining the trim allowance in the subsequent process.
【図１】本発明を実施するためのシステム構成図であ
る。FIG. 1 is a system configuration diagram for implementing the present invention.
【図２】カメラによって撮像された鋼板のエッジ欠陥部
を示す図である。FIG. 2 is a diagram showing an edge defect portion of a steel plate imaged by a camera.
【図３】エッジ欠陥部の輝度レベルを示す図である。FIG. 3 is a diagram showing a luminance level of an edge defect portion.
【図４】検出方法を説明するためのエッジ部の模式図で
ある。FIG. 4 is a schematic diagram of an edge portion for explaining a detection method.
【図５】エッジ欠陥検出方法のフローチャートである。FIG. 5 is a flowchart of an edge defect detection method.
１ 熱延板 ２ 圧延ロール ３ 高速シャッタカメラ（撮像手段） ４ 画像処理ＣＰＵ ５ プロセスコントローラ ６ 統括ＣＰＵ 1 Hot Rolled Sheet 2 Rolling Roll 3 High Speed Shutter Camera (Imaging Means) 4 Image Processing CPU 5 Process Controller 6 Overall CPU
Claims (1)
れ任意の画素に分割して影像し、あらかじめ定めた２値
化のしきい値と比較して基準エッジを求め、次に板進行
方向の２ライン目のエッジを求めるに当たり、前記の基
準エッジから少なくとも１画素を除いた非発光部の輝度
レベルで前記しきい値を補正し、この補正後のしきい値
により２ライン目のエッジを検出し、以降各ライン毎に
前記の操作を繰り返し求められたエッジ位置から欠陥を
検出する熱延板のエッジ欠陥の検出方法。1. A light-emitting part and a non-light-emitting part of a self-luminous steel plate are divided into arbitrary pixels and imaged, and a reference edge is obtained by comparing with a predetermined binarization threshold value, and then the plate progress In determining the edge of the second line in the direction, the threshold value is corrected by the brightness level of the non-light-emitting portion obtained by removing at least one pixel from the reference edge, and the edge of the second line is corrected by the corrected threshold value. And detecting the defect from the edge position obtained by repeatedly performing the above operation for each line thereafter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5078365A JPH06288934A (en) | 1993-04-05 | 1993-04-05 | Method for detecting edge defect of hot-rolled sheet steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5078365A JPH06288934A (en) | 1993-04-05 | 1993-04-05 | Method for detecting edge defect of hot-rolled sheet steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06288934A true JPH06288934A (en) | 1994-10-18 |
Family
ID=13659984
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5078365A Withdrawn JPH06288934A (en) | 1993-04-05 | 1993-04-05 | Method for detecting edge defect of hot-rolled sheet steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06288934A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018179595A (en) * | 2017-04-05 | 2018-11-15 | 株式会社カネカ | Device for determining presence or absence of fine crack at edge part of conveyance film, and film manufacturing method |
| CN109540918A (en) * | 2018-11-28 | 2019-03-29 | 鞍钢集团自动化有限公司 | A kind of hot rolled coil edge fault detection device and method |
| CN110146514A (en) * | 2019-04-19 | 2019-08-20 | 广州超音速自动化科技股份有限公司 | Plate edge sealing defect detecting device and application method |
| JP2019181562A (en) * | 2018-04-10 | 2019-10-24 | Ｊｆｅスチール株式会社 | Method of measuring amount of curvature and device for measuring amount of curvature of rolled material |
| JPWO2022038668A1 (en) * | 2020-08-18 | 2022-02-24 |
-
1993
- 1993-04-05 JP JP5078365A patent/JPH06288934A/en not_active Withdrawn
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018179595A (en) * | 2017-04-05 | 2018-11-15 | 株式会社カネカ | Device for determining presence or absence of fine crack at edge part of conveyance film, and film manufacturing method |
| JP2019181562A (en) * | 2018-04-10 | 2019-10-24 | Ｊｆｅスチール株式会社 | Method of measuring amount of curvature and device for measuring amount of curvature of rolled material |
| CN109540918A (en) * | 2018-11-28 | 2019-03-29 | 鞍钢集团自动化有限公司 | A kind of hot rolled coil edge fault detection device and method |
| CN109540918B (en) * | 2018-11-28 | 2021-04-16 | 鞍钢集团自动化有限公司 | Hot-rolled coil edge defect detection device and method |
| CN110146514A (en) * | 2019-04-19 | 2019-08-20 | 广州超音速自动化科技股份有限公司 | Plate edge sealing defect detecting device and application method |
| JPWO2022038668A1 (en) * | 2020-08-18 | 2022-02-24 | ||
| WO2022038668A1 (en) * | 2020-08-18 | 2022-02-24 | Ｐｒｉｍｅｔａｌｓ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｊａｐａｎ株式会社 | Edge crack detection apparatus, rolling equipment, and edge crack detection method |
| US11808720B2 (en) | 2020-08-18 | 2023-11-07 | Primetals Technologies Japan, Ltd. | Edge crack detection device, rolling mill facility and edge crack detection method |
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