JPH0643119A - Detecting method for pinhole of steel piece - Google Patents
Detecting method for pinhole of steel pieceInfo
- Publication number
- JPH0643119A JPH0643119A JP19984892A JP19984892A JPH0643119A JP H0643119 A JPH0643119 A JP H0643119A JP 19984892 A JP19984892 A JP 19984892A JP 19984892 A JP19984892 A JP 19984892A JP H0643119 A JPH0643119 A JP H0643119A
- Authority
- JP
- Japan
- Prior art keywords
- defect
- pinhole
- camera
- steel piece
- width direction
- 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- Withdrawn
Links
Landscapes
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ＣＣＤカメラ、例えば
一次元ＣＣＤカメラを用いて、アズキャスト鋼片（以
下、鋼片と言う）のピンホールを検出する方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting pinholes in as-cast steel pieces (hereinafter referred to as steel pieces) using a CCD camera, for example, a one-dimensional CCD camera.
【０００２】[0002]
【従来の技術】従来、鋼片の表面疵検査は、蛍光磁粉探
傷法（鋼片に磁界を与え、欠陥部で発生する漏洩磁束に
蛍光磁粉が付着し、紫外線照射することにより、その付
着蛍光磁粉が鮮明化されることに基づき検査する）が適
用されており、主に鋼片のワレ疵，ヘゲ疵等が検査対象
疵となり、その多くは人間の目視検査に依存している。
また従来、照明光を照射し表面疵による反射光を得て表
面疵の検査をする装置としては、例えば、特開昭５８−
１６０８５２号公報に記載されたものがある。その基本
的構成を図６に示す。この図で、２１は低圧ナトリウム
ランプ、２２はＣＣＤカメラ、２３は被検査物であるシ
ート状物、２４はロールであり、ロール２４で送られる
シート状物２３を低圧ナトリウムランプ２１で照射しＣ
ＣＤカメラ２２で撮像する。２５は信号処理回路で一次
元ＣＣＤカメラのセル数に相当するメモリを有する累積
器なるものを備え、線状微小欠陥と緩徐欠陥（断面形状
の緩やかな凹凸欠陥）を検出する点に特徴を有するもの
で、各セルの信号をカメラ走査毎に累積し、予め設定さ
れた累積値に対し越えた場合に線状微小欠陥の存在を認
識し、累積値と次の１走査分のデータとの差をとり、そ
の差の積分値が予め設定された値を越えた場合に緩徐欠
陥の存在を認識するものである。更に同公報において
は、単発的に発生する大きな欠陥を認識するための判定
も合わせて行っている。2. Description of the Related Art Conventionally, the surface flaw inspection of a steel piece is performed by a fluorescent magnetic particle flaw detection method (a magnetic field is applied to the steel piece, and the magnetic flux adheres to the leakage magnetic flux generated at the defect portion, and when the ultraviolet light is irradiated, the attached fluorescent light is detected. The inspection is based on the fact that the magnetic powder is made clear) is applied, and the flaws to be inspected and the bald flaws of the steel pieces are mainly the flaws to be inspected, and most of them depend on the visual inspection by humans.
Conventionally, as an apparatus for inspecting a surface flaw by illuminating light and obtaining reflected light due to the surface flaw, there is, for example, Japanese Patent Laid-Open No. 58-
There is one described in Japanese Patent No. 160852. The basic structure is shown in FIG. In this figure, 21 is a low-pressure sodium lamp, 22 is a CCD camera, 23 is a sheet-like object to be inspected, 24 is a roll, and the sheet-like material 23 sent by the roll 24 is irradiated with the low-pressure sodium lamp 21 and C
The image is taken by the CD camera 22. A signal processing circuit 25 is provided with an accumulator having a memory corresponding to the number of cells of a one-dimensional CCD camera, and is characterized in that it detects linear minute defects and slow defects (defects with a gentle cross-section). The signal of each cell is accumulated for each camera scan, and if the preset cumulative value is exceeded, the existence of linear microdefects is recognized, and the difference between the cumulative value and the data for the next scan is detected. The presence of a slow defect is recognized when the integrated value of the difference exceeds a preset value. Further, in this publication, a determination for recognizing a large defect that occurs sporadically is also made.
【０００３】[0003]
【発明が解決しようとする課題】このように、従来の欠
陥検出装置においては、一つの検査材に対し存在し得る
多種多様の欠陥全てを検出できるような工夫がなされて
いる。しかし、このような検査装置は、鋼片のピンホー
ル欠陥検出に適用することが困難である。すなわち、蛍
光磁粉探傷法では、ピンホール欠陥の形状が円形で且つ
小さく漏洩磁束の発生が少ないことにより検出が困難で
あること、また人間の目視検査による見逃しが多いこと
が問題となる。また、前記の特開昭５８−１６０８５２
号公報に記載された光学的検査方法では、表面凹凸が小
さく外乱要因の少ないシート状を対象とした場合には微
小な欠陥でも精度良く検出ができるが、鋼片のように表
面凹凸が１００μｍ程度もある場合には、これが外乱と
なってしまい、無害な表面凹凸を欠陥として検出する問
題がある。As described above, the conventional defect detection apparatus is devised so as to be able to detect all of various kinds of defects that may exist in one inspection material. However, such an inspection device is difficult to apply to the detection of pinhole defects in a steel slab. In other words, the fluorescent magnetic particle flaw detection method has problems that it is difficult to detect because the pinhole defect has a circular shape and a small amount of leakage magnetic flux is generated, and that it is often overlooked by human visual inspection. In addition, the above-mentioned JP-A-58-160852.
According to the optical inspection method described in Japanese Patent Publication, when a sheet shape with small surface irregularities and few disturbance factors can be detected accurately, even a minute defect can be accurately detected, but the surface irregularity is about 100 μm like a steel piece. In some cases, this becomes a disturbance, and there is a problem that harmless surface irregularities are detected as defects.
【０００４】詳述すると、図７に鋼片の縦断面の一例を
示すが、表面凹凸３１およびスリ疵３２が慢性的に存在
し、その中に、ワレ疵，ヘゲ疵（図示せず）やピンホー
ル４が欠陥として存在する。ここで、製品圧延された後
では、鋼片で比較的形状の緩やかな表面凹凸やスリ疵は
圧延の減面比により減少し無害となり、ワレ疵，ヘゲ
疵，ピンホール等の欠陥が有害疵として残るが、前記公
報における累積器等を用いたときには、製品圧延後では
無害な表面凹凸やスリ疵まで検出してしまい、鋼片段階
でのグラインダによる疵の除去作業は膨大となり、生産
能率の低下，コスト的損失が大きくなる等の問題点があ
る。More specifically, FIG. 7 shows an example of a vertical cross section of the steel slab. Surface irregularities 31 and scratches 32 are chronically present, among which cracks and hair marks (not shown) are present. The pinhole 4 is present as a defect. Here, after the product is rolled, surface irregularities and scratches with a relatively gentle shape on the steel slab are reduced and become harmless due to the reduction ratio of the rolling, and defects such as cracks, bald marks and pinholes are harmful. Although it remains as a flaw, when using the accumulator etc. in the above-mentioned publication, harmless surface irregularities and scratches are detected after product rolling, and the flaw removal work by the grinder at the billet stage becomes enormous, resulting in a high production efficiency. There is a problem such as a decrease in power consumption and a large cost loss.
【０００５】[0005]
【課題を解決するための手段】この発明は上記した従来
の問題点に鑑みてなされたもので、移動する鋼片に照明
光を照射し被照射部の反射光をＣＣＤカメラで移動する
方向と交差せしめて走査し表面欠陥を検査する方法にお
いて、鋼片の滑らかな表面凹凸による反射光の強度差を
無くすようにＣＣＤカメラで走査する鋼片検査領域部と
の一定距離にＣＣＤカメラを挟んで少なくとも一対の照
明装置を設け、前記ＣＣＤカメラで検出した急峻な凹状
のピンホール欠陥で発生する光の影を欠陥信号として抽
出し、一走査毎の欠陥の幅方向の大きさを求め、該幅方
向大きさの最大位置を中心として欠陥の形状が対象であ
ることの判定を加えてピンホール欠陥を判別することを
特徴とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and illuminates a moving steel slab with illumination light and reflects the reflected light from the irradiated portion in a CCD camera. In the method of inspecting for surface defects by scanning while crossing each other, the CCD camera is sandwiched at a constant distance from the steel strip inspection area to be scanned by the CCD camera so as to eliminate the intensity difference of the reflected light due to the smooth surface unevenness of the steel strip. Providing at least a pair of illuminating devices, the shadow of light generated by the steep concave pinhole defect detected by the CCD camera is extracted as a defect signal, and the size in the width direction of the defect for each scanning is calculated. The feature is that the pinhole defect is determined by additionally determining that the shape of the defect is the target with the maximum position of the direction size as the center.
【０００６】[0006]
【作用】この発明では、上記した如く、鋼片での検査領
域部を多方向からの光の均一照射を行い、表面凹凸の光
の強度差を無くすことにより急峻な凹状ピンホールで発
生する光の影を欠陥として検出し、更に欠陥形状の代表
特性値から円形状欠陥を判定できることから、高い精度
でピンホールのみを検出することができる。According to the present invention, as described above, the inspection area portion of the steel slab is uniformly irradiated with light from multiple directions to eliminate the difference in the intensity of the light on the surface irregularities, and thus the light generated by the steep concave pinhole. Since it is possible to detect the shadow of No. 1 as a defect and determine the circular defect from the representative characteristic value of the defect shape, it is possible to detect only the pinhole with high accuracy.
【０００７】つぎに図８により、この発明の検出原理に
ついて説明する。図８は鋼片１に照明装置３と一次元Ｃ
ＣＤカメラ２を配置し、同図（ａ）の表面凹凸３１での
凹みと、同図（ｂ）のピンホール４とを一次元ＣＣＤカ
メラ２で受光する場合の、光路の概要を示すものである
が、図８の（ａ）に示す表面凹凸３１では照明光が凹み
の中に到達し光の影が生じないため、鋼片１の欠陥の無
い平坦部と同等のカメラ受光信号のレベルとなる。また
実際には表面凹凸３１の形状は多種多様であることか
ら、照明装置３は検査領域部に対し距離を一定に、該一
次元ＣＣＤカメラを挟み少なくとも一対以上の複数台数
とすることで多方向からの照明光の照射となり表面凹凸
３１での光の強度差を無くすることができる。一方、図
８の（ｂ）に示すピンホール４では、急峻な凹み形状で
あるため照明光が凹みの中に到達せず光の影５が生じ、
カメラ受光信号のレベルが低下することにより検出が可
能となる。かくして、該輝度信号を所定のしきい値で欠
陥判別し欠陥の幅方向の大きさを求めることが可能とな
り、合わせて得られた欠陥の一定移動距離毎の欠陥の幅
方向の大きさを計測し欠陥形状が対象形状であることを
もって円形状欠陥即ちピンホール欠陥を判別することが
可能となる。Next, the detection principle of the present invention will be described with reference to FIG. FIG. 8 shows a steel piece 1, a lighting device 3 and a one-dimensional C
The outline of the optical path is shown when the one-dimensional CCD camera 2 receives the CD camera 2 and the recesses in the surface unevenness 31 of FIG. 11A and the pinhole 4 of FIG. However, in the surface unevenness 31 shown in FIG. 8A, the illumination light reaches the inside of the depression and no light shadow is generated, so that the level of the camera light reception signal is the same as that of the flat portion of the steel piece 1 having no defect. Become. In addition, since the surface irregularities 31 have various shapes in practice, the illuminating device 3 is provided with a constant distance from the inspection area, and at least one pair of the illuminating devices 3 sandwiches the one-dimensional CCD camera so that a plurality of illuminating devices 3 are provided in multiple directions. It is possible to eliminate the difference in the intensity of the light on the surface unevenness 31 due to the irradiation of the illumination light from. On the other hand, in the pinhole 4 shown in FIG. 8B, since the illumination light does not reach the inside of the dent due to the steep dent shape, a light shadow 5 is generated,
The detection becomes possible when the level of the camera light reception signal decreases. Thus, it becomes possible to determine the size of the defect in the width direction by discriminating the luminance signal with a predetermined threshold value, and measure the size of the defect in the width direction for each constant moving distance of the defect obtained. However, it is possible to discriminate a circular defect, that is, a pinhole defect, because the defect shape is the target shape.
【０００８】つぎに、図４にもとづき円形状欠陥の識別
方法について説明する。ピンホール４は正面から見た図
で円形状であり、Ｔ１、Ｔ２、・・・Ｔｎは移動する鋼
片１の欠陥判定のタイミングで一定距離間隔Ｐとなり、
このときの欠陥座標値を（Ｘ11 、Ｘ21 )、(Ｘ12 、Ｘ
22 )・・・・（Ｘ1n 、Ｘ2n )とすると、欠陥の大きさ
は各々の差をとりＬ１、Ｌ２、・・・、Ｌmax-1、
Ｌmax、Ｌmax+1、・・・Ｌｎで表すことができる。欠陥
形状が円形であるならば、欠陥大きさの最大値Ｌmax は
長手方向の欠陥座標個数ｎとしたときｎ／２番目の近傍
に存在することから、最大値Ｌmax を挟み前後の欠陥大
きさの差の絶対値｜Ｌmax-1 −Ｌmax+1 |をとり、予め
設定した参照値以内であれば、欠陥形状が対象形状であ
ること即ち円形形状であると判定する。Next, a method of identifying circular defects will be described with reference to FIG. The pinhole 4 has a circular shape when viewed from the front, and T1, T2, ... Tn are fixed distance intervals P at the timing of the defect determination of the moving steel piece 1,
The defect coordinate values at this time are (X 11 , X 21 ), (X 12 , X
22 ) ... (X 1n , X 2n ), the sizes of the defects take respective differences, L 1 , L 2, ..., L max-1 ,
It can be represented by L max , L max + 1 , ... Ln. If the defect shape is circular, the maximum value L max of the defect size exists in the n / 2th vicinity when the number of defect coordinates in the longitudinal direction is n, so the defect size before and after the maximum value L max is sandwiched. The absolute value of the difference | L max-1 −L max + 1 | is taken, and if it is within a preset reference value, it is determined that the defect shape is a target shape, that is, a circular shape.
【０００９】[0009]
【実施例】以下、この発明の一実施例を図面を参照して
説明する。図１の（ａ）は本発明の一実施態様を示す斜
視図であり、図１の（ｂ）は鋼片１の縦断面図である。
これらの図面において、１は鋼片、２は一次元ＣＣＤカ
メラ、３は照明装置である。４がピンホールで検出すべ
き欠陥である。一次元ＣＣＤカメラ２は、鋼片１の幅方
向Ｄwに高速で走査し、照明装置３で照射光の反射光を
輝度信号として検出するものである。同図（ｂ）におい
て、照明装置３は一次元ＣＣＤカメラ２を挟み複数台数
を検査領域部からの距離を一定に、且つ多方向からカメ
ラ視野を照明するように配置し、鋼片１の検査領域部の
表面照度を１６〜１７万ルクスで均一照射することによ
り、該鋼片1の表面凹凸による輝度のばらつきを制御
し、ピンホール４の特有の光の影５を検出する。なお、
本実施例では、照明装置３に高出力型メタルハライドラ
ンプを使用し前記表面照度を確保した。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A is a perspective view showing an embodiment of the present invention, and FIG. 1B is a vertical cross-sectional view of a steel piece 1.
In these drawings, 1 is a steel piece, 2 is a one-dimensional CCD camera, and 3 is an illuminating device. 4 is a defect to be detected in the pinhole. The one-dimensional CCD camera 2 scans the steel piece 1 in the width direction Dw at a high speed, and the illumination device 3 detects the reflected light of the irradiation light as a luminance signal. In FIG. 1B, the illuminating device 3 is arranged so as to sandwich the one-dimensional CCD camera 2 at a fixed distance from the inspection area and to illuminate the field of view of the camera from multiple directions. By uniformly irradiating the surface illuminance of the area portion with 160 to 170,000 lux, the variation of the brightness due to the surface unevenness of the steel piece 1 is controlled, and the shadow 5 of the light peculiar to the pinhole 4 is detected. In addition,
In this embodiment, a high-power metal halide lamp is used as the lighting device 3 to secure the surface illuminance.
【００１０】図２に、カメラ２の撮影信号からピンホ−
ルを検出する画像処理回路を示す。一次元ＣＣＤカメラ
２は同期信号発生回路１０により一定周期で輝度信号の
送出をせしめ、該輝度信号は比較回路１１により２値化
される。ピンホ−ル（欠陥）では輝度信号がしきい値以
下であるので２値化デ−タは例えば低レベル「０」とな
る。しきい値以上のときには高レベル「１」となる。移
動する鋼片1に接触し一定距離間隔でパルス信号ＰＧを
発生するパルス発生器１５は、マイクロプロセッサ１２
に接続される回路であって、マイクロプロセッサ１２
は、該パルス信号ＰＧを外部割り込み入力端に受け、パ
ルス信号ＰＧの立上りａ，ｂ，ｃをカウントして鋼片の
検査位置を表わすデ−タ（位置デ−タ）を生成しかつこ
れらの立上りａ，ｂ，ｃに応答して割込処理を実行す
る。すなわち、立上りが到来してから次に発生する一ラ
イン分の２値化デ−タを記憶回路１３に書込む。これに
おいて、記憶回路１３にｎライン分の２値化デ−タを記
憶する態様では、第ｊライン記憶領域に第ｊ＋１ライン
記憶領域の２値化デ−タを移し、第ｎライン記憶領域に
今回の１ライン分の２値化デ−タを記憶するという具合
に、最も古い１ライン分のデ−タを捨て、最新の１ライ
ン分のデ−タを追記する。このような記憶の更新が行な
われる毎に信号処理装置１４が、記憶回路１３に蓄積し
た鋼片１の各ラインの２値化デ−タを読み出し、その中
の欠陥デ−タ（「０」）の分布から円形状を判定しピン
ホールを識別する。そして欠陥判別した結果を位置デ−
タ対応で記憶する。図３は、この動作について補足説明
したタイミングチャートであり、一次元ＣＣＤカメラ２
の輝度信号Ｓ、欠陥判定する信号しきい値ＴＨ、一定距
離間隔でのパルス信号ＰＧを示す。周知のように、一次
元ＣＣＤカメラの輝度信号Ｓ（１ライン分）は、図２の
同期信号発生回路１０の信号により定まる周期で発生す
るので、欠陥有無を示す２値化デ−タも、これと同じ周
期で比較回路１１より発生される。マイクロプロセッサ
１２は、鋼片の一定距離移動につき１パルス発生される
パルス信号ＰＧの、立上りａ，ｂ，ｃをカウントし、こ
れらの立上りａ，ｂ，ｃがあってから次に発生する１ラ
イン分の２値化デ−タを位置デ−タ対応で記憶回路１３
に記憶するので、パルス信号ＰＧの立上りａ，ｂ，ｃに
対応して、イ，ロ，ハの輝度信号（各１ライン分）の２
値化デ−タが記憶回路１３に記憶される。これにより、
記憶回路１３には、面展開すると長さ方向および幅方向
共に所定ピッチで分布する、鋼片表面の欠陥の有
（「０」）／無（「１」）を示す２値化デ−タが蓄積さ
れることになる。信号処理装置１４が、記憶回路１３に
蓄積した２値化デ−タの「０」分布を参照して、図４を
用いて説明した態様で「０」分布が円形状であるかを判
定し、円形状と判定するとこれをピンホールと決定し、
そのときの位置デ−タと該円形状の位置（面展開座標上
の位置）から、その位置（長手方向および幅方向）と判
定情報を記憶し、所定のタイミングで出力する。 つぎ
に図５には、かくして得られたピンホールの検出結果に
ついて示す。横軸にピンホールの開口径を、縦軸にピン
ホールと表面凹凸による反射輝度信号の比をとりプロッ
トした結果であるが、０．４ｍｍ程度の小さな開口径の
ピンホールでもＳ／Ｎ比２〜３倍と精度良く検出されて
いる。FIG. 2 shows a pinhole from a photographing signal of the camera 2.
2 shows an image processing circuit for detecting a fault. The one-dimensional CCD camera 2 causes the sync signal generation circuit 10 to send out a luminance signal at a constant cycle, and the luminance signal is binarized by the comparison circuit 11. In the pinhole (defect), since the luminance signal is below the threshold value, the binarized data becomes a low level "0", for example. When it is equal to or higher than the threshold value, the high level is "1". The pulse generator 15 that comes into contact with the moving steel bill 1 and generates the pulse signal PG at a constant distance is a microprocessor 12
A circuit connected to the microprocessor 12
Receives the pulse signal PG at an external interrupt input terminal, counts the rising edges a, b, c of the pulse signal PG to generate data (position data) representing the inspection position of the steel piece, and The interrupt processing is executed in response to the rising edges a, b, and c. That is, the binarized data for one line that occurs next after the rising edge is written is written in the memory circuit 13. In this case, in the mode in which the binarized data for n lines is stored in the memory circuit 13, the binarized data in the (j + 1) th line memory area is moved to the jth line memory area and is stored in the nth line memory area. The oldest one-line data is discarded and the latest one-line data is additionally written, such as storing the one-line binarized data this time. Each time such a memory update is performed, the signal processing device 14 reads out the binarized data of each line of the steel slab 1 accumulated in the memory circuit 13, and the defect data (“0”) therein. ) Is used to determine the circular shape and pinholes are identified. Then, the result of the defect determination is the position data
It is stored in correspondence with the data. FIG. 3 is a timing chart supplementarily explaining this operation. The one-dimensional CCD camera 2
The luminance signal S, the defect determination signal threshold value TH, and the pulse signal PG at constant distance intervals are shown. As is well known, since the luminance signal S (for one line) of the one-dimensional CCD camera is generated at a cycle determined by the signal of the synchronizing signal generating circuit 10 of FIG. 2, the binarized data indicating the presence or absence of a defect also It is generated by the comparison circuit 11 in the same cycle as this. The microprocessor 12 counts the rising edges a, b, and c of the pulse signal PG that is generated for one movement of the steel strip for a certain distance, and one line is generated after these rising edges a, b, and c. Minute binary data corresponding to position data is stored in the storage circuit 13
Therefore, the luminance signals of a, b, and c (each for one line) corresponding to the rising edges a, b, and c of the pulse signal PG are stored in 2
The digitized data is stored in the storage circuit 13. This allows
In the memory circuit 13, binarized data indicating presence (“0”) / absence (“1”) of defects on the surface of the billet, which is distributed at a predetermined pitch in both the length direction and the width direction when the surface is expanded. Will be accumulated. The signal processing device 14 refers to the “0” distribution of the binarized data accumulated in the storage circuit 13 and determines whether the “0” distribution is circular in the manner described with reference to FIG. , If it is determined to be circular, it is determined to be a pinhole,
The position (longitudinal direction and width direction) and the determination information are stored from the position data at that time and the position of the circular shape (position on the surface development coordinates), and output at a predetermined timing. Next, FIG. 5 shows the pinhole detection results thus obtained. The horizontal axis is the pinhole opening diameter, and the vertical axis is the ratio of the reflected luminance signal due to surface irregularities to the pinhole. The results show that even a pinhole with a small opening diameter of about 0.4 mm has an S / N ratio of 2 It has been detected with a precision of ~ 3 times.
【００１１】[0011]
【発明の効果】この発明は以上説明した通り、鋼片の表
面凹凸が多数存在する中のピンホール欠陥をＣＣＤカメ
ラを挟む多方向からの光の均一照射により、特徴的なピ
ンホールのみで発生する光の影を欠陥として抽出でき、
この欠陥の大きさから円形状特有の対象性を計測するこ
とによる方法であることから、連続鋳造鋼片のピンホー
ルを高精度に検出することができ産業上極めて効果大で
ある。As described above, according to the present invention, a pinhole defect in which there are many surface irregularities of a steel slab is generated only by a characteristic pinhole by uniformly irradiating light from multiple directions sandwiching a CCD camera. You can extract the shadow of the
Since this method is based on measuring the symmetry peculiar to the circular shape from the size of this defect, it is possible to detect the pinhole of the continuously cast steel slab with high accuracy, which is extremely effective in industry.
【図１】 本発明の一実施態様を示す図面であり、
（ａ）は斜視図、（ｂ）は鋼片１の縦断面図である。FIG. 1 is a view showing an embodiment of the present invention,
(A) is a perspective view and (b) is a longitudinal sectional view of the steel piece 1.
【図２】 本発明を一態様で実施する装置構成を示すブ
ロック図である。FIG. 2 is a block diagram showing a device configuration for implementing the present invention in one aspect.
【図３】 図２に示すＣＣＤカメラ２の出力とパルス発
生器１５の出力信号を示すタイムチャ−トである。3 is a time chart showing the output of the CCD camera 2 and the output signal of the pulse generator 15 shown in FIG.
【図４】 図２に示す信号処理装置１４による円形状判
定の原理を説明するための、２値化デ−タ分布を示す平
面図であり、２値化デ−タは図中の大径円内では
「０」、外部は「１」である。4 is a plan view showing a binarized data distribution for explaining the principle of circular shape determination by the signal processing device 14 shown in FIG. 2, and the binarized data is a large diameter in the figure. It is "0" inside the circle and "1" outside.
【図５】 本発明の一実施例でのピンホールの検出結果
を示すグラフである。FIG. 5 is a graph showing the detection results of pinholes in an example of the present invention.
【図６】 従来の欠陥検出装置の概要を示す斜視図であ
る。FIG. 6 is a perspective view showing an outline of a conventional defect detection device.
【図７】 鋼片の縦断面を示す断面図である。FIG. 7 is a cross-sectional view showing a vertical cross section of a steel slab.
【図８】 本発明の検出原理を説明するための、鋼片の
縦断面図であり、（ａ）は定常の凹凸を示し、（ｂ）は
ピンホ−ルを示す。FIG. 8 is a vertical cross-sectional view of a steel slab for explaining the detection principle of the present invention, in which (a) shows steady irregularities and (b) shows a pinhole.
１：鋼片 ２：一次元ＣＣ
Ｄカメラ ３：照明装置 ４：ピンホール ５：光の影 １０：同期発生回
路 １１：比較回路 １２：マイクロ
プロセッサ １３：記憶回路 １４：信号処理
装置 １５：パルス発生器1: Steel piece 2: One-dimensional CC
D camera 3: Illumination device 4: Pinhole 5: Shadow of light 10: Synchronization generation circuit 11: Comparison circuit 12: Microprocessor 13: Memory circuit 14: Signal processing device 15: Pulse generator
───────────────────────────────────────────────────── フロントページの続き (72)発明者 佐 藤 文 紀 室蘭市仲町12番地 ニッテツ北海道制御シ ステム株式会社内 (72)発明者 桜 井 昭 夫 室蘭市仲町12番地 ニッテツ北海道制御シ ステム株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fuminori Sato 12 Nakamachi, Muroran City Nittetsu Hokkaido Control System Co., Ltd. (72) Inventor Akio Sakurai 12 Nakamachi, Muroran City Nittetsu Hokkaido Control System Co. Within
Claims (1)
の反射光をＣＣＤカメラで鋼片移動方向と交差せしめて
走査し表面欠陥を検査する方法において、鋼片の滑らか
な表面凹凸による反射光の強度差を無くすようにＣＣＤ
カメラで走査する鋼片検査領域部との一定距離にＣＣＤ
カメラを挟んで少なくとも一対の照明装置を設け、前記
ＣＣＤカメラで検出した急峻な凹状のピンホール欠陥で
発生する光の影を欠陥信号として抽出し、一走査毎の欠
陥の幅方向の大きさを求め、該幅方向大きさの最大位置
を中心として欠陥の形状が対象であることの判定を加え
てピンホール欠陥を判別することを特徴とする鋼片のピ
ンホール検出方法1. A method for inspecting a surface defect by irradiating a moving steel slab with illumination light and scanning the reflected light of an irradiated portion with a CCD camera so as to intersect the steel slab moving direction and scanning. CCD to eliminate the difference in intensity of reflected light due to unevenness
CCD at a certain distance from the steel strip inspection area scanned by the camera
At least a pair of illuminating devices is provided across the camera, and the shadow of light generated by the steep concave pinhole defect detected by the CCD camera is extracted as a defect signal to determine the size of the defect in each scanning in the width direction. A method of detecting a pinhole in a steel slab, characterized in that a pinhole defect is determined by determining that the shape of the defect is a target with the maximum position of the size in the width direction as the center.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19984892A JPH0643119A (en) | 1992-07-27 | 1992-07-27 | Detecting method for pinhole of steel piece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19984892A JPH0643119A (en) | 1992-07-27 | 1992-07-27 | Detecting method for pinhole of steel piece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0643119A true JPH0643119A (en) | 1994-02-18 |
Family
ID=16414659
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19984892A Withdrawn JPH0643119A (en) | 1992-07-27 | 1992-07-27 | Detecting method for pinhole of steel piece |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0643119A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009042193A (en) * | 2007-08-11 | 2009-02-26 | Kao Corp | Palette inspection apparatus |
| US7599050B2 (en) | 2003-10-21 | 2009-10-06 | Daihatsu Motor Co., Ltd. | Surface defect inspecting method and device |
-
1992
- 1992-07-27 JP JP19984892A patent/JPH0643119A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7599050B2 (en) | 2003-10-21 | 2009-10-06 | Daihatsu Motor Co., Ltd. | Surface defect inspecting method and device |
| JP2009042193A (en) * | 2007-08-11 | 2009-02-26 | Kao Corp | Palette inspection apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH08285780A (en) | Method for inspecting flaw on outer surface of steel pipe | |
| JPH06148098A (en) | Surface defect inspection apparatus | |
| JPH0643119A (en) | Detecting method for pinhole of steel piece | |
| JP3332208B2 (en) | Defect detection method and apparatus for netted glass | |
| JPH09113465A (en) | Detection apparatus for surface fault for galvanized steel plate | |
| JPH07333197A (en) | Automatic surface flaw detector | |
| JP3089079B2 (en) | Circuit pattern defect inspection method | |
| JPH10123066A (en) | Apparatus and method for detection of singularity point | |
| JPH079403B2 (en) | Surface defect inspection method for objects | |
| JPH08271440A (en) | Flaw inspection equipment | |
| JPH10103938A (en) | Method and apparatus for visual examination of cast product | |
| JPH06273349A (en) | Flaw decision system | |
| JP3421967B2 (en) | Flat surface inspection equipment | |
| JP2010210322A (en) | Scale residue inspection device of pickled steel sheet | |
| JPH08190633A (en) | Defect judging method | |
| JPS62156547A (en) | Detecting method for surface defect | |
| JPH0882604A (en) | Method for inspecting surface defect of steel plate | |
| JP3210846B2 (en) | Sheet-shaped object dent detection method and sheet-shaped object dent detection device | |
| JP7131509B2 (en) | Surface defect detection device, surface defect detection method, and steel manufacturing method | |
| JP2536745B2 (en) | PCB cut condition inspection method | |
| JP3038092B2 (en) | Appearance inspection method | |
| JPS63124944A (en) | Inspecting method for through hole charging state | |
| JP2698697B2 (en) | Surface flaw inspection method | |
| JPH06294748A (en) | Surface flaw inspection method at welded part of uo steel pipe | |
| JP3197047B2 (en) | Defect inspection equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19991005 |