JPH06102194A - Surface flaw inspection device - Google Patents
Surface flaw inspection deviceInfo
- Publication number
- JPH06102194A JPH06102194A JP25150392A JP25150392A JPH06102194A JP H06102194 A JPH06102194 A JP H06102194A JP 25150392 A JP25150392 A JP 25150392A JP 25150392 A JP25150392 A JP 25150392A JP H06102194 A JPH06102194 A JP H06102194A
- Authority
- JP
- Japan
- Prior art keywords
- intensity
- defect
- light source
- flaw
- light intensity
- 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.)
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- 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、例えば熱延鋼板などの
高速移動する帯状の被検査材の表面欠陥を光学的に検査
する表面欠陥検査装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface defect inspection apparatus for optically inspecting surface defects of a strip-shaped inspected material such as a hot rolled steel sheet which moves at high speed.
【０００２】[0002]
【従来の技術】図７に従来の代表的な表面欠陥検査装置
の構成を示した。鋼板などの帯状の被検査材１は矢印方
向に連続的に搬送され被検査材１の上方に配置した光源
１４で被検査材１の表面を照明し、その表面像を一次元
ＣＣＤ等を用いたラインセンサカメラ１５で撮像し、カ
メラ１５からのビデオ信号を処理することによって被検
査材の表面欠陥を抽出する。2. Description of the Related Art FIG. 7 shows the structure of a typical conventional surface defect inspection apparatus. A strip-shaped inspected material 1 such as a steel plate is continuously conveyed in the direction of the arrow, and the light source 14 arranged above the inspected material 1 illuminates the surface of the inspected material 1, and the surface image is used by a one-dimensional CCD or the like. The line sensor camera 15 is used to take an image, and the video signal from the camera 15 is processed to extract the surface defect of the inspected material.
【０００３】[0003]
【発明が解決しようとする課題】このような従来の技術
では光源の照射角度、検出器の受光角度等の光学的配置
が明確にされていなかったため、その決定には実験機を
実際のラインにおいて調節して光学的配置を決定するし
か方法がなかった。しかし、実際のラインいおいてこの
ような光学的配置を決定することは、悪環境等の理由に
より極めて困難であり、十分な検討もできない。さら
に、そのときのラインの条件、例えば走行す鋼板の温度
や鋼板の種類等によってある幅をもって変化するため、
光学的配置を実験室的にあらかじめ決定しておくことは
実際のラインにおいてそのラインに対応して光学的配置
を決定する場合にも極めて重要なことである。In such a conventional technique, the optical arrangement such as the irradiation angle of the light source and the light receiving angle of the detector has not been clarified. The only option was to adjust and determine the optical configuration. However, it is extremely difficult to determine such an optical arrangement in an actual line due to a bad environment or the like, and sufficient examination cannot be performed. Furthermore, since it changes with a certain width depending on the conditions of the line at that time, such as the temperature of the running steel plate and the type of steel plate,
Preliminary determination of the optical arrangement in a laboratory is extremely important when determining the optical arrangement corresponding to the actual line.
【０００４】また、例えば熱延鋼板など欠陥部分の反射
率が欠陥のない周辺部分の反射率より低く、暗く見える
欠陥と、そうでない明るく見える欠陥の両方がある場
合、一種類の光学的配置では両方の種類の欠陥を効率よ
く高いＳ／Ｎで検出することは不可能であり、従来この
ような欠陥に対応することができる光学的配置はいまだ
明らかにされていない。Further, when the defect portion, such as a hot-rolled steel sheet, has a lower reflectance than the peripheral portion having no defect, and there are both a dark-looking defect and a bright-looking defect which is not so, one type of optical arrangement is used. It is impossible to detect both types of defects efficiently and with high S / N, and an optical arrangement capable of coping with such defects has not been clarified so far.
【０００５】本発明は、前記問題点を解決するために、
熱延鋼板に発生する表面欠陥に対し高い感度で検査を行
うことが可能である表面欠陥検査装置を提供することを
目的とする。In order to solve the above problems, the present invention provides
An object of the present invention is to provide a surface defect inspection apparatus capable of inspecting a surface defect generated in a hot-rolled steel sheet with high sensitivity.
【０００６】[0006]
【課題を解決するための手段】本発明者等は前記従来の
問題点を解決するために熱延鋼板の表面状態及びその表
面による光の反射について検討を行ったところ、熱延鋼
板の表面状態は粗さパラメータなどは多種多様であり、
その表面による光の反射状態も正確には言えない状況で
ある。また、熱延鋼板表面に発生する表面欠陥の形状も
その種類が多く形状は一概に言えない状態にある。Means for Solving the Problems The inventors of the present invention investigated the surface condition of a hot-rolled steel sheet and the reflection of light by the surface in order to solve the above conventional problems. Is a wide variety of roughness parameters,
The state of reflection of light by the surface cannot be accurately stated. Further, there are many types of surface defects that occur on the surface of the hot rolled steel sheet, and the shape cannot be generally stated.
【０００７】しかし、熱延鋼板の表面に白色光を投射し
た場合、表面欠陥のない部分では、図２（ａ）に示すよ
うな、正反射方向に強い強度を持ちその周辺は拡散した
強度をもつ反射分布になることが知られている。一方、
欠陥のある部分に白色光を投射した場合は欠陥の形状に
より反射状態が大きく変化し、その反射状態は欠陥の形
状に大きく依存し、一概には言えないが、欠陥のない部
分の反射に比較して全体的に広く拡散した反射状態にな
り、欠陥の無い表面では反射強度の低い方向にも図２
（ｂ）に見られるように、比較的高い反射強度がでるの
である。However, when white light is projected onto the surface of the hot-rolled steel sheet, a portion having no surface defect has a strong intensity in the specular reflection direction as shown in FIG. It is known that the reflection distribution has a certain value. on the other hand,
When white light is projected on a defective part, the reflection state changes greatly depending on the shape of the defect, and the reflection state greatly depends on the shape of the defect. As a result, the diffused state is diffused as a whole, and even on the surface with no defects, even in the direction of low reflected intensity,
As shown in (b), a relatively high reflection intensity is obtained.
【０００８】本発明は、以上の知見より、欠陥の無い部
分において正反射方向の光強度の３０％未満の光強度と
なるような光学的配置で検出器を設置することを特徴と
する表面欠陥検査装置である。この装置によれば欠陥部
からの拡散反射光からの光強度が欠陥の無い表面からの
ノイズ成分となる光強度より高い光強度となって、高い
Ｓ／Ｎを得ることができるまた、熱延鋼板の場合には表
面に酸化スケールが付着しており、特に、温度の高い状
態で欠陥が発生した時などは欠陥部分にも酸化スケール
が厚く付着している場合があり、欠陥部分の表面の反射
率が著しく下がり、光源から白色光を投射しても欠陥部
分が暗くなってしまう場合がある。また赤スケールなど
一般にスケール疵と呼ばれるような欠陥でも、やはり欠
陥表面の反射率が下がっており、欠陥部分は暗くなって
しまう。このような場合に、検出器を正反射方向の光強
度の３０％〜９０％の光強度となるような光学的配置に
設置する。この装置によれば欠陥のない周辺部分の強度
を高く、欠陥部分の強度を低く撮るような形で高いＳ／
Ｎで前記のような暗くなる欠陥を検出することが可能と
なる。From the above knowledge, the present invention is characterized in that the detector is installed in such an optical arrangement that the light intensity is less than 30% of the light intensity in the specular reflection direction in the defect-free portion. It is an inspection device. According to this apparatus, the light intensity from the diffusely reflected light from the defect portion becomes higher than the light intensity which becomes a noise component from the surface without defects, and a high S / N can be obtained. In the case of a steel sheet, oxide scale adheres to the surface, and in particular, when a defect occurs at a high temperature, the oxide scale may adhere to the defect part thickly. The reflectance may be significantly reduced, and even if white light is projected from the light source, the defective portion may become dark. Further, even in a defect such as a red scale, which is generally called a scale defect, the reflectance of the defect surface is also lowered, and the defect portion becomes dark. In such a case, the detector is installed in an optical arrangement such that the light intensity is 30% to 90% of the light intensity in the specular reflection direction. According to this device, the strength of the peripheral portion having no defect is high, and the strength of the defective portion is low.
With N, it becomes possible to detect the darkening defect as described above.
【０００９】さらに、走行する鋼帯の表面に光源からの
光束を投射し、その反射光を一次元撮像装置で検出し、
被検査材の表面欠陥を検出する装置において、投射する
光源の正反射方向の光強度の３０％未満の光強度となる
第１の光学的配置に少なくとも１台以上の検出器を設置
し、投射する光源の正反射方向の光強度の３０％以上９
０％以下の光強度となる第２の光学的配置に少なくとも
１台以上の検出器を設置する。このように、第２の光学
的配置に設置した第２の検出器と第１の光学的配置に設
置した第２の検出器とを併設することにより、あらゆる
種類の欠陥を高いＳ／Ｎで検出することが可能となる。Further, a luminous flux from a light source is projected on the surface of a running steel strip, and the reflected light is detected by a one-dimensional image pickup device,
In a device for detecting a surface defect of a material to be inspected, at least one or more detectors are installed in a first optical arrangement where the light intensity is less than 30% of the light intensity in the regular reflection direction of a light source to be projected, and projection is performed. 30% or more of the light intensity in the regular reflection direction of the light source
At least one or more detectors are installed in the second optical arrangement where the light intensity is 0% or less. In this way, by installing the second detector installed in the second optical arrangement and the second detector installed in the first optical arrangement together, all kinds of defects with high S / N can be achieved. It becomes possible to detect.
【００１０】[0010]
【作用】本発明者らは、熱延鋼板の表面状態、及びその
表面による光の反射について検討を行った。具体的には
様々な光強度の光学的配置に検出器を設置し欠陥の撮像
を行い、欠陥部分の信号強度のＳ／Ｎを調べた。また、
様々なサンプルについて欠陥部分の信号強度のＳ／Ｎを
調べたところ欠陥のサイズが大きければ大きいほど欠陥
部分の信号強度のＳ／Ｎは高くなるということが分っ
た。従って、最も小さな欠陥で検出が可能であればその
欠陥より大きい欠陥は同じ条件で検出が可能である。The present inventors examined the surface condition of the hot rolled steel sheet and the reflection of light by the surface. Specifically, detectors were installed in optical arrangements with various light intensities, images of defects were taken, and the S / N of the signal intensity of the defect was examined. Also,
When the S / N of the signal intensity of the defective portion was examined for various samples, it was found that the larger the defect size, the higher the S / N of the signal intensity of the defective portion. Therefore, if the smallest defect can be detected, the larger defect can be detected under the same condition.
【００１１】図３（ａ）は正反射方向の光強度の２０％
の光強度となる光学的配置に一次元撮像装置を設置し欠
陥の撮像を行った時の信号（上段の図）と、その信号に
デジタルフィルタを掛けて得られた信号（下段の図）で
ある。Ｓ／Ｎはデジタルフィルタを掛けた信号から得
た。この光学的配置においてＳ／Ｎは約３であった。図
３（ｂ）は正反射方向の光強度の約６０％の光強度とな
る光学的配置に一次元撮像装置を設置し欠陥の撮像を行
った時の図３（ａ）と同様の図である。この光学的配置
においては欠陥からの信号強度は周りのノイズに埋もれ
てしまい全く見えなくなっており、欠陥部分の判別が不
可能となっている。FIG. 3A shows 20% of the light intensity in the regular reflection direction.
The signal (upper figure) when the one-dimensional imaging device is installed in the optical arrangement that gives the light intensity of (1) and the image of the defect is taken, and the signal obtained by applying the digital filter to that signal (lower figure) is there. The S / N was obtained from the digitally filtered signal. The S / N was about 3 in this optical arrangement. FIG. 3B is a view similar to FIG. 3A when the defect is imaged by installing the one-dimensional imaging device in an optical arrangement in which the light intensity is about 60% of the light intensity in the regular reflection direction. is there. In this optical arrangement, the signal intensity from the defect is buried in the surrounding noise and is completely invisible, making it impossible to identify the defective portion.
【００１２】このような撮像実験をもっとも小さなサイ
ズのサンプルに対して様々な光学的配置において繰り返
し実験を行い、Ｓ／Ｎを調べたところ、図４の結果を得
た。図４では欠陥部分の信号の判別ができない光学的配
置の場合のＳ／Ｎを１としてある。正反射方向の光強度
に比較して欠陥のない部分での反射強度が殆どない場合
においても、欠陥部分からの反射強度はあることが分か
る。欠陥検出可能となる光学的配置を決定する基準とし
て検出可能なＳ／Ｎを１．５以上とした場合、その光強
度は正反射方向の３０％未満の光強度であることが分か
った。Such an imaging experiment was repeated with respect to the sample of the smallest size in various optical arrangements to examine the S / N, and the results shown in FIG. 4 were obtained. In FIG. 4, the S / N is set to 1 in the case of the optical arrangement in which the signal of the defective portion cannot be discriminated. It can be seen that there is reflection intensity from the defective portion even when there is almost no reflection intensity in the defect-free portion compared to the light intensity in the regular reflection direction. It was found that the light intensity was less than 30% in the specular reflection direction when the detectable S / N was set to 1.5 or more as a reference for determining the optical arrangement that enables the defect detection.
【００１３】したがって、本発明によれば光源からの投
射した白色光源の反射強度が欠陥の無い部分で正反射方
向の光強度の３０％未満の光強度となるような光学的配
置に検出器を設置することにより、欠陥部分からの反射
光強度が、ノイズ成分となる欠陥の無い部分からの反射
光強度より高くなり、高いＳ／Ｎで欠陥を検出すること
が可能になる。Therefore, according to the present invention, the detector is arranged in such an optical arrangement that the reflection intensity of the white light source projected from the light source becomes less than 30% of the light intensity in the specular reflection direction in the defect-free portion. With the installation, the intensity of the reflected light from the defective portion becomes higher than the intensity of the reflected light from the portion having no defect that becomes a noise component, and the defect can be detected with a high S / N.
【００１４】さらに、欠陥部分表面にスケールが厚く付
着しており欠陥部分の反射率が低くなっている欠陥に対
して、様々な光学的配置で検討を行った。図５（ａ）は
正反射方向の光強度の８０％の光強度となるような光学
的配置に一次元撮像装置を設置し欠陥の撮像を行った時
の信号（上段の図）と、その信号にデジタルフィルタを
掛けて得られた信号（下段の図）である。図５（ｃ）は
正反射方向の２０％の光強度となる光学的配置に配設さ
れた一次元撮像装置での信号の同様な図である。Further, with respect to the defect in which the scale is thickly attached to the surface of the defect portion and the reflectance of the defect portion is low, various optical arrangements were examined. FIG. 5A shows a signal (upper diagram) when a one-dimensional image pickup device is installed in an optical arrangement such that the light intensity is 80% of the light intensity in the regular reflection direction and an image of a defect is shown, It is a signal (lower figure) obtained by applying a digital filter to the signal. FIG. 5C is a similar diagram of a signal in the one-dimensional image pickup device arranged in the optical arrangement in which the light intensity is 20% in the regular reflection direction.
【００１５】図を見てもわかるように８０％の光強度と
なる位置で撮像を行った場合には、欠陥による信号強度
が周辺部分の信号強度より明かに低く現れており、欠陥
部分がはっきりと現れているのに対し、９５％、２０％
の光学的配置位置で撮像を行った場合には欠陥からの信
号強度は周辺部分のノイズとあまり差がなく、欠陥がは
っきりとは見えなくなってしまっている。Ｓ／Ｎの決定
は、図３の場合と同じであるが、このような欠陥の場
合、欠陥部分の信号が周辺の信号に比べて低くなるため
デジタルフィルタを掛けた信号において、負の強度でＳ
／Ｎを決定した。８０％ではＳ／Ｎは４．７である。９
５％、２０％では欠陥部分が判別できない。As can be seen from the figure, when the image is picked up at a position where the light intensity is 80%, the signal intensity due to the defect appears clearly lower than the signal intensity of the peripheral part, and the defect part is clearly visible. It appears that 95%, 20%
When the image is picked up at the optical arrangement position, the signal intensity from the defect is not so different from the noise in the peripheral portion, and the defect cannot be clearly seen. The determination of S / N is the same as in the case of FIG. 3, but in the case of such a defect, the signal of the defective portion becomes lower than the signals of the surroundings, so that the signal with a digital filter has a negative intensity. S
/ N was determined. At 80%, the S / N is 4.7. 9
At 5% and 20%, the defective portion cannot be identified.
【００１６】このような撮像実験をもっとも小さなサイ
ズのサンプルに対して様々な光学的配置において繰り返
し実験を行い、Ｓ／Ｎを調べたところ、図６の結果を得
た。欠陥抽出可能なＳ／Ｎは図４の場合と同様に１．５
以上としたところ、正反射方向の光強度の３０％以上９
０％以下の光強度となるような光学的配置に検出器を設
置することによって検出可能となることが分った。Such an imaging experiment was repeated for various samples in various optical arrangements for the smallest sample, and the S / N was examined. The results shown in FIG. 6 were obtained. The S / N from which defects can be extracted is 1.5 as in the case of FIG.
As a result, 30% or more of the light intensity in the specular reflection direction 9
It has been found that detection can be performed by installing the detector in an optical arrangement in which the light intensity is 0% or less.
【００１７】したがって、欠陥部分表面にスケールが付
着しているような欠陥あるいは赤スケール等スケール疵
と呼ばれる欠陥など、表面の反射率が欠陥の無い部分に
比べ低くなっているものについては、異なる二つの光学
的配置に検出器を設置し、少なくとも１台以上の検出器
を正反射方向の光強度の３０％未満の光強度となる第１
の光学的配置に設置し、正反射方向の光強度の３０％以
上９０％以下の光強度となるような第２の光学的配置に
少なくとも１台以上の検出器を設置することによって、
欠陥の無い周辺部分の強度を高く、欠陥部分の強度を低
く撮るような形で、高いＳ／Ｎで前記のような暗くなる
欠陥をも検出することが可能となる。従ってあらゆる種
類の欠陥を高いＳ／Ｎで検出することが可能となるので
ある。Therefore, a defect having a surface reflectance lower than that of a defect-free portion, such as a defect in which scale is attached to the surface of the defect portion or a defect called scale flaw such as red scale, is different. The detectors are installed in two optical arrangements, and at least one or more detectors have a light intensity of less than 30% of the light intensity in the specular reflection direction.
And the second optical arrangement that provides a light intensity of 30% or more and 90% or less of the light intensity in the specular reflection direction.
It is possible to detect such a darkening defect with a high S / N by taking a high intensity in the defect-free peripheral portion and a low intensity in the defect portion. Therefore, it becomes possible to detect all kinds of defects with high S / N.
【００１８】[0018]
【実施例】本発明の実施例を熱延鋼板に適用した結果を
説明する。図１は検出器を２個設置した本発明の実施例
を示す構成図である。図において被検査材１である熱延
鋼板の表面に棒状光源２を照射する。連続照射をするこ
とが可能である。棒状光源２は被検査材１に垂直な方向
から約３０度の角度で配置されている。光源用電源３は
棒状光源に電力を供給する。被検査材１の表面を撮像す
るＣＣＤラインセンサカメラなどの一次元撮像装置４は
得られた検出信号を伝送する機能をも有する。一次元撮
像装置４は被検査材１にほぼ垂直な方向に設置され、被
検査材１が熱延鋼板である場合はこの方向で正反射方向
の光強度が５〜１０％の光強度となる。EXAMPLES The results of applying the examples of the present invention to hot-rolled steel sheets will be described. FIG. 1 is a block diagram showing an embodiment of the present invention in which two detectors are installed. In the figure, the bar-shaped light source 2 is irradiated onto the surface of the hot-rolled steel sheet that is the material 1 to be inspected. Continuous irradiation is possible. The rod-shaped light source 2 is arranged at an angle of about 30 degrees from the direction perpendicular to the inspected material 1. The light source power source 3 supplies electric power to the rod-shaped light source. The one-dimensional image pickup device 4 such as a CCD line sensor camera for picking up an image of the surface of the material 1 to be inspected also has a function of transmitting the obtained detection signal. The one-dimensional imaging device 4 is installed in a direction substantially perpendicular to the inspected material 1, and when the inspected material 1 is a hot rolled steel sheet, the light intensity in the specular reflection direction is 5 to 10% in this direction. .
【００１９】第２の一次元撮像装置１０は正反射方向の
光強度の３０％〜９０％の範囲の光強度となる光学的配
置に設置され、この実施例では被検査材１に垂直となる
方向から光源と反対側に２０度の角度に設置されてお
り、この角度で正反射方向の光強度の約７０％の光強度
を得ている。熱線カット用光学フィルタ５は、被検査材
１である熱延鋼板からの自発光の影響を小さくする。Ａ
／Ｄ変換装置６は、一次元撮像装置４、１１から伝送さ
れた検出信号をＡ／Ｄ変換する。信号処理装置７は、一
次元撮像装置から伝送された検出信号を信号処理して欠
陥の抽出を行う。画像処理装置８は、信号処理によって
抽出された欠陥を出力して画像処理を行う。９は、オペ
レータ用の表示装置である。The second one-dimensional image pickup device 10 is installed in an optical arrangement in which the light intensity is in the range of 30% to 90% of the light intensity in the specular reflection direction. In this embodiment, it is perpendicular to the material 1 to be inspected. It is installed at an angle of 20 degrees on the side opposite to the light source from the direction, and at this angle, a light intensity of about 70% of the light intensity in the specular reflection direction is obtained. The heat ray-cutting optical filter 5 reduces the influence of self-luminous light from the hot-rolled steel sheet that is the inspection target material 1. A
The / D conversion device 6 performs A / D conversion on the detection signals transmitted from the one-dimensional imaging devices 4 and 11. The signal processing device 7 performs signal processing on the detection signal transmitted from the one-dimensional imaging device to extract defects. The image processing device 8 outputs the defects extracted by the signal processing and performs image processing. Reference numeral 9 is a display device for the operator.
【００２０】電源３から電力の供給を受けた棒状光源２
から被検査材１に照射された白色光源は被検査材表面に
よって散乱されその一部が第１の一次元撮像装置４に入
射され、撮像される。その際高温表面である被検査材１
からの放射エネルギーによるノイズ成分は光学フィルタ
ー５によってカットされる。被検査材１表面に欠陥があ
る場合は一次元撮像装置４を正反射方向の光強度の３０
％未満の光強度となるような光学的配置に設置しておく
ことにより、欠陥の無い部分からの光強度より欠陥部分
からの光強度が高くなり、得られる検出信号の強度が大
きく変化する。A rod-shaped light source 2 which is supplied with power from a power source 3.
The white light source applied to the inspection material 1 from the above is scattered by the surface of the inspection material, and a part of the light source is incident on the first one-dimensional imaging device 4 and is imaged. At that time, the material to be inspected 1 having a high temperature surface
The noise component due to the radiant energy from is cut by the optical filter 5. If there is a defect on the surface of the material 1 to be inspected, the one-dimensional image pickup device 4 is set to a light intensity of 30 in the regular reflection direction.
If the optical arrangement is such that the light intensity is less than%, the light intensity from the defective portion becomes higher than the light intensity from the defect-free portion, and the intensity of the obtained detection signal greatly changes.
【００２１】また、被検査材である熱延鋼板上に発生す
る反射率の低い、例えば温度の極めて高い圧延初期の頃
に発生した凹凸欠陥で表面に酸化スケールが付着してい
るもの、又は赤スケール等のスケール疵と呼ばれるもの
は、第１の一次元撮像装置４では検出することができ
ず、第２の一次元撮像装置１０によって検出される。そ
して検出信号は一次元撮像装置４、１０からＡ／Ｄ変換
装置６によってＡ／Ｄ変換され信号処理装置７に伝送さ
れ、そこで信号処理によって欠陥の抽出が行われるので
ある。さらに、欠陥があった場合は、欠陥信号の抽出さ
れた検出信号が画像処理装置８に伝送され、そこで画像
処理を施され、欠陥種類、等級判別が行われ、表示装置
９に欠陥の種類、等級が表示される。[0021] Further, a low-reflectance generated on the hot-rolled steel sheet to be inspected, for example, an uneven scale defect generated in the early rolling stage when the temperature is extremely high and oxide scale adheres to the surface, or red. What is called a scale flaw such as a scale cannot be detected by the first one-dimensional imaging device 4 and is detected by the second one-dimensional imaging device 10. Then, the detection signal is A / D converted by the A / D conversion device 6 from the one-dimensional imaging devices 4 and 10 and transmitted to the signal processing device 7, where the defect is extracted by signal processing. Furthermore, if there is a defect, the detection signal from which the defect signal has been extracted is transmitted to the image processing device 8, where image processing is performed to determine the defect type and grade, and the display device 9 displays the defect type, The grade is displayed.
【００２２】各欠陥の種類に対する検出の際のＳ／Ｎは
次のとおりである。The S / N at the time of detection for each defect type is as follows.
【００２３】[0023]
【表１】 ──────────────────────────────────── 欠陥の種類 擦り疵 Ｓ／Ｎ １．９〜４．６ へげ ３．５〜５．１ 噛み込み疵 ２．１〜３．６ 圧着疵 ２．３〜３．５ へばり疵 １．７〜２．２ 押し疵 ３．１〜４．８ かき疵 ３．３〜５．６ 赤スケール １．６〜１．９ ────────────────────────────────────[Table 1] ──────────────────────────────────── Type of defects Scratches S / N 1. 9-4.6 Hacks 3.5-5.1 Biting flaws 2.1-3.6 Crimping flaws 2.3-3.5 Heading flaws 1.7-2.2 Push flaws 3.1-4 .8 Scratch defect 3.3 to 5.6 Red scale 1.6 to 1.9 ─────────────────────────────── ──────
【００２４】[0024]
【発明の効果】本発明によれば、被検査材の表面の欠陥
の無い部分に光源から光束を投射してその反射光強度が
３０％未満の光強度となるような光学的配置に検出器を
設置することにより欠陥部分からの反射光強度に比べノ
イズ成分となる欠陥のない部分の反射光強度を低くする
ことが可能となり、高いＳ／Ｎで欠陥検出が可能とな
る。さらに、異なる二種類の光学的配置に検出器を設置
し、第２の検出器を正反射方向の光強度の３０％〜９０
％の光強度となるような光学的配置に設置することで、
欠陥の無い周辺部分の強度を高く、欠陥部分の強度を低
くするような形で、高いＳ／Ｎで反射率の低くなった暗
くなる欠陥をも検出することが可能となった。従って、
表面疵欠陥と呼ばれる凹凸欠陥のみならず、スケール疵
と呼ばれる非凹凸欠陥についても高いＳ／Ｎで検出する
ことが可能となる。According to the present invention, the detector is arranged in such an optical arrangement that the luminous flux is projected from the light source to the defect-free portion of the surface of the material to be inspected and the reflected light intensity is less than 30%. By installing, it becomes possible to lower the reflected light intensity of a portion having no defect, which becomes a noise component, as compared with the reflected light intensity of the defective portion, and it becomes possible to detect a defect with a high S / N. Further, the detectors are installed in two different optical arrangements, and the second detector is set to 30% to 90% of the light intensity in the specular reflection direction.
By installing in an optical arrangement that gives a light intensity of%,
It becomes possible to detect a darkening defect having a low reflectance at a high S / N ratio by increasing the intensity of the defect-free peripheral portion and decreasing the intensity of the defect portion. Therefore,
It is possible to detect not only unevenness defects called surface defects but also non-concave defects called scale defects with high S / N.
【図面の簡単な説明】[Brief description of drawings]
【図１】表面欠陥検査装置の実施例を示す構成図であ
る。FIG. 1 is a configuration diagram showing an embodiment of a surface defect inspection apparatus.
【図２】被検査材に入射した白色光の反射状態を表わし
た図である。FIG. 2 is a diagram showing a reflection state of white light incident on a material to be inspected.
【図３】正反射方向の光強度の２０％と６０％の光強度
となる光学的配置で被検査材上の欠陥を撮像した時の信
号とその信号にフィルタを掛けた信号の例を示す図であ
る。FIG. 3 shows an example of a signal obtained when an image of a defect on a material to be inspected is picked up by an optical arrangement in which the light intensity is 20% and 60% of the light intensity in the regular reflection direction, and a signal obtained by filtering the signal. It is a figure.
【図４】欠陥部分の信号を明るく撮像して検出する場合
の反射強度とＳ／Ｎの相関を表わした図である。FIG. 4 is a diagram showing a correlation between reflection intensity and S / N when a signal of a defective portion is brightly imaged and detected.
【図５】正反射方向の光強度の８０％と９５％と２０％
の光強度なる光学的配置で被検査材上の反射率の小さい
欠陥を撮像した時の信号とその信号にフィルタを掛けた
信号の例を示す図である。FIG. 5: 80%, 95% and 20% of the light intensity in the direction of regular reflection
FIG. 5 is a diagram showing an example of a signal when an image of a defect having a small reflectance on an inspection object is picked up by an optical arrangement having the light intensity of and a signal obtained by filtering the signal.
【図６】欠陥部分の信号を暗く撮像して検出する場合の
反射強度とＳ／Ｎの相関を表わした図である。FIG. 6 is a diagram showing a correlation between reflection intensity and S / N when a signal of a defect portion is darkly imaged and detected.
【図７】従来の表面欠陥検査装置の構成図である。FIG. 7 is a configuration diagram of a conventional surface defect inspection apparatus.
１ 被検査材 ２ 棒状光源 ３ 光源用電源 ４ 一次元撮像装置 ５ 熱線カットフィルタ ６ Ａ／Ｄ変換装置 ７ 信号処理装置 ８ 画像処理装置 ９ 表示装置 １０ 一次元撮像装置 １１ 光源 １２ 被検査材 １３ 欠陥 １４ 光源 １５ カメラ DESCRIPTION OF SYMBOLS 1 Inspected material 2 Rod-shaped light source 3 Power source for light source 4 One-dimensional imaging device 5 Heat ray cut filter 6 A / D conversion device 7 Signal processing device 8 Image processing device 9 Display device 10 One-dimensional imaging device 11 Light source 12 Inspected material 13 Defect 14 light source 15 camera
───────────────────────────────────────────────────── フロントページの続き (72)発明者 横尾 雅一 千葉市中央区川崎町１番地 川崎製鉄株式 会社技術研究本部内 (72)発明者 丸山 智 千葉市中央区川崎町１番地 川崎製鉄株式 会社技術研究本部内 (72)発明者 守屋 進 千葉市中央区川崎町１番地 川崎製鉄株式 会社技術研究本部内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Yokoo 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Satoshi Maruyama 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Susumu Moriya 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Co., Ltd. Technical Research Headquarters
Claims (3)
投射し、その反射光を一次元撮像装置で検出し、被検査
材の表面欠陥を検出する装置において、投射する光源の
正反射方向の光強度の３０％未満の光強度となる光学的
配置に検出器を設置したことを特徴とする表面欠陥検査
装置。1. A device for projecting a light beam from a light source onto the surface of a traveling steel strip, detecting the reflected light with a one-dimensional image pickup device, and detecting a surface defect of a material to be inspected, the specular reflection of the light source being projected. A surface defect inspection apparatus characterized in that a detector is installed in an optical arrangement in which the light intensity is less than 30% of the light intensity in the direction.
投射し、その反射光を一次元撮像装置で検出し、被検査
材の表面欠陥を検出する装置において、投射する光源の
正反射方向の光強度の３０％以上９０％以下の光強度と
なる光学的配置に検出器を設置したことを特徴とする表
面欠陥検査装置。2. A device for projecting a light beam from a light source onto the surface of a running steel strip, detecting the reflected light with a one-dimensional image pickup device, and detecting a surface defect of a material to be inspected, the specular reflection of the light source being projected. A surface defect inspection apparatus characterized in that a detector is installed in an optical arrangement in which the light intensity is 30% or more and 90% or less of the directional light intensity.
投射し、その反射光を一次元撮像装置で検出し、被検査
材の表面欠陥を検出する装置において、投射する光源の
正反射方向の光強度の３０％未満の光強度となる第１の
光学的配置に少なくとも１台以上の検出器を設置し、投
射する光源の正反射方向の光強度の３０％以上９０％以
下の光強度となる第２の光学的配置に少なくとも１台以
上の検出器を設置したことを特徴とする表面欠陥検査装
置。3. A device for projecting a light flux from a light source onto the surface of a running steel strip, detecting the reflected light with a one-dimensional image pickup device, and detecting a surface defect of a material to be inspected, the specular reflection of the light source being projected. 30% or more and 90% or less of the light intensity in the specular reflection direction of the light source for projection, in which at least one detector is installed in the first optical arrangement having a light intensity of less than 30% of the light intensity in the direction A surface defect inspection apparatus characterized in that at least one or more detectors are installed in a second optical arrangement having a high intensity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25150392A JPH06102194A (en) | 1992-09-21 | 1992-09-21 | Surface flaw inspection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25150392A JPH06102194A (en) | 1992-09-21 | 1992-09-21 | Surface flaw inspection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06102194A true JPH06102194A (en) | 1994-04-15 |
Family
ID=17223781
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25150392A Withdrawn JPH06102194A (en) | 1992-09-21 | 1992-09-21 | Surface flaw inspection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06102194A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009028883A1 (en) * | 2007-08-28 | 2009-03-05 | Posco | Device and method for optically detecting surface defect of round wire rod |
| JP2010210322A (en) * | 2009-03-09 | 2010-09-24 | Jfe Steel Corp | Scale residue inspection device of pickled steel sheet |
-
1992
- 1992-09-21 JP JP25150392A patent/JPH06102194A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009028883A1 (en) * | 2007-08-28 | 2009-03-05 | Posco | Device and method for optically detecting surface defect of round wire rod |
| KR100891842B1 (en) * | 2007-08-28 | 2009-04-07 | 주식회사 포스코 | Device for detecting the optic bug of archetypal rod and method thereof |
| US8306308B2 (en) | 2007-08-28 | 2012-11-06 | Posco | Method for optically detecting surface defect of round wire rod |
| JP2010210322A (en) * | 2009-03-09 | 2010-09-24 | Jfe Steel Corp | Scale residue inspection device of pickled steel sheet |
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Legal Events
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|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19991130 |