JP3340879B2 - Surface defect detection method and apparatus - Google Patents

Surface defect detection method and apparatus

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Publication number
JP3340879B2
JP3340879B2 JP06977795A JP6977795A JP3340879B2 JP 3340879 B2 JP3340879 B2 JP 3340879B2 JP 06977795 A JP06977795 A JP 06977795A JP 6977795 A JP6977795 A JP 6977795A JP 3340879 B2 JP3340879 B2 JP 3340879B2
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JP
Japan
Prior art keywords
inspection object
dimensional
light receiving
receiving angle
imaging
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.)
Expired - Fee Related
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JP06977795A
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Japanese (ja)
Other versions
JPH08271442A (en
Inventor
眞 奥野
進 守屋
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JFE Steel Corp
Original Assignee
JFE Steel Corp
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Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は、紙、鋼板、アルミ板な
どの走行する帯状の被検査物の表面に生ずる欠陥を光学
的に検出する表面欠陥検出方法及びその装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a surface defect which optically detects a defect occurring on the surface of a running belt-like inspection object such as paper, steel plate, aluminum plate or the like.

【0002】[0002]

【従来の技術】紙、鋼板、アルミ板などの被検査物の表
面に生ずる欠陥には、種々の形態のものがあり、これら
の欠陥を検出し、形態、受光量の変化等から欠陥の種類
を判別することにより、表面品質の管理や欠陥の発生防
止に役立てている。従来より、表面欠陥検出方法とし
て、走行する被検査物の表面に光を照射し、被検査物か
らの反射光を一次元撮像器により撮像し、その光量変化
から表面欠陥を検出する方法が知られている。また、被
検査物からの反射光を複数の撮像器により異なる受光角
で撮像し、これらの撮像データを処理して欠陥を判別す
る方法も知られている。
2. Description of the Related Art There are various types of defects generated on the surface of an object to be inspected, such as paper, steel plate, aluminum plate, etc., and these defects are detected. By judging this, it is useful for managing the surface quality and preventing the occurrence of defects. Conventionally, as a surface defect detection method, there is known a method of irradiating the surface of a running inspection object with light, capturing reflected light from the inspection object with a one-dimensional imager, and detecting a surface defect from a change in the light amount. Have been. There is also known a method in which reflected light from an inspection object is imaged by a plurality of imagers at different light receiving angles, and the image data is processed to determine a defect.

【0003】図3は、表面欠陥検査装置の概略構成を示
す模式図であり、この表面欠陥検査装置は、走行する被
検査物1の表面に光を照射する照光手段2と、被検査物
表面を正反射方向から撮像する第1の一次元撮像器3
と、被検査物表面を乱反射方向から撮像する第2の一次
元撮像器4と、これら2つの一次元撮像器3,4からの
撮像信号を処理する信号処理手段5とから構成されてい
る。
FIG. 3 is a schematic diagram showing a schematic configuration of a surface defect inspection apparatus. The surface defect inspection apparatus includes an illuminating means 2 for irradiating a surface of a running inspection object 1 with light, and a surface of the inspection object surface. One-dimensional imaging device 3 for imaging the object from the regular reflection direction
And a second one-dimensional imaging device 4 for imaging the surface of the inspection object from the irregular reflection direction, and signal processing means 5 for processing imaging signals from the two one-dimensional imaging devices 3 and 4.

【0004】この表面欠陥検査装置を用い、例えば、第
1の一次元撮像器3からの撮像信号を処理して、正反射
方向に受光量変化を生ずるような模様状の表面欠陥を検
出し、第2の一次元撮像器4からの撮像信号を処理し
て、乱反射方向に受光量変化を生ずるような凹凸状の表
面欠陥を検出することにより、異なる2種類の表面欠陥
を同時に検出し、判別することができる。ここで一次元
撮像器とは、光電素子を1列状に並べて線状領域の反射
光を撮像するものであり、一次元CCDカメラが好まし
く用いられる。
Using this surface defect inspection apparatus, for example, an image pickup signal from the first one-dimensional image pickup device 3 is processed to detect a pattern-like surface defect that causes a change in the amount of received light in the regular reflection direction. An image signal from the second one-dimensional image pickup device 4 is processed to detect an irregular surface defect that causes a change in the amount of received light in the irregular reflection direction, thereby simultaneously detecting and discriminating two different types of surface defects. can do. Here, a one-dimensional imaging device is a device in which photoelectric elements are arranged in a line to capture reflected light in a linear region, and a one-dimensional CCD camera is preferably used.

【0005】[0005]

【発明が解決しようとする課題】図3に示すように複数
台の一次元撮像器を用いて表面欠陥の検査を行う場合に
は、すべての一次元撮像器が被検査物表面上の同一位置
を検査することが肝要である。この理由については後述
する。ところで、被検査物の厚さは必ずしも一定ではな
く、また被検査物が走行中にばたつきを生じて走行方向
に垂直な方向に上下動を発生することもある。この被検
査物の厚さ変化あるいはばたつき(高さ変動)により、
被検査物表面と表面欠陥検査装置の光学系との距離が図
4に示すように変化するものとする。この距離変化量を
被検査物表面の高さ変動量Δdと呼ぶことにする。
When a plurality of one-dimensional imagers are used for surface defect inspection as shown in FIG. 3, all the one-dimensional imagers are located at the same position on the surface of the inspection object. It is important to test for The reason will be described later. Incidentally, the thickness of the object to be inspected is not always constant, and the object to be inspected may fluctuate during traveling and move up and down in a direction perpendicular to the traveling direction. Due to the thickness change or fluttering (height fluctuation) of this inspection object,
It is assumed that the distance between the surface of the inspection object and the optical system of the surface defect inspection apparatus changes as shown in FIG. This distance change amount is referred to as a height change amount Δd of the surface of the inspection object.

【0006】被検査物表面に高さ変動が生じた場合、図
4に示すように、複数台の一次元撮像器による被検査物
表面上の視野(検査位置)が、被検査物の走行方向に距
離δだけずれることになる。このように複数台の一次元
撮像器間で被検査物表面における視野のずれが生じる
と、以下に説明するように、欠陥の誤検出あるいは欠陥
種類の誤判定を招くおそれがあるという問題がある。
When the height of the surface of the inspection object fluctuates, as shown in FIG. 4, the visual field (inspection position) on the surface of the inspection object by a plurality of one-dimensional imaging devices is determined by the traveling direction of the inspection object. Is shifted by the distance δ. As described below, there is a problem that erroneous detection of a defect or erroneous determination of a type of a defect may be caused if the displacement of the visual field on the surface of the object to be inspected among a plurality of one-dimensional imagers in this manner. .

【0007】図5は、図3に示した従来の2台の一次元
撮像器を用いた表面欠陥検査装置における、各一次元撮
像器による撮像データに基づいて検出された欠陥を示す
各画像、およびそれらの画像を組合せた表面欠陥検出装
置出力を模式的に示した図である。図5(a)は検査位
置ずれ量δ(図4参照)がない(δ=0)場合、図5
(b),(c)は検査位置ずれ量δがある(δ≠0)場
合を示す。
FIG. 5 is a view showing each image showing a defect detected based on image data obtained by each one-dimensional image pickup device in the conventional surface defect inspection apparatus using two one-dimensional image pickup devices shown in FIG. FIG. 4 is a diagram schematically showing outputs of a surface defect detection device obtained by combining these images. FIG. 5A shows the case where there is no inspection position deviation amount δ (see FIG. 4) (δ = 0).
(B) and (c) show the case where there is an inspection position deviation amount δ (δ ≠ 0).

【0008】図5(b)は検査位置ずれ量δが比較的小
さい場合であるが、この場合であっても表面欠陥検査装
置出力は、それぞれの欠陥の検出位置が走行方向(X方
向)にずれて重なるために欠陥の長さを実際よりも大き
く評価してしまっている。この欠陥長さの誤評価は、欠
陥種類の誤判定を招く恐れがある。また、図5(c)は
δが比較的大きい場合であり、この例では被検査物上の
1つの欠陥をあたかも2つの欠陥のように誤検出するお
それがある。
FIG. 5B shows the case where the inspection position deviation amount δ is relatively small. Even in this case, the output of the surface defect inspection apparatus indicates that the detection position of each defect is in the traveling direction (X direction). Due to the shift and overlap, the length of the defect is evaluated to be larger than the actual length. The erroneous evaluation of the defect length may cause an erroneous determination of the defect type. FIG. 5C shows a case where δ is relatively large. In this example, there is a possibility that one defect on the inspection object is erroneously detected as if it were two defects.

【0009】本発明は、上記のような問題点を解決し、
被検査物の高さ変動がある場合でも、表面欠陥を正確に
検出し、またその種類を正確に判定することのできる表
面欠陥検出方法およびその方法を実現するための装置を
提供することを目的とする。
The present invention solves the above problems,
An object of the present invention is to provide a surface defect detection method capable of accurately detecting a surface defect and accurately determining the type of the surface defect even when the height of the inspection object varies, and an apparatus for implementing the method. And

【0010】[0010]

【課題を解決するための手段】上記目的を達成する本発
明の表面欠陥検出方法のうちの第1の表面欠陥検出方法
は、走行する被検査物の走行方向に交わる幅方向の一次
元画像を、複数の一次元撮像器により、複数の受光角度
から繰り返し撮像して各受光角度毎の撮像データを得、
該撮像データに基づいて、被検査物表面の欠陥を検出す
る表面欠陥検出方法において、被検査物に対する前記複
数の一次元撮像器の幾何学的な配置位置と該被検査物表
面の高さ変動量とに基づく計算により、各受光角度ごと
の撮像データの、該被検査物表面の相対的な位置ずれ量
δを求め、各受光角度ごとの撮像データを、求められた
該位置ずれ量δに相当する量だけ相対的に遅延させるこ
とにより、各受光角度毎の位置補正撮像データを得、
位置補正撮像データに基づいて各受光角度ごとの受光量
変化をとらえることにより、被検査物表面の欠陥を検出
することを特徴とする。
A first surface defect detection method of the surface defect detection method of the present invention for achieving the above object.
May give the one-dimensional image in the width direction intersecting the traveling direction of the object to be inspected traveling, a plurality of one-dimensional imaging device, and imaging repeated a plurality of light-receiving angles imaging data of the light receiving angle each,
Based on the imaging data, the surface defect detection method for detecting a defect of the inspection object surface, the double with respect to the inspection object
By based rather calculated and height variation of the geometrical arrangement position and obtaining step piece surface one-dimensional image pickup device having, for each receiving angle
Relative displacement of the surface of the inspection object in the imaging data
δ was determined, and the imaging data for each light receiving angle was determined.
It should be relatively delayed by an amount corresponding to the displacement amount δ.
And allows to obtain a position correction imaging data for each receiving angle, the
Received light amount at each light receiving angle based on position corrected imaging data
By detecting the change, a defect on the surface of the inspection object is detected.

【0011】また、本発明の表面欠陥検出方法のうちの
第2の表面欠陥検出方法は、走行する被検査物の走行方
向に交わる幅方向の一次元画像を、複数の一次元撮像器
により、複数の受光角度から繰り返し撮像して各受光角
度毎の撮像データを得、該撮像データに基づいて、被検
査物表面の欠陥を検出する表面欠陥検出方法において、
被検査物に対する前記複数の一次元撮像器の幾何学的な
配置位置と該被検査物の高さ変動量とに基づく計算によ
り、各受光角度ごとの撮像データの、該被検査物表面の
相対的な位置ずれ量δを求め、該位置ずれ量δと該被検
査物の走行速度Vとから求められる時間遅れδ/V分だ
け、前記複数の一次元撮像器による撮像開始のタイミン
グを相対的にずらすことにより、各受光角度毎の位置補
正撮像データを得、 該位置補正撮像データに基づいて各
受光角度ごとの受光量変化をとらえることにより、被検
査物表面の欠陥を検出することを特徴とする
Further , in the surface defect detection method of the present invention,
The second surface defect detection method is based on a method of traveling of a traveling inspection object.
One-dimensional images in the width direction intersecting
By repeatedly capturing images from multiple light receiving angles,
Obtain imaging data for each degree, and based on the imaging data,
In a surface defect detection method for detecting defects on the surface of an inspection object,
The geometrical shape of the plurality of one-dimensional imagers with respect to the object to be inspected.
By calculation based on the arrangement position and the height variation of the inspection object
Of the surface of the inspection object of the imaging data for each light receiving angle.
The relative displacement δ is determined, and the relative displacement δ and the
It is a time delay δ / V minutes obtained from the running speed V of the inspected object.
The timing of starting the imaging by the plurality of one-dimensional imaging devices
The relative position of each light receiving angle
Obtain the normal imaging data, and based on the position corrected imaging data,
By detecting the change in the amount of received light at each receiving angle,
It is characterized by detecting defects on the surface of the inspection object .

【0012】また、本発明の表面欠陥検出方法は、高さ
変動量を取得する方法について限定されるものではな
く、例えばその高さ変動量が被検査物の厚さ等によりあ
らかじめデータとしてわかっている場合はそのデータを
受け取るだけであってもよい。ただし、走行方向上流側
で被検査物の高さ変動量を測定し、この測定された高さ
変動量に基づいて上記位置ずれ量δを求めることが好ま
しい。
The method for detecting a surface defect according to the present invention is not limited to a method for obtaining the amount of height variation. For example, the amount of height variation is known as data based on the thickness of the inspection object. If so, it may simply receive the data. However, it is preferable to measure the amount of height variation of the inspection object on the upstream side in the traveling direction, and to determine the positional deviation amount δ based on the measured amount of height variation.

【0013】また、上記本発明の表面欠陥検出方法の実
施に用いられる本発明の表面欠陥検出装置のうちの第1
の表面欠陥検出装置は、走行する被検査物の走行方向に
交わる幅方向の一次元画像を、複数の受光角度から繰り
返し撮像する複数の一次元撮像器と、被検査物表面の高
さ変動量を入力する高さ変動量入力手段と、被検査物に
対する前記複数の一次元撮像器の幾何学的な配置位置と
被検査物の高さ変動量とに基づく計算により、各受光角
度ごとの撮像データの、該被検査物表面の相対的な位置
ずれ量δを求め、各受光角度ごとの撮像データを、求め
られた該位置ずれ量δに相当する量だけ相対的に遅延さ
せることにより、各受光角度毎の位置補正撮像データを
得る位置補正画像データ取得手段と、 前記位置補正撮像
データに基づいて各受光角度ごとの受光量変化をとらえ
ることにより、被検査物表面の欠陥を検出する表面欠陥
検出手段とを備えたことを特徴とする。 また、本発明の
表面欠陥検出装置のうちの第2の表面欠陥検出装置は、
走行する被検査物の走行方向に交わる幅方向の一次元画
像を、複数の受光角度から繰り返し撮像する複数の一次
元撮像器と、 被検査物表面の高さ変動量を入力する高さ
変動量入力手段と、 被検査物に対する前記複数の一次元
撮像器の幾何学的な配置位置と被検査物の高さ変動量と
に基づく計算により、各受光角度ごとの撮像データの、
該被検査物表面の相対的な位置ずれ量δを求め、該位置
ずれ量δと該被検査物の走行速度Vとから求められる時
間遅れδ/V分だけ、前記複数の一次元撮像器による撮
像開始のタイミングを相対的にずらすことにより、各受
光角度毎の位置補正撮像データを得る位置補正撮像デー
タ取得手段と、 前記位置補正撮像データに基づいて各受
光角度ごとの受光量変化をとらえることにより、被検査
物表面の欠陥を検出する表面欠陥検出手段とを備えたこ
とを特徴とする。
Further, a first one of the surface defect detecting devices of the present invention used for carrying out the surface defect detecting method of the present invention .
The surface defect detection device includes a plurality of one-dimensional imagers that repeatedly image a one-dimensional image in a width direction intersecting a traveling direction of a traveling inspection object from a plurality of light receiving angles, and a height variation amount of a surface of the inspection object. the height variation input means for inputting, to the object to be inspected
Geometric arrangement positions of the plurality of one-dimensional imagers with respect to
Each light receiving angle is calculated by the calculation based on the height variation of the inspection object.
The relative position of the surface of the inspection object in the imaging data for each degree
The shift amount δ is obtained, and the imaging data for each light receiving angle is obtained.
Is relatively delayed by an amount corresponding to the displacement amount δ.
The position-corrected imaging data for each light-receiving angle.
Means for obtaining position-corrected image data, and said position-corrected imaging
Captures the change in received light amount at each light receiving angle based on data
Surface defects to detect defects on the surface of the inspection object
And a detecting means. In addition, the present invention
The second surface defect detection device among the surface defect detection devices includes:
One-dimensional image in the width direction intersecting the traveling direction of the moving inspection object
Multiple primary images that repeatedly capture images from multiple light receiving angles
The original imager and the height to input the height variation of the surface of the inspection object
A variation input means; and the plurality of one-dimensional objects with respect to the inspection object.
The geometric arrangement of the imager and the height variation of the inspection object
By the calculation based on, the imaging data of each light receiving angle,
The relative displacement δ of the surface of the inspection object is determined,
When calculated from the deviation amount δ and the traveling speed V of the inspection object
Shooting by the plurality of one-dimensional imaging devices by the delay δ / V
By relatively shifting the image start timing,
Position corrected imaging data to obtain position corrected imaging data for each light angle
Data acquisition means, and each reception based on the position-corrected imaging data.
By detecting the change in the amount of light received at each light angle,
Surface defect detecting means for detecting defects on the surface of the object.
And features.

【0014】ここで、高さ変動量入力手段は、入力の相
手先、すなわち高さ変動量の出力先を限定するものでは
なく、例えばホストのコンピュータから入力してもよ
く、あるいは高さ変動量を測定する測定器を備え、その
測定器の出力を入力してもよい。
Here, the height variation input means does not limit the destination of the input, that is, the output destination of the height variation. For example, the height variation may be input from a host computer, or the height variation may be input. May be provided, and the output of the measuring device may be input.

【0015】[0015]

【作用】本発明は、被検査物の高さ変動量に基づいて走
行方向の相対的な位置ずれが補正された、各受光角度毎
の位置補正撮像データを得、その位置補正撮像データに
基づいて被検査物表面の欠陥を検出するものであるた
め、欠陥の寸法や個数が誤判定や誤検出されることな
く、被検査物表面の欠陥を高精度に検出することができ
る。
According to the present invention, position-corrected imaging data for each light-receiving angle in which relative displacement in the traveling direction has been corrected based on the height variation of the inspection object is obtained, and based on the position-corrected imaging data. Therefore, the defect on the surface of the inspection object can be detected with high accuracy without erroneous determination or erroneous detection of the size and number of the defects.

【0016】ここで、位置補正撮像データを得るにあた
って、被検査物の高さ変動量に基づいて、複数の一次元
撮像器による撮像開始のタイミングを相対的にずらすこ
とにより位置撮像データを得ることとすると、撮像と同
時に位置補正が行われ、高速な画像処理が可能となる。
ただし、高さ変動量に応じて撮像開始のタイミングを種
々に変更するための制御回路を付加する必要を生じる。
Here, in obtaining the position-corrected image data, the position image data is obtained by relatively shifting the timing of starting the image pickup by a plurality of one-dimensional image pickup devices based on the height variation of the inspection object. Then, the position is corrected at the same time as the imaging, and high-speed image processing can be performed.
However, it becomes necessary to add a control circuit for variously changing the timing of starting the imaging in accordance with the height fluctuation amount.

【0017】一方、位置補正撮像データを得るにあたっ
て、被検査物の高さ変動量に基づいて、複数の一次元撮
像器による撮像により得られた撮像データを補正するこ
とにより位置補正撮像データを得ることとすると、撮像
後に位置補正の演算を行う必要から画像処理に若干時間
がかかることとなるが、その補正のための特別なハード
ウェアは不要であり、コスト上有利である。
On the other hand, when obtaining position-corrected image data, position-corrected image data is obtained by correcting image data obtained by imaging with a plurality of one-dimensional imagers on the basis of the height fluctuation amount of the inspection object. In this case, since it is necessary to perform the position correction operation after the image pickup, it takes some time for the image processing, but no special hardware for the correction is required, which is advantageous in cost.

【0018】本発明は、このように、位置補正撮像デー
タを得る具体的な手法の如何を問うものではなく、各手
法の得失を考慮して任意の手法を採用することができ
る。また、本発明は、上述したように、高さ変動量を得
る方法についても限定されるものではないが、走行方向
上流側で被検査物の高さ変動量を測定し、この測定され
た高さ変動量に基づいて位置補正データを得ることする
と、高さ変動量のデータがあらかじめ存在しない場合、
あるいは不正確な場合や、被検査体にばたつきが生じる
場合であっても、走行方向の位置が正確に補正された位
置補正撮像データを得ることができる。
As described above, the present invention does not ask a specific method for obtaining position-corrected imaging data, but may employ an arbitrary method in consideration of the advantages and disadvantages of each method. Further, as described above, the present invention is not limited to a method of obtaining the height variation, but measures the height variation of the inspection object on the upstream side in the traveling direction, and determines the measured height. By obtaining position correction data based on the amount of height variation, if there is no height variation data in advance,
Alternatively, even in the case of inaccuracy or fluttering of the test object, it is possible to obtain position-corrected imaging data in which the position in the traveling direction is accurately corrected.

【0019】[0019]

【実施例】以下、本発明の実施例について説明する。図
1は、本発明の一実施例を示す表面欠陥検出装置の模式
図である。照光手段2によって、走行する被検査物1の
幅方向(走行方向に垂直な方向)に光を照射するととも
に、被検査物1の表面からの反射光を、異なる受光角度
位置に設置した2台の一次元撮像器3,4で撮像する。
一方、被検査物1の厚さ変化あるいはばたつき等に起因
する被検査物表面の高さ変動(図1における被検査物1
の上面の上下方向変動)を高さ変動検出器6で検出す
る。高さ変動検出器6としては、渦流式、超音波式、あ
るいはレーザ式の変位計などが好適である。
Embodiments of the present invention will be described below. FIG. 1 is a schematic diagram of a surface defect detection device showing one embodiment of the present invention. The two illuminating units 2 irradiate light in the width direction (direction perpendicular to the running direction) of the running inspection object 1 and reflect light reflected from the surface of the inspection object 1 at different light receiving angle positions. Are imaged by the one-dimensional imaging devices 3 and 4.
On the other hand, a change in the height of the surface of the inspection object 1 due to a change in thickness or fluttering of the inspection object 1 (the inspection object 1 in FIG. 1).
Of the upper surface in the vertical direction) is detected by the height fluctuation detector 6. As the height fluctuation detector 6, an eddy current type, ultrasonic type, or laser type displacement meter is suitable.

【0020】2台の一次元撮像器3,4による撮像デー
タ、および高さ変動検出器6の測定結果は信号処理手段
5に送られる。信号処理手段5は、順次得られる一次元
の撮像データを時系列的につなぎ合わせて被検査物表面
の2次元の撮像データを得、この画像内の受光量変化を
所定のしきい値処理により抽出して表面欠陥を検出す
る。なお被検査物1の走行速度が一定でない場合は、被
検査物の走行速度を検出する手段を別途設けて、走行速
度変化に同期させて一次元撮像データをつなぎ合わせる
ようにする。信号処理手段5は、このような表面欠陥検
出処理を2つの一次元撮像器3,4に対してそれぞれ独
立に行った後、これら2つの表面欠陥データを組合せ
て、その欠陥の形状、受光量、あるいは検出に寄与した
一次元撮像器3,4の別などにより、表面欠陥の種類を
判定する。この過程において、高さ変動検出器6により
被検査物の高さ変動が検出された場合、その高さ変動量
Δdに基づいて、走行方向の位置ずれ(図4参照)が補
正される。
The image data obtained by the two one-dimensional imaging devices 3 and 4 and the measurement result of the height fluctuation detector 6 are sent to the signal processing means 5. The signal processing means 5 obtains two-dimensional imaging data of the surface of the inspection object by connecting the one-dimensional imaging data obtained sequentially in time series, and determines a change in the amount of received light in this image by a predetermined threshold processing. Extract and detect surface defects. If the traveling speed of the inspection object 1 is not constant, a means for detecting the traveling speed of the inspection object is separately provided, and the one-dimensional imaging data is connected in synchronization with the change in the traveling speed. After performing such surface defect detection processing independently on the two one-dimensional image pickup devices 3 and 4, the signal processing means 5 combines the two surface defect data to form the defect shape and the amount of received light. The type of the surface defect is determined by the one-dimensional imaging devices 3 and 4 that have contributed to the detection. In this process, when the height variation of the inspection object is detected by the height variation detector 6, the displacement in the traveling direction (see FIG. 4) is corrected based on the height variation Δd.

【0021】2台の一次元撮像器3,4の視野の走行方
向のずれ量δは、第1および第2の一次元撮像器3,4
の受光角度をそれぞれθ,φ、被検査物の高さ変動量を
Δdとすると、図4から幾何学的な計算により、 δ = Δd × (tanφ−tanθ) ……(1) と求められる。この計算は信号処理手段5によって行わ
れる。
The displacement δ of the visual field of the two one-dimensional imaging devices 3 and 4 in the running direction is determined by the first and second one-dimensional imaging devices 3 and 4.
If the light receiving angles are θ and φ, respectively, and the height variation of the object to be inspected is Δd, δ = Δd × (tan φ−tan θ) (1) is obtained by a geometric calculation from FIG. This calculation is performed by the signal processing means 5.

【0022】具体的には、一次元撮像器の被検査物長手
方向の走査速度をf[line/sec]、被検査物1
の走行速度をV[m/sec]とすると、第2の撮像器
による撮像データを走行方向にf・(δ/V)[lin
e]だけ遅らせてやればよい(δの単位は[m]とす
る)。この位置ずれを補正する手法として、2台の一次
元撮像器による撮像により得られた撮像データをずらす
代わりに、2台の一次元撮像器による撮像開始のタイミ
ングをずらしてもよい。
Specifically, the scanning speed of the one-dimensional imaging device in the longitudinal direction of the inspection object is f [line / sec], and the inspection object 1
Is the traveling speed of V [m / sec], the image data obtained by the second imager is converted to f · (δ / V) [lin] in the traveling direction.
e] (the unit of δ is [m]). As a method of correcting the positional deviation, the timing of starting the imaging by the two one-dimensional imaging devices may be shifted instead of shifting the imaging data obtained by the imaging by the two one-dimensional imaging devices.

【0023】すなわち、図4からわかるように、被検査
物1の高さ変動量Δdが正(上方に変動)のときは、第
2の一次元撮像器4の方が第1の一次元撮像器3よりも
被検査物の走行方向の下流側を撮像することになるの
で、第2の一次元撮像器4による撮像開始のタイミング
を、第1の一次元撮像器3による撮像開始のタイミング
よりも、被検査物1が距離δ走行する時間δ/Vだけ遅
らせる。こうすることにより2台の一次元撮像器3,4
で被検査体表面の同一領域を撮像することができる。
That is, as can be seen from FIG. 4, when the amount of height change Δd of the inspection object 1 is positive (changes upward), the second one-dimensional imaging device 4 performs the first one-dimensional imaging. Since the imaging is performed on the downstream side of the inspection object in the traveling direction of the inspection device 3, the timing of starting the imaging by the second one-dimensional imaging device 4 is determined by the timing of starting the imaging by the first one-dimensional imaging device 3. Is also delayed by the time δ / V during which the inspection object 1 travels the distance δ. By doing so, two one-dimensional imaging devices 3, 4
Can image the same region on the surface of the inspection object.

【0024】図2は、本発明の表面欠陥検出装置の、さ
らに具体的な実施例を示す模式図である。本実施例で
は、白色光源12から、走行する鋼板11の板幅方向に
線状の白色光を入射角10°で照射し、その反射光を受
光角10°および受光角45°の2つの一次元CCDカ
メラ13,14でそれぞれ撮像する。また光源12の上
流側にはレーザ式変位計16を板幅方向中央位置に設置
し、鋼板11の表面の高さ変動を非接触で検出する。さ
らに鋼板1の走行とともに回転する支持ロール17に走
行速度検出器18を設ける。2台のCCDカメラ13,
14の各出力、レーザ式変位計16の出力、および走行
速度検出器18の出力は全てコンピュータ15に送ら
れ、そのコンピュータ15で高速に信号処理が行われ
る。この処理では、検出された走行速度Vに同期してC
CDカメラ13,14の各出力を取り込み、レーザ変位
計出力Δdを用いて上記(1)式の計算を行い、2台の
CCDカメラ13,14の出力を距離δ分だけ、すなわ
ち時間(δ/V)分だけずらせて組合せることにより、
CCDカメラ間の視野ずれを補正している。
FIG. 2 is a schematic diagram showing a more specific embodiment of the surface defect detecting device of the present invention. In the present embodiment, linear white light is emitted from the white light source 12 in the width direction of the running steel plate 11 at an incident angle of 10 °, and the reflected light is reflected on two primary light beams having a light receiving angle of 10 ° and a light receiving angle of 45 °. Images are taken by the original CCD cameras 13 and 14, respectively. In addition, a laser displacement gauge 16 is installed at the center of the plate width direction on the upstream side of the light source 12 to detect a change in height of the surface of the steel plate 11 in a non-contact manner. Further, a traveling speed detector 18 is provided on a support roll 17 which rotates as the steel sheet 1 travels. Two CCD cameras 13,
All the outputs of 14, the output of the laser displacement meter 16, and the output of the traveling speed detector 18 are sent to a computer 15, which performs high-speed signal processing. In this processing, C is synchronized with the detected traveling speed V.
Each output of the CD cameras 13 and 14 is taken in, the above equation (1) is calculated using the laser displacement meter output Δd, and the outputs of the two CCD cameras 13 and 14 are divided by the distance δ, that is, the time (δ / V) By combining by shifting by minutes,
It corrects the visual field shift between the CCD cameras.

【0025】本実施例は、鋼板11の高さ変動が約±5
mmである製造ラインに設置した例であり、CCDカメ
ラ13,14の受光角が図2に示す角度のとき、5mm
の高さ変動により、カメラ間の視野ずれ量δは4.12
mmとなる。CCDカメラ13,14の走行方向の走査
周波数10KHz,鋼板11の走行速度300m/mi
n,鋼板11の幅1350mm,鋼板11の長さ約50
0mの条件にて本実施例を用いて表面欠陥の検出・判定
を行った結果、正答率は92%となり、一方、レーザ変
位計出力を用いずカメラ視野ずれを補正しない従来方法
時の場合は、上記と同一条件のときに正答率は75%で
あった。このように、本発明により、大幅な性能向上を
図ることができた。
In this embodiment, the height variation of the steel plate 11 is about ± 5.
In this example, the light receiving angles of the CCD cameras 13 and 14 are 5 mm when the light receiving angles of the CCD cameras 13 and 14 are the angles shown in FIG.
Of the field of view between the cameras δ is 4.12
mm. The scanning frequency of the CCD cameras 13 and 14 in the traveling direction is 10 KHz, and the traveling speed of the steel plate 11 is 300 m / mi.
n, width of steel plate 1 1350 mm, length of steel plate 11 about 50
As a result of detecting and judging the surface defect using this embodiment under the condition of 0 m, the correct answer rate is 92%. On the other hand, in the case of the conventional method in which no camera displacement is corrected without using the output of the laser displacement meter. Under the same conditions as above, the correct answer rate was 75%. As described above, according to the present invention, the performance was significantly improved.

【0026】なお上記の実施例では、鋼板の高さ変動を
非接触レーザ式変位計16で測定したが、被検査物のば
たつきが小さく、被検査物の厚さが別手段により既知で
ある場合には、このような変位計を設けず、厚さ情報を
コンピュータに取り込むことにより視野ずれを補正する
ようにしても差し支えない。また、以上の実施例では2
台の一次元撮像器を用いたが、使用する一次元撮像器は
3台以上であっても構わない。この場合、それぞれの一
次元撮像器に対して、(1)式で求める視野ずれ量を補
正する必要がある。
In the above embodiment, the height variation of the steel plate is measured by the non-contact laser displacement meter 16. In the case where the fluttering of the inspection object is small and the thickness of the inspection object is known by another means. However, such a displacement meter may not be provided, and the thickness information may be taken into a computer to correct the field of view deviation. In the above embodiment, 2
Although one one-dimensional imager was used, three or more one-dimensional imagers may be used. In this case, it is necessary to correct the visual field shift amount obtained by Expression (1) for each one-dimensional image pickup device.

【0027】[0027]

【発明の効果】以上説明したように、本発明によれば、
被検査物の厚さおよび一次元撮像器に接近・離反する方
向の高さ変動が生じる場合であっても、表面欠陥を正確
に検出し、欠陥の種類を正確に判別することができる。
As described above, according to the present invention,
Even when the thickness of the inspection object and the height change in the direction approaching / separating from the one-dimensional image pickup device occur, the surface defect can be accurately detected, and the type of the defect can be accurately determined.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の一実施例を示す表面欠陥検出装置の模
式図である。
FIG. 1 is a schematic diagram of a surface defect detection device according to an embodiment of the present invention.

【図2】本発明の表面欠陥検出装置の、さらに具体的な
実施例を示す模式図である。
FIG. 2 is a schematic diagram showing a more specific embodiment of the surface defect detection device of the present invention.

【図3】従来の表面欠陥検出装置の構成を示す模式図で
ある。
FIG. 3 is a schematic diagram showing a configuration of a conventional surface defect detection device.

【図4】高さ変動による視野ずれの説明図である。FIG. 4 is an explanatory diagram of a visual field shift due to a height change.

【図5】従来の表面欠陥検出装置における問題点の説明
図である。
FIG. 5 is an explanatory diagram of a problem in a conventional surface defect detection device.

【符号の説明】[Explanation of symbols]

1 被検査物 2 照光手段 3,4 一次元撮像器 5 信号処理手段 6 高さ変動検出器 11 鋼板 12 白色光源 13,14 CCDカメラ 15 コンピュータ 16 レーザ式変位計 17 支持ロール 18 走行速度検出器 DESCRIPTION OF SYMBOLS 1 Inspection object 2 Illumination means 3, 4 One-dimensional imaging device 5 Signal processing means 6 Height fluctuation detector 11 Steel plate 12 White light source 13, 14 CCD camera 15 Computer 16 Laser displacement meter 17 Support roll 18 Traveling speed detector

───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平3−267745(JP,A) 特開 昭55−87907(JP,A) 特開 平4−320908(JP,A) 特開 昭58−77642(JP,A) 特開 平6−138055(JP,A) (58)調査した分野(Int.Cl.7,DB名) G01N 21/88 - 21/892 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-267745 (JP, A) JP-A-55-87907 (JP, A) JP-A-4-320908 (JP, A) JP-A-58-58 77642 (JP, A) JP-A-6-138055 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01N 21/88-21/892

Claims (5)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 走行する被検査物の走行方向に交わる幅
方向の一次元画像を、複数の一次元撮像器により、複数
の受光角度から繰り返し撮像して各受光角度毎の撮像デ
ータを得、該撮像データに基づいて、被検査物表面の欠
陥を検出する表面欠陥検出方法において、被検査物に対する前記複数の一次元撮像器の幾何学的な
配置位置と該 被検査物表面の高さ変動量に基づく計算
により、各受光角度ごとの撮像データの、該被検査物表
面の相対的な位置ずれ量δを求め、各受光角度ごとの撮
像データを、求められた該位置ずれ量δに相当する量だ
け相対的に遅延させることにより、各受光角度毎の位置
補正撮像データを得、 該位置補正撮像データに基づいて各受光角度ごとの受光
量変化をとらえることにより、被検査物表面の欠陥を検
出することを特徴とする表面欠陥検出方法。
1. A one-dimensional image in a width direction intersecting a traveling direction of a traveling inspection object is repeatedly imaged from a plurality of light receiving angles by a plurality of one-dimensional imagers to obtain image data for each light receiving angle. In the surface defect detection method for detecting a defect on the surface of the inspection object based on the imaging data, a geometrical detection of the plurality of one-dimensional imaging devices with respect to the inspection object is performed.
Position and based rather calculated and height variation of the object to be inspected surface
The inspection object table of the imaging data for each light receiving angle
The relative displacement δ of the surface is determined, and the
The image data is an amount corresponding to the obtained positional deviation amount δ.
By only relatively delayed to obtain a position correction imaging data for each receiving angle, receiving for each receiving angle based on the position correction captured data
A surface defect detection method characterized by detecting a defect on the surface of an inspection object by detecting a change in the amount .
【請求項2】 走行する被検査物の走行方向に交わる幅
方向の一次元画像を、複数の一次元撮像器により、複数
の受光角度から繰り返し撮像して各受光角度毎の撮像デ
ータを得、該撮像データに基づいて、被検査物表面の欠
陥を検出する表面欠陥検出方法において、 被検査物に対する前記複数の一次元撮像器の幾何学的な
配置位置と該 被検査物の高さ変動量に基づく計算によ
り、各受光角度ごとの撮像データの、該被検査物表面の
相対的な位置ずれ量δを求め、該位置ずれ量δと該被検
査物の走行速度Vとから求められる時間遅れδ/V分だ
け、前記複数の一次元撮像器による撮像開始のタイミン
グを相対的にずらすことにより、各受光角度毎の位置補
正撮像データを得、該位置補正撮像データに基づいて各受光角度ごとの受光
量変化をとらえることにより、被検査物表面の欠陥を検
出する ことを特徴とする表面欠陥検出方法。
2. The width of the traveling inspection object crossing the traveling direction.
One-dimensional images in multiple directions can be
The image is repeatedly taken from the light receiving angle of
Data on the surface of the inspection object based on the imaging data.
In the surface defect detection method for detecting a defect , a geometrical detection of the plurality of one-dimensional imagers with respect to an inspection object is performed.
In based rather calculated and height variation of positions and the object to be inspected
Of the surface of the inspection object of the imaging data for each light receiving angle.
The relative displacement δ is determined, and the relative displacement δ and the
It is a time delay δ / V minutes obtained from the running speed V of the inspected object.
Only, by shifting relatively to the timing of the start imaging by the plurality of one-dimensional imaging unit, to obtain a position correction imaging data for each receiving angle, receiving for each receiving angle based on the position correction captured data
By detecting changes in volume, defects on the surface of the inspection object can be detected.
Front surface defect detecting how to characterized by the output.
【請求項3】 走行方向上流側で被検査物の高さ変動量
を測定し、この測定された高さ変動量を用いた計算によ
り前記位置ずれ量δを求めることを特徴とする請求項1
又は2記載の表面欠陥検出方法。
3. An amount of height variation of an inspection object on an upstream side in a traveling direction.
Is measured and calculated by using the measured height fluctuation.
2. The method according to claim 1, wherein the position shift amount is obtained.
Or the surface defect detection method according to 2.
【請求項4】 走行する被検査物の走行方向に交わる幅
方向の一次元画像を、複数の受光角度から繰り返し撮像
する複数の一次元撮像器と、 被検査物表面の高さ変動量を入力する高さ変動量入力手
段と、 被検査物に対する前記複数の一次元撮像器の幾何学的な
配置位置と被検査物の高さ変動量とに基づく計算によ
り、各受光角度ごとの撮像データの、該被検査物表面の
相対的な位置ずれ量δを求め、各受光角度ごとの撮像デ
ータを、求められた該位置ずれ量δに相当する量だけ相
対的に遅延させることにより、各受光角度毎の位置補正
撮像データを得る位置補正画像データ取得手段と、 前記位置補正撮像データに基づいて各受光角度ごとの受
光量変化をとらえることにより、被検査物表面の欠陥を
検出する表面欠陥検出手段とを備えたことを特徴とする
表面欠陥検出装置。
4. The width of the traveling inspection object crossing the traveling direction.
One-dimensional images in various directions from multiple light receiving angles
And a height change amount input means for inputting a height change amount of the surface of the inspection object.
A step and a geometrical configuration of the plurality of one-dimensional imagers with respect to the object to be inspected.
By calculation based on the arrangement position and the height variation of the inspection object
Of the surface of the inspection object of the imaging data for each light receiving angle.
The relative displacement δ is determined, and the imaging data for each light receiving angle is calculated.
Data by an amount corresponding to the obtained positional deviation amount δ.
Position correction for each light receiving angle
A position correction image data obtaining means for obtaining imaging data; and a receiving unit for each light receiving angle based on the position correction imaging data.
By detecting changes in light intensity, defects on the surface of the inspection object can be detected.
Surface defect detecting means for detecting
Surface defect detection device.
【請求項5】 走行する被検査物の走行方向に交わる幅
方向の一次元画像を、複数の受光角度から繰り返し撮像
する複数の一次元撮像器と、 被検査物表面の高さ変動量を入力する高さ変動量入力手
段と、被検査物に対する前記複数の一次元撮像器の幾何学的な
配置位置と被検査物の 高さ変動量とに基づく計算によ
り、各受光角度ごとの撮像データの、該被検査物表面の
相対的な位置ずれ量δを求め、該位置ずれ量δと該被検
査物の走行速度Vとから求められる時間遅れδ/V分だ
け、前記複数の一次元撮像器による撮像開始のタイミン
グを相対的にずらすことにより、各受光角度毎の位置補
正撮像データを得る位置補正撮像データ取得手段と、 前記位置補正撮像データに基づいて各受光角度ごとの受
光量変化をとらえることにより、被検査物表面の欠陥を
検出する表面欠陥検出手段とを備えたことを特徴とする
表面欠陥検出装置。
5. A plurality of one-dimensional imagers for repeatedly capturing a one-dimensional image in a width direction intersecting a traveling direction of a traveling inspection object from a plurality of light receiving angles, and inputting a height variation amount of a surface of the inspection object. Height variation input means, and a geometrical configuration of the plurality of one-dimensional imaging devices with respect to the inspection object.
By calculation based on the arrangement position and the height variation of the inspection object
The relative displacement δ of the imaging data at each light receiving angle on the surface of the inspection object is determined, and the displacement δ and the
It is a time delay δ / V minutes obtained from the running speed V of the inspected object.
The timing of starting the imaging by the plurality of one-dimensional imaging devices
A position-corrected image data obtaining means for obtaining position-corrected image data for each light-receiving angle,
A surface defect detection device comprising: a surface defect detection unit configured to detect a defect on a surface of an inspection object by capturing a change in light amount .
JP06977795A 1995-03-28 1995-03-28 Surface defect detection method and apparatus Expired - Fee Related JP3340879B2 (en)

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Application Number Priority Date Filing Date Title
JP06977795A JP3340879B2 (en) 1995-03-28 1995-03-28 Surface defect detection method and apparatus

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JP3340879B2 true JP3340879B2 (en) 2002-11-05

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DE102004007828B4 (en) * 2004-02-18 2006-05-11 Isra Vision Systems Ag Method and system for inspecting surfaces
KR20130056473A (en) * 2011-11-22 2013-05-30 동우 화인켐 주식회사 Apparatus and method for correction of vibration noise using optical inspection system
US8772731B2 (en) * 2012-04-15 2014-07-08 Kla-Tencor Corporation Apparatus and method for synchronizing sample stage motion with a time delay integration charge-couple device in a semiconductor inspection tool

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