JP3275737B2 - Surface inspection device and surface inspection method - Google Patents
Surface inspection device and surface inspection methodInfo
- Publication number
- JP3275737B2 JP3275737B2 JP29789796A JP29789796A JP3275737B2 JP 3275737 B2 JP3275737 B2 JP 3275737B2 JP 29789796 A JP29789796 A JP 29789796A JP 29789796 A JP29789796 A JP 29789796A JP 3275737 B2 JP3275737 B2 JP 3275737B2
- Authority
- JP
- Japan
- Prior art keywords
- flaw
- light
- pattern
- signal processing
- type
- 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
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
- G01N21/8914—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the material examined
- G01N2021/8918—Metal
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、例えば薄鋼板等
の表面疵等を光学的に検出する表面検査装置及び表面検
査方法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 inspection apparatus and a surface inspection apparatus for optically detecting, for example, surface flaws of a thin steel plate or the like.
It relates to the inspection method .
【０００２】[0002]
【従来の技術】例えば鋼板の表面疵を光学的に検出する
装置としては、レ−ザ光の散乱又は回折パタ−ンの変化
を利用して疵を検出する方法が多く用いられている。こ
の方法は鋼板の表面に明らかな凹凸を形成している疵を
検出する場合には有効な方法である。2. Description of the Related Art For example, as a device for optically detecting a surface flaw of a steel sheet, a method of detecting flaws by utilizing the scattering of laser light or a change in diffraction pattern is often used. This method is an effective method for detecting flaws having obvious irregularities on the surface of a steel sheet.
【０００３】一方、鋼板等の疵には、表面の凹凸はな
く、物性値のむら，ミクロな粗さのむら，薄い酸化膜等
の局所的な存在あるいはコ−ティング膜厚の厚さむらと
いった模様状疵といわれるものがある。このような模様
状疵はレ−ザ光の散乱や回折パタ−ンの変化では検出が
困難である。例えば正常部で100Å程度の酸化膜が付い
ている鋼板表面に、局所的に400Å程度の酸化膜が厚く
付いている異常部がある場合、このような異常部の領域
は表面処理工程において塗装不良が生じるため、疵とし
て検出して除去したい要請がある。しかしながら、異常
部と正常部の酸化膜厚の差は鋼板表面の粗さに埋もれて
しまい、光の散乱や回折を利用した方法では全く検出が
不可能である。On the other hand, flaws on steel plates and the like have no irregularities on the surface, and have a pattern such as unevenness of physical properties, unevenness of micro roughness, local existence of a thin oxide film or uneven thickness of a coating film. Some are said to be flaws. Such a pattern-like flaw is difficult to detect by scattering of laser light or a change in diffraction pattern. For example, if there is an abnormal part with a thick oxide film of about 400 mm locally on the surface of the steel sheet with an oxide film of about 100 mm in the normal part, such abnormal part area will have poor coating in the surface treatment process Therefore, there is a demand to detect and remove as a flaw. However, the difference in the oxide film thickness between the abnormal part and the normal part is buried in the roughness of the steel sheet surface, and cannot be detected at all by a method utilizing light scattering or diffraction.
【０００４】このように光の散乱や回折を利用した方法
では検出できない疵を検出するために、偏光を用いた疵
検査方法が例えば特開昭52−138183号公報や特開昭58−
204356号公報等に開示されている。特開昭52−138183号
公報に示された検査方法は被検査体の表面から反射した
Ｐ偏光とＳ偏光の比があらかじめ定めた比較レベルより
高いか否可によって欠陥の有無を検知するものである。
また、特開昭58−204356号公報に示された検出方法は被
検査体の表面に特定角度の入射角で光を照射して、表面
欠陥を検出するときのＳ／Ｎ比を向上するようにしたも
のである。また、疵検査方法ではないが、偏光を用いた
膜厚，表面物性の測定方法が例えば特開昭62−293104号
公報や特開平４−58138号公報等に開示されている。特
開昭62−293104号公報に示された検査方法は、試料から
反射した偏光を方位角の異なる３個の検光子を通して受
光し、異なる３種類の偏光の光強度から各位置のエリプ
ソパラメ−タすなわち反射光の電気ベクトルのうち入射
面方向の成分であるＰ偏光と入射面に垂直方向の成分で
あるＳ偏光との振幅反射率比tanΨと位相差Δを演算し
て、被検査面上の酸化膜やコ−ティング厚さあるいは物
性値を制度良く測定する方法である。特開平４−58138
号公報に示された検出方法は、試料から反射した偏光を
１/４波長板からなる移相子と検光子とを介してイメ−
ジセンサに導くときに、移相子の透過軸の位置を所定角
度変え、各角度毎に検光子を回転させてイメ−ジセンサ
の画素毎に偏光パラメ−タを求めて複屈折分布を精度良
く測定する方法である。[0004] In order to detect flaws which cannot be detected by the method utilizing light scattering or diffraction, a flaw inspection method using polarized light is disclosed in, for example, JP-A-52-138183 and JP-A-58-138183.
No. 204356 discloses this. The inspection method disclosed in Japanese Patent Application Laid-Open No. 52-138183 detects the presence or absence of a defect depending on whether or not the ratio of P-polarized light and S-polarized light reflected from the surface of the test object is higher than a predetermined comparison level. is there.
Further, the detection method disclosed in Japanese Patent Application Laid-Open No. 58-204356 is designed to improve the S / N ratio when a surface defect is detected by irradiating the surface of the test object with light at a specific angle of incidence. It was made. Although not a flaw inspection method, a method for measuring film thickness and surface properties using polarized light is disclosed in, for example, JP-A-62-293104 and JP-A-4-58138. In the inspection method disclosed in Japanese Patent Application Laid-Open No. 62-293104, the polarized light reflected from the sample is received through three analyzers having different azimuth angles, and the ellipsometric parameters at each position are determined from the light intensities of the three different polarized lights. That is, of the electric vector of the reflected light, the amplitude reflectance ratio tanΨ and the phase difference Δ between the P-polarized light, which is a component in the direction of the incident surface, and the S-polarized light, which is a component in the direction perpendicular to the incident surface, are calculated. This is a method for measuring the thickness of the oxide film, coating thickness or physical properties with high accuracy. JP-A-4-58138
In the detection method disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, the polarized light reflected from the sample is imaged through a phase shifter comprising a quarter-wave plate and an analyzer.
When the light is guided to the image sensor, the position of the transmission axis of the phase shifter is changed by a predetermined angle, the analyzer is rotated at each angle, and the polarization parameter is obtained for each pixel of the image sensor to accurately measure the birefringence distribution. How to
【０００５】[0005]
【発明が解決しようとする課題】特開昭52−138183号公
報や特開昭58−204356号公報に示された検査方法は、偏
光を用いて正常部と異常部とを弁別しているが、測定し
ている偏光方向は２方向のみである。鋼板等の表面の疵
部は光学的物性が正常部と異なった部分であることが多
く、その種類や形態は様々であるため鋼板で反射された
光の偏光状態も様々である。このような場合、３方向以
上の偏光を測定しないと、測定対象の偏光特性を一意に
表すことができないため、例えば検査結果として異常部
が検出できたとしても、それが油のしみか、酸化膜のむ
らか、又は何らかしらの異常な付着物が付着したのであ
るか等、多数の疵種を弁別するこができず、適用できる
疵種は制限されていた。また、偏光を用いたどのような
方法，装置を使用すれば多種多様の疵を弁別できるかに
ついても明らかにされていなかった。The inspection methods disclosed in JP-A-52-138183 and JP-A-58-204356 discriminate a normal part from an abnormal part using polarized light. The measured polarization directions are only two directions. A flaw on the surface of a steel plate or the like is often a portion having optical properties different from that of a normal portion, and since the types and forms are various, the polarization state of light reflected by the steel plate also varies. In such a case, the polarization characteristics of the measurement target cannot be uniquely expressed unless the polarization in three or more directions is measured. Therefore, even if an abnormal part can be detected as a result of the inspection, for example, oil spots or oxidation may be detected. Many types of flaws could not be discriminated, such as whether the film was uneven or any abnormal deposits were attached, and applicable flaw types were limited. Further, it has not been clarified what kind of method and apparatus using polarized light can be used to discriminate various kinds of flaws.
【０００６】これに対して特開昭62−293104号公報に示
された検査方法は、エリプソパラメ−タの振幅反射率比
tanΨと位相差Δを使用しているから、油のしみや酸化
膜のむら，異物の付着を弁別できる可能性がある。しか
しながら、この方法は基本的に点測定であり、鋼板等の
表面全体の検査に適さない。仮に、特開昭62−293104号
公報に示されている装置を鋼板の幅方向に多数並べた
り、幅方向に高速に移動可能な機構を持った手段によっ
て１台の装置を走査したり、何らかの工夫により全面走
査が可能になったとしても、信号処理部は全測定点につ
いて偏光強度信号からエリプソパラメ−タの振幅反射率
比tanΨと位相差Δを演算し、画像処理装置などを用い
て疵種と疵の等級を判定する必要がある。しかし、幅方
向１ラインで1000点以上の偏光強度信号を処理しなけら
ばならず、特にエリプソパラメ−タ演算はソフトウェア
演算で行った場合、約数10秒の演算時間がかかるため、
例えば毎分数100ｍの速度で通過する鋼板等のシ−ト状
製品の表面をオンラインで連続的に検査することは不可
能であった。このために専用の偏光パラメ−タ等の演算
処理装置が必要となり、装置が高価になってしまう。On the other hand, the inspection method disclosed in Japanese Patent Application Laid-Open No. 62-293104 discloses an amplitude reflectance ratio of an ellipsometer.
Since tan Ψ and phase difference Δ are used, there is a possibility that oil stains, oxide film unevenness and foreign matter adhesion can be discriminated. However, this method is basically a point measurement and is not suitable for inspecting the entire surface of a steel plate or the like. For example, a large number of devices disclosed in Japanese Patent Application Laid-Open No. 62-293104 may be arranged in the width direction of a steel sheet, or one device may be scanned by means having a mechanism capable of moving at high speed in the width direction. Even if the entire surface can be scanned by devising, the signal processing unit calculates the amplitude reflectance ratio tanΨ and phase difference Δ of the ellipsometric parameters from the polarization intensity signals for all measurement points, and uses an image processing device or the like to determine the flaw. It is necessary to determine the seed and flaw grade. However, it is necessary to process more than 1000 polarization intensity signals in one line in the width direction. In particular, when the ellipsometric parameter calculation is performed by software calculation, it takes about several tens of seconds for calculation.
For example, it has not been possible to continuously inspect online the surface of a sheet-like product such as a steel sheet passing at a speed of several hundred meters per minute. For this reason, an arithmetic processing device such as a dedicated polarization parameter is required, and the device becomes expensive.
【０００７】しかしながら、この方法は検査手法として
は非常に敏感であり、他の種類の疵や汚れ，油むら，ス
ケ−ルなどから相対的に微弱な検出強度した与えない模
様状の表面疵の情報のみを弁別して検出することは困難
であった。特に、表面に油膜が塗布されて製造ライン上
を移動する鋼板を検査する場合には、その油膜むらと本
来検出すべき表面疵の両方を含んだ偏光パラメ−タを検
出してしまい、表面疵の情報だけを弁別して検出するこ
とはできなかった。このため、特に防錆のために表面に
油膜が塗布されていることが多い冷延鋼板等の通常の鋼
板の表面疵の検出に使える可能性がないと考えられてお
り、鋼板の模様状疵を光学的手段で検出すること、さら
に表面疵の種類や等級までを判定することは不可能とさ
れていた。[0007] However, this method is very sensitive as an inspection method, and it has relatively low detection strength from other types of flaws, dirt, oil unevenness, scale, and the like. It was difficult to discriminate and detect only information. In particular, when inspecting a steel sheet moving on a production line with an oil film applied to its surface, polarization parameters including both the oil film unevenness and the surface flaw to be originally detected are detected, and the surface flaw is detected. Could not be discriminated and detected. For this reason, it is considered that there is no possibility that it can be used for detecting the surface flaw of a normal steel sheet such as a cold-rolled steel sheet which often has an oil film applied to the surface particularly for rust prevention, and the pattern flaw of the steel sheet It has been considered impossible to detect the surface defect by optical means and to determine the type and grade of the surface flaw.
【０００８】また、この方法は元々膜厚あるいは物性値
を測定する方法であり、そのためにはエリプソパラメ−
タの振幅反射率比tanΨと位相差Δを測定すれば十分で
あった、しかしながら、これらのパラメ−タは必ずしも
人の目で見た状態と一致するものではなく、人が疵と認
識できてもエリプソパラメ−タは変化しない疵について
は検出することができなかった。Further, this method is a method of measuring the film thickness or the physical property value from the beginning.
It was sufficient to measure the amplitude reflectivity ratio tanΨ and the phase difference Δ of the parameters, however, these parameters do not always correspond to the state seen by human eyes, and humans can recognize as flaws. However, no ellipsoparameter flaw could be detected with no change.
【０００９】また、特開平４−58138号公報に示された
検査方法は、薄膜評価等に使用されているエリプソメ−
タを２次元に拡大したものであり、この場合は、各画素
毎に複屈折率が求められるため、正常部と異常部とでは
異なる値として複屈折率が測定され、その違いにより正
常部と異常部を弁別できる可能性がある。しかしなが
ら、移相子と検光子を機械的に回転させて測定している
ため、被検査体の各位置の複屈折率を測定するには、少
なくとも１回の測定中は被検査体を停止させている必要
があった。このため、例えば鋼板等のように連続的に製
造されて送られるシ−ト状製品の表面をオンラインで連
続的に検査することは不可能であった。The inspection method disclosed in Japanese Patent Application Laid-Open No. 4-58138 discloses an ellipsometry method used for thin film evaluation and the like.
In this case, the birefringence is determined for each pixel, and thus the birefringence is measured as a different value between the normal part and the abnormal part. Abnormal parts may be discriminated. However, since the phase shifter and the analyzer are mechanically rotated for measurement, in order to measure the birefringence at each position of the test object, the test object must be stopped during at least one measurement. Had to be. For this reason, it has not been possible to continuously inspect the surface of a sheet-like product that is continuously manufactured and sent, such as a steel plate, on-line and continuously.
【００１０】この発明はかかる短所を改善するためにな
されたものであり、簡単な構成でシ−ト状製品の表面に
ある模様状疵や凹凸状の疵をオンラインで連続的に検出
して、その種別や程度を弁別することができる表面検査
装置及び表面検査方法を提供することを目的とするもの
である。The present invention has been made in order to improve such disadvantages, and detects a pattern-like or irregular flaw on the surface of a sheet-like product continuously with a simple configuration online. It is an object of the present invention to provide a surface inspection apparatus and a surface inspection method capable of discriminating the type and degree.
【００１１】[0011]
【課題を解決するための手段】この発明に係る表面検査
装置は、投光部と受光部と信号処理部とを有し、投光部
は被検査面に偏光を入射し、受光部は少なくとも３方向
の異なる角度の偏光を受光する複数の受光光学系を有
し、被検査面で反射した反射光を検出して画像信号に変
換し、信号処理部は変換した画像信号から所定の疵特徴
量を算出し、算出した疵特徴量をあらかじめ定めたパタ
−ンと比較し疵種あるいは疵種と等級を判定することを
特徴とする。上記信号処理部は疵特徴量として光強度分
布の変化極性から疵種を判定したり、疵特徴量として目
視相当光量を算出し、疵の等級を判定する。また、信号
処理部は各受光光学系から出力された光強度分布を平均
値があらかじめ定めた基準値となるように規格化した後
に疵特徴量を算出する。A surface inspection apparatus according to the present invention has a light projecting section, a light receiving section, and a signal processing section, wherein the light projecting section enters polarized light on a surface to be inspected, and the light receiving section has at least a light receiving section. It has a plurality of light receiving optical systems that receive polarized light with different angles in three directions, detects reflected light reflected on the surface to be inspected, converts it into an image signal, and a signal processing unit determines a predetermined flaw feature from the converted image signal. The amount is calculated, and the calculated flaw characteristic amount is compared with a predetermined pattern to determine a flaw type or a flaw type and a grade. The signal processing unit determines the flaw type from the change polarity of the light intensity distribution as the flaw characteristic amount, or calculates the visual equivalent light amount as the flaw characteristic amount to determine the grade of the flaw. The signal processing unit calculates the flaw feature quantity after normalizing the light intensity distribution output from each light receiving optical system so that the average value becomes a predetermined reference value.
【００１２】この発明に係る表面検査方法は、被検査面
に偏光を入射し、被検査面で反射した反射光の少なくと
も３方向の異なる角度の偏光を受光し、受光信号により
所定の疵特徴量を算出し、算出した疵特徴量をあらかじ
め定めたパタ−ンと比較し疵種あるいは疵種と疵の等級
を判定することを特徴とする。 According to the surface inspection method of the present invention, a surface to be inspected is provided.
Polarized light is incident on the surface to be inspected, and at least
Also receive polarized light at different angles in three directions, and
Calculate the predetermined flaw feature quantity and pre-calculate the calculated flaw feature quantity.
Flaw type or flaw type and flaw grade in comparison with the determined pattern
Is determined.
【００１３】[0013]
【発明の実施の形態】偏光は反射表面の物性、特に薄膜
に対して敏感である。また反射表面の物性により最大強
度の偏光方向も変化する。金属表面の疵部は正常部と異
なる表面特性を有し、表面の物性が母材と異なるため疵
となったり、あるいは例えば凹凸のように正常部と表面
幾何学形状が異なるために疵となるものがある。前者は
偏光を用いることにより検出でき、後者は反射率の相違
となって現れるため反射光量変化により検出できる。BEST MODE FOR CARRYING OUT THE INVENTION Polarized light is sensitive to the physical properties of a reflecting surface, especially to thin films. In addition, the polarization direction of the maximum intensity changes depending on the physical properties of the reflection surface. The flaws on the metal surface have surface characteristics different from those of the normal part and become flaws because the surface properties are different from those of the base material, or become flaws because the surface geometry differs from the normal part, for example, asperities There is something. The former can be detected by using polarized light, and the latter can be detected by a change in the amount of reflected light because it appears as a difference in reflectance.
【００１４】そこで、この発明においては、被検査面に
対して一定入射角で被検査面の幅方向全体に偏光を入射
するように投光部を配置し、被検査面からの反射光を受
光する受光部を所定の位置に配置する。受光部は入射し
た光を例えば３本のビ−ムに分離するビ−ムスプリッタ
と、分離した３本のビ−ムを別々に入射して画像信号を
出力する例えばＣＣＤセンサを有する３組のリニアアレ
イカメラと、ビ−ムスプリッタと各リニアアレイカメラ
の間に設けられ、被検査面からの反射光を異なる振動面
の偏光にする検光子とが設けられている。３個の検光子
はそれぞれ異なる方位角、すなわち透過軸が被検査面の
入射面となす角が、例えば０，π／４，−π／４になる
ように配置されている。Therefore, in the present invention, the light projecting section is arranged so that polarized light is incident on the whole surface of the surface to be inspected at a constant incident angle with respect to the surface to be inspected, and the reflected light from the surface to be inspected is received. The light receiving unit to be used is arranged at a predetermined position. The light receiving unit has three sets of a beam splitter that separates the incident light into, for example, three beams, and a CCD sensor that outputs the image signals by separately entering the three separated beams, for example. A linear array camera and an analyzer that is provided between the beam splitter and each linear array camera and converts reflected light from the surface to be inspected into polarized light of a different vibration surface are provided. The three analyzers are arranged so that different azimuth angles, that is, angles formed by the transmission axis and the incident surface of the surface to be inspected are, for example, 0, π / 4, -π / 4.
【００１５】信号処理部は各リニアアレイカメラからの
出力画像信号をシェ−ディング補正して正常部が全階調
の中心濃度になるように正規化して平坦化し、正常部に
対する相対的な変化を示す光強度信号に変換する。この
正常部に対する相対的な変化を示す３種類の光強度信号
の分布の変化極性と変化量とをそれぞれあらかじめ定め
たパタ−ンと比較して偏光の変化を検出する。この３種
類の光強度信号の正常部に対する変化極性と変化量の大
小から表面の物性が母材と異なる疵の疵種を判定する。The signal processing section performs shading correction on the output image signal from each linear array camera, normalizes the output image signal so that the normal portion has the central density of all gradations, and flattens it. Is converted into the indicated light intensity signal. The change in the polarization is detected by comparing the change polarity and the change amount of the distribution of the three types of light intensity signals indicating the relative change with respect to the normal part with a predetermined pattern. The types of flaws whose surface properties are different from those of the base material are determined from the magnitudes of the change polarities and the amounts of change of the three types of light intensity signals with respect to the normal part.
【００１６】また、信号処理部は上記処理とともに各受
光光学系から出力された光強度分布から目視相当の光量
変化すなわち表面反射強度を演算し、演算した光量変化
をあらかじめ定めたパタ−ンと比較し、光量変化の変化
極性と変化量の大小から例えば凹凸のように正常部と表
面幾何学形状が異なるために疵の等級を判定する。Further, the signal processing section calculates a change in the amount of light corresponding to visual observation, that is, a surface reflection intensity, from the light intensity distribution output from each light receiving optical system together with the above processing, and compares the calculated change in the amount of light with a predetermined pattern. Then, the grade of the flaw is determined based on the change polarity of the light amount change and the magnitude of the change amount, because the surface geometric shape is different from that of the normal part such as unevenness.
【００１７】[0017]
【実施例】図１はこの発明の一実施例の光学系を示す配
置図である。図に示すように、光学系１は投光部２と３
板式偏光リニアアレイカメラ３を有する。投光部２は被
検査体例えば鋼板４の表面に一定の入射角で偏光を入射
するものであり、光源５と光源５の前面に設けられた偏
光子６とを有する。光源５は鋼板４の幅方向に伸びた棒
状発光装置からなり、鋼板４の幅方向全体に一様な強度
分布を有する光を照射する。偏光子６は例えば偏光板又
は偏光フィルタからなり、図２の配置説明図に示すよう
に、透過軸Ｐが鋼板４の入射面となす角α1がπ／４に
なるように配置されている。３板式偏光リニアアレイカ
メラ３は、図３の構成図に示すように、ビ−ムスプリッ
タ７と３個の検光子８ａ，８ｂ，８ｃと３個のリニアア
レイセンサ９ａ，９ｂ，９ｃとを有する。ビ−ムスプリ
ッタ７は３個のプリズムからなり、入射面に誘電体多層
膜を蒸着した半透過性を有する反射面が２面設けられ、
鋼板４からの反射光を入射する第１の反射面７ａは透過
率と反射率が２対１の割合になっており、第１の反射面
７ａを透過した光を入射する第２の反射面７ｂは透過率
と反射率が１対１の割合になっており、鋼板４からの反
射光を同じ光量の３本のビ−ムに分離する。また、ビ−
ムスプリッタ７の入射面から分離した３本のビ−ムの出
射面までの光路長は同じにしてある。検光子８ａは第２
の反射面１０ｂの透過光の光路に設けられ、図２に示す
ように、方位角すなわち透過軸が鋼板４の入射面となす
角α2が０度になるように配置され、検光子８ｂは第２
の反射面７ｂの反射光の光路に設けられ、方位角α2が
π/４度になるように配置され、検光子８ｃは第１の反
射面７ａの反射光の光路に設けられ、方位角α2が−π/
４になるように配置されている。リニアアレイセンサ９
ａ，９ｂ，９ｃは例えばＣＣＤセンサからなり、それぞ
れ検光子８ａ，８ｂ，８ｃの後段に配置されている。ま
た、ビ−ムスプリッタ７と検光子８ａ，８ｂ，８ｃの間
にはビ−ムスプリッタ７内の多重反射光や不必要な散乱
光をカットするスリット１０ａ，１０ｂ，１０ｃが設け
られ、ビ−ムスプリッタ７の前段にはレンズ群１１が設
けられている。また、リニアアレイセンサ９ａ，９ｂ，
９ｃは同じ光強度の光が入射したときに同じ信号を出力
するように利得が調整してある。FIG. 1 is an arrangement diagram showing an optical system according to an embodiment of the present invention. As shown in the figure, an optical system 1 includes light emitting units 2 and 3
It has a plate-type polarization linear array camera 3. The light projecting unit 2 emits polarized light at a predetermined incident angle on the surface of the inspection object, for example, the steel plate 4, and includes a light source 5 and a polarizer 6 provided on the front surface of the light source 5. The light source 5 is composed of a rod-shaped light emitting device extending in the width direction of the steel plate 4 and emits light having a uniform intensity distribution over the entire width of the steel plate 4. The polarizer 6 is made of, for example, a polarizing plate or a polarizing filter, and is arranged such that the angle α 1 between the transmission axis P and the incident surface of the steel plate 4 is π / 4, as shown in the layout explanatory diagram of FIG. . The three-plate polarization linear array camera 3 has a beam splitter 7, three analyzers 8a, 8b, 8c, and three linear array sensors 9a, 9b, 9c, as shown in the configuration diagram of FIG. . The beam splitter 7 is composed of three prisms, and is provided with two semi-transmissive reflecting surfaces formed by depositing a dielectric multilayer film on the incident surface.
The first reflection surface 7a on which the reflected light from the steel plate 4 is incident has a transmittance and a reflectance of 2: 1, and the second reflection surface on which the light transmitted through the first reflection surface 7a is incident. Reference numeral 7b denotes a one-to-one ratio between the transmittance and the reflectance, and separates the reflected light from the steel plate 4 into three beams having the same light amount. Also, bee
The optical path lengths from the entrance surface of the splitter 7 to the exit surfaces of the three beams are the same. The analyzer 8a is the second
Provided on an optical path of the transmitted light of the reflecting surface 10b, shown in Figure 2, the azimuth angle or transmission axes are arranged so that the incident surface and the angle alpha 2 of the steel plate 4 is 0 degrees, the analyzer 8b is Second
Is provided in the optical path of the reflected light from the reflecting surface 7b, and the azimuth angle α 2 is disposed so as to be π / 4 degrees. The analyzer 8c is provided in the optical path of the reflected light from the first reflecting surface 7a. α 2 is −π /
4 are arranged. Linear array sensor 9
Reference numerals a, 9b, and 9c each include, for example, a CCD sensor, and are disposed downstream of the analyzers 8a, 8b, and 8c, respectively. Slits 10a, 10b, and 10c are provided between the beam splitter 7 and the analyzers 8a, 8b, and 8c for cutting multiple reflected light and unnecessary scattered light in the beam splitter 7. A lens group 11 is provided at a stage preceding the splitter 7. Also, the linear array sensors 9a, 9b,
In 9c, the gain is adjusted so that the same signal is output when light having the same light intensity enters.
【００１８】このように入射した光を分離した３本のビ
−ムの光路に検光子８ａ〜８ｃとリニアアレイセンサ９
ａ〜９ｃが一体化して設けられているから、リニアアレ
イセンサ９ａ〜９ｃ等を鋼板４の搬送路近傍に設置して
鋼板４からの反射光を検出するときに、リニアアレイセ
ンサ９ａ〜９ｃ等の位置調整を必要としないとともに、
鋼板４の同じ位置からの反射光を同じタイミングで検出
することができる。また、３板式偏光リニアアレイカメ
ラ３内に３組のリニアアレイセンサ９ａ〜９ｃがまとま
って収納されて小型化しているから、３板式偏光リニア
アレイカメラ３を鋼板４の反射光の光路に簡単に配置す
ることができるとともに、配置位置を任意に選択するこ
とができ、光学系１の配置の自由度を向上することがで
きる。The analyzers 8a to 8c and the linear array sensor 9 are provided on the optical paths of the three beams that separate the light thus incident.
When the linear array sensors 9a to 9c are installed near the conveyance path of the steel plate 4 and the reflected light from the steel plate 4 is detected, the linear array sensors 9a to 9c and the like are integrated. Position adjustment is not required,
The reflected light from the same position on the steel plate 4 can be detected at the same timing. In addition, since three sets of linear array sensors 9a to 9c are collectively housed in the three-plate polarization linear array camera 3 and miniaturized, the three-plate polarization linear array camera 3 can be easily placed on the optical path of the reflected light of the steel plate 4. The optical system 1 can be arranged, and the arrangement position can be arbitrarily selected, so that the degree of freedom of arrangement of the optical system 1 can be improved.
【００１９】３板式偏光リニアアレイカメラ３のリニア
アレイセンサ９ａ〜９ｃは、図４のブロック図に示すよ
うに、信号処理部１２に接続されている。信号処理部１
２は信号前処理部１３ａ，１３ｂ，１３ｃとＩ1メモリ
１４ａ，Ｉ2メモリ１４ｂ，Ｉ3メモリ１４ｃと、疵パラ
メ−タ演算部１５と、パタ−ン記憶部１６と、光量記憶
部１７と、基準パタ−ン記憶部１８と、疵種判定部１９
と、等級パタ−ン記憶部２０と、疵等級判定部２１及び
出力部２２を有する。信号前処理部１３ａ〜１３ｃはリ
ニアアレイセンサ９ａ〜９ｃから出力された偏光の光強
度信号Ｉ1，Ｉ2，Ｉ3の幅方向等の感度むら等を補正す
るシェ−ディング補正等を行ってから正常部の信号を基
準レベルとして、正常部の信号が255階調の中心濃度で
ある128階調になるように正規化して、正規化した光強
度信号Ｉ1，Ｉ2，Ｉ3をそれぞれＩ1メモリ１４ａ，Ｉ2
メモリ１４ｂ，Ｉ3メモリ１４ｃに格納する。疵パラメ
−タ演算部１５はＩ1メモリ１４ａ〜Ｉ3メモリ１４ｃに
格納された光強度信号Ｉ1，Ｉ2，Ｉ3の分布に表れた疵
部のピ−ク値を正常部の値である128階調を基準にして
プラスであるかマイナスであるかを示す極性パタ−ン
と、128階調を基準にした変化量を示す値パタ−ンを算
出するとともに、疵部の光強度から目視相当光量を演算
する。パタ−ン記憶部１６は算出された極性パタ−ンと
値パタ−ンを記憶し、光量記憶部１７は算出された目視
相当光量Ｉmaxを記憶する。基準パタ−ン記憶部１８に
は各種極性パタ−ンと値パタ−ン及びこれらに対応する
疵種があらかじめ格納されている。疵種判定部１９はパ
タ−ン記憶部１６に記憶された極性パタ−ンと値パタ−
ンとを基準パタ−ン記憶部１８に記憶された各種極性パ
タ−ンと値パタ−ンと比較して疵種を判定する。等級パ
タ−ン記憶部２０には各疵種毎に光量に対する疵の等級
を示す等級基準パタ−ンがあらかじめ格納してある。疵
等級判定部２１は光量記憶部１７に記憶した目視相当光
量Ｉmaxと疵種判定部１９で判定した疵種を等級パタ−
ン記憶部２０に記憶してある等級基準パタ−ンと比較し
て疵の等級を判定する。出力部２２は疵等級判定部２１
から出力される疵種と疵の等級を不図示の表示装置や記
録装置に出力する。The linear array sensors 9a to 9c of the three-plate polarization linear array camera 3 are connected to a signal processing unit 12, as shown in the block diagram of FIG. Signal processing unit 1
2 signal preprocessing unit 13a, 13b, 13c and I 1 memory 14a, I 2 memory 14b, a I 3 memory 14c, flaw parameters - the data calculation unit 15, pattern - the emission storage unit 16, a light amount storing section 17 A reference pattern storage unit 18 and a flaw type determination unit 19
And a grade pattern storage unit 20, a flaw grade determination unit 21 and an output unit 22. Signal preprocessing unit 13a~13c linear array sensor 9a~9c light intensity signal outputted polarization from I 1, I 2, shell corrects the sensitivity unevenness in the width direction and the like of the I 3 - performing loading correction, , The signal of the normal part is set as a reference level, the signal of the normal part is normalized so as to have 128 gradations, which is the central density of 255 gradations, and the normalized light intensity signals I 1 , I 2 and I 3 are respectively obtained. I 1 memory 14a, I 2
Memory 14b, and stores the I 3 memory 14c. The value of the normal portion the click value - flaw parameters - peak of data operation part 15 flaw portion appears in the distribution of I 1 memory 14A～I 3 light intensities stored in the memory 14c signals I 1, I 2, I 3 A polarity pattern indicating whether it is positive or negative based on a certain 128 gradations and a value pattern indicating a change amount based on the 128 gradations are calculated, and from the light intensity of the flaw portion, The visual equivalent light quantity is calculated. The pattern storage unit 16 stores the calculated polarity pattern and value pattern, and the light amount storage unit 17 stores the calculated visual equivalent light amount Imax. The reference pattern storage unit 18 previously stores various polarity patterns, value patterns, and flaw types corresponding thereto. The flaw type judging section 19 stores the polarity pattern and the value pattern stored in the pattern storage section 16.
Is compared with the various polarity patterns and the value patterns stored in the reference pattern storage unit 18 to determine the type of flaw. The grade pattern storage unit 20 previously stores a grade reference pattern indicating the grade of the flaw with respect to the light amount for each flaw type. The flaw grade determination unit 21 classifies the visual equivalent light amount Imax stored in the light quantity storage unit 17 and the flaw type determined by the flaw type determination unit 19 into a grade pattern.
The grade of the flaw is determined by comparing it with the grade reference pattern stored in the storage unit 20. The output unit 22 is a flaw grade determination unit 21
The flaw type and the flaw grade output from are output to a display device or a recording device (not shown).
【００２０】次に上記のように構成された表面検査装置
で鋼板４の表面を検査する時の動作を説明する。Next, the operation of inspecting the surface of the steel plate 4 with the surface inspection apparatus configured as described above will be described.
【００２１】投光部２から出射されて一定速度で移動し
ている鋼板４の表面で反射した偏光は３板式偏光リニア
アレイカメラ３で受光される。３板式偏光リニアアレイ
カメラ３に入射した鋼板４の反射光はビ−ムスプリッタ
７で分離され検光子８ａ，８ｂ，８ｃを通ってリニアア
レイセンサ９ａ〜９ｃに入射する。このリニアアレイセ
ンサ９ａ〜９ｃで反射光の光強度を検出するときに、リ
ニアアレイセンサ９ａ〜９ｃの前面に異なる方位角の検
光子８ａ〜８ｃが設けられているから，リニアアレイセ
ンサ９ａ〜９ｃは異なる偏光の光強度Ｉ1，Ｉ2，Ｉ3を
検出し信号処理部１２に送る。The polarized light emitted from the light projecting unit 2 and reflected on the surface of the steel plate 4 moving at a constant speed is received by the three-plate polarization linear array camera 3. The reflected light of the steel plate 4 that has entered the three-plate polarization linear array camera 3 is split by the beam splitter 7 and passes through the analyzers 8a, 8b, 8c and enters the linear array sensors 9a to 9c. When the light intensity of the reflected light is detected by the linear array sensors 9a to 9c, the analyzers 8a to 8c having different azimuth angles are provided in front of the linear array sensors 9a to 9c. Detects the light intensities I 1 , I 2 , I 3 of different polarizations and sends them to the signal processing unit 12.
【００２２】信号処理部１２の信号前処理部１３ａ〜１
３ｃはリニアアレイセンサ９ａ〜９ｃから出力された偏
光の光強度信号Ｉ1，Ｉ2，Ｉ3の幅方向等の感度むら等
を補正するシェ−ディング補正等を行ってから、例えば
図５の疵信号分布図に示すように、正常部の信号が128
階調になるように正規化して、正規化した光強度信号Ｉ
1，Ｉ2，Ｉ3をそれぞれＩ1メモリ１４ａ〜Ｉ3メモリ１
４ｃに格納する。図５において、（ａ）は光強度信号Ｉ
1の分布、（ｂ）は光強度信号Ｉ2の分布、（ｃ）は光強
度信号Ｉ3の分布を示す。疵パラメ−タ演算部１５はＩ1
メモリ１４ａ〜Ｉ3メモリ１４ｃに格納された光強度信
号Ｉ1，Ｉ2，Ｉ3の分布に表れた疵部のピ−ク値をそれ
ぞれ正常部の値である128階調よりプラスであるかマイ
ナスであるかを示す極性パタ−ンと、128階調を基準に
した変化量を示す値パタ−ンを算出する。図５に示す例
では正規化した光強度信号Ｉ1，Ｉ2，Ｉ3の疵部のピ−
ク値は全て128階調よりプラスであるから、極性パタ−
ンは（＋，＋，＋）と算出し、128階調を基準にした光
強度信号Ｉ1，Ｉ2，Ｉ3の疵部のピ−ク値の変化量は
（＋38，＋10，＋32）になる。この変化量を最大値を基
準に規格化すると、（1.0，0.26，0.84）になる。この
変化量の最大値を基準にした規格値例えば（1.0，0.2
6，0.84）を値パタ−ンとして算出する。そして算出し
た極性パタ−ンと値パタ−ンをパタ−ン記憶部１６に格
納する。また、疵パラメ−タ演算部１５は光強度信号Ｉ
1，Ｉ2，Ｉ3の分布から目視相当光量Ｉmaxを、Ｉmax＝
ＭＡＸ〔Ｉ2（ｘ）＋Ｉ3（ｘ）−Ｉ1（ｘ）〕で演算し
て光量記憶部１７に記憶させる。例えば、図５に示した
例では、光強度信号Ｉ1，Ｉ2，Ｉ3の疵部のピ−ク値の
変化量は（＋38，＋10，＋32）であるから、目視相当光
量Ｉmaxは「４」になる。The signal preprocessing units 13a to 13a of the signal processing unit 12
3c is Chez corrects the linear array sensor the light intensity signal I 1 of the polarized light output from 9a to 9c, I 2, sensitivity unevenness in the width direction and the like of the I 3 and the like - from performing loading correction, for example, in FIG. 5 As shown in the flaw signal distribution diagram, the signal of the normal part was 128
The normalized light intensity signal I is normalized so as to be a gradation.
1 , I 2 , and I 3 are stored in I 1 memories 14a to I 3 memory 1 respectively.
4c. In FIG. 5, (a) shows the light intensity signal I
1 distribution, (b) is the light intensity signal I 2 distribution shows the distribution of (c) is the light intensity signal I 3. The flaw parameter calculator 15 calculates I 1
Whether it is positive than 128 gradation is click value the value of the normal portion each - peak flaw portion appears in the distribution of memory 14A～I 3 light intensities stored in the memory 14c signals I 1, I 2, I 3 A polarity pattern indicating whether the value is negative and a value pattern indicating the amount of change based on 128 gradations are calculated. In the example shown in FIG. 5, the peaks of the flaws of the normalized light intensity signals I 1 , I 2 and I 3 are shown.
Since all the mask values are more positive than 128 gradations, the polarity pattern
Is calculated as (+, +, +), and the peak value change amount of the flaw portion of the light intensity signals I 1 , I 2 , I 3 based on 128 gradations is (+38, +10, +32) become. When this variation is normalized on the basis of the maximum value, it becomes (1.0, 0.26, 0.84). A standard value based on the maximum value of the change amount, for example, (1.0, 0.2
6, 0.84) as a value pattern. Then, the calculated polarity pattern and value pattern are stored in the pattern storage unit 16. Also, the flaw parameter calculation unit 15 outputs the light intensity signal I
From the distribution of 1 , I 2 and I 3 , the visual equivalent light amount Imax is calculated as
MAX [I 2 (x) + I 3 (x) −I 1 (x)] is stored in the light amount storage unit 17. For example, in the example shown in FIG. 5, the amount of change in the peak value of the flaw portion of the light intensity signals I 1 , I 2 , and I 3 is (+38, +10, +32). 4 ".
【００２３】基準パタ−ン記憶部１８には疵の程度に応
じて複数の疵種に対応する極性パタ−ンと値パタ−ンが
実験で定められて、例えば図６に示すように、基準パタ
−ンとして格納してある。図６において、疵種Ｘ〜疵種
Ｗは例えば有害度が低い疵から有害度が高い疵の順に疵
種を示し、各疵種Ｘ〜疵種Ｗに対応する極性パタ−ンと
値パタ−ンの基準値を示す。また、等級パタ−ン記憶部
２０には各疵種Ｘ〜疵種Ｗに応じて目視相当光量と疵の
等級を示す相関をあらかじめ調べて、例えば図７の相関
図に示すように格納してある。In the reference pattern storage section 18, polar patterns and value patterns corresponding to a plurality of types of flaws are determined by experiments in accordance with the degree of flaws. For example, as shown in FIG. It is stored as a pattern. In FIG. 6, flaw types X to W indicate flaw types in the order of, for example, flaws with low harmfulness to flaws with high harmfulness. Polar patterns and value patterns corresponding to each of flaw types X to W are shown. Indicates the reference value of the Also, the grade pattern storage unit 20 previously checks the correlation indicating the visual equivalent light amount and the grade of the flaw according to each of the flaw types X to W and stores it as shown in a correlation diagram of FIG. is there.
【００２４】疵種判定部１９はパタ−ン記憶部１６に記
憶された、極性パタ−ンと値パタ−ン、例えば図５に示
す例の場合、極性パタ−ン（＋，＋，＋）と値パタ−ン
（1.0，0.26，0.84）と、図４に示す基準パタ−ン記憶
部１８に記憶された基準パタ−ンとを比較して疵種を判
定する。例えば図５に示す例の場合には疵種Ｘと判定す
る。このように複数の異なる疵Ａ〜疵Ｈの疵種を極性パ
タ−ンと値パタ−ンにより判定した例を図８に示す。こ
の疵種を判定する場合に、例えば極性パタ−ンが同じ
（−，−，−）の疵Ｂと疵Ｃでも、値パタ−ンにより有
害度の低い疵種Ｙと有害度の高い疵種Ｚに分類すること
ができ、疵種を正確に判定することができる。また、疵
の状態によっては疵Ｇに示すように極性パタ−ンの３つ
の符号のうち１つが反対、あるいは「０」であっても値
パタ−ンを併用することにより疵種を正確に判別するこ
とができる。また、このように極性パタ−ンと値パタ−
ンで疵種を判定するから、疵種判定のための処理が簡略
化され、短時間で精度良く疵種を判定することができ
る。The flaw type judging section 19 stores the polarity pattern and the value pattern stored in the pattern storage section 16, for example, in the case of the example shown in FIG. 5, the polarity pattern (+, +, +). And the value pattern (1.0, 0.26, 0.84) and the reference pattern stored in the reference pattern storage unit 18 shown in FIG. For example, in the case of the example shown in FIG. FIG. 8 shows an example in which a plurality of different types of flaws A to H are determined based on the polarity pattern and the value pattern. When determining the flaw type, for example, even if the flaws B and C have the same polarity pattern (-,-,-), the flaw types Y having a low harmfulness and the flaw types having a high harmfulness are determined by the value pattern. Z, and the type of flaw can be accurately determined. Further, depending on the state of the flaw, as shown in the flaw G, one of the three signs of the polarity pattern is opposite, or even if the sign is "0", the flaw type is accurately determined by using the value pattern together. can do. Also, as described above, the polarity pattern and the value pattern
Since the type of flaw is determined by the method, the processing for determining the type of flaw is simplified, and the type of flaw can be accurately determined in a short time.
【００２５】一方、疵等級判定部２１は光量記憶部１７
に記憶した目視相当光量Ｉmaxと疵種判定部１９で判定
した疵種とを等級パタ−ン記憶部２０に記憶してある各
疵種Ｘ〜疵種Ｗに応じて目視相当光量と疵の等級を示す
相関図と比較して疵の等級を判定する。例えば図７に示
すように疵種Ｘで目視相当光量Ｉmaxが「４」の場合に
は疵の等級をＢと判定し、疵種Ｙで目視相当光量Ｉmax
が「37」の場合には疵の等級をＣと判定する。このよう
に目視相当光量Ｉmaxと疵種により疵の等級を判定する
から、鋼板４の表面に生じた凹凸のない模様状疵だけで
なく凹凸状の疵の程度を精度良く判別することができ
る。疵等級判定部２１は疵種判定部１９で判定した疵種
と判別した疵の等級を出力部２２に送る。出力部２２は
疵等級判定部２１から出力される疵種と疵の等級を表示
装置や記録装置に出力する。On the other hand, the flaw grade judging section 21
The visual equivalent light amount Imax and the flaw type determined by the flaw type determination unit 19 are stored in the pattern storage unit 20 according to the flaw types X to W. The grade of the flaw is determined by comparing with a correlation diagram showing. For example, as shown in FIG. 7, when the visual equivalent light amount Imax is "4" for the flaw type X, the grade of the flaw is determined to be B, and the visual equivalent light amount Imax is used for the flaw type Y.
Is "37", the grade of the flaw is determined to be C. As described above, since the grade of the flaw is determined based on the visual equivalent light amount Imax and the flaw type, it is possible to accurately determine not only the pattern-like flaw having no unevenness on the surface of the steel sheet 4 but also the degree of the uneven flaw. The flaw grade determining unit 21 sends the flaw grade determined by the flaw type determining unit 19 to the output unit 22. The output unit 22 outputs the flaw type and the flaw grade output from the flaw grade determination unit 21 to a display device or a recording device.
【００２６】[0026]
【発明の効果】この発明は以上説明したように、被検査
面に対して一定入射角で偏光を入射し、その反射光の異
なる複数の偏光の光強度分布を検出し、検出した強度分
布を正規化し、正常部に対する疵部の異なる偏光の光強
度信号の変化極性と変化量とを算出し、算出した変化極
性と変化量とをそれぞれあらかじめ定めたパタ−ンと比
較して疵種を判定すようにしたから、簡単な処理で迅速
に疵種を判別することができる。As described above, according to the present invention, a polarized light is incident on a surface to be inspected at a constant incident angle, the light intensity distribution of a plurality of polarized lights having different reflected lights is detected, and the detected intensity distribution is determined. Normalization is performed to calculate the change polarity and the change amount of the light intensity signal of the polarized light having a different flaw from the normal part, and compare the calculated change polarity and the change amount with a predetermined pattern to determine the flaw type. Thus, the type of flaw can be quickly determined by a simple process.
【００２７】また、各受光光学系から出力された光強度
分布から目視相当の光量変化すなわち無偏光時の表面反
射強度を演算し、演算した光量変化から疵の等級を判定
するようにしたから、凹凸のない模様状疵だけでなく凹
凸状の疵の程度を簡単な処理で精度良く判別することが
できる。Further, since a change in the amount of light corresponding to visual observation, that is, the surface reflection intensity in the case of non-polarization, is calculated from the light intensity distribution output from each light receiving optical system, and the grade of the flaw is determined from the calculated change in the amount of light. It is possible to accurately determine not only the pattern-like flaws having no unevenness but also the degree of the uneven flaws by a simple process.
【００２８】さらに、簡単な処理で迅速に疵種と疵の等
級を判定するから、装置自体のの構成を簡略化すること
ができるとともに、高速で移動しているシ−ト状製品の
表面にある異常部をオンラインで精度良く検出すること
ができる。Further, since the type of flaw and the grade of flaw are quickly determined by a simple process, the structure of the apparatus itself can be simplified and the surface of the sheet-like product moving at high speed can be used. An abnormal part can be accurately detected online.
【図１】この発明の実施例の光学系を示す構成図であ
る。FIG. 1 is a configuration diagram showing an optical system according to an embodiment of the present invention.
【図２】光学系の動作を示す配置説明図である。FIG. 2 is an explanatory diagram illustrating an arrangement of an operation of an optical system.
【図３】上記実施例の３板式偏光リニアアレイカメラの
構成図である。FIG. 3 is a configuration diagram of a three-plate polarization linear array camera of the embodiment.
【図４】上記実施例の信号処理部を示すブロック図であ
る。FIG. 4 is a block diagram showing a signal processing unit of the embodiment.
【図５】疵信号を示す光強度分布図である。FIG. 5 is a light intensity distribution diagram showing a flaw signal.
【図６】疵種と疵パタ−ンと値パタ−ンを示す基準パタ
−ン図である。FIG. 6 is a reference pattern diagram showing a flaw type, a flaw pattern, and a value pattern.
【図７】光量レベルと疵の等級の相関図である。FIG. 7 is a correlation diagram between a light amount level and a flaw grade.
【図８】各種疵の疵種と等級の具体例を示す説明図であ
る。FIG. 8 is an explanatory diagram showing specific examples of the types and grades of various flaws.
１ 光学系 ２ 投光部 ３ ３板式偏光リニアアレイカメラ ４ 鋼板 ５ 光源 ６ 偏光子 ７ ビ−ムスプリッタ ８ 検光子 ９ リニアアレイセンサ １２ 信号処理部 １３ 信号前処理部 １４ａ Ｉ1メモリ １４ｂ Ｉ2メモリ １４ｃ Ｉ3メモリ １５ 疵パラメ−タ演算部 １６ パタ−ン記憶部 １７ 光量記憶部 １８ 基準パタ−ン記憶部 １９ 疵種判定部 ２９ 等級パタ−ン記憶部 ２１ 疵等級判定部1 optical system 2 light projector 3 3-plate type polarization linear array camera 4 steel 5 light source 6 polarizer 7 bi - beam splitter 8 analyzer 9 linear array sensor 12 signal processing unit 13 the signal preprocessing unit 14a I 1 memory 14b I 2 memory 14c I 3 memory 15 flaw parameter calculation section 16 pattern storage section 17 light quantity storage section 18 reference pattern storage section 19 flaw type determination section 29 grade pattern storage section 21 flaw grade determination section
───────────────────────────────────────────────────── フロントページの続き (72)発明者 大重 貴彦 東京都千代田区丸の内一丁目１番２号 日本鋼管株式会社内 (56)参考文献 特開 昭62−293104（ＪＰ，Ａ) 特開 平４−110758（ＪＰ，Ａ) 特開 平４−238207（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 21/84 - 21/958 G01B 11/00 - 11/30 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takahiko Oshige 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (56) References JP-A-62-293104 (JP, A) 4-110758 (JP, A) JP-A-4-238207 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01N 21/84-21/958 G01B 11/00-11 / 30
Claims (5)
投光部は被検査面に偏光を入射し、受光部は少なくとも
３方向の異なる角度の偏光を受光する複数の受光光学系
を有し、被検査面で反射した反射光を検出して画像信号
に変換し、信号処理部は変換した画像信号から所定の疵
特徴量を算出し、算出した疵特徴量をあらかじめ定めた
パタ−ンと比較し疵種あるいは疵種と等級を判定するこ
とを特徴とする表面検査装置。A light-emitting unit, a light-receiving unit, and a signal processing unit;
The light projecting unit receives polarized light on the surface to be inspected, and the light receiving unit has a plurality of light receiving optical systems for receiving polarized light at different angles in at least three directions. And the signal processing section converts the converted image signal into a predetermined defect.
Calculate the feature quantity and determine the calculated flaw feature quantity in advance
A surface inspection apparatus characterized by determining a flaw type or a flaw type and a grade by comparing with a pattern .
度分布の変化極性から疵種を判定する請求項１記載の表
面検査装置。2. The surface inspection apparatus according to claim 1, wherein the signal processing unit determines a flaw type from a change polarity of the light intensity distribution as a flaw characteristic amount.
相当光量を算出し、疵の等級を判定する請求項１又は２
記載の表面検査装置。3. The signal processing unit calculates a visual equivalent light amount as a flaw characteristic quantity and determines a flaw grade.
Surface inspection device as described.
力された光強度分布を平均値があらかじめ定めた基準値
となるように規格化した後に疵特徴量を算出する請求項
１，２又は３記載の表面検査装置。4. The signal processing unit calculates a flaw feature quantity after normalizing a light intensity distribution output from each light receiving optical system so that an average value becomes a predetermined reference value. Or the surface inspection device according to 3.
射した反射光の少なくとも３方向の異なる角度の偏光を
受光し、受光信号により所定の疵特徴量を算出し、算出
した疵特徴量をあらかじめ定めたパタ−ンと比較し疵種
あるいは疵種と疵の等級を判定することを特徴とする表
面検査方法。5. A polarized light is incident on a surface to be inspected, polarized light having different angles in at least three directions of reflected light reflected from the surface to be inspected is received, and a predetermined flaw characteristic amount is calculated based on a received light signal, and the calculated flaw is calculated. A surface inspection method characterized by comparing a feature amount with a predetermined pattern to determine a flaw type or a flaw type and a flaw class.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29789796A JP3275737B2 (en) | 1995-10-24 | 1996-10-23 | Surface inspection device and surface inspection method |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29883295 | 1995-10-24 | ||
| JP7-298832 | 1995-10-24 | ||
| JP29789796A JP3275737B2 (en) | 1995-10-24 | 1996-10-23 | Surface inspection device and surface inspection method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001339142A Division JP2002181723A (en) | 1995-10-24 | 2001-11-05 | Surface inspection apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09178669A JPH09178669A (en) | 1997-07-11 |
| JP3275737B2 true JP3275737B2 (en) | 2002-04-22 |
Family
ID=26561288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29789796A Expired - Fee Related JP3275737B2 (en) | 1995-10-24 | 1996-10-23 | Surface inspection device and surface inspection method |
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| Country | Link |
|---|---|
| JP (1) | JP3275737B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002303513A (en) * | 2001-01-30 | 2002-10-18 | Fujitsu Ltd | Observation device |
| DE10362349B3 (en) * | 2003-08-12 | 2014-05-08 | Sick Ag | Optical examination of the surface or a layer of an object or medium, whereby the surface is illuminated with polarized visual radiation and reflected or scattered radiation is measured on an area by area basis |
| DE10337040B4 (en) * | 2003-08-12 | 2013-01-17 | Sick Ag | Device for examining a surface or a layer |
| JP5118311B2 (en) * | 2006-03-27 | 2013-01-16 | 株式会社フォトニックラティス | Measuring device for phase difference and optical axis orientation |
| JP6149990B2 (en) * | 2016-09-02 | 2017-06-21 | Ｊｆｅスチール株式会社 | Surface defect detection method and surface defect detection apparatus |
-
1996
- 1996-10-23 JP JP29789796A patent/JP3275737B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09178669A (en) | 1997-07-11 |
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