JPS61264207A - Optical defect detection - Google Patents

Optical defect detection

Info

Publication number
JPS61264207A
JPS61264207A JP10552185A JP10552185A JPS61264207A JP S61264207 A JPS61264207 A JP S61264207A JP 10552185 A JP10552185 A JP 10552185A JP 10552185 A JP10552185 A JP 10552185A JP S61264207 A JPS61264207 A JP S61264207A
Authority
JP
Japan
Prior art keywords
image sensor
light
light source
holes
defect
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.)
Granted
Application number
JP10552185A
Other languages
Japanese (ja)
Other versions
JPH0418247B2 (en
Inventor
Kenichi Matsumura
謙一 松村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP10552185A priority Critical patent/JPS61264207A/en
Publication of JPS61264207A publication Critical patent/JPS61264207A/en
Publication of JPH0418247B2 publication Critical patent/JPH0418247B2/ja
Granted legal-status Critical Current

Links

Abstract

PURPOSE:To distinguish holes and defects from each other with a simple circuit by receiving reflected light and transmitted light by one image sensor to obtain signals of holes and defects simultaneously and with a large signal difference. CONSTITUTION:The reflected light from a light source 11 for regular reflection reflected regularly from an object 13 to be detected and the transmitted light from a light source 14 transmitted through the object 13 to be detected are inputted to an image sensor 15. Intensity distributions of the reflected light and the transmitted light are as shown by graphs (a) and (b), and the intensity distribution of the received light of the image sensor 15 is as shown by a graph (c). Since the image sensor 15 generates an output signal correspondig to the intensity of received light, the output signal is sliced with two slice levels 19A and 19B by a signal processor 17 to obtain signals corresponding to a hole 12 and a defect 16 shown by graphs b' and c'.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、光学的欠陥検出方法、特に穴のある物体の表
面欠陥を穴と区別して検出する方法に関する。
DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical defect detection method, and particularly to a method for detecting surface defects of an object having holes, distinguishing them from holes.

〔従来の技術〕[Conventional technology]

従来、穴のある物体の表面欠陥を穴と区別して光学的に
検出する方法として、「事前に大の位置を検出もしくは
設定しておきマスクをかけて欠陥検出を行なう方法」お
よび「欠陥と穴とのパターンの相異を利用して穴と欠陥
とを識別して欠陥を検出する方法」があった。
Conventionally, methods for optically detecting surface defects on objects with holes by distinguishing them from holes include ``detecting or setting the large position in advance and detecting defects by applying a mask'' and ``detecting defects by detecting defects and holes.'' There was a method for detecting defects by distinguishing between holes and defects by using the differences in patterns between the two.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

しかしながら、前者の方法においては、穴検知のために
マツチングを取る必要があシ、複雑な形状の穴ではマス
クを大きめに設定しなけれはならないうえに、マツチン
グに時間がかかる等の問題がある。また、穴の位置や大
きさの検出用に別個の検出系もしくは複数回の計測が必
要であシ、検査装置が複雑になるもしくは検査時間が長
くなる。
However, in the former method, there are problems such as it is necessary to perform matching to detect holes, the mask must be set larger for holes with complicated shapes, and matching takes time. Further, a separate detection system or multiple measurements are required to detect the position and size of the hole, which makes the inspection device complicated or increases the inspection time.

更に穴の位置および大きさを設定する方式で杜、設定値
と実物とで位置や大きさが異なると、マスクがかけにく
い。
Furthermore, if the position and size of the hole are different between the setting value and the actual size, it will be difficult to apply the mask.

後者の方法において、パターンマツチングを使って両者
を識別する場合には、高速汎用装置を採用しなければな
らない。また、欠陥と穴との太きさの相異を使用して両
者を識別する場合には、大きさに差があまシなけれは利
用できない。更に1光の強度分布を位置によって微分し
て両者を識別する場合には、ノイズに影響されやすい欠
点があるO したがって、本発明の目的は、穴の位置設定を必要とせ
ずに欠陥と穴との同時検出を行なう光学的欠陥検出方法
を提供することである。
In the latter method, if pattern matching is used to identify the two, a high-speed general-purpose device must be employed. Further, when identifying a defect and a hole using the difference in thickness, this cannot be used unless the difference in size is small. Furthermore, when distinguishing between the two by differentiating the intensity distribution of one light depending on the position, there is a drawback that it is easily influenced by noise. Therefore, an object of the present invention is to distinguish between defects and holes without the need to set the position of the holes. An object of the present invention is to provide an optical defect detection method that performs simultaneous detection of defects.

〔問題点を解決するための手段〕[Means for solving problems]

本発明によれは、第一の光源と、穴のある被検出物体に
関して前記第一の光源とは反対側に設けられた第二の光
源と、前記被検出物体に関して前記第一の光源と同じ側
に設けられたイメージセンサと、前記イメージセンサの
出力信号を処理して前記被検出物体の表面の欠陥を検出
する信号処理手段とを具備する光学的欠陥検出方法を得
ることができる。
According to the present invention, a first light source, a second light source provided on the opposite side of the first light source with respect to the detected object having a hole, and a second light source that is the same as the first light source with respect to the detected object It is possible to obtain an optical defect detection method including an image sensor provided on the side, and a signal processing means for processing an output signal of the image sensor to detect a defect on the surface of the object to be detected.

〔実施例〕〔Example〕

次に1本発明の一実施例を示した図面を参照して、本発
明をよシ詳細に説明する。
Next, the present invention will be explained in detail with reference to the drawings showing one embodiment of the present invention.

第1図を参照すると、本発明の一実施例は、正反射用光
源(第一の光源)11と、穴12のある被検出物体13
に関して正反射用光源11とは反対側に設けられた透過
光用光源14と、被検出物体13に関して正反射用光源
11と同じ側に設けられたイメージセンサ15と、イメ
ージセンサ15の出力信号を処理して被検出物体13の
表面の欠陥16を検出する信号処理装置17どを具備し
ている。
Referring to FIG. 1, one embodiment of the present invention includes a specular reflection light source (first light source) 11 and a detection object 13 having a hole 12.
A transmitted light light source 14 provided on the opposite side of the specular reflection light source 11 with respect to the object 13, an image sensor 15 provided on the same side as the specular reflection light source 11 with respect to the detected object 13, and an output signal of the image sensor 15. It is equipped with a signal processing device 17 for processing and detecting defects 16 on the surface of the object 13 to be detected.

イメージセンサ15には、被検出物体13で正反射され
た正反射用光源11からの反射光と、被検出物体13を
透過した透過光用光源14からの透過光とが入力される
。反射光および透過光のi度分布は、それぞれ第2図(
alおよび(b) K示すようKなるので、イメージセ
ンサ15の受光強度分布は第2図(cl K示すよりに
なる。
The image sensor 15 receives the reflected light from the specular reflection light source 11 that is specularly reflected by the detection object 13 and the transmitted light from the transmission light source 14 that has passed through the detection object 13 . The i degree distributions of reflected light and transmitted light are shown in Figure 2 (
al and (b) K, so the received light intensity distribution of the image sensor 15 becomes as shown in FIG. 2 (cl K).

イメージセンサ15は、受光強度に応じた出力信号を発
生するので、その出力信号は第3図(al K示すよう
Kなる。この出力信号を、信号処理装置17において、
第3図(a)に示す二つのスライスレベル19Aおよび
19Bでスライスすれば、第3図(b)および(cl 
Kそれぞれ示すように、穴12および欠陥16に対応し
た信号を得ることができる。
Since the image sensor 15 generates an output signal according to the intensity of the received light, the output signal becomes K as shown in FIG.
By slicing at the two slice levels 19A and 19B shown in FIG. 3(a),
As shown in K, signals corresponding to the hole 12 and the defect 16 can be obtained.

次に第4図を参照して、本実施例、%に信号処理装置1
7の動作を詳細に説明する。信号処理装置17において
は、イメージセンサ15の出力信号を二つの比較器で二
値化し、穴のエツジの部分での不都合を除くために遅延
回路を通してマスクをかけて欠陥と穴とを別々に検出す
る。
Next, with reference to FIG. 4, in this embodiment, % signal processing device 1
7 will be explained in detail. In the signal processing device 17, the output signal of the image sensor 15 is binarized by two comparators, and in order to eliminate inconveniences at the edge of the hole, the signal is masked through a delay circuit and defects and holes are detected separately. do.

イメージセンサ15からの出力ビデオ信号a(第5図(
a))は二つの比較器20Aおよび20Bでスライスレ
ベル19Aおよび19Bと比較するととKよって二値化
され、二値化されたデータのうち、欠陥用比較器20B
の出力データはインバータ21を通される。このようK
して、第5図(b)および(cl K示すような穴部デ
ータbおよび欠陥部データCがそれぞれ得られる。
Output video signal a from the image sensor 15 (Fig. 5 (
a)) is binarized by comparing the slice levels 19A and 19B with the two comparators 20A and 20B, and among the binarized data, the defect comparator 20B
The output data of is passed through the inverter 21. K like this
As a result, hole data b and defect data C as shown in FIGS. 5(b) and (clK) are obtained, respectively.

欠陥部データcKついては、穴のエツジ部でも出力デー
タが発生するので、このままではエツジ部も欠陥とみな
すととKなる。このため、本実施例においては、フリッ
プフロップ22(22A〜22H)、NOR回路23お
よびAND回路24を備え、エツジ部の影響を除いてい
る。
Regarding the defect data cK, since output data is generated even at the edge of the hole, if the edge is also considered to be defective, it becomes K. For this reason, this embodiment includes a flip-flop 22 (22A to 22H), a NOR circuit 23, and an AND circuit 24 to eliminate the influence of the edge portion.

欠陥部データCは遅延用フリップフロップ22八〜22
Cで3画素分遅延した遅延欠陥部データbとなる。一方
、穴部データbは、遅延用7リツプフロツプ22D〜2
2Hをそれぞれ通し、それらの出力をNOR回路23に
印加して、穴部を片側につき実効的に2画素分大きくし
た第5図(d)に示すよう々マスク信号dに変換される
。遅延欠陥部データfとマスク信号dとをAND回路2
4に印加することによって、穴のエツジ部の影響なく、
第5図telに示すような、欠陥16のみに対応した欠
陥検出データeが得られる。
Defect part data C is for delay flip-flops 228 to 22.
C becomes delayed defective portion data b delayed by three pixels. On the other hand, hole data b is 7 delay lip-flops 22D to 2.
2H, and their outputs are applied to the NOR circuit 23 and converted into a mask signal d as shown in FIG. 5(d) in which the hole is effectively enlarged by two pixels on one side. The delay defect data f and the mask signal d are connected to an AND circuit 2.
4, without the influence of the edge of the hole,
Defect detection data e corresponding only to the defect 16 as shown in FIG. 5 is obtained.

イメージセンサ15のビデオロック信号は、7リツプフ
ロツプ22に印加される他、ビテオアドレスカウンタ2
5および信号処理回路26にもクロックとして印加され
る。アドレスカウンタ25からのビデオアドレスデータ
は、それぞれ欠陥検出データeとフリップフロップ22
Fの出力信号が供給されるアドレスラッチ回路27Aお
よび27Bに印加され、欠陥16および穴12のアドレ
スがそれぞれラッチされ、信号処理回路26に供給され
る。
The video lock signal of the image sensor 15 is applied to the 7 lip-flop 22 as well as to the video address counter 2.
5 and the signal processing circuit 26 as a clock. The video address data from the address counter 25 is the defect detection data e and the flip-flop 22, respectively.
The output signal of F is applied to the supplied address latch circuits 27A and 27B, and the addresses of the defect 16 and the hole 12 are respectively latched and supplied to the signal processing circuit 26.

上述の実施例において、ビデオ信号をA/D変換して専
用ハードウェアで処理を行なえは、照明が不均一に々る
ような曲面を有するサンプルに対しても、浮動スライス
レベルを用いることによ)、実時間で穴および欠陥の識
別が可能である。
In the embodiment described above, the video signal can be A/D converted and processed using dedicated hardware.The floating slice level can also be used for samples with curved surfaces with non-uniform illumination. ), holes and defects can be identified in real time.

〔発明の効果〕〔Effect of the invention〕

本発明においては、反射光と透過光とを一つのイメージ
センナで受けているので、穴と欠陥との信号が同時にか
つ大きな信号差で得られる。このため、穴と欠陥とを区
別するために穴の部分にマスクをかける際のマツチング
が不要となシ、欠陥検出が簡単た回路もしくはソフトウ
ェアで短時間に処理できる。
In the present invention, since reflected light and transmitted light are received by one image sensor, signals for holes and defects can be obtained simultaneously and with a large signal difference. Therefore, there is no need for matching when masking the hole portion in order to distinguish between the hole and the defect, and defect detection can be processed in a short time using a simple circuit or software.

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

第1図は本発明の一実施例の斜視図、第2図(a)〜(
c)および第3図(a)〜(C)は本発明の詳細な説明
する図、第4図は本実施例の詳細ブロック図、第5図f
at〜(e)は第4図の各部における信号波形図である
0 11・・・・・・正反射用光源、12・・・・・・穴、
13・・・・・・被検出物体、14・・・・・・透過光
用光源、15・・・・・・イメージセンサ、16・・・
・・・欠陥、17・・・・・・信号処理装置。 代理人 弁理士  内 原   晋 8 f 図 スー    L膚装置 Z 82 図 tZ   Ll、仕置 躬 3図 葛4図
FIG. 1 is a perspective view of one embodiment of the present invention, and FIGS. 2(a) to (
c) and FIGS. 3(a) to (C) are diagrams explaining the present invention in detail, FIG. 4 is a detailed block diagram of this embodiment, and FIG. 5f
at~(e) are signal waveform diagrams at each part in FIG. 4. 0 11... Specular reflection light source, 12... Hole,
13... Object to be detected, 14... Light source for transmitted light, 15... Image sensor, 16...
...Defect, 17...Signal processing device. Agent Patent Attorney Susumu Uchihara 8 f Figure Sue L Skin Device Z 82 Figure tZ Ll, Shioki Man 3 Figure Kuzu 4 Figure

Claims (1)

【特許請求の範囲】[Claims] 第一の光源と、穴のある被検出物体に関して前記第一の
光源とは反対側に設けられた第二の光源と、前記被検出
物体に関して前記第一の光源と同じ側に設けられたイメ
ージセンサと、前記イメージセンサの出力信号を処理し
て前記被検出物体の表面の欠陥を検出する信号処理手段
とを具備することを特徴とする光学的欠陥検出方法。
a first light source, a second light source provided on the opposite side of the first light source with respect to the detected object having a hole, and an image provided on the same side of the detected object as the first light source; An optical defect detection method comprising: a sensor; and a signal processing means for processing an output signal of the image sensor to detect a defect on the surface of the object to be detected.
JP10552185A 1985-05-17 1985-05-17 Optical defect detection Granted JPS61264207A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10552185A JPS61264207A (en) 1985-05-17 1985-05-17 Optical defect detection

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10552185A JPS61264207A (en) 1985-05-17 1985-05-17 Optical defect detection

Publications (2)

Publication Number Publication Date
JPS61264207A true JPS61264207A (en) 1986-11-22
JPH0418247B2 JPH0418247B2 (en) 1992-03-27

Family

ID=14409903

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10552185A Granted JPS61264207A (en) 1985-05-17 1985-05-17 Optical defect detection

Country Status (1)

Country Link
JP (1) JPS61264207A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5283642A (en) * 1992-03-16 1994-02-01 The Boeing Company Scratch measurement apparatus and method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5283642A (en) * 1992-03-16 1994-02-01 The Boeing Company Scratch measurement apparatus and method

Also Published As

Publication number Publication date
JPH0418247B2 (en) 1992-03-27

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