JPH0121883B2 - - Google Patents
Info
- Publication number
- JPH0121883B2 JPH0121883B2 JP55154202A JP15420280A JPH0121883B2 JP H0121883 B2 JPH0121883 B2 JP H0121883B2 JP 55154202 A JP55154202 A JP 55154202A JP 15420280 A JP15420280 A JP 15420280A JP H0121883 B2 JPH0121883 B2 JP H0121883B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- inspected
- scan
- normal surface
- flaw
- 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
Links
- 238000007689 inspection Methods 0.000 claims description 14
- 238000004441 surface measurement Methods 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims 1
- 230000003287 optical effect Effects 0.000 claims 1
- 238000004364 calculation method Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 238000007792 addition Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/28—Measuring arrangements characterised by the use of optical techniques for measuring areas
- G01B11/285—Measuring arrangements characterised by the use of optical techniques for measuring areas using photoelectric detection means
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Length Measuring Devices By Optical Means (AREA)
Description
【発明の詳細な説明】
この発明はレーザ光が被検査体表面に線状に走
査するように照射し、その反射光あるいは透過光
の変化を検出して被検査体の表面傷を検査する表
面傷検査装置の改良に関する。DETAILED DESCRIPTION OF THE INVENTION This invention is a method of inspecting the surface of an object to be inspected for surface flaws by irradiating the surface of the object to be inspected with a laser beam in a linear scanning manner and detecting changes in the reflected light or transmitted light. Related to improvements in flaw inspection equipment.
この種の表面傷検査装置は被検査体にレーザ光
を照射すると正常表面からは所定の反射光が検出
されるが、被検査体表面に傷が存在すると、この
傷によりレーザ光が散乱を受け、反射光あるいは
透過光の強度が変化することを利用したものであ
り、ある一定の速度で移動または回転している被
検査体の表面にレーザ光を走査する装置と、被検
査体からの反射あるいは透過レーザ光を受光し、
電気信号に変換する装置と、この装置により得ら
れた信号の変化から表面傷を検出し、かつ、傷面
積を算出するとともに被検査体の良否を判定する
信号処理装置とから表面検査装置が構成されてい
る。 When this type of surface flaw inspection device irradiates a laser beam onto an object to be inspected, a certain amount of reflected light is detected from the normal surface, but if there is a flaw on the surface of the object to be inspected, the laser beam is scattered by the flaw. , which utilizes changes in the intensity of reflected or transmitted light, and includes a device that scans the surface of an object to be inspected that is moving or rotating at a certain speed, and a device that scans a laser beam on the surface of an object to be inspected that is moving or rotating at a certain speed, and a device that scans a laser beam on the surface of an object to be inspected that is moving or rotating at a certain speed. Or receive transmitted laser light,
The surface inspection device consists of a device that converts it into an electrical signal, and a signal processing device that detects surface flaws from changes in the signal obtained by this device, calculates the flaw area, and determines the quality of the inspected object. has been done.
第１図はこの種の表面傷検査装置の構成例を示
す図であり、円柱体の側面検査を行うものであ
る。 FIG. 1 is a diagram showing an example of the configuration of this type of surface flaw inspection device, which inspects the side surface of a cylindrical body.
第１図において１は所定のスポツト径を有する
レーザ光２を発するレーザ装置、３は円柱形被検
査体４の側面上の所定の位置にレーザ光２を走査
するための振動鏡、５ａ，５ｂは円柱形被検査体
４を一定速度で回転させるための回転ローラ、６
は被検査体４に投射したレーザ光２の反射光、７
は反射光６を光検出器８の受光面に集光するため
の集光レンズ、９は光検出器８の反射光信号、１
０は反射光信号９にもとづき被検査体の傷の検
出、傷面積の計測、及び被検査体の良否の判定等
の信号処理を行う信号処理装置である。 In FIG. 1, 1 is a laser device that emits a laser beam 2 having a predetermined spot diameter, 3 is a vibrating mirror for scanning the laser beam 2 at a predetermined position on the side surface of a cylindrical object 4, and 5a, 5b. 6 is a rotating roller for rotating the cylindrical test object 4 at a constant speed;
is the reflected light of the laser beam 2 projected onto the object to be inspected 4, and 7
9 is a condensing lens for condensing the reflected light 6 onto the light receiving surface of the photodetector 8; 9 is a reflected light signal from the photodetector 8; 1
0 is a signal processing device that performs signal processing such as detecting flaws on the object to be inspected, measuring the area of the flaw, and determining whether the object to be inspected is good or bad based on the reflected light signal 9.
以上の装置において、被検査体４上をレーザ光
が走査されている場合には反射光６は受光される
が、被検査体４の外側を走査されている場合には
反射光６は受光されない。また、被検査体の表面
に傷が存在する場合は反射光６の強度が変化す
る。 In the above apparatus, when the laser beam is scanning the object 4 to be inspected, the reflected light 6 is received, but when the outside of the object 4 to be inspected is being scanned, the reflected light 6 is not received. . Furthermore, if there is a flaw on the surface of the object to be inspected, the intensity of the reflected light 6 changes.
第２図に被検査体からの反射光信号と反射光の
強度の傷のない表面からのものであることを示す
正常面判定信号の例を示す。 FIG. 2 shows an example of a reflected light signal from an object to be inspected and a normal surface determination signal indicating that the intensity of the reflected light is from a surface without flaws.
第２図において被検査体４上をレーザ光２が走
査されると反射光６の強度、すなわち反射光信号
９は被検査体表面に傷が全く無い場合(ア)のよう
に、また、被検査体の中央部及び端部に傷１２が
ある場合(イ)及び(ウ)のようになるため、被検査体４
の表面傷１２の存在が検出されることになる。反
射光信号９に対して正常面判定レベル１３を設定
すれば各々について正常面判定信号１４が得られ
る。レーザ光の走査毎にこの正常面判定信号１４
の長さを計測し、この長さと被検査体本来の長さ
とを比較すれば各走査における傷の長さを知るこ
とができる。各走査に対する正常面の長さをクロ
ツクパルスの計数値として計測する場合を例にと
り説明する。 In FIG. 2, when the laser beam 2 scans the object 4 to be inspected, the intensity of the reflected light 6, that is, the reflected light signal 9, changes as in the case (a) where there are no scratches on the surface of the object to be inspected, and If there are scratches 12 at the center and edges of the object to be inspected, as shown in (a) and (c), the object to be inspected 4.
The presence of surface flaws 12 will be detected. If a normal surface determination level 13 is set for each reflected light signal 9, a normal surface determination signal 14 can be obtained for each. This normal surface determination signal 14 is generated every time the laser beam scans.
By measuring the length of the flaw and comparing this length with the original length of the object to be inspected, the length of the flaw in each scan can be determined. An example will be explained in which the length of the normal surface for each scan is measured as a count value of clock pulses.
ｉ番目の走査に対する長さ（計数値）をNi、
被検査体本来の長さをNLとすればｉ番目の走査
に対する傷の長さ△Niは
△Ni＝NL−Ni ……(1)
として求めることができる。被検査体の全周を検
査するために必要な走査線数をｎ、１クロツクパ
ルスに相当する面積をＡとすれば傷の面積Ｄは
Ｄ＝Ａo
〓i=1
△Ni＝Ａo
〓i=1
（NL−Ni） ……(2)
で求めることができる。 The length (count value) for the i-th scan is N i ,
If the original length of the object to be inspected is N L , the length of the flaw ΔN i for the i-th scan can be obtained as ΔN i =N L −N i (1). If the number of scanning lines required to inspect the entire circumference of the object to be inspected is n, and the area corresponding to one clock pulse is A, the area of the flaw D is D=A o 〓 i=1 △N i = A o 〓 i=1 (N L −N i ) ……(2).
第３図は上記従来の方法により傷面積を求めた
一例を示すものである。 FIG. 3 shows an example of determining the flaw area using the above-mentioned conventional method.
第３図において傷面積Ｄは斜線部として表現で
きる。すなわち１番目の走査に対する正常面の長
さはN1＝NLであるので１番目の走査部分には傷
が無い。また、５番目の走査に対してはN5＝NL
−２であるので５番目の走査部分には長さ２の傷
があることになる。簡単のために20番目〜ｎ番目
の走査部分には傷が無いとし、また、Ａ＝0.01mm2
と仮定すれば(2)式より
Ｄ＝0.01mm2×20＝0.2mm2
と計算できる。 In FIG. 3, the flaw area D can be expressed as a hatched area. That is, since the length of the normal surface for the first scan is N 1 =N L , there is no flaw in the first scan portion. Also, for the fifth scan, N 5 =N L
-2, so there is a flaw with a length of 2 in the fifth scanned portion. For simplicity, it is assumed that there are no scratches in the 20th to nth scanning areas, and A = 0.01mm 2
Assuming that, D=0.01mm 2 ×20=0.2mm 2 can be calculated from equation (2).
ところで、(2)式により傷面積を計算する場合、
被検査体の長さを求め、さらにｎ個の減算とｎ回
の加算と１回の乗算が必要である。なお、被検査
体の長さNLは従来Niの最大値あるいは最大値よ
り一定値差し引いた値が用いられていた。上記従
来の傷面積計算方式では計算ステツプが多いこと
により傷面積計算時間が長いことが欠点であつ
た。 By the way, when calculating the scratch area using equation (2),
After finding the length of the object to be inspected, it is necessary to perform n subtractions, n additions, and one multiplication. Note that the length N L of the object to be inspected has conventionally been the maximum value of N i or a value obtained by subtracting a certain value from the maximum value. The disadvantage of the above-mentioned conventional wound area calculation method is that it takes a long time to calculate the wound area due to the large number of calculation steps.
この発明は上記欠点を克服するためになされた
もので各走査毎に得られた正常面カウント数を記
憶装置のカウント数に対応した番地に度数として
入力し、記憶装置の内部で正常面カウント数に対
する度数分布を作成し、この度数分布を利用する
ことにより計算ステツプを減少せしめ、傷面積計
算時間を短縮することを特徴とした表面傷検査装
置を提供するものである。 This invention was made to overcome the above-mentioned drawbacks.The normal surface count obtained for each scan is input as a frequency to the address corresponding to the count in the storage device, and the normal surface count is stored inside the storage device. The present invention provides a surface flaw inspection device which is characterized by creating a frequency distribution for a surface area and utilizing this frequency distribution to reduce calculation steps and shorten flaw area calculation time.
以下この発明の一実施例について図面により詳
述する。 An embodiment of the present invention will be described in detail below with reference to the drawings.
第４図はこの発明の一実施例を示す信号処理装
置の構成例、第５図は度数分布作成等の信号処理
フローチヤートの例、第６図は度数分布の例を示
す図である。 FIG. 4 shows an example of the configuration of a signal processing device according to an embodiment of the present invention, FIG. 5 shows an example of a signal processing flowchart for creating a frequency distribution, etc., and FIG. 6 shows an example of a frequency distribution.
第４図において反射光信号９は正常面判定回路
（例えばウインドウコンパレータ）１５により２
値化され正常面判定信号１４に変換される。正常
面判定信号１４は各走査毎に発生される検査域信
号１６及び計数用のクロツクパルス１７と共に
ANDゲート１８に入力され、正常面パルス１９
として計数回路２０に入力される。１走査分の正
常面パルスの計数結果である正常面計数値２１は
計数終了信号２２と共にCPU２３に入力され必
要な演算処理をされて記憶装置２５に記憶され
る。また、CPUは必要な処理を行つた後計数回
路２０にリセツト信号２４を出力する。CPU２
３と記憶装置２５の間では第５図に示すように度
数分布の作成、傷面積計算及び良否判定等の信号
処理が行なわれる。なお、度数分布は各走査で得
られた正常面計数値２１のカウント数に対応した
メモリの内容に１を加算する方法で作成する。こ
のようにして作成された度数分布の例を第６図に
示す。第６図において横軸は正常面計数値であ
り、正常面の長さを示している。縦軸は度数（走
査数）である。 In FIG. 4, the reflected light signal 9 is converted to 2
It is converted into a value and converted into a normal surface determination signal 14. The normal surface determination signal 14 is generated together with an inspection area signal 16 and a clock pulse 17 for counting, which are generated for each scan.
Input to AND gate 18, normal surface pulse 19
It is input to the counting circuit 20 as . A normal surface count value 21, which is the result of counting normal surface pulses for one scan, is inputted to the CPU 23 together with a counting end signal 22, subjected to necessary arithmetic processing, and stored in the storage device 25. Further, the CPU outputs a reset signal 24 to the counting circuit 20 after performing necessary processing. CPU2
3 and the storage device 25, signal processing such as creation of frequency distribution, calculation of flaw area, and quality determination is performed as shown in FIG. Note that the frequency distribution is created by adding 1 to the contents of the memory corresponding to the normal surface count value 21 obtained in each scan. An example of the frequency distribution created in this way is shown in FIG. In FIG. 6, the horizontal axis is the normal surface count value, indicating the length of the normal surface. The vertical axis is the frequency (number of scans).
以下に度数分布を利用して傷面積計算方法の一
例について述べる。 An example of a method for calculating the flaw area using the frequency distribution will be described below.
(2)式を用いて傷面積を計算する場合 (ア) NL−Niが負になることがある。 When calculating the scratch area using equation (2) (a) N L −N i may be negative.
(イ) Ｄを求めるために走査線数の減算と加算及び
１回の乗算が必要であり、計算時間が長い。(a) In order to obtain D, subtraction and addition of the number of scanning lines and one multiplication are required, which takes a long calculation time.
という欠点がある。しかし、度数分布を利用すれ
ば比較的簡単な計算で傷面積を求めることができ
る。以下第６図においてNL＝159とした場合を例
にとり説明する。NLよりカウント数が１少ない
ものは重み１の傷とし、その度数〔NL−１〕と
この重みの積を傷の大きさとみなすことができ
る。すなわち、Ｎ＝158については、〔Ｎ〕＝〔158〕
＝40、故に傷の大きさは40×１＝40同様にNL−
Ｋ（Ｋは自然数）については傷の重みがＫ、度数
が〔NL−Ｋ〕したがつて傷の大きさはＫ・〔NL
−Ｋ〕とすることができる。故に傷面積Ｄは
Ｄ＝Ａ・h
〓K=1
Ｋ・［NL−ｋ］ ……(3)
により計算できる。ここでｈは最大値NLの自然
数であるが傷の形状等によりNLの1/4程度に選ぶ
ことも可能である。また、(3)式を用いると(ア)の問
題も同時に解決できる。一般に傷は全体に比較し
て小部分に存在するために実際に必要な演算回数
は（2n＋１）回に比較すれば相当少いものにな
る。There is a drawback. However, by using the frequency distribution, the flaw area can be determined with relatively simple calculations. The following will explain the case where N L =159 in FIG. 6 as an example. A scratch whose count number is 1 less than N L is a scratch with a weight of 1, and the product of its frequency [N L -1] and this weight can be regarded as the size of the scratch. That is, for N=158, [N]=[158]
= 40, therefore the size of the scratch is 40 × 1 = 40 Similarly, N L −
Regarding K (K is a natural number), the weight of the scratch is K and the frequency is [N L −K], so the size of the scratch is K・[N L
-K]. Therefore, the flaw area D can be calculated by D=A・h 〓 K=1 K・[N L −k] ……(3). Here, h is a natural number of the maximum value N L , but it can also be selected to be about 1/4 of N L depending on the shape of the flaw, etc. Furthermore, by using equation (3), problem (a) can be solved at the same time. Generally, flaws exist in a small portion compared to the whole, so the number of operations actually required is considerably smaller than (2n+1) times.
また、傷検査の場合被検査体の端部に不感帯と
呼ばれる非検査領域を設定し、端部の微少傷ある
いは計数誤差をマスクすることが多くみられる
が、これと同様な概念を(3)式に導入することがで
きる。すなわち傷判定のためのしきい値として
Dthを設定し、傷面積Ｄを
Ｄ＝Ａh
〓K=D
th+1ｋ・［NL−ｋ］ ……(4)
で求めることができる。 In addition, in the case of flaw inspection, a non-inspection area called a dead zone is often set at the edge of the object to be inspected to mask minute flaws or counting errors at the edge, but a similar concept (3) can be introduced into Eq. In other words, as a threshold for determining scratches.
D th is set, and the flaw area D can be obtained by D=A h 〓 K=D th+1 k・[N L −k] ……(4).
以上述べたようにこの発明によれば各走査毎に
得られる正常面計数値を記憶するとともにその計
数値に対する度数分布を作成し、その度数分布を
用いることにより比較的簡単に被検査体の傷面積
Ｄを求めることができ、傷検査装置の傷面積演算
時間の短縮が実現できる。 As described above, according to the present invention, the normal surface count value obtained for each scan is stored, a frequency distribution is created for the count value, and by using the frequency distribution, scratches on the object to be inspected can be relatively easily detected. The area D can be determined, and the flaw area calculation time of the flaw inspection device can be shortened.
なお、上記説明は被検査体が円柱形のものを例
にとり行つたが、長さあるいは幅が一定の平板状
のものについても可能なことはいうまでもない。 Although the above description has been made with reference to a cylindrical object to be inspected, it goes without saying that the object to be inspected may also be a flat object having a constant length or width.
第１図は円柱形被検査体の表面傷検査装置を示
す構成図、第２図は被検査体からの反射光信号と
正常面判定信号の例を示す図、第３図は従来の方
法により傷面積を求めた例を示す図、第４図はこ
の発明による信号処理装置の構成図、第５図は信
号処理フローチヤート図、第６図は度数分布の例
を示す図である。
図中、１はレーザ装置、２はレーザ光、３は振
動鏡、４は円柱形被検査体、５ａ，５ｂは回転ロ
ーラ、６は反射光、７は集光レンズ、８は光検出
器、９は反射光信号、１０は信号処理装置、１２
は表面傷、１３は正常面判定信号レベル、１４は
正常面判定信号、１５は正常面判定回路、１６は
検査域信号、１７はクロツクパルス、１８は
ANDゲート、１９は正常面パルス、２０は計数
回路、２１は正常面計数値、２２は計数終了信
号、２３はCPU、２４は計数回路リセツト信号、
２５は記憶装置である。なお図中同一あるいは相
当部分には同一符号を付して示してある。
Fig. 1 is a configuration diagram showing a surface flaw inspection device for a cylindrical object to be inspected, Fig. 2 is a diagram showing an example of a reflected light signal from the object to be inspected and a normal surface determination signal, and Fig. 3 is a diagram showing an example of a surface flaw inspection device for a cylindrical object to be inspected. FIG. 4 is a block diagram of a signal processing device according to the present invention, FIG. 5 is a signal processing flowchart, and FIG. 6 is a diagram showing an example of frequency distribution. In the figure, 1 is a laser device, 2 is a laser beam, 3 is a vibrating mirror, 4 is a cylindrical object to be inspected, 5a, 5b are rotating rollers, 6 is reflected light, 7 is a condensing lens, 8 is a photodetector, 9 is a reflected light signal, 10 is a signal processing device, 12
is a surface flaw, 13 is a normal surface judgment signal level, 14 is a normal surface judgment signal, 15 is a normal surface judgment circuit, 16 is an inspection area signal, 17 is a clock pulse, and 18 is a
AND gate, 19 is a normal plane pulse, 20 is a counting circuit, 21 is a normal plane count value, 22 is a counting end signal, 23 is a CPU, 24 is a counting circuit reset signal,
25 is a storage device. Note that the same or corresponding parts in the figures are indicated by the same reference numerals.
Claims (1)
上記被検査体からの上記レーザ光の反射光あるい
は透過光を検出する手段と、上記検出手段により
検出された光信号を２値化し、正常判定信号に変
換する正常面判定回路、上記正常判定信号と各走
査毎に発生される検査域信号および計数用クロツ
クパルスとを入力して正常面パルスを出力する
AND回路、上記AND回路からの正常面パルスを
入力し、１走査分の正常面パルスの計数結果であ
る正常面計数値を計数終了信号とともに出力する
計数回路、記憶手段、上記正常面計数値と計数終
了信号を入力し、必要な演算処理を行い、各走査
毎に得られた正常面計数値を用いて度数分布を作
成し、その度数分布を上記記憶手段に記憶させる
とともに上記計数回路に各走査毎にリセツト信号
を発生し、かつ上記記憶手段で記憶された各走査
毎の度数分布から被検査体の傷面積を求める
CPUとを有する信号処理装置とを備えたことを
特徴とする表面傷検査装置。1 means for scanning the surface of the object to be inspected with a laser beam;
means for detecting reflected light or transmitted light of the laser beam from the object to be inspected; a normal surface determination circuit that binarizes the optical signal detected by the detection means and converts it into a normality determination signal; and the normality determination signal. inputs the inspection area signal and counting clock pulse generated for each scan, and outputs the normal surface pulse.
an AND circuit, a counting circuit that inputs the normal surface pulses from the AND circuit and outputs the normal surface count value which is the counting result of the normal surface pulses for one scan together with a counting end signal; a storage means; A counting end signal is input, necessary arithmetic processing is performed, a frequency distribution is created using the normal surface count values obtained for each scan, and the frequency distribution is stored in the storage means, and each count is sent to the counting circuit. A reset signal is generated for each scan, and the flaw area on the object to be inspected is determined from the frequency distribution for each scan stored in the storage means.
A surface flaw inspection device comprising: a signal processing device having a CPU; and a signal processing device having a CPU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15420280A JPS5777907A (en) | 1980-10-31 | 1980-10-31 | Surface flaw detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15420280A JPS5777907A (en) | 1980-10-31 | 1980-10-31 | Surface flaw detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5777907A JPS5777907A (en) | 1982-05-15 |
| JPH0121883B2 true JPH0121883B2 (en) | 1989-04-24 |
Family
ID=15579067
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15420280A Granted JPS5777907A (en) | 1980-10-31 | 1980-10-31 | Surface flaw detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5777907A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01143945A (en) * | 1987-11-30 | 1989-06-06 | Fuji Photo Film Co Ltd | Detecting method for defect in tape |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5379593A (en) * | 1976-12-24 | 1978-07-14 | Hitachi Ltd | Surface inspecting method of objects and apparatus for the same |
-
1980
- 1980-10-31 JP JP15420280A patent/JPS5777907A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5379593A (en) * | 1976-12-24 | 1978-07-14 | Hitachi Ltd | Surface inspecting method of objects and apparatus for the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5777907A (en) | 1982-05-15 |
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