JPH06201607A - Method for inspecting surface - Google Patents
Method for inspecting surfaceInfo
- Publication number
- JPH06201607A JPH06201607A JP4347181A JP34718192A JPH06201607A JP H06201607 A JPH06201607 A JP H06201607A JP 4347181 A JP4347181 A JP 4347181A JP 34718192 A JP34718192 A JP 34718192A JP H06201607 A JPH06201607 A JP H06201607A
- Authority
- JP
- Japan
- Prior art keywords
- pattern
- image
- unit
- inspected
- lattice
- 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.)
- Pending
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
- G01N21/8806—Specially adapted optical and illumination features
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Image Processing (AREA)
- Closed-Circuit Television Systems (AREA)
- Image Analysis (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は面検査方法に関する。
この発明は、自動車の車体表面点検等に利用できる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection method.
INDUSTRIAL APPLICABILITY The present invention can be used for inspecting the body surface of an automobile.
【０００２】[0002]
【従来の技術】自動車車体表面等の被検査面の検査部を
照明し、被照明部の像を読取装置により読み取って信号
化し、この信号を閾値処理することにより被検査面上の
異常個所（傷等）を検出する方法は従来から良く知られ
ている。2. Description of the Related Art An inspection part on a surface to be inspected such as an automobile body surface is illuminated, an image of the illuminated part is read by a reading device and converted into a signal, and this signal is thresholded to detect an abnormal portion on the surface to be inspected ( Conventionally, methods for detecting scratches) are well known.
【０００３】このような面検査方法の場合、被検査面の
色等により異常個所とその周辺部との輝度差が不十分で
ある場合があり、このような場合には単純な閾値処理に
よる２値化では異常個所を検出できないことが多い。In such a surface inspection method, the difference in brightness between the abnormal portion and its peripheral portion may be insufficient due to the color of the surface to be inspected, etc. The digitization often fails to detect abnormal points.
【０００４】[0004]
【発明が解決しようとする課題】この発明は上述した事
情に鑑みてなされたものであって、異常個所を容易且つ
確実に検出できる新規な面検査方法の提供を目的とす
る。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel surface inspection method capable of easily and surely detecting an abnormal point.
【０００５】[0005]
【課題を解決するための手段】この発明の面検査方法
は、「被検査面上の検査部に、光強度が１方向へ周期的
に変化する１次元格子状のパターンを照射し、検査部の
像を読取装置により読み取り、読み取ったパターン像情
報を、格子の縞方向に従って微分処理を行い、その結果
に閾値処理を施すことにより、検査部の異常個所を検出
する」ことを特徴とする。According to the surface inspection method of the present invention, "the inspection portion on the surface to be inspected is irradiated with a one-dimensional lattice-like pattern in which the light intensity periodically changes in one direction, and the inspection portion is irradiated. Is read by a reading device, the read pattern image information is subjected to differential processing in accordance with the stripe direction of the lattice, and the result is subjected to threshold processing to detect an abnormal portion in the inspection section. "
【０００６】「格子の縞方向」とは、パターン像の明暗
による縞の方向、即ち明暗の変化が無い方向を意味す
る。The "grid stripe direction" means a stripe direction due to light and dark of the pattern image, that is, a direction in which there is no change in light and dark.
【０００７】[0007]
【作用】上記のように、この発明においては、被検査面
の検査部における異常個所を検出するために、「読み取
ったパターン像情報を、格子の縞方向に従って微分処理
を行う」ため、パターン画像における格子構造は、微分
情報では実質的に除去される。また異常個所の部分で
は、光強度の局所的な変化が微分演算により強調される
ことになる。As described above, in the present invention, in order to detect the abnormal portion in the inspection portion of the surface to be inspected, "the read pattern image information is subjected to the differential processing according to the stripe direction of the lattice". The lattice structure at is substantially removed in the differential information. In the abnormal portion, the local change in light intensity is emphasized by the differential operation.
【０００８】[0008]
【実施例】図１は１実施例を示している。図１（ａ）に
おいて、符号１０は被検査体の被検査面を示す。符号１
２で示す投影機は制御部１６に制御されて、図１（Ｂ）
に示すような「光透過率がｘ方向に周期的に変化する１
次元格子状のパターン１１（以下スリットパターン）」
の拡大像、即ち１次元格子状のパターン１３を被検査面
１０の検査部へ照射する。図１（Ｃ）はパターン１１に
おけるｘ方向における透過率の変化を示している。EXAMPLE FIG. 1 shows one example. In FIG. 1A, reference numeral 10 indicates an inspected surface of an inspected body. Code 1
The projector shown by 2 is controlled by the control unit 16 and is shown in FIG.
“The light transmittance changes periodically in the x direction as shown in
Dimensional grid pattern 11 (hereinafter slit pattern) "
The enlarged image, that is, the one-dimensional lattice-shaped pattern 13 is applied to the inspection portion of the surface 10 to be inspected. FIG. 1C shows the change in the transmittance in the x direction in the pattern 11.
【０００９】パターン１３を照射された検査部の像は、
読取装置であるＣＣＤカメラ１４により読み取られ、そ
の結果は演算処理部１８に取り込まれる。演算情報部１
８は、具体的にはコンピューター等である。The image of the inspection part irradiated with the pattern 13 is
The result is read by the CCD camera 14 which is a reading device, and the result is taken into the arithmetic processing unit 18. Calculation information section 1
Reference numeral 8 is specifically a computer or the like.
【００１０】例えば、パターン１３の照射部を読み取る
ＣＣＤカメラ１４の受光面上のパターン像が図１（Ｄ）
に示す如くであるものとする。この図において、符号１
００は異常個所としての「傷」の像を示している。スリ
ットパターンにおける光透過率変化方向（ｘ方向）に対
応して、図１（Ｄ）のパターン像に対してもｘ，ｙ方向
を図示のように定めると、ｙ方向は「格子の縞方向」に
対応する。For example, the pattern image on the light receiving surface of the CCD camera 14 for reading the irradiation portion of the pattern 13 is shown in FIG.
As shown in. In this figure, reference numeral 1
00 indicates an image of a "scratch" as an abnormal portion. Corresponding to the light transmittance change direction (x direction) in the slit pattern, if the x and y directions are determined as shown in the figure also for the pattern image of FIG. 1D, the y direction is the “grid stripe direction”. Corresponding to.
【００１１】図１（Ｄ）において、「傷」の像１００が
存在している部分の「明部」におけるｘ座標をｘ1、
「暗部」におけるｘ座標をｘ2とすると、「座標ｘ1，ｘ
2に対応するｙ方向の光強度」に対応する読み取り信号
Ｐは、それぞれ図１（Ｅ）の左右の図のようになり、傷
の像１００の部分で信号値が低下する。しかし、信号Ｐ
の低下はさほど大きくなく、読み取り信号はパターン像
の明暗に従って変化しているので、このままの状態で閾
値処理をしても、「傷部分」を検出することは極めて困
難である。In FIG. 1D, the x-coordinate in the "bright part" of the part where the "scratch" image 100 is present is x 1 ,
When the x-coordinate and x 2 in the "dark portion", "coordinates x 1, x
The read signal P corresponding to the “light intensity in the y direction corresponding to 2 ” is as shown on the left and right of FIG. 1E, and the signal value decreases at the portion of the scratch image 100. However, the signal P
Is not so large, and the read signal changes according to the lightness and darkness of the pattern image, so it is extremely difficult to detect the "scratch portion" even if the threshold processing is performed in this state.
【００１２】そこで、演算処理部１８において、取り込
んだパターン像情報を「格子の縞方向」であるｙ方向に
微分処理すると、その結果であるＰ’（＝ｄＰ／ｄｙ）
は、上記ｘ座標値ｘ1，ｘ2に対しそれぞれ図１（Ｆ）の
左右の図に示すようになる。即ち、パターン像における
スリットパターンに応じた明暗の、縞方向における微分
値は実質的に０となり、傷の像１００に対応する部分は
大きな値で正・負に変化する。Therefore, the arithmetic processing unit 18 differentiates the captured pattern image information in the y direction which is the "grid stripe direction", and the result is P '(= dP / dy).
Are as shown in the left and right views of FIG. 1 (F) for the x coordinate values x 1 and x 2 , respectively. That is, the differential value of the light and darkness according to the slit pattern in the pattern image in the stripe direction is substantially 0, and the portion corresponding to the scratch image 100 changes to a positive value or a negative value with a large value.
【００１３】従って、この微分処理した信号に対し、そ
の「正値」もしくは「負値（破線で示す）」に対して適
当な閾値Ｅを用いて２値化を行えば、検査部における傷
の部分のみを検出することができる。Therefore, if the "positive value" or the "negative value (shown by the broken line)" of the differentiated signal is binarized by using an appropriate threshold value E, a flaw in the inspection section may be detected. Only parts can be detected.
【００１４】図１（Ｇ）は、上記微分処理と２値化を行
った結果を図１（Ａ）に符号２０で示すＣＲＴに表示し
た状態を示す。傷の存在位置が異常個所１００Ａとして
表示されている。FIG. 1G shows a state in which the result of the above-described differential processing and binarization is displayed on the CRT indicated by reference numeral 20 in FIG. The location of the scratch is displayed as the abnormal point 100A.
【００１５】[0015]
【発明の効果】以上のように、この発明によれば新規な
面検査方法を提供できる。この発明は上記の如く構成さ
れているので、被検査面検査部の異常個所を容易且つ確
実に検出することができる。As described above, according to the present invention, a novel surface inspection method can be provided. Since the present invention is configured as described above, it is possible to easily and surely detect an abnormal portion in the inspection portion of the surface to be inspected.
【００１６】なお、検査部に照射する１次元格子状のパ
ターンにおける格子のピッチを異ならせて、所謂空間の
コード化を行えば検査部を３次元的に検査できることを
付記しておく。It should be noted that the inspection unit can be inspected three-dimensionally by changing the pitch of the grating in the one-dimensional lattice-like pattern with which the inspection unit is irradiated and performing so-called space coding.
【図１】この発明の１実施例を説明する図である。FIG. 1 is a diagram illustrating an embodiment of the present invention.
【符号の説明】 １０ 被検査面を表面として有する被検査体 １２ 投影機 １４ 読取装置 １００ 傷（検査部における異常個所）の像[Explanation of Codes] 10 Object to be inspected having surface to be inspected 12 Projector 14 Reader 100 Image of flaw (abnormal portion in inspection section)
Claims (1)
周期的に変化する１次元格子状のパターンを照射し、上
記検査部の像を読取装置により読み取り、 読み取ったパターン像情報を、格子の縞方向に従って微
分処理を行い、その結果に閾値処理を施すことにより、
上記検査部の異常個所を検出することを特徴とする面検
査方法。1. A pattern image read by irradiating an inspection portion on a surface to be inspected with a one-dimensional lattice pattern in which light intensity periodically changes in one direction, and reading the image of the inspection portion by a reading device. By differentiating the information according to the stripe direction of the lattice and applying threshold processing to the result,
A surface inspection method comprising detecting an abnormal portion of the inspection section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4347181A JPH06201607A (en) | 1992-12-25 | 1992-12-25 | Method for inspecting surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4347181A JPH06201607A (en) | 1992-12-25 | 1992-12-25 | Method for inspecting surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06201607A true JPH06201607A (en) | 1994-07-22 |
Family
ID=18388474
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4347181A Pending JPH06201607A (en) | 1992-12-25 | 1992-12-25 | Method for inspecting surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06201607A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8233694B2 (en) | 2009-10-21 | 2012-07-31 | GM Global Technology Operations LLC | Method of appearance deformation indexing |
| JP2016109532A (en) * | 2014-12-05 | 2016-06-20 | コマツＮｔｃ株式会社 | Method and device for estimating surface |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6373139A (en) * | 1986-09-17 | 1988-04-02 | Canon Inc | surface inspection equipment |
-
1992
- 1992-12-25 JP JP4347181A patent/JPH06201607A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6373139A (en) * | 1986-09-17 | 1988-04-02 | Canon Inc | surface inspection equipment |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8233694B2 (en) | 2009-10-21 | 2012-07-31 | GM Global Technology Operations LLC | Method of appearance deformation indexing |
| JP2016109532A (en) * | 2014-12-05 | 2016-06-20 | コマツＮｔｃ株式会社 | Method and device for estimating surface |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 19980623 |