JPH07280532A - Shape inspector for object - Google Patents
Shape inspector for objectInfo
- Publication number
- JPH07280532A JPH07280532A JP10068794A JP10068794A JPH07280532A JP H07280532 A JPH07280532 A JP H07280532A JP 10068794 A JP10068794 A JP 10068794A JP 10068794 A JP10068794 A JP 10068794A JP H07280532 A JPH07280532 A JP H07280532A
- Authority
- JP
- Japan
- Prior art keywords
- slit
- light
- laser light
- shape
- lens
- 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
Landscapes
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、線状に変形させたスリ
ット状のレーザ光を物体に照射し、この物体の表面の形
状に従って変形されたスリット状のレーザ光を撮影して
目視検査や自動検査などに供する物体の形状検査装置に
関する．BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates an object with slit-shaped laser light deformed linearly, and photographs the slit-shaped laser light deformed according to the shape of the surface of the object to perform visual inspection or visual inspection. The present invention relates to an object shape inspection device for automatic inspection.
【０００２】[0002]
【従来の技術】従来、線状（スリット状）の光を物体に
照射し、この物体の表面の傷などに起因する凹凸に従っ
て変形されたスリット状の光を撮影して目視検査や自動
検査などに供する物体の形状検査方法が知られている。
このような形状検査方法は光切断法による形状検査方法
とも称されており、物体に照射され撮影されたスリット
光の像は光切断像とも称されている。このような光切断
法に関しては、従来から多くの方法が考えられ提案され
ている。例えば、特開昭50-46356号公報に開示されたよ
うにＨ型鋼の形状検査に光切断法を導入して物体の寸法
や形状の検査を行う例や、特開昭57-144404 号公報に開
示されたように帯状（スリット状）光源を多方向から照
射して形状検査を行う方法などが知られている。2. Description of the Related Art Conventionally, a linear (slit-shaped) light is applied to an object, and the slit-shaped light deformed according to the unevenness caused by scratches on the surface of the object is photographed for visual inspection or automatic inspection. There is known a method for inspecting the shape of an object to be used.
Such a shape inspection method is also referred to as a shape inspection method by a light section method, and an image of the slit light irradiated on the object and photographed is also referred to as a light section image. Many methods have been proposed and proposed for such a light cutting method. For example, as disclosed in Japanese Unexamined Patent Publication No. 50-46356, an example in which an optical cutting method is introduced to inspect the shape of H-section steel to inspect the size and shape of an object, and Japanese Unexamined Patent Publication No. 57-144404 are disclosed. As disclosed, a method of irradiating a strip-shaped (slit-shaped) light source from multiple directions to perform shape inspection is known.
【０００３】また，特開平３-149795 号公報に開示され
たように、パルス状の大光量のレーザ光をロッドレンズ
を通すことによってスポット状からスリット状に変形さ
せながら拡大したものを検査対象の物体に照射し、物体
の表面の形状や凹凸に従って変形したスリット状のレー
ザ光を特殊な高速撮影装置で撮影する方法も知られてい
る。Further, as disclosed in Japanese Patent Application Laid-Open No. 3-149795, an object to be inspected is a pulsed laser beam having a large amount of light which is enlarged while being transformed from a spot shape to a slit shape by passing through a rod lens. There is also known a method of irradiating an object and photographing a slit-shaped laser beam which is deformed according to the shape and unevenness of the surface of the object with a special high-speed photographing device.
【０００４】[0004]
【発明が解決しようとする課題】上記スリット状のレー
ザ光を利用する検査装置では、ロッドレンズを通すこと
によって発生させたスリット状のレーザ光の光量密度分
布が端部に近づくほど低下し、検査の精度の低下を招く
という問題がある。この原因は、レーザダイオードなど
の光源から放射されるスポット状のレーザビームにもと
もとガウシァン分布と称される光量密度分布が存在する
ことと、このような光量密度分布がロッドレンズの光学
的特性によって更に強調されてしまうこととによる。こ
の結果、撮像中にその中央部分が明るくなる照明斑が発
生し、スリットの全範囲にわたって高精度の検査を行う
ことが困難になる。このような現象は、シェーディング
補正を行うことによって解決できるが、これを行う画像
処理回路の負担が増大し、装置が高価になるという問題
がある。従って、本発明の一つの目的は、簡易・安価な
構成により光量密度分布の均一化を実現できる物体の形
状検査装置を提供することにある。In the inspection device utilizing the slit-shaped laser light, the light quantity density distribution of the slit-shaped laser light generated by passing through the rod lens decreases as it approaches the end, and the inspection is performed. However, there is a problem in that the accuracy of is reduced. This is because the spot-like laser beam emitted from the light source such as a laser diode originally has a light amount density distribution called Gaussian distribution, and such a light amount density distribution is further caused by the optical characteristics of the rod lens. It is because it is emphasized. As a result, an illumination spot whose central portion becomes bright is generated during imaging, making it difficult to perform a highly accurate inspection over the entire range of the slit. Although such a phenomenon can be solved by performing shading correction, there is a problem in that the load of the image processing circuit that performs this is increased and the apparatus becomes expensive. Therefore, one object of the present invention is to provide an object shape inspection apparatus capable of realizing uniform light quantity density distribution with a simple and inexpensive structure.
【０００５】また、従来の形状検査装置では、物体表面
の凸部で生じた反射光の向きが撮影装置の方向から大き
くずれてしまい、撮影装置の受光レンズに入射できなく
なるという問題もある。さらに、物体表面の凸部が小さ
いためそこで生じた反射光が撮影装置の受光レンズに入
射できたとしても、受光レンズを透過した反射光が、通
常、受光レンズの結像位置に設置されるアパチァに阻止
されて撮像素子までは到達できなくなり、この結果、凸
部稜線が欠落してしまってその形状が検査できなくなる
という問題もある。従って、本発明の他の目的は、凸部
稜線の欠落を防止して検査可能とできる物体の形状検査
装置を提供することにある。Further, in the conventional shape inspection apparatus, there is also a problem that the direction of the reflected light generated at the convex portion on the surface of the object is largely deviated from the direction of the photographing apparatus, and the light cannot be incident on the light receiving lens of the photographing apparatus. Further, even if the reflected light generated there is allowed to enter the light receiving lens of the image pickup device because the convex portion of the object surface is small, the reflected light transmitted through the light receiving lens is usually an aperture that is installed at the image forming position of the light receiving lens. Therefore, there is also a problem that the image pickup device cannot reach the image pickup element, and as a result, the ridgeline of the convex portion is missing and its shape cannot be inspected. Therefore, another object of the present invention is to provide an object shape inspection apparatus capable of inspecting by preventing the ridgeline of a convex portion from being missing.
【０００６】[0006]
【課題を解決するための手段】上記従来技術の課題を解
決する本発明の物体検査装置は、スリット状のレーザ光
よりもほぼ 10nm 〜40nm 長い波長の透過中心波長とほ
ぼ 10nm 〜100nm の半値幅とを有するバンドパス・フィ
ルタを、スリット状のレーザ光の入射角がこのスリット
の中央部分についてはほぼ0 o 、両端部分についてはほ
ぼ30o 以下となるようにして照射装置と撮影装置との間
に設置している。The object inspection apparatus of the present invention for solving the above-mentioned problems of the prior art has a transmission center wavelength of about 10 nm to 40 nm longer than a slit laser beam and a half-value width of about 10 nm to 100 nm. Between the irradiation device and the image pickup device so that the incident angle of the slit-shaped laser light is about 0 o at the central part of the slit and about 30 o or less at both end parts. It is installed in.
【０００７】本発明の好適な実施例によれば、撮影装置
はその受光レンズの主平面と光検査物体上の照射領域と
の距離がこの受光レンズの有効径の10倍を超えない位置
に設置されると共に、この受光レンズの焦点から撮像面
側にずらしてアパチァが設置されている。According to a preferred embodiment of the present invention, the photographing apparatus is installed at a position where the distance between the main plane of the light receiving lens and the irradiation area on the optical inspection object does not exceed 10 times the effective diameter of the light receiving lens. At the same time, the aperture is set so as to be shifted from the focus of the light receiving lens toward the image pickup surface side.
【０００８】[0008]
【作用】適切な透過中心波長と半値幅とを有するバンド
パス・フィルタは、これに入射する光線に対して入射角
が増加するほど大きな透過率を与える。従って、スリッ
トの中央部からほぼ 0 oの入射角で入射する成分よりも
スリットの端部から大きな入射角で入射する成分の方が
透過率が高くなり、ガウシァン分布で代表されるスリッ
ト状のレーザ光に対して光量密度分布の補正が行われ
る。A bandpass filter having an appropriate transmission center wavelength and a full width at half maximum gives a larger transmittance for a ray incident on the bandpass filter as the incident angle increases. Therefore, the transmittance of the component incident at a large incident angle from the end of the slit is higher than that of the component incident at an incident angle of almost 0 o from the center of the slit, and the slit-shaped laser represented by Gaussian distribution is used. The light quantity density distribution of the light is corrected.
【０００９】[0009]
【実施例】図１は、本発明の一実施例に係わる物体の形
状検査装置の概略の構成を示す図であり、（Ａ）は概ね
断面図に相当し、（Ｂ）は概ね平面図に相当する。１は
照射装置、２は撮影装置、３は表示装置、Ｔは表面形状
を検査しよとする被検査物体である。本実施例では被検
査物体として図中の矢印方向に搬送される厚板鋼板が想
定されている。1 is a diagram showing a schematic structure of an object shape inspection apparatus according to an embodiment of the present invention. FIG. 1A is a sectional view and FIG. 1B is a plan view. Equivalent to. 1 is an irradiation device, 2 is a photographing device, 3 is a display device, and T is an inspected object whose surface shape is to be inspected. In this embodiment, a thick steel plate conveyed in the direction of the arrow in the drawing is assumed as the object to be inspected.
【００１０】照射装置１は、波長 790nmのスポット状の
レーザ光を連続的に放射するレーザダイオードなどのレ
ーザ発光素子１ａと、このレーザ発光素子から放射され
たスポット状のレーザ光をスリット状（線状）に変形さ
せながら拡大して被検査物体Ｔに照射するロッドレンズ
１ｂとから構成されている。撮影装置２は、受光レンズ
２ａと、その後方に配置された二次元ＣＣＤなどから構
成される撮像素子２ｂと、その前方に配置されたアパチ
ァ２ｃとから構成されている。被検査物体Ｔのレーザ光
照射領域と撮影装置２との間には光学的なバンドパス・
フィルタ４が配置されている。このバンドパス・フィル
タ４は、多層蒸着膜から構成され、レーザ光の波長より
も 20nm 長い 810nm の透過中心波長と、60nm の半値
幅とを有している。撮影装置２の視野角は60゜であり、
被検査物体Ｔ上の照射領域からの反射光は、バンドパス
・フィルタ４に立てた法線に対して30゜以下の入射角で
入射するように設定されている。The irradiation device 1 includes a laser light emitting element 1a such as a laser diode that continuously emits a spot-shaped laser light having a wavelength of 790 nm, and a spot-shaped laser light emitted from the laser light-emitting element in a slit shape (line). And a rod lens 1b for irradiating the object T to be inspected while deforming it into a rectangular shape. The image pickup device 2 is composed of a light receiving lens 2a, an image pickup element 2b arranged behind the light receiving lens 2a, such as a two-dimensional CCD, and an aperture 2c arranged in front of the image pickup element 2b. An optical band pass is provided between the laser light irradiation area of the inspection object T and the imaging device 2.
The filter 4 is arranged. This bandpass filter 4 is composed of a multilayer vapor deposition film, and has a transmission center wavelength of 810 nm, which is 20 nm longer than the wavelength of laser light, and a half-value width of 60 nm. The viewing angle of the photographing device 2 is 60 °,
The reflected light from the irradiation area on the object T to be inspected is set so as to be incident at an incident angle of 30 ° or less with respect to the normal line set up on the bandpass filter 4.
【００１１】図１のバンドパス・フィルタ４に波長 790
nm のレーザ光を入射させた場合の透過率は、計算結果
からも実験結果からも図２に示すように入射角に応じて
変化する。このバンドパス・フィルタ４の透過中心波長
が入射レーザ光の波長よりも長波長側に20nmずれている
と共に透過帯域の半値幅が 60nm に設定されているた
め、入射レーザ光の透過率はその入射角の増加と共に増
加する。すなわち、透過率は、入射角が０゜の場合は 2
2 ％と低いが、入射角が10゜では約 30 ％、20゜では約
44 ％、30゜では75％という具合に、入射角の増加と共
に放物曲線に近い形で増加する。入射角 30 ゜付近から
透過率の増加率が鈍っているが、これはバンドパス・フ
ィルタの表面における反射光が増加し、入射光の反射割
合が増える結果総合的に透過率の上昇が頭打ちとなるこ
とによる。The bandpass filter 4 of FIG.
The transmittance when a laser beam of nm is incident changes according to the incident angle as shown in FIG. 2 both from the calculation result and the experimental result. Since the transmission center wavelength of the bandpass filter 4 is 20 nm longer than the wavelength of the incident laser light and the half bandwidth of the transmission band is set to 60 nm, the transmittance of the incident laser light is Increases with increasing horn. That is, the transmittance is 2 when the incident angle is 0 °.
It is as low as 2%, but it is about 30% at an incident angle of 10 ° and about 30% at an incident angle of 20 °.
It increases in the form of a parabolic curve as the incident angle increases, such as 44% and 75% at 30 °. The increase rate of the transmittance is slow from the incident angle of about 30 °. This is because the reflected light on the surface of the bandpass filter increases and the reflection rate of the incident light increases, so that the increase in the transmittance is almost leveled off. It depends.
【００１２】このように、バンドパス・フィルタ４を撮
影装置２の前方に設置すると、このバンドパス・フィル
タ４を透過して撮影装置２に入射する反射光の光量を、
物体表面のスリット状の照射領域の中央部分から発した
反射光ほど抑えることができる。この結果、レーザダイ
オード１ａが発生したスポット状のレーザビーム内に出
現する光量密度のガウシァン分布と、ロッドレンズ１ｂ
の光学的特性とが重畳されて生じる照明斑が補正され
る。また、スリット状の照射領域の各部から発した反射
光のバンドパス・フィルタ４への入射角を、中心部分に
ついては 0゜、端部については30゜となるように設定す
れば、透過率の変化が大きな入射角の範囲を有効に利用
できる。この結果、スリット状の照射領域の端部で反射
された微弱な反射光を効率よく集光しながら照明斑を補
正できる。As described above, when the bandpass filter 4 is installed in front of the photographing device 2, the amount of reflected light that passes through the bandpass filter 4 and enters the photographing device 2 is
The reflected light emitted from the central portion of the slit-shaped irradiation area on the surface of the object can be suppressed more. As a result, the Gaussian distribution of the light amount density appearing in the spot-shaped laser beam generated by the laser diode 1a and the rod lens 1b
The unevenness of illumination caused by the superimposition of the optical characteristics of the. Moreover, if the incident angle of the reflected light emitted from each part of the slit-shaped irradiation area to the bandpass filter 4 is set to 0 ° at the central part and 30 ° at the end part, the transmittance can be improved. It is possible to effectively use the range of the incident angle that greatly changes. As a result, the illumination spots can be corrected while efficiently collecting the feeble reflected light reflected at the end of the slit-shaped irradiation area.
【００１３】図２に示した入射角に対する透過率の依存
性の曲線は、使用するバンドパス・フィルタの透過中心
波長と半値幅に応じて微妙に変化する。このため、使用
するレーザ光の波長、光量、光量密度分布やロッドレン
ズの光学的特性などに応じてバンドパス・フィルタの透
過中心波長や半値幅などの光学的なパラメータを最適値
に設定すればよい。バンドパス・フィルタの半値幅を小
さくするほど、スリット状の照射領域の中心部分と端部
との透過率の差は大きくなる。しかしながら、この半値
幅を小さくするにつれて全般的に透過率が低下し、半値
幅が 9nm 以下になると入射光量の不足によって鮮明な
切断画像を得ることが困難になる。逆に、半値幅が 101
nm 以上になるとバンドパス・フィルタへの入射角が変
化しても透過率がそれほど変化しなくなり、照明斑の補
正の効果は減少する。従って、好適な半値幅の範囲は、
ほぼ10nmからほぼ100nm までの範囲といえる。The curve of the dependence of the transmittance on the incident angle shown in FIG. 2 slightly changes depending on the transmission center wavelength and the half width of the bandpass filter used. Therefore, it is necessary to set the optical parameters such as the transmission center wavelength and half width of the bandpass filter to the optimum values according to the wavelength of the laser light used, the light quantity, the light quantity density distribution and the optical characteristics of the rod lens. Good. The smaller the half-width of the bandpass filter, the larger the difference in transmittance between the central portion and the end portion of the slit-shaped irradiation region. However, as the full width at half maximum is decreased, the transmittance generally decreases, and when the full width at half maximum is 9 nm or less, it becomes difficult to obtain a clear cut image due to insufficient incident light amount. Conversely, the FWHM is 101
At wavelengths above nm, the transmittance does not change so much even if the incident angle to the bandpass filter changes, and the effect of correcting illumination spots decreases. Therefore, the preferred half-width range is
It can be said that the range is from about 10 nm to about 100 nm.
【００１４】また、バンドパス・フィルタの透過中心波
長については、半値幅との関係もあるが半値幅が上述し
た好適な 10 〜100nm の範囲にあれば、入射レーザ光よ
りも10nm〜40nm長い波長を透過中心波長とすることで補
正効果を得られることが発明者らの実験で確かめられ
た。入射レーザ光との波長の差が 41nm 以上になると半
値幅を相当大きな値に設定しなければならず、上述した
ように、照明斑の補正の効果が失われる．Regarding the transmission center wavelength of the bandpass filter, there is a relationship with the full width at half maximum, but if the full width at half maximum is within the preferable range of 10 to 100 nm described above, a wavelength longer by 10 nm to 40 nm than the incident laser beam is obtained. It has been confirmed by experiments by the inventors that a correction effect can be obtained by setting the transmission center wavelength to. When the wavelength difference from the incident laser light is 41 nm or more, the half-width must be set to a considerably large value, and as described above, the effect of correcting the illumination unevenness is lost.
【００１５】本実施例で使用したバンドパス・フィルタ
による照明斑補正の結果を図３に示す。図３の（Ａ）は
バンドパス・フィルタ４を透過する前の反射光の光量密
度分布を示しており、（Ｂ）はバンドパス・フィルタ４
を透過した後の光量密度分布を示している。このよう
に、バンドパス・フィルタ４の透過中心波長を長波長側
に適正な値だけずらすと共に半値幅を適正な値に設定す
ることによって、レーザスリット光に固有の照明斑を補
正して検査精度を向上させることができる。また、この
ようなバンドパス・フィルタを配置することにより、外
乱となる背景光を遮断してスリット状の光切断像のみを
明瞭に撮影できるという副次的な効果も奏される。FIG. 3 shows the result of illumination spot correction by the bandpass filter used in this embodiment. 3A shows the light quantity density distribution of the reflected light before passing through the bandpass filter 4, and FIG. 3B shows the bandpass filter 4.
4 shows the light amount density distribution after passing through the. In this way, by shifting the transmission center wavelength of the bandpass filter 4 to the long wavelength side by an appropriate value and setting the half width to an appropriate value, the illumination unevenness unique to the laser slit light is corrected and the inspection accuracy is improved. Can be improved. In addition, by arranging such a bandpass filter, there is also a secondary effect that background light that becomes disturbance can be blocked and only a slit-shaped light section image can be clearly captured.
【００１６】なお、光学的バンドパス・フィルタ４を、
被検査物体Ｔと撮影装置２との間に配置する構成を説明
した。しかしながら、同一の光学的特性のバンドパス・
フィルタ４を、図１中の４’で示すように、照射装置１
と被検査物体との間に配置しても同様の効果が得られる
ことは明らかである。The optical bandpass filter 4 is
The configuration arranged between the inspected object T and the imaging device 2 has been described. However, a bandpass with the same optical characteristics
The filter 4 is, as indicated by 4'in FIG. 1, an irradiation device 1
It is obvious that the same effect can be obtained by disposing it between the inspection object and the inspection object.
【００１７】ところで、従来の光切断法による物体の形
状の検査装置では、光切断像中の凸部稜線が欠落してし
まうという問題がある。このような凸部稜線の欠落の原
因を図４を参照しながら説明する。図４は、被検査物体
Ｔの表面に存在する凸部によって反射光がどのような光
路をたどるかを例示している。ロッドレンズで拡大され
たレーザスリット光が凸部に照射されると、ここで生じ
る反射光βは凸部稜線面に立てた法線の周りに対称とな
るため、平坦部で生じた反射光γよりも外側に向かうこ
とになる。このため、被検査物体Ｔと撮影装置２との距
離が大きくなるにつれて、凸部稜線で生じた外側に向か
う反射光は撮影装置２の受光レンズ２ａに入射できなく
なり、切断画像は図５（Ａ）に示すような凸部の稜線が
欠落してしまい、形状検査が不能となった。By the way, the conventional apparatus for inspecting the shape of an object by the light-section method has a problem that the ridgeline of the convex portion in the light-section image is missing. The cause of such a missing ridgeline of the convex portion will be described with reference to FIG. FIG. 4 exemplifies what kind of optical path the reflected light follows due to the convex portions existing on the surface of the inspection object T. When the laser slit light magnified by the rod lens is applied to the convex portion, the reflected light β generated here becomes symmetrical around the normal line standing on the ridge line of the convex portion, so the reflected light γ generated at the flat portion Will be more outward than. For this reason, as the distance between the object T to be inspected and the image capturing apparatus 2 increases, the outward reflected light generated at the ridge of the convex portion cannot enter the light receiving lens 2a of the image capturing apparatus 2, and the cut image is shown in FIG. The ridgeline of the convex portion as shown in) was missing, and the shape inspection was impossible.
【００１８】本発明者の実験結果によれば、被検査物体
Ｔと撮影装置２の受光レンズ２ａの主面との距離を受光
レンズ２ａの有効径の 10 倍以内の範囲に設定すること
により上記凸部の稜線の欠落を有効に防止できることが
確認された。図１に示した実施例では、上記距離を受光
レンズ２ａの有効径の３倍に設定することにより図５の
（Ｂ）に示すように、稜線の形状を十分把握可能な画像
を得ることができた。被検査物体Ｔと受光レンズ２ａの
主面との距離が受光レンズ２ａの有効径の10倍を超える
と、検査画像は図５（Ａ）に示すように凸部の稜線が欠
落してしまい形状検査は不可能となる。According to the results of experiments conducted by the present inventor, the distance between the object T to be inspected and the main surface of the light receiving lens 2a of the image pickup apparatus 2 is set within the range of 10 times the effective diameter of the light receiving lens 2a. It was confirmed that the lack of the ridgeline of the convex portion can be effectively prevented. In the embodiment shown in FIG. 1, by setting the above distance to be three times the effective diameter of the light receiving lens 2a, it is possible to obtain an image in which the shape of the ridge line can be sufficiently grasped, as shown in FIG. 5B. did it. When the distance between the object T to be inspected and the main surface of the light receiving lens 2a exceeds 10 times the effective diameter of the light receiving lens 2a, the inspection image has a shape in which the ridge line of the convex portion is missing as shown in FIG. 5 (A). Inspection becomes impossible.
【００１９】さらに、従来の形状検査装置では、鮮明な
光切断画像を得るために、受光レンズ２ａの焦点Ｆにア
パチァを配置することにより、この焦点Ｆを通過した反
射光のみを集光して撮像素子に結像させていた。しかし
ながら、受光レンズ２ａと被検査物体Ｔとの距離を短縮
することにより凸部で生じた反射光を受光レンズ２ａに
入射できるようにしても、図４中の光線βで例示するよ
うに、受光レンズの焦点Ｆに配置されたアパチァに阻ま
れて撮像素子に到達することができなくなる。このよう
に、従来のアパチァの構造と配置のままでは、受光レン
ズと被検査物体との距離を短縮しても、撮影される切断
画像には図５（Ａ）に例示するような凸部の稜線の欠落
した画像となる。Further, in the conventional shape inspection apparatus, in order to obtain a clear light section image, an aperture is arranged at the focal point F of the light receiving lens 2a so that only the reflected light passing through this focal point F is condensed. The image was formed on the image sensor. However, even if the reflected light generated at the convex portion can be made incident on the light receiving lens 2a by shortening the distance between the light receiving lens 2a and the object T to be inspected, as shown by the ray β in FIG. The aperture located at the focal point F of the lens prevents the image sensor from reaching the image sensor. Thus, with the conventional structure and arrangement of the apertures, even if the distance between the light receiving lens and the object to be inspected is shortened, the cut image to be photographed has a convex portion as illustrated in FIG. The image has missing edges.
【００２０】そこで、本発明の検査装置では、凸部稜線
の欠落を防止するために、受光レンズの焦点Ｆから撮像
面（撮像素子の表面）側にずらした位置にこのアパチァ
２ｃを配置している。これによって焦点Ｆのやや後方を
通過する凸部からの反射光が撮像素子２ｂの表面まで到
達できるようになると共に、他の方向から入ってくる不
要な雑音成分が遮断される。この構成によれば、稜線の
欠落が有効に防止でき高精度な形状検査が可能になる。Therefore, in the inspection apparatus of the present invention, this aperture 2c is arranged at a position displaced from the focal point F of the light receiving lens toward the image pickup surface (the surface of the image pickup element) in order to prevent the projection ridgeline from being missing. There is. As a result, the reflected light from the convex portion that passes slightly behind the focus F can reach the surface of the image sensor 2b, and unnecessary noise components coming from other directions are blocked. According to this configuration, it is possible to effectively prevent the ridgeline from being lost and to perform a highly accurate shape inspection.
【００２１】以上、撮影した光切断画像を表示装置３に
表示して目視検査を行う場合の構成について説明した。
しかしながら、表示検査物体表面の形状に応じて変形さ
れた光切断画像を三角測量の原理を用いて解析する画像
処理装置を撮影装置２の後段に配置したり、さらに、こ
のような画像処理装置によるよる解析結果から、物体の
表面に所定値以上の疵や規格外寸法が出現した場合など
には警報を発する警報発生装置などを追加した自動検査
システムなどを構成することもできる。The configuration for displaying the photographed light-section image on the display device 3 for visual inspection has been described above.
However, an image processing device for analyzing the light section image deformed according to the shape of the surface of the display inspection object by using the principle of triangulation is arranged in the latter stage of the photographing device 2, and further, by such an image processing device. According to the analysis result, it is possible to configure an automatic inspection system or the like in which an alarm generation device or the like that issues an alarm when a flaw or a nonstandard dimension of a predetermined value or more appears on the surface of the object is added.
【００２２】[0022]
【発明の効果】以上詳細に説明したように、本発明の検
査装置によれば、撮影装置に入射するスリット状の光切
断像中に出現する照明斑がバンドパス・フィルタの透過
率の入射角依存性によって補正されて均一化される。こ
のため、画像中央部から端部まで均一な検査が可能とな
った。As described in detail above, according to the inspection apparatus of the present invention, the illumination spots appearing in the slit-shaped light section image incident on the image pickup apparatus are incident angles of transmittance of the bandpass filter. It is corrected by the dependency and uniformed. Therefore, it is possible to perform a uniform inspection from the center of the image to the end.
【００２３】また、撮影装置を被検査物体との距離が受
光レンズの有効径の10倍以内になるように接近させて配
置すると共に、アパチァを受光レンズの焦点から撮像面
側にずらして配置することにより、被検査物体表面の凹
凸側面で生じた反射光を撮像面まで到達させる構成であ
るから、従来困難であった凹凸側面の様子を正確に検査
することができた。Further, the photographing device is arranged so as to be close to the object to be inspected within 10 times the effective diameter of the light receiving lens, and the aperture is arranged so as to be shifted from the focus of the light receiving lens to the image pickup surface side. Thus, since the reflected light generated on the uneven side surface of the surface of the object to be inspected reaches the image pickup surface, the state of the uneven side surface, which was difficult in the past, can be accurately inspected.
【図１】本発明の一実施例に係わる物体の検査装置の構
成を示す図である。FIG. 1 is a diagram showing a configuration of an object inspection apparatus according to an embodiment of the present invention.
【図２】図１のバンドパス・フィルタ４に入射するレー
ザ光の入射角と透過率との関係を示す図である。FIG. 2 is a diagram showing a relationship between an incident angle and a transmittance of laser light incident on the bandpass filter 4 of FIG.
【図３】図１のバンドパス・フィルタ４に入射する前後
のスリット状レーザ光の光量密度分布を示す図である。3 is a diagram showing a light quantity density distribution of slit-shaped laser light before and after being incident on the bandpass filter 4 of FIG.
【図４】光検査物体の平坦部と凸部で反射されたレーザ
光線がたどる光跡を比較して示す図である。FIG. 4 is a view showing, in comparison, light traces of a laser beam reflected by a flat portion and a convex portion of an optical inspection object.
【図５】従来の検査装置による凸部の検査結果（Ａ）と
上記実施例の検査装置による凸部の検査結果を比較して
示す図である。FIG. 5 is a diagram showing a comparison between the inspection result (A) of the convex portion by the conventional inspection device and the inspection result of the convex portion by the inspection device of the above-described embodiment.
１ 照射装置 1a レーザ発光素子 1b ロッドレンズ 2 撮影装置 2a 受光レンズ 2b 撮像素子 2c アパチァ 3 表示装置 4 バンドパス・フィルタ T 被検査物体 1 Irradiation device 1a Laser light emitting element 1b Rod lens 2 Imaging device 2a Light receiving lens 2b Imaging element 2c Aperture 3 Display device 4 Bandpass filter T Object to be inspected
Claims (4)
通すことにより線状に変形させながら拡大したスリット
状のレーザ光を検査対象の物体に照射するレーザ光照射
装置と、物体に照射されその表面の形状に従って変形さ
れたスリット状のレーザ光を撮影する撮影装置とを備え
た物体の形状検査装置において、 前記スリット状のレーザ光よりもほぼ 10nm 〜40nm 長
い波長の透過中心波長とほぼ 10nm 〜100nm の半値幅と
を有するバンドパス・フィルタを、前記スリット状のレ
ーザ光の入射角がこのスリットの中央部分についてはほ
ぼ0 o 、両端部分についてはほぼ30o 以下となるように
して前記照射装置と前記撮影装置との間に設置したこと
を特徴とする物体の形状検査装置。1. A laser beam irradiating device for irradiating an object to be inspected with a slit-shaped laser beam expanded while being linearly deformed by passing through a rod lens or a cylindrical lens, and according to the shape of the surface irradiated on the object. In an object shape inspection device equipped with a photographing device for photographing the deformed slit-shaped laser light, a transmission center wavelength of a wavelength approximately 10 nm to 40 nm longer than the slit-shaped laser light and a half-value width of approximately 10 nm to 100 nm. The irradiation device and the photographing device are configured so that the incident angle of the slit-shaped laser light is approximately 0 ° at the central portion of the slit and approximately 30 ° or less at both end portions of the bandpass filter having A shape inspection device for an object, which is installed between and.
照射領域との距離がこの受光レンズの有効径の10倍を超
えない位置に設置されると共に、この受光レンズの焦点
から撮像面側にずらしてアパチァが設置されたことを特
徴とする物体の形状検査装置。2. The image pickup device according to claim 1, wherein the distance between the main plane of the light receiving lens and the irradiation area on the object does not exceed 10 times the effective diameter of the light receiving lens, An object shape inspection apparatus, wherein an aperture is installed by displacing from the focus of the light receiving lens toward the imaging surface side.
表示する表示部を更に備えたことを特徴とする物体の形
状検査装置。3. The object shape inspection device according to claim 1, further comprising a display unit that displays an image of the slit-shaped laser light imaged by the imaging device.
ら三角測量の原理に基づき物体の形状を検出する形状検
出部を更に備えたことを特徴とする物体の形状検査装
置。4. The shape detection unit according to claim 1, further comprising a shape detection unit that detects the shape of the object based on the principle of triangulation from the image of the slit-shaped laser light photographed by the photographing device. Shape inspection device for objects.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10068794A JPH07280532A (en) | 1994-04-14 | 1994-04-14 | Shape inspector for object |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10068794A JPH07280532A (en) | 1994-04-14 | 1994-04-14 | Shape inspector for object |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07280532A true JPH07280532A (en) | 1995-10-27 |
Family
ID=14280651
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10068794A Pending JPH07280532A (en) | 1994-04-14 | 1994-04-14 | Shape inspector for object |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07280532A (en) |
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| US6683675B2 (en) | 2000-10-30 | 2004-01-27 | Honda Giken Kogyo Kabushiki Kaisha | Distance measuring apparatus and distance measuring method |
| JP2004340822A (en) * | 2003-05-16 | 2004-12-02 | Fuji Heavy Ind Ltd | Apparatus for detecting foreign substances and method of detecting foreign substances |
| WO2005103608A1 (en) * | 2004-04-21 | 2005-11-03 | Remote Vision Solutions Pty Ltd | Continuous surface deformation measurement |
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| JP2012242134A (en) * | 2011-05-16 | 2012-12-10 | Jfe Steel Corp | Shape measurement device and optical filter used for the same |
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| JP2004340822A (en) * | 2003-05-16 | 2004-12-02 | Fuji Heavy Ind Ltd | Apparatus for detecting foreign substances and method of detecting foreign substances |
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