JP2019039798A - Metal strip surface inspection method and inspection apparatus - Google Patents
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Abstract
【課題】表面欠陥の検出能力および分別能力に優れる金属帯表面の検査方法及び検査装置を提供すること。【解決手段】走行する金属帯の表面の幅方向同一ラインに、３つ以上の線光源からのそれぞれ波長の異なる光をそれぞれ異なる方向から平行照射し、前記照射されたラインを、前記光を検出可能なラインスキャンカメラでスキャンしつつ撮像する金属帯表面の検査方法であって、前記３つ以上の線光源は、それぞれ金属帯の幅方向に平行に設置され、前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯進行方向の正面から見て金属帯幅方向に対し斜めから光を平行照射し、前記金属帯の表面の幅方向同一ライン上の同一点を基点とし、前記基点から光照射面までの前記３つ以上の線光源からそれぞれ平行照射された光の光路長が等しい金属帯表面の検査方法。【選択図】図１PROBLEM TO BE SOLVED: To provide an inspection method and an inspection apparatus for a metal strip surface having excellent surface defect detecting ability and sorting ability. SOLUTION: Lights having different wavelengths from three or more line light sources are irradiated in parallel on the same line in the width direction of the surface of a traveling metal band from different directions, and the irradiated line detects the light. A possible line scan method, which is a method of inspecting the surface of a metal band while scanning with a camera. The three or more line light sources are installed in parallel with each other in the width direction of the metal band, and the three or more line light sources are installed. Of these, at least two line light sources irradiate light in parallel with respect to the width direction of the metal band when viewed from the front in the traveling direction of the metal band, and use the same point on the same line in the width direction of the surface of the metal band as a base point. A method for inspecting the surface of a metal band having the same optical path length of light emitted in parallel from the three or more line light sources from a base point to a light irradiation surface. [Selection diagram] Fig. 1
Description
本発明は、金属帯表面の検査方法および検査装置に関する。本発明は、特に連続ラインによって製造される金属帯表面の表面欠陥を検出する検査方法および検査装置に関する。 The present invention relates to a metal strip surface inspection method and inspection apparatus. The present invention particularly relates to an inspection method and an inspection apparatus for detecting surface defects on the surface of a metal strip manufactured by a continuous line.
従来の金属帯の連続ラインに設置される金属帯表面の検査装置は、一つの光源から検査箇所を照射し、単体のカメラ或いは複数のカメラによって撮像する方法での検査が行われている。（例えば、特許文献１参照。）
また、特許文献２には、ＲＧＢ（赤緑青）各々の環状光源を用いて、その中心からの反射像をカラーカメラで撮像する方法が記載されている。
特許文献３には、青、黄、赤の三原色光線を用いて圧延製品または圧延ロール表面の疵を検出する装置が記載されている。
特許文献４には、ＲＧＢ光源を用いてスラブ等の製品の表面特徴に関する情報を確定および記憶する方法が記載されている。
特許文献５には、ＲＧＢの３原色光源を用いて対象物表面の疵を検知する装置が記載されている。
A conventional metal strip surface inspection apparatus installed on a continuous line of metal strips is inspected by a method of irradiating an inspection location from a single light source and imaging with a single camera or a plurality of cameras. (For example, refer to Patent Document 1.)
Further, Patent Document 2 describes a method of capturing a reflection image from the center using an RGB (red, green, and blue) annular light source with a color camera.
Patent Document 3 describes an apparatus for detecting wrinkles on the surface of a rolled product or a rolling roll using three primary colors of blue, yellow, and red.
Patent Document 4 describes a method for determining and storing information on surface characteristics of a product such as a slab using an RGB light source.
Patent Document 5 describes an apparatus for detecting wrinkles on the surface of an object using three primary color light sources of RGB.
金属帯の連続ラインに設置される金属帯表面の検査装置としては、一つの光源によって検査箇所を照射し、それに対して単体或いは複数のカメラによって撮像を行う構成が一般的である。金属帯表面の検査装置によって、金属帯表面に生じた多様な欠陥を検出する場合、噛み疵等の凹凸性の表面欠陥については複数の正反射光による撮像を得ることでより詳細な特定が可能となる。また、鍍金ムラやテンパーカラー等の変色性欠陥については、ＲＧＢそれぞれの色要素を検出するカラー撮影が有効となる。 As a metal band surface inspection apparatus installed in a continuous line of metal bands, a configuration is generally used in which an inspection location is irradiated with a single light source, and an image is picked up by a single camera or a plurality of cameras. When detecting various defects generated on the surface of the metal band using a metal band surface inspection device, more detailed identification of uneven surface defects such as bites can be obtained by obtaining images with multiple specular reflection lights. It becomes. In addition, for color-changing defects such as plating unevenness and temper color, color imaging for detecting each RGB color element is effective.
しかし、従来方法では、そのカラーカメラによる撮像は変色などの有色性の表面欠陥に対しては有効であるものの、それ以外の撮像は金属帯表面の欠陥部分での変化が比較的小さく、モノクロによる撮像の場合とほぼ同様であり性能の向上をあまり望めなかった。一方でＲＧＢそれぞれ個々の明度情報を取得する事から情報量が三倍以上に増加し、これらを利用しようとする場合、情報処理の負担が大幅に増加する為、増加した情報を充分に活用できないという問題が存在した。 However, in the conventional method, the imaging by the color camera is effective for colored surface defects such as discoloration, but the other imaging has a relatively small change in the defective portion on the surface of the metal band, and is monochrome. It was almost the same as in the case of imaging and could not be expected to improve performance. On the other hand, the amount of information increases by a factor of three or more due to the acquisition of individual brightness information for each RGB, and when trying to use these, the burden of information processing increases significantly, so the increased information cannot be fully utilized. There was a problem.
また、単一の光源を用いた従来のモノクロカメラ及びカラーカメラによる凹凸性及び表面性状由来の欠陥の検出においては、その撮影画像は欠陥位置の反射明度しか画像に反映されないため、表面欠陥の周囲の形状だけでなく、その内部の形状等を正確に認識する事が難しく、表面欠陥の検出能力及び分別能力の向上の障害となっていた。 In addition, in the detection of defects due to unevenness and surface properties by conventional monochrome cameras and color cameras using a single light source, the captured image reflects only the reflected brightness at the defect location, so the surroundings of the surface defect It was difficult to accurately recognize not only the shape of the inside but also the shape of the inside of the surface, which hindered the improvement of the surface defect detection ability and separation ability.
更に、表面検査で照射する単色または白色光源とカメラを金属帯進行方向に平行な方向に配置した場合、幅方向の凹凸に対しては反射方向の変化が小さくて感度が低いという問題がある。一方で、単色または白色光源とカメラを金属帯の幅方向に平行な方向に配置した場合、金属帯進行方向の凹凸欠陥に対する感度が低下する。また、同一色の単色光または白色光を同時に二方向から照射した場合はカメラが二つの光源から照射された光を判別できない為に効果が無く、いずれか一方から照射された単色光または白色光による信号に絞らざるを得なかった。 Furthermore, when the monochromatic or white light source and the camera to be irradiated in the surface inspection are arranged in a direction parallel to the metal band traveling direction, there is a problem that the change in the reflection direction is small and the sensitivity is low with respect to the unevenness in the width direction. On the other hand, when the monochromatic or white light source and the camera are arranged in the direction parallel to the width direction of the metal band, the sensitivity to the uneven defect in the metal band traveling direction is lowered. Also, if the same color monochromatic light or white light is emitted from two directions at the same time, the camera cannot distinguish the light emitted from the two light sources, so there is no effect. Monochromatic light or white light emitted from either one I had to focus on the signal.
また、特許文献２に記載のＲＧＢ各々の環状光源を用いると、カラーカメラは垂直面を撮像せざるを得ず、その環の中央には、３６０°あらゆる方向からＲＧＢの各光が照射されるため、反射光が干渉して、単色光の環状光源を照射した場合と同様に特定の方向に特徴を持つ金属帯表面の凹凸欠陥はきわ立って明瞭になるが、その特定方向と垂直な方向の凹凸欠陥は検出しにくくなり、場合によっては全く検出されない課題を有していた。
また、環状光源を用いると、照射する部位は環状光源の中心部に限定されるため、金属帯の幅方向全体に広く撮像することは複数の装置を必要とし多大なコストが掛かるため困難であった。
In addition, when each of the RGB light sources described in Patent Document 2 is used, the color camera is forced to pick up a vertical plane, and the center of the ring is irradiated with each light of RGB from all directions of 360 °. Therefore, the irregularities on the surface of the metal band, which are characterized by a specific direction, become distinctly clear, as in the case where the reflected light interferes and irradiates an annular light source of monochromatic light, but the direction perpendicular to the specific direction In this case, there is a problem that it is difficult to detect the uneven defect of the above-mentioned and is not detected at all.
In addition, when an annular light source is used, the portion to be irradiated is limited to the central portion of the annular light source, and thus it is difficult to image widely in the entire width direction of the metal strip because a plurality of devices are required and a great deal of cost is required. It was.
特許文献３では、青、黄、赤の照射装置を用いて圧延製品または圧延ロール表面を照射しているが、圧延製品または圧延ロール表面の同一ラインを照射してもおらず、しかも、それぞれの照射装置が圧延製品または圧延ロール表面の幅方向に平行に設置されていないことから（第２図、第３図）、照射装置から照射された光の圧延製品または圧延ロール表面までの光路長がばらばらで、３原色による疵の判定の精度が著しく低下していた。また、特許文献４、５においても、表面の同一ラインを照射していないため、特許文献３と同様、疵の判定の精度が著しく低下していた。 In Patent Document 3, the surface of the rolled product or the rolling roll is irradiated using a blue, yellow, and red irradiation device, but the same line on the surface of the rolled product or the rolling roll is not irradiated. Since the irradiation device is not installed in parallel with the width direction of the rolled product or the roll surface (FIGS. 2 and 3), the optical path length of the light irradiated from the irradiation device to the rolled product or the roll surface is The accuracy of the determination of wrinkles with the three primary colors was significantly reduced. Also, in Patent Documents 4 and 5, since the same line on the surface is not irradiated, the accuracy of wrinkle determination is significantly reduced as in Patent Document 3.
本発明は、表面欠陥の検出能力および分別能力に優れる金属帯表面の検査方法及び検査装置を提供することを目的とする。 It is an object of the present invention to provide a metal strip surface inspection method and inspection apparatus having excellent surface defect detection ability and separation ability.
本発明は、以下の構成を備える。
［１］走行する金属帯の表面の幅方向同一ラインに、３つ以上の線光源からのそれぞれ波長の異なる光をそれぞれ異なる方向から平行照射し、前記照射されたラインを、前記光を検出可能なラインスキャンカメラでスキャンしつつ撮像する金属帯表面の検査方法であって、前記３つ以上の線光源は、それぞれ金属帯の幅方向に平行に設置され、前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯進行方向の正面から見て金属帯幅方向に対し斜めから光を平行照射し、前記金属帯の表面の幅方向同一ライン上の同一点を基点とし、前記基点から光照射面までの前記３つ以上の線光源からそれぞれ平行照射された光の光路長が等しいことを特徴とする金属帯表面の検査方法。
［２］前記３つ以上の線光源のうち少なくとも１つの線光源は、金属帯上方から見て金属帯進行方向に平行に光を平行照射することを特徴とする［１］に記載の金属帯表面の検査方法。
［３］前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯上方から見て金属帯進行方向に対し斜めから光を平行照射することを特徴とする［１］または［２］に記載の金属帯表面の検査方法。
［４］前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯上方から見て前記照射されたラインと同一直線上から光を平行照射することを特徴とする［１］〜［３］のいずれかに記載の金属帯表面の検査方法。
［５］前記ラインスキャンカメラの光軸を金属帯表面垂直方向とし、前記３つ以上の線光源は、前記ラインスキャンカメラの光軸廻りにそれぞれ均等な角度からなる方向から光路長を等しくして照射することを特徴とする［１］〜［４］のいずれかに記載の金属帯表面の検査方法。
［６］前記３つ以上の線光源が、可視光領域の波長を有する光を照射する線光源を含むことを特徴とする［１］〜［５］のいずれかに記載の金属帯表面の検査方法。
［７］前記３つ以上の線光源が、赤、緑、青の光を照射する線光源を含むことを特徴とする［１］〜［６］のいずれかに記載の金属帯表面の検査方法。
［８］前記３つ以上の線光源が、赤外領域の波長を有する光を照射する線光源を含むことを特徴とする［１］〜［７］のいずれかに記載の金属帯表面の検査方法。
［９］前記３つ以上の線光源が、紫外領域の波長を有する光を照射する線光源を含むことを特徴とする［１］〜［８］のいずれかに記載の金属帯表面の検査方法。
［１０］走行する金属帯の表面の幅方向同一ラインにライン状に光を照射する照射手段と、前記照射手段により照射されたラインをスキャンしつつ撮像する前記光を検出可能なラインスキャンカメラと、を備え、前記照射手段は、それぞれ波長の異なる光を平行照射する３つ以上の線光源を有し、前記３つ以上の線光源は、それぞれ金属帯の幅方向に平行に設置され、前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯進行方向の正面から見て金属帯幅方向に対し斜めから光を平行照射し、前記金属帯の表面の幅方向同一ライン上の同一点を基点とし、前記基点から光照射面までの前記３つ以上の線光源からそれぞれ平行照射された光の光路長が等しいことを特徴とする金属帯表面の検査装置。
［１１］前記３つ以上の線光源のうち少なくとも１つの線光源は、金属帯上方から見て金属帯進行方向に平行に光を平行照射することを特徴とする［１０］に記載の金属帯表面の検査装置。
［１２］前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯上方から見て金属帯進行方向に対し斜めから光を平行照射することを特徴とする［１０］または［１１］に記載の金属帯表面の検査装置。
［１３］前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯上方から見て前記照射されたラインと同一直線上から光を平行照射することを特徴とする［１０］〜［１２］のいずれかに記載の金属帯表面の検査装置。
［１４］前記ラインスキャンカメラの光軸を金属帯表面垂直方向とし、前記３つ以上の線光源は、前記ラインスキャンカメラの光軸廻りにそれぞれ均等な角度からなる方向から光路長を等しくして照射することを特徴とする［１０］〜［１３］のいずれかに記載の金属帯表面の検査装置。
［１５］前記３つ以上の線光源が、可視光領域の波長を有する光を照射する線光源を含むことを特徴とする［１０］〜［１４］のいずれかに記載の金属帯表面の検査装置。
［１６］前記３つ以上の線光源が、赤、緑、青の光を照射する線光源を含むことを特徴とする［１０］〜［１５］のいずれかに記載の金属帯表面の検査装置。
［１７］前記３つ以上の線光源が、赤外領域の波長を有する光を照射する線光源を含むことを特徴とする［１０］〜［１６］のいずれかに記載の金属帯表面の検査装置。
［１８］前記３つ以上の線光源が、紫外領域の波長を有する光を照射する線光源を含むことを特徴とする［１０］〜［１７］のいずれかに記載の金属帯表面の検査装置。
The present invention has the following configuration.
[1] The same line in the width direction of the surface of the traveling metal band can be irradiated in parallel with different wavelengths of light from three or more line light sources from different directions, and the irradiated line can detect the light. A method for inspecting the surface of a metal strip that is imaged while scanning with a simple line scan camera, wherein the three or more line light sources are respectively installed in parallel to the width direction of the metal strip, and are among the three or more line light sources. The at least two line light sources irradiate light parallel to the metal band width direction when viewed from the front in the metal band traveling direction, and use the same point on the same line in the width direction of the surface of the metal band as the base point. A method for inspecting the surface of a metal band, characterized in that the optical path lengths of lights irradiated in parallel from the three or more line light sources from the light source to the light irradiation surface are equal.
[2] The metal strip according to [1], wherein at least one line light source among the three or more line light sources emits light parallel to the traveling direction of the metal strip as viewed from above the metal strip. Surface inspection method.
[3] At least two line light sources among the three or more line light sources emit light parallel to the metal band traveling direction as viewed from above the metal band [1] or [2] The inspection method of the metal belt surface as described in 2.
[4] Of the three or more line light sources, at least two line light sources emit light in parallel from the same straight line as the irradiated line when viewed from above the metal strip. [3] The method for inspecting a metal strip surface according to any one of [3].
[5] The optical axis of the line scan camera is the metal band surface vertical direction, and the three or more line light sources have the same optical path length from the direction of an equal angle around the optical axis of the line scan camera. The method for inspecting a metal strip surface according to any one of [1] to [4], wherein irradiation is performed.
[6] The metal strip surface inspection according to any one of [1] to [5], wherein the three or more line light sources include a line light source that irradiates light having a wavelength in a visible light region. Method.
[7] The metal strip surface inspection method according to any one of [1] to [6], wherein the three or more line light sources include a line light source that emits red, green, and blue light. .
[8] The metal strip surface inspection according to any one of [1] to [7], wherein the three or more line light sources include a line light source that emits light having a wavelength in an infrared region. Method.
[9] The method for inspecting a metal strip surface according to any one of [1] to [8], wherein the three or more line light sources include a line light source that emits light having a wavelength in the ultraviolet region. .
[10] Irradiation means for irradiating light in a line shape on the same line in the width direction of the surface of the traveling metal strip, and a line scan camera capable of detecting the light imaged while scanning the line irradiated by the irradiation means; The irradiating means includes three or more line light sources that irradiate light beams having different wavelengths, respectively, and the three or more line light sources are installed in parallel in the width direction of the metal strip, At least two of the three or more line light sources emit light parallel to the metal band width direction when viewed from the front in the metal band traveling direction, and are on the same line in the width direction of the surface of the metal band. An inspection apparatus for a surface of a metal band, characterized in that the optical path lengths of lights irradiated in parallel from the three or more line light sources from the base point to the light irradiation surface are the same as the base point, and are equal to each other.
[11] The metal strip according to [10], wherein at least one line light source among the three or more line light sources irradiates light parallel to the traveling direction of the metal strip as viewed from above the metal strip. Surface inspection device.
[12] Of the three or more line light sources, at least two line light sources emit light parallel to the metal band traveling direction when viewed from above the metal band [10] or [11] The inspection apparatus of the metal strip surface as described in 2.
[13] At least two line light sources among the three or more line light sources emit light in parallel from the same straight line as the irradiated line when viewed from above the metal band. 12] The metal strip surface inspection device according to any one of [12].
[14] The optical axis of the line scan camera is the metal band surface vertical direction, and the three or more line light sources have the same optical path length from the direction of an equal angle around the optical axis of the line scan camera. Irradiating the metal strip surface inspection apparatus according to any one of [10] to [13].
[15] The metal strip surface inspection according to any one of [10] to [14], wherein the three or more line light sources include a line light source that emits light having a wavelength in the visible light region. apparatus.
[16] The metal strip surface inspection apparatus according to any one of [10] to [15], wherein the three or more line light sources include a line light source that emits red, green, and blue light. .
[17] The inspection of the metal strip surface according to any one of [10] to [16], wherein the three or more line light sources include a line light source that emits light having a wavelength in an infrared region. apparatus.
[18] The metal strip surface inspection apparatus according to any one of [10] to [17], wherein the three or more line light sources include a line light source that emits light having a wavelength in the ultraviolet region. .
本発明によれば、表面欠陥の検出能力および分別能力により優れる金属帯表面の検査方法および検査装置を提供できる。
本発明の金属帯表面の検査方法および検査装置によれば、凹凸性の表面欠陥、表面性状や有色性の表面欠陥等の金属帯の表面欠陥に対する撮像に色情報を与え、これらの欠陥の特徴を際立たせて検出できる。そのため、本発明の金属帯表面の検査方法および検査装置によれば、これらの表面欠陥を精度よく検出でき、かつ分別することができる。また、凹凸性の表面欠陥について、二次元的な情報のみならず、深さ（高さ）方向等の三次元的な形状に関する情報が得られる。
ADVANTAGE OF THE INVENTION According to this invention, the inspection method and inspection apparatus of the metal strip surface which are excellent in the detection capability and classification capability of a surface defect can be provided.
According to the inspection method and inspection apparatus for the surface of the metal strip of the present invention, color information is given to imaging for surface defects of the metal strip such as uneven surface defects, surface properties and colored surface defects, and the characteristics of these defects Can be detected. Therefore, according to the inspection method and inspection apparatus for the metal strip surface of the present invention, these surface defects can be detected with high accuracy and can be sorted. Further, regarding uneven surface defects, not only two-dimensional information but also information on a three-dimensional shape such as a depth (height) direction can be obtained.
本発明では、それぞれ波長の異なる光を照射する３つ以上の線光源を使用する。前記線光源は、表面欠陥の検出能力および分別能力を考慮して適宜に選択することができる。線光源としては、例えば、１００ｎｍ〜４００ｎｍの紫外領域の光を照射する線光源、４００ｎｍ〜８００ｎｍの可視光領域の波長を照射する線光源、８００ｎｍ〜１ｍｍの赤外領域の光を照射する線光源が挙げられる。 In the present invention, three or more line light sources that irradiate light having different wavelengths are used. The line light source can be appropriately selected in consideration of the surface defect detection ability and classification ability. Examples of the linear light source include a linear light source that irradiates light in the ultraviolet region of 100 nm to 400 nm, a linear light source that irradiates wavelengths in the visible light region of 400 nm to 800 nm, and a linear light source that irradiates light in the infrared region of 800 nm to 1 mm. Is mentioned.
１００ｎｍ〜４００ｎｍの紫外領域の光を照射する線光源としては、例えば、ＵＶ−Ａ（３１５ｎｍ〜４００ｎｍ）、ＵＶ−Ｂ（２８０ｎｍ〜３１５ｎｍ）、ＵＶ−Ｃ（１００ｎｍ〜２８０ｎｍ）の光を照射する線光源が挙げられる。 As a linear light source for irradiating light in the ultraviolet region of 100 nm to 400 nm, for example, a line for irradiating UV-A (315 nm to 400 nm), UV-B (280 nm to 315 nm), UV-C (100 nm to 280 nm) light A light source.
４００ｎｍ〜８００ｎｍの可視光領域の波長を照射する線光源としては、例えば、紫（４００ｎｍ〜４３５ｎｍ）、青（４３５ｎｍ〜４８０ｎｍ）、緑青（４８０ｎｍ〜４９０ｎｍ）、青緑（４９０ｎｍ〜５００ｎｍ）、緑（５００ｎｍ〜５６０ｎｍ）、黄緑（５６０ｎｍ〜５８０ｎｍ）、黄（５８０ｎｍ〜５９５ｎｍ）、橙（５９５ｎｍ〜６１０ｎｍ）、赤（６１０ｎｍ〜７５０ｎｍ）、赤紫（７５０ｎｍ〜８００ｎｍ）の光を照射する線光源が挙げられる。 As a linear light source for irradiating a wavelength in the visible light region of 400 nm to 800 nm, for example, purple (400 nm to 435 nm), blue (435 nm to 480 nm), green blue (480 nm to 490 nm), blue green (490 nm to 500 nm), green ( 500 nm to 560 nm), yellowish green (560 nm to 580 nm), yellow (580 nm to 595 nm), orange (595 nm to 610 nm), red (610 nm to 750 nm), red purple (750 nm to 800 nm) It is done.
８００ｎｍ〜１ｍｍの赤外領域の光を照射する線光源としては、例えば、ＩＲ−Ａ（８００ｎｍ〜１４００ｎｍ）、ＩＲ−Ｂ（１．４μｍ〜３μｍ）、ＩＲ−Ｃ（３μｍ〜１ｍｍ）の光を照射する線光源が挙げられる。 As a linear light source for irradiating light in the infrared region of 800 nm to 1 mm, for example, IR-A (800 nm to 1400 nm), IR-B (1.4 μm to 3 μm), IR-C (3 μm to 1 mm) is used. Examples include a linear light source for irradiation.
本発明では、上記のような線光源のなかから、任意に３つ以上の線光源を選択して使用することができる。表面欠陥の検出能力および分別能力がより高められる点からは、それぞれの線光源から照射される光の波長の重なりがないか、若しくは、重なりが小さいものを選択することが好ましい。さらに、取扱い性や入手の容易性などの点からは、可視光領域と赤外領域から３つ以上の線光源を選択することが好ましい。特に好ましい線光源は、青、緑、赤、ＩＲ−Ａの光を照射する線光源であり、これらの線光源を３つ以上組み合わせて使用することが好ましい。 In the present invention, it is possible to arbitrarily select and use three or more line light sources from the above-described line light sources. From the standpoint of further enhancing the ability to detect and classify surface defects, it is preferable to select one that does not overlap or has a small overlap of wavelengths of light emitted from the respective line light sources. Furthermore, it is preferable to select three or more line light sources from the visible light region and the infrared region from the viewpoint of handleability and availability. A particularly preferable line light source is a line light source that emits light of blue, green, red, and IR-A, and it is preferable to use a combination of three or more of these line light sources.
以下、本発明例の一実施形態について図面を参照しながら説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
〔第１の実施形態〕
（金属帯表面の検査装置）
図１は、本発明の一実施形態（第１の実施形態）にかかる金属帯表面の検査装置（以下、単に「検査装置」ともいう。）の実装例を示す金属帯の上方から見た平面図であり、図２は、その金属帯の幅方向から見た側面図である。
[First Embodiment]
(Metal strip surface inspection device)
FIG. 1 is a plan view of a metal band surface inspection apparatus (hereinafter also simply referred to as “inspection apparatus”) according to an embodiment (first embodiment) of the present invention as viewed from above the metal band. FIG. 2 is a side view seen from the width direction of the metal strip.
図１に示すように、本発明の検査装置は、矢印６の方向に走行する金属帯５の表面をライン状に可視光を照射する照射手段（１、２、３）と、前記照射手段により照射されたラインをスキャンしつつ撮像するカラーラインスキャンカメラ４を備える。以下、カラーラインスキャンカメラ４がスキャン（走査）する金属帯５の表面のラインを、スキャンラインＳという。 As shown in FIG. 1, the inspection apparatus of the present invention includes an irradiation means (1, 2, 3) for irradiating the surface of a metal strip 5 traveling in the direction of an arrow 6 with visible light in a line shape, and the irradiation means. A color line scan camera 4 that captures an image while scanning the irradiated line is provided. Hereinafter, the line on the surface of the metal strip 5 scanned by the color line scan camera 4 is referred to as a scan line S.
本実施形態において照射手段は、赤色光（Ｒ光）を照射する第１の線光源１（以下、単に「線光源１」ともいう。）と、緑色光（Ｇ光）を照射する第２の線光源２（以下、単に「線光源２」ともいう。）と、青色光（Ｂ光）を照射する第３の線光源３（以下、単に「線光源３」ともいう）と、を有する（図１）。なお、赤色光、緑色光、青色光の各線光源の色は、図１にこだわるものではなく、いずれかの線光源がそれぞれ赤色光、緑色光、青色光であればよい。また、金属帯５の走行方向は矢印６の反対方向であってもよい。 In the present embodiment, the irradiating means emits a first line light source 1 that emits red light (R light) (hereinafter also simply referred to as “line light source 1”) and a second line that emits green light (G light). A linear light source 2 (hereinafter also simply referred to as “line light source 2”) and a third linear light source 3 that emits blue light (B light) (hereinafter also simply referred to as “line light source 3”) ( FIG. 1). Note that the color of each line light source of red light, green light, and blue light is not particularly limited to FIG. 1, and any one of the line light sources may be red light, green light, and blue light. Further, the traveling direction of the metal strip 5 may be the direction opposite to the arrow 6.
本実施形態において線光源１は、カラーラインスキャンカメラ４に対して金属帯５の上流側に配置されている。図３は、前記線光源１による照射パターンを説明する模式図であり、図３（ａ）は、線光源１による照射パターンを金属帯５の上方からみた平面図、図３（ｂ）は、線光源１による照射パターンを金属帯５の進行方向である正面からみた正面図である。 In the present embodiment, the line light source 1 is disposed on the upstream side of the metal strip 5 with respect to the color line scan camera 4. FIG. 3 is a schematic diagram for explaining an irradiation pattern by the line light source 1. FIG. 3A is a plan view of the irradiation pattern by the line light source 1 as viewed from above the metal band 5, and FIG. It is the front view which looked at the irradiation pattern by the line light source 1 from the front which is the advancing direction of the metal strip.
図１、図３に示すように、線光源１は、例えばそのＲ光の金属帯５への照射面が金属帯５の幅方向に平行になるように配置されている。本実施形態においては、線光源１として、例えば、Ｒ光を発光する単色光源であるＬＥＤを用いている。線光源１は、ＬＥＤ発光部が細長くライン状に並んで構成されており、金属帯５の表面を幅方向に均等にライン状に平行照射を可能とする。 As shown in FIGS. 1 and 3, the linear light source 1 is arranged so that, for example, the irradiation surface of the R light on the metal band 5 is parallel to the width direction of the metal band 5. In the present embodiment, for example, an LED that is a monochromatic light source that emits R light is used as the linear light source 1. The line light source 1 includes LED light emitting portions that are elongated and arranged in a line, and enables the surface of the metal strip 5 to be irradiated in parallel in a line in the width direction.
図１、図３に示すように、線光源１から照射されるＲ光は、その照射方向が金属帯５の進行方向６に平行な平行照射である。すなわち、図１、図３（ａ）に示すように、線光源１は、平面視で金属帯５の進行方向６に平行に特定波長領域の光（例えばＲ光）を照射し、スキャンラインＳを幅方向に均等に平行照射する。また、図３（ｂ）に示すように、線光源１は、正面視において、上方から下方に向けて金属帯５の幅方向に対して垂直にＲ光を照射し、スキャンラインＳを幅方向に均等に平行照射する。 As shown in FIGS. 1 and 3, the R light emitted from the line light source 1 is parallel irradiation whose irradiation direction is parallel to the traveling direction 6 of the metal strip 5. That is, as shown in FIGS. 1 and 3A, the line light source 1 irradiates light (for example, R light) in a specific wavelength region in parallel with the traveling direction 6 of the metal band 5 in plan view, and the scan line S Are evenly irradiated in the width direction. Further, as shown in FIG. 3B, the line light source 1 emits R light perpendicularly to the width direction of the metal strip 5 from the upper side to the lower side in the front view, and the scan line S in the width direction. Irradiate evenly.
また、図１に示すように、例えば、線光源２及び線光源３は、カラーラインスキャンカメラ４に対して金属帯５の下流側に配置されている。図４は、前記線光源２、３による照射パターンを説明する模式図であり、図４（ａ）は、線光源２、３による照射パターンを金属帯５の上方からみた平面図、図４（ｂ）は、線光源２、３による照射パターンを金属帯５の進行方向である正面からみた正面図である。 Further, as shown in FIG. 1, for example, the line light source 2 and the line light source 3 are arranged on the downstream side of the metal band 5 with respect to the color line scan camera 4. FIG. 4 is a schematic diagram for explaining an irradiation pattern by the line light sources 2 and 3, and FIG. 4A is a plan view of the irradiation pattern by the line light sources 2 and 3 as viewed from above the metal band 5. b) is a front view of an irradiation pattern from the line light sources 2 and 3 as seen from the front which is the traveling direction of the metal strip 5.
図１、図４に示すように、線光源２は、そのＧ光の金属帯への照射面が金属帯５の幅方向に平行に配置されている。また、線光源３は、そのＢ光の金属帯５への照射面が金属帯５の幅方向に平行に配置されている。さらに、線光源２及び線光源３は、金属帯５の幅方向に並列されており、線光源２及び線光源３の光照射面はスキャンラインＳに平行に面一とされている。なお、図２の側面図では、説明の便宜のため、線光源２及び線光源３の光照射面を面一とせず若干ずらして記載しているが、線光源２及び線光源３は面一とするものである。 As shown in FIGS. 1 and 4, in the line light source 2, the irradiation surface of the G light on the metal band is arranged in parallel to the width direction of the metal band 5. The line light source 3 is arranged such that the irradiation surface of the B light to the metal band 5 is parallel to the width direction of the metal band 5. Further, the line light source 2 and the line light source 3 are arranged in parallel in the width direction of the metal strip 5, and the light irradiation surfaces of the line light source 2 and the line light source 3 are flush with the scan line S. In the side view of FIG. 2, for convenience of explanation, the light irradiation surfaces of the line light source 2 and the line light source 3 are shown slightly shifted without being flush with each other, but the line light source 2 and the line light source 3 are flush with each other. It is what.
本実施形態においては、例えば、線光源２として、Ｇ光を発光する単色光源であるＬＥＤを用いており、線光源３として、Ｂ光を発光する単色光源であるＬＥＤを用いている。線光源２、３は、ＬＥＤ発光部が細長くライン状に並んで構成されており、それぞれ金属帯５の表面を斜め方向から幅方向均等にライン状に平行照射を可能とする。 In the present embodiment, for example, an LED that is a monochromatic light source that emits G light is used as the line light source 2, and an LED that is a monochromatic light source that emits B light is used as the line light source 3. The line light sources 2 and 3 are configured by LED light emitting portions being elongated and arranged in a line, and each of the surfaces of the metal strip 5 can be irradiated in parallel in a line from the oblique direction to the width direction.
図１、図４に示すように、線光源２、３から照射されるＧ光、Ｂ光は、それぞれ照射方向が金属帯５の進行方向６に対して傾斜している斜方平行照射である。図１、図４（ａ）に示すように、線光源２は、平面視で右斜め上方に向けてＧ光を平行に照射し、スキャンラインＳを左斜め下方向から幅方向に平行に均等に照射する。また、図４（ｂ）に示すように、線光源２は、正面視で右斜め下方に向けて金属帯５の幅方向に対し斜めからＧ光を平行に照射し、スキャンラインＳを左斜め上方から平行に幅方向に均等に照射する。 As shown in FIGS. 1 and 4, the G light and B light emitted from the line light sources 2 and 3 are obliquely parallel irradiations in which the irradiation directions are inclined with respect to the traveling direction 6 of the metal strip 5. . As shown in FIG. 1 and FIG. 4A, the line light source 2 irradiates G light in parallel toward the upper right direction in plan view, and the scan line S is evenly distributed in the width direction from the lower left direction. Irradiate. Further, as shown in FIG. 4B, the line light source 2 irradiates G light parallel to the width direction of the metal strip 5 obliquely downward to the right in front view and obliquely scans the scan line S to the left. Irradiate evenly in the width direction in parallel from above.
また、図１、図４（ａ）に示すように、線光源３は、平面視で左斜め上方に向けて平行にＢ光を照射し、スキャンラインＳを右斜め下方向から平行に幅方向に均等に照射する。また、図４（ｂ）に示すように、線光源３は、正面視で左斜め下方に向けて金属帯５の幅方向に対し斜めからＢ光を平行に照射し、スキャンラインＳを右斜め上方から平行に幅方向に均等に照射する。 As shown in FIGS. 1 and 4A, the line light source 3 irradiates B light parallel to the upper left diagonally in a plan view, and the scan line S is parallel to the right diagonally downward direction in the width direction. Irradiate evenly. Further, as shown in FIG. 4B, the line light source 3 irradiates B light parallel to the width direction of the metal strip 5 obliquely downward to the left in front view, and obliquely scans the scan line S to the right. Irradiate evenly in the width direction in parallel from above.
線光源１、線光源２、線光源３を、上記のような配置及び照射パターンとすることで、線光源１、線光源２、線光源３により、それぞれ異なる方向から、同一のスキャンラインＳを幅方向に均等に照射できる。 By setting the line light source 1, the line light source 2, and the line light source 3 as described above and the irradiation pattern, the same scan line S is generated from different directions by the line light source 1, the line light source 2, and the line light source 3. Irradiates evenly in the width direction.
図５は、本発明の一実施形態にかかる一例として線光源１、線光源２、線光源３による照射パターンを説明する模式図である。 FIG. 5 is a schematic diagram for explaining an irradiation pattern by the line light source 1, the line light source 2, and the line light source 3 as an example according to the embodiment of the present invention.
図５に示すように、本実施形態では、金属帯５の上方から見た平面視で、Ｒ光を線光源からの平行照射により金属帯５の進行方向６と平行方向に照射し、Ｇ光、Ｂ光を線光源からの斜方平行照射により金属帯５の進行方向６に対してぞれぞれ６０°傾いた方向から照射しており、全体としては１２０°ずつ均等な方向からスキャンラインＳ上の任意の点（Ｓ１、Ｓ２、・・Ｓｎ、・）を均等に照射する。さらに、この際、スキャンラインＳ上の同一点を基点として、線光源１から平行に照射されたＲ光の光照射面までの光路長ＲＬと、線光源２から平行に照射されたＧ光の光照射面までの光路長ＧＬと、線光源３から平行に照射されたＢ光の光照射面までの光路長ＢＬとが等しくなるように、線光源１、線光源２、線光源３が配置されている。そのため、Ｒ光、Ｇ光、Ｂ光により、スキャンラインＳを金属帯５の幅方向により均等に照射できる。また、スキャンラインＳでのＲ光、Ｇ光、Ｂ光の反射光の強度が同程度となり、スキャンラインＳをカラーラインスキャンカメラ４でスキャンしつつ撮像した際に、より精細な撮像が得られ、表面欠陥の検出能力がより高められる。 As shown in FIG. 5, in this embodiment, the R light is irradiated in parallel with the traveling direction 6 of the metal band 5 by parallel irradiation from the line light source in a plan view seen from above the metal band 5, and the G light. , B light is irradiated from the direction inclined by 60 ° with respect to the traveling direction 6 of the metal strip 5 by obliquely parallel irradiation from a line light source, and the scan line from 120 ° in a uniform direction as a whole. Arbitrary points (S 1 , S 2 ,... S n ,...) On S are irradiated uniformly. Furthermore, at this time, with the same point on the scan line S as a base point, the optical path length RL to the light irradiation surface of the R light irradiated in parallel from the line light source 1 and the G light irradiated in parallel from the line light source 2 of the optical path length G L to the light irradiation surface, so that the optical path length B L from the line light source 3 to the light irradiation surface of the parallel irradiated B light become equal, a linear light source 1, a line light source 2, a linear light source 3 is arranged. Therefore, the scan line S can be evenly irradiated in the width direction of the metal band 5 with R light, G light, and B light. Further, the intensities of the reflected light of the R light, G light, and B light at the scan line S are approximately the same, and when the scan line S is imaged while being scanned by the color line scan camera 4, a finer image can be obtained. In addition, the ability to detect surface defects is further enhanced.
また、図２において側面視したときの線光源１から照射された光と金属帯５表面のなす角θ１と、線光源２および線光源３から照射された光と金属帯５表面のなす角θ２は、それぞれ金属帯５の表面欠陥を検出しやすいように適宜に調整すればよいが、スキャンラインＳをより均等に照射する点やＲ光、Ｇ光、Ｂ光の反射光の強度を同程度に揃える点等から、前記θ１とθ２が同じ角度となるように調整されることが好ましい。 2, the angle θ 1 formed between the light emitted from the line light source 1 and the surface of the metal band 5 and the angle formed between the light irradiated from the line light source 2 and the line light source 3 and the surface of the metal band 5 when viewed from the side. θ 2 may be adjusted as appropriate so that surface defects of the metal band 5 can be easily detected, but the intensity of the reflected light of the R light, G light, and B light can be determined by irradiating the scan line S more evenly. It is preferable that the angles θ 1 and θ 2 are adjusted so as to have the same angle, for example, in order to make them equal.
このように照射されたスキャンラインＳを、金属帯５の上方に設置したカラーラインスキャンカメラ４で撮像する。カラーラインスキャンカメラ４は、走行する金属帯５の連続的な撮像に適している。本実施形態において、カラーラインスキャンカメラ４は、ＲＧＢの受光素子を搭載したラインスキャンカメラであり、ＲＧＢの異なる色情報を別々の素子によって個別に取得することが可能である。 The scan line S irradiated in this way is imaged by a color line scan camera 4 installed above the metal strip 5. The color line scan camera 4 is suitable for continuous imaging of the traveling metal strip 5. In the present embodiment, the color line scan camera 4 is a line scan camera equipped with RGB light receiving elements, and can acquire different color information of RGB individually by different elements.
図１に示すように、本実施形態において、カラーラインスキャンカメラ４は、平面視で金属帯５の進行方向６に対して線光源１と線光源２（線光源３）の間に配置されている。また、図２に示すように、カラーラインスキャンカメラ４は、スキャンラインＳの直上において、スキャンラインＳを撮像可能に鉛直下向きに設置するとよく、線光源１、線光源２、線光源３から照射されたＲＧＢ各光の反射光を均等に受光可能にするとよい。好ましい形態としては、カラーラインスキャンカメラ４の光軸を金属帯表面垂直方向とし、線光源１、線光源２、線光源３を前記カラーラインスキャンカメラ４の光軸廻りに１２０°ずつ異なる方向から光路長を同じにして照射する形態が挙げられる（図２、図５）。 As shown in FIG. 1, in the present embodiment, the color line scan camera 4 is arranged between the line light source 1 and the line light source 2 (line light source 3) with respect to the traveling direction 6 of the metal strip 5 in plan view. Yes. As shown in FIG. 2, the color line scan camera 4 may be installed vertically above the scan line S so that the scan line S can be imaged, and is irradiated from the line light source 1, the line light source 2, and the line light source 3. It is preferable that the reflected light of each of the RGB lights can be received evenly. As a preferred form, the optical axis of the color line scan camera 4 is set to the metal band surface vertical direction, and the line light source 1, the line light source 2 and the line light source 3 are different from each other by 120 ° around the optical axis of the color line scan camera 4. The form which irradiates by making optical path length the same is mentioned (FIG. 2, FIG. 5).
カラーラインスキャンカメラ４により得られた撮像は、適宜パーソナルコンピュータ等の演算手段に転送され処理される。そして、その結果を前記演算手段に接続されたモニタ上に表示する。 The image obtained by the color line scan camera 4 is appropriately transferred to an arithmetic means such as a personal computer for processing. Then, the result is displayed on a monitor connected to the calculation means.
以上、説明したように、本発明の一実施形態にかかる検査装置は、カラーラインスキャンカメラが撮像を行う際にＲＧＢの異なる色情報を別々の素子によって個別に取得する。本発明では、走行する金属帯の表面の連続的な撮像検査に適したカラーラインスキャンカメラを使用し、カラーラインスキャンカメラによってスキャンする金属帯のスキャンライン上を、カラーラインスキャンカメラが備えるＲＧＢの受光素子に対応したＲＧＢそれぞれの単色光源によって照射する。この時、単色光源を一つは金属帯の進行方向に平行な平行照射とし、他の二つは斜方平行照射として金属帯の進行方向に対してそれぞれ異なる方向からスキャンラインを照射するものとする。また、金属帯の進行方向でこれらの光源の照射位置から中間の位置にカラーラインスキャンカメラを設置する。これによって、均等に各方向から単色光によって照射されている状態のスキャンラインをカラーラインスキャンカメラで撮像する。 As described above, the inspection apparatus according to the embodiment of the present invention individually acquires different color information of RGB by separate elements when the color line scan camera performs imaging. In the present invention, a color line scan camera suitable for continuous imaging inspection of the surface of the traveling metal strip is used, and the RGB line included in the color line scan camera is scanned on the scan line of the metal strip scanned by the color line scan camera. Irradiation is performed by RGB single color light sources corresponding to the light receiving elements. At this time, one of the monochromatic light sources is parallel irradiation parallel to the traveling direction of the metal band, and the other two are obliquely parallel irradiation, and the scan lines are irradiated from different directions with respect to the traveling direction of the metal band. To do. In addition, a color line scan camera is installed at an intermediate position from the irradiation position of these light sources in the traveling direction of the metal strip. As a result, the scan line in a state where it is uniformly irradiated with monochromatic light from each direction is imaged by the color line scan camera.
（金属帯表面の検査方法）
上記検査装置を用いて行う本発明の金属帯表面の検査方法では、スキャンラインＳを、それぞれ異なる方向から、ＲＧＢの各光により均等に照射し、このスキャンラインＳをカラーラインスキャンカメラ４で撮像することで、金属帯５の表面に生じた全方向の凹凸性に対してその方向別に色情報を付与することが可能である。
(Inspection method for metal strip surface)
In the metal strip surface inspection method of the present invention performed using the above inspection apparatus, the scan lines S are evenly irradiated with RGB light from different directions, and the scan lines S are imaged by the color line scan camera 4. By doing so, it is possible to provide color information for each direction with respect to unevenness in all directions generated on the surface of the metal strip 5.
一例として、本発明の検査方法により、図６（ａ）に示すような断面形状の凹状欠陥１０を撮像した場合について説明する。この場合には、図６（ｂ）のような色情報をもった撮像（平面図）を得ることができる。 As an example, a case where a concave defect 10 having a cross-sectional shape as shown in FIG. 6A is imaged by the inspection method of the present invention will be described. In this case, imaging (plan view) having color information as shown in FIG. 6B can be obtained.
すなわち、金属帯５のバルク部（正常部）では、Ｒ光、Ｇ光、Ｂ光が反射され、これらの反射光がカラーラインスキャンカメラ４でスキャンされるため、図６（ｂ）の撮像では、バルク部はグレーで表示される。また、グレーのバルク部とＲ光、Ｇ光、Ｂ光の各反射光の外側との輪郭の境界が金属帯表面の欠陥の形状として判別できる。さらに、凹状欠陥１０に対し、Ｒ光は、金属帯５の上流側（図６（ａ）の紙面奥側）から凹状欠陥１０を照射する。当該Ｒ光は、凹状欠陥１０の紙面手前側の壁（図６（ｂ）の下側）で反射され、その反射光がカラーラインスキャンカメラ４でスキャンされる。その結果、図６（ｂ）の撮像では、凹状欠陥１０の領域のうち下方側が赤色の領域（Ｒ領域）で示される。 That is, in the bulk part (normal part) of the metal band 5, R light, G light, and B light are reflected, and these reflected lights are scanned by the color line scan camera 4, so in the imaging of FIG. The bulk part is displayed in gray. Further, the boundary of the contour between the gray bulk portion and the outside of each of the reflected lights of R light, G light, and B light can be determined as the shape of the defect on the surface of the metal strip. Further, the R light irradiates the concave defect 10 from the upstream side of the metal strip 5 (the back side of the paper surface in FIG. 6A). The R light is reflected by the wall on the front side of the concave defect 10 (the lower side in FIG. 6B), and the reflected light is scanned by the color line scan camera 4. As a result, in the imaging of FIG. 6B, the lower side of the region of the concave defect 10 is indicated by a red region (R region).
また、Ｇ光は、金属帯５の下流側（図６（ａ）の紙面左手前側）から凹状欠陥１０を照射する。当該Ｇ光は、凹状欠陥１０の紙面右奥側の壁で反射され、その反射光がカラーラインスキャンカメラ４でスキャンされる。その結果、図６（ｂ）の撮像では、凹状欠陥１０の領域のうち右上側が緑色の領域（Ｇ領域）で示される。 Further, the G light irradiates the concave defect 10 from the downstream side of the metal strip 5 (the left front side in FIG. 6A). The G light is reflected by the wall on the right back side of the paper surface of the concave defect 10, and the reflected light is scanned by the color line scan camera 4. As a result, in the imaging of FIG. 6B, the upper right side of the region of the concave defect 10 is indicated by a green region (G region).
Ｂ光は、金属帯５の下流側（図６（ａ）の紙面右手前側）から凹状欠陥１０を照射する。当該Ｂ光は、凹状欠陥１０の紙面左奥側の壁で反射され、その反射光がカラーラインスキャンカメラ４でスキャンされる。その結果、図６（ｂ）の撮像では、凹状欠陥１０の左上側が青色の領域（Ｂ領域）で示される。 The B light irradiates the concave defect 10 from the downstream side of the metal strip 5 (the right front side in FIG. 6A). The B light is reflected by the wall on the back left side of the paper surface of the concave defect 10, and the reflected light is scanned by the color line scan camera 4. As a result, in the imaging of FIG. 6B, the upper left side of the concave defect 10 is indicated by a blue region (B region).
また、前記Ｒ領域と前記Ｇ領域の間の領域は、Ｒ光とＧ光の反射光による色情報が与えられるため黄色で示され、前記Ｇ領域と前記Ｂ領域の間の領域は、Ｇ光とＢ光の反射光による色情報が与えられるため水色で示され、前記Ｂ領域と前記Ｒ領域の間の領域はＢ光とＲ光の反射光による色情報が与えられるため紫色で示される。 The region between the R region and the G region is shown in yellow because color information is provided by reflected light of R light and G light, and the region between the G region and the B region is G light. Since the color information by the reflected light of the B light and the B light is given, the region between the B area and the R area is shown in purple because the color information by the reflected light of the B light and the R light is given.
なお、凹部の底の形状によっては、図６（ｂ）に示すように、凹状欠陥１０の中央の領域ＯでもＲ光、Ｇ光、Ｂ光が反射されるため、中央の領域Ｏもグレーで表示される場合がある。 Depending on the shape of the bottom of the concave portion, as shown in FIG. 6B, the R region, G light, and B light are reflected even in the central region O of the concave defect 10, so that the central region O is also gray. It may be displayed.
さらに、凹状欠陥１０の壁の傾斜角により、Ｒ光、Ｇ光、Ｂ光それぞれの反射強度が異なるため、凹状欠陥１０の深さ方向の傾斜角が、図６（ｂ）の撮像のｒ方向の彩度に反映され、傾斜角が急峻なほど鮮明になる（例えば図８）。また、凹状欠陥１０の周方向の傾斜角は、図６（ｂ）の撮像のｗ方向の色相に反映され、均等深さの周方向の色相に比べ特定の色の周方向分布が大小変化する（例えば図９）。そのため、本発明の検査方法によれば、金属帯５表面の凹状欠陥１０を検出できるだけでなく、凹状欠陥１０の内部の形状（凹状欠陥１０の深さ、深さ方向及び周方向の凹凸形状など）まで検出することができる。 Furthermore, since the reflection intensity of each of the R light, G light, and B light differs depending on the inclination angle of the wall of the concave defect 10, the inclination angle in the depth direction of the concave defect 10 is the r direction of imaging in FIG. As the inclination angle becomes steeper, the image becomes clearer (for example, FIG. 8). Further, the inclination angle in the circumferential direction of the concave defect 10 is reflected in the hue in the w direction of imaging in FIG. 6B, and the circumferential distribution of a specific color changes in magnitude compared to the circumferential hue of uniform depth. (For example, FIG. 9). Therefore, according to the inspection method of the present invention, not only can the concave defect 10 on the surface of the metal strip 5 be detected, but also the internal shape of the concave defect 10 (the depth of the concave defect 10, the concave and convex shape in the depth direction and the circumferential direction, etc.) ) Can be detected.
次に、本発明の検査方法により、図７（ａ）に示すような断面形状の凸状欠陥１１を撮像した場合について説明する。この場合には、図７（ｂ）のような色情報をもった撮像（平面図）を得ることができる。 Next, the case where the convex defect 11 having a cross-sectional shape as shown in FIG. 7A is imaged by the inspection method of the present invention will be described. In this case, imaging (plan view) having color information as shown in FIG. 7B can be obtained.
すなわち、凸状欠陥１１に対し、Ｒ光は、金属帯５の上流側（図７（ａ）の紙面奥側）から凸状欠陥１１を照射する。当該Ｒ光は、凸状欠陥１１の紙面奥側の壁で反射され、その反射光がカラーラインスキャンカメラ４でスキャンされる。その結果、図７（ｂ）の撮像では、凸状欠陥１１の領域のうち上方側が赤色の領域（Ｒ領域）で示される。 That is, the R light irradiates the convex defect 11 from the upstream side of the metal strip 5 (the back side of the paper surface in FIG. 7A). The R light is reflected by the wall on the back side of the paper surface of the convex defect 11, and the reflected light is scanned by the color line scan camera 4. As a result, in the imaging of FIG. 7B, the upper side of the region of the convex defect 11 is indicated by a red region (R region).
また、Ｇ光は、金属帯５の下流側（図７（ａ）の紙面左手前側）から凸状欠陥１１を照射する。当該Ｇ光は、凸状欠陥１１の紙面左手前側の壁で反射され、その反射光がカラーラインスキャンカメラ４でスキャンされる。その結果、図７（ｂ）の撮像では、凸状欠陥１１の領域のうち左下側が緑色の領域（Ｇ領域）で示される。 Further, the G light irradiates the convex defect 11 from the downstream side of the metal strip 5 (the left front side in FIG. 7A). The G light is reflected by the wall on the left front side of the paper surface of the convex defect 11, and the reflected light is scanned by the color line scan camera 4. As a result, in the imaging of FIG. 7B, the lower left side of the region of the convex defect 11 is indicated by a green region (G region).
Ｂ光は、金属帯５の下流側（図７（ａ）の紙面右手前側）から凸状欠陥１１を照射する。当該Ｂ光は、凸状欠陥１１の紙面右手前側の壁で反射され、その反射光がカラーラインスキャンカメラ４でスキャンされる。その結果、図７（ｂ）の撮像では、凸状欠陥１１の領域のうち右下側が青色の領域（Ｂ領域）で示される。 The B light irradiates the convex defect 11 from the downstream side of the metal strip 5 (the right front side of FIG. 7A). The B light is reflected by the wall on the right front side of the paper surface of the convex defect 11, and the reflected light is scanned by the color line scan camera 4. As a result, in the imaging of FIG. 7B, the lower right side of the region of the convex defect 11 is indicated by a blue region (B region).
また、前記Ｒ領域と前記Ｇ領域の間の領域は、Ｒ光とＧ光の反射光による色情報が与えられるため黄色で示され、前記Ｇ領域と前記Ｂ領域の間の領域は、Ｇ光とＢ光の反射光による色情報が与えられるため水色で示され、前記Ｂ領域と前記Ｒ領域の間の領域はＢ光とＲ光の反射光による色情報が与えられるため紫色で示される。 The region between the R region and the G region is shown in yellow because color information is provided by reflected light of R light and G light, and the region between the G region and the B region is G light. Since the color information by the reflected light of the B light and the B light is given, the region between the B area and the R area is shown in purple because the color information by the reflected light of the B light and the R light is given.
金属帯５のバルク部では、Ｒ光、Ｇ光、Ｂ光が反射され、これらの反射光がカラーラインスキャンカメラ４でスキャンしつつ撮像されるため、図７（ｂ）の撮像では、バルク部はグレーで表示され、その輪郭から欠陥の形状がわかる。また、図７（ｂ）に示すように、凸状欠陥１１の中央の領域ＯでもＲ光、Ｇ光、Ｂ光が反射されるため、中央の領域Ｏもグレーで表示される場合がある。 In the bulk portion of the metal band 5, R light, G light, and B light are reflected, and these reflected lights are imaged while being scanned by the color line scan camera 4, so in the imaging of FIG. Is displayed in gray, and the shape of the defect can be seen from its outline. Further, as shown in FIG. 7B, since the R light, G light, and B light are also reflected in the central region O of the convex defect 11, the central region O may be displayed in gray.
さらに、凸状欠陥１１の壁の傾斜角により、Ｒ光、Ｇ光、Ｂ光それぞれの反射強度が異なるため、凸状欠陥１１の高さ方向の傾斜角が、図７（ｂ）の撮像のｒ方向の彩度に反映され、高さ方向の傾斜角が大きいほど鮮明になる。また、凸状欠陥１１の周方向の傾斜角は、図７（ｂ）の撮像のｗ方向の色相に反映され、周方向に均等な傾斜角の場合に比べて、特定の色の周方向の変化が大きい。そのため、本発明の検査方法によれば、金属帯５表面の凸状欠陥１１を検出できるだけでなく、凸状欠陥の三次元的形状（凸状欠陥１１の高さ、高さ方向及び周方向の凹凸形状など）まで検出することができる。 Furthermore, since the reflection intensity of each of the R light, the G light, and the B light varies depending on the inclination angle of the wall of the convex defect 11, the inclination angle in the height direction of the convex defect 11 is the same as that in FIG. Reflected in the saturation in the r direction, the larger the inclination angle in the height direction, the clearer it becomes. Further, the inclination angle in the circumferential direction of the convex defect 11 is reflected in the hue in the w direction of imaging in FIG. 7B, and the circumferential angle of a specific color is compared to the case of uniform inclination angles in the circumferential direction. The change is great. Therefore, according to the inspection method of the present invention, not only can the convex defect 11 on the surface of the metal strip 5 be detected, but also the three-dimensional shape of the convex defect (the height, height direction and circumferential direction of the convex defect 11). It is possible to detect even uneven shapes.
また、凸状欠陥１１の撮像（図７（ｂ））は、凹状欠陥１０の撮像（図６（ｂ））を上下左右に反転した画像として得られる。そのため、本発明の検査方法により線光源の方向を把握していれば、表面欠陥の凹凸を分別して検出することができる。 The imaging of the convex defect 11 (FIG. 7B) is obtained as an image obtained by inverting the imaging of the concave defect 10 (FIG. 6B) vertically and horizontally. Therefore, if the direction of the line light source is grasped by the inspection method of the present invention, the irregularities of the surface defect can be classified and detected.
さらに、本発明の検出方法によれば、凹凸を有さない表面欠陥も検出可能である。例えば、面状に発生した錆や、鍍金ムラ等の変色は、取得した撮像において色彩に反映され、例えば茶色等の領域で表示され、グレーで表示されるバルク部や、ＲＧＢの領域で表示される凹凸欠陥と分別される。 Furthermore, according to the detection method of the present invention, it is possible to detect a surface defect having no unevenness. For example, discoloration such as surface rust and plating unevenness is reflected in color in the acquired image, and is displayed in a brown area, for example, and is displayed in a gray area or RGB area. It is separated from uneven defects.
このように、本発明の検出方法によれば、凹凸性の表面欠陥、表面性状や有色性の表面欠陥等の金属帯の表面欠陥に対する撮像に色情報を与え、これらの欠陥の特徴を際立たせて検出できる。そのため、本発明の金属帯表面の検査方法によれば、これらの表面欠陥を精度よく検出でき、かつ分別することができる。さらに、欠陥の凹凸についての三次元的な情報も得られる。 Thus, according to the detection method of the present invention, color information is given to imaging of surface defects of metal bands such as uneven surface defects, surface textures and colored surface defects, and the characteristics of these defects are highlighted. Can be detected. Therefore, according to the metal strip surface inspection method of the present invention, these surface defects can be accurately detected and sorted. Furthermore, three-dimensional information about the irregularities of the defect can also be obtained.
なお、本発明における照射手段の配置パターンは、上述の実施形態に限定されない。本発明の検査方法及び検査装置では、線光源１、線光源２、線光源３により、金属帯５表面の同一のラインを、それぞれ異なる方向から照射できればよく、例えば、線光源１と、線光源２または線光源３の配置を入れ替えたり、線光源２と線光源３の配置を入れ替えてもよい。また、上述の実施形態では、金属帯５の上流側に１つ、下流側に２つの線光源を配置したが、これとは逆に、金属帯５の上流側に２つ、下流側に１つの線光源を配置してもよい。 In addition, the arrangement pattern of the irradiation means in this invention is not limited to the above-mentioned embodiment. In the inspection method and inspection apparatus of the present invention, the line light source 1, the line light source 2, and the line light source 3 may irradiate the same line on the surface of the metal strip 5 from different directions. For example, the line light source 1 and the line light source 2 or the arrangement of the line light source 3 may be exchanged, or the arrangement of the line light source 2 and the line light source 3 may be exchanged. In the above-described embodiment, one line light source is disposed on the upstream side of the metal strip 5 and two line light sources are disposed on the downstream side. Conversely, two line light sources are disposed on the upstream side of the metal strip 5 and one is disposed on the downstream side. Two line light sources may be arranged.
また、線光源１、線光源２、線光源３から照射される各色光は、波長の重なりが小さい方が好ましく、例えばバンドパスフィルタ等を用いて各色光の波長の重なりを小さくするように調整してもよい。 In addition, it is preferable that each color light emitted from the line light source 1, the line light source 2, and the line light source 3 has a smaller wavelength overlap. For example, a band pass filter or the like is used to reduce the wavelength overlap of each color light. May be.
また、上述の実施形態では、図５のようにＲＧＢ各光の入射方向を１２０°ずつずらして均等に照射しているが、欠陥の形態によっては、ＲＧＢ各光の入射方向を特定角度の方向に特化すると検出しやすい場合には、線光源から光を平行照射し、光照射面までの光路長を同一としたまま、均等では無く意図的に照射角度を偏らせてもよい。 In the above-described embodiment, the incident directions of the RGB lights are uniformly shifted by 120 ° as shown in FIG. 5. However, depending on the form of the defect, the incident directions of the RGB lights are directed at a specific angle. If it is easy to detect, it is possible to irradiate light from a linear light source in parallel and intentionally bias the irradiation angle rather than equally while keeping the optical path length to the light irradiation surface the same.
〔第２の実施形態〕
次に、本発明の一実施形態（第２の実施形態）にかかる金属帯表面の検査装置および検査方法について説明する。なお、以下に記載する実施形態において、第１の実施形態に対応する構成要素には同一の符号を付してその詳細な説明を省略する。
[Second Embodiment]
Next, a metal strip surface inspection apparatus and inspection method according to an embodiment (second embodiment) of the present invention will be described. In the embodiments described below, the same reference numerals are given to the components corresponding to the first embodiment, and the detailed description thereof is omitted.
図１０は、本発明の一実施形態（第２の実施形態）にかかる照明パターンを説明する模式図である。 FIG. 10 is a schematic diagram for explaining an illumination pattern according to one embodiment (second embodiment) of the present invention.
本実施形態において照射手段は、線光源１と、線光源２と、線光源３と、赤外光（ＩＲ光（ＩＲ−Ａ光））を照射する第４の線光源２０（以下、単に「線光源２０」ともいう）と、を有する（図１０）。なお、Ｒ光、Ｇ光、Ｂ光、ＩＲ光の各線光源は、図１０にこだわるものではなく、いずれかの線光源がそれぞれＲ光、Ｇ光、Ｂ光、ＩＲ光であればよい。また、金属帯５の走行方向は矢印６の反対方向であってもよい。 In the present embodiment, the irradiation means includes a linear light source 1, a linear light source 2, a linear light source 3, and a fourth linear light source 20 that irradiates infrared light (IR light (IR-A light)) (hereinafter simply “ (Also referred to as a line light source 20 ”) (FIG. 10). In addition, each line light source of R light, G light, B light, and IR light does not stick to FIG. 10, and any line light source should just be R light, G light, B light, and IR light, respectively. Further, the traveling direction of the metal strip 5 may be the direction opposite to the arrow 6.
金属帯５の上方から見た図１０に示すように、本実施形態において、線光源１及び線光源２０は、赤外・カラーラインスキャンカメラ２１に対して金属帯５の上流側に配置されており、線光源２及び線光源３は、赤外・カラーラインスキャンカメラ２１に対して金属帯５の下流側に配置されている。 As shown in FIG. 10 as viewed from above the metal band 5, in the present embodiment, the line light source 1 and the line light source 20 are arranged on the upstream side of the metal band 5 with respect to the infrared / color line scan camera 21. The line light source 2 and the line light source 3 are arranged on the downstream side of the metal band 5 with respect to the infrared / color line scan camera 21.
線光源１、線光源２、線光源３、線光源２０は、それら光の金属帯への照射面が金属帯５の幅方向に平行に配置されている。さらに、線光源１と線光源２０、線光源２と線光源３は、金属帯５の幅方向に並列されており、線光源１と線光源２０、線光源２と線光源３の光照射面はスキャンラインＳに平行に面一とされている。 In the line light source 1, the line light source 2, the line light source 3, and the line light source 20, the irradiation surface of the light on the metal band is arranged in parallel to the width direction of the metal band 5. Furthermore, the line light source 1 and the line light source 20, the line light source 2 and the line light source 3 are arranged in parallel in the width direction of the metal strip 5, and the light irradiation surface of the line light source 1 and the line light source 20, the line light source 2 and the line light source 3. Is flush with the scan line S.
本実施形態においては、線光源２０は、例えば、ＬＥＤ発光部が細長くライン状に並んで構成されており、金属帯５の表面を斜め方向から幅方向に均等にライン状に平行照射を可能とする。 In the present embodiment, for example, the line light source 20 includes LED light emitting portions that are elongated and arranged in a line, and the surface of the metal strip 5 can be irradiated in parallel in a line from the oblique direction to the width direction. To do.
図１０に示すように、線光源１、線光源２、線光源３、線光源２０から照射される光は、それぞれ照射方向が金属帯５の進行方向６に対して傾斜している斜方平行照射である。また、線光源１、線光源２、線光源３、線光源２０は、それぞれ金属帯５の進行方向正面から見て金属帯幅方向に対し斜めから光を平行に照射し、スキャンラインＳを斜め上方から平行に幅方向に均等に照射する。各線光源を上記のような配置及び照射パターンとすることで、各線光源によりそれぞれ異なる方向から、同一のスキャンラインＳを幅方向に均等に照射できる。 As shown in FIG. 10, the light emitted from the line light source 1, the line light source 2, the line light source 3, and the line light source 20 is obliquely parallel whose irradiation direction is inclined with respect to the traveling direction 6 of the metal strip 5. Irradiation. The line light source 1, the line light source 2, the line light source 3, and the line light source 20 each irradiate light parallel to the metal band width direction when viewed from the front in the traveling direction of the metal band 5 and obliquely scan the scan line S. Irradiate evenly in the width direction in parallel from above. By setting each line light source as described above and the irradiation pattern, the same scan line S can be evenly irradiated in the width direction from different directions depending on each line light source.
図１０に示すように、本実施形態では、金属帯の上方から見た平面視で、それぞれの光を線光源からの斜方平行照射により金属帯５の進行方向６に対してぞれぞれ４５°傾いた方向から照射しており、全体としては９０°ずつ均等な方向からスキャンラインＳ上の任意の点（Ｓ１、Ｓ２、・・Ｓｎ、・）を均等に照射する。さらに、この際、スキャンラインＳ上の同一点を基点として、それぞれの線光源の光路長が等しくなるように、各線光源が配置されている。そのため、スキャンラインＳを金属帯５の幅方向により均等に照射できる。また、スキャンラインＳでのそれぞれの光の反射光の強度が同程度となり、スキャンラインＳを赤外・カラーラインスキャンカメラ２１でスキャンしつつ撮像した際により精細な撮像が得られ、表面欠陥の検出能力がより高められる。 As shown in FIG. 10, in this embodiment, each of the light beams is obliquely irradiated from a line light source in a plan view as viewed from above the metal band 5 with respect to the traveling direction 6 of the metal band 5. Irradiation is performed from a direction inclined by 45 °, and as a whole, arbitrary points (S 1 , S 2 ,... S n ,...) On the scan line S are irradiated uniformly from a uniform direction by 90 °. Further, at this time, each line light source is arranged so that the optical path lengths of the respective line light sources are equal with the same point on the scan line S as a base point. Therefore, the scan line S can be evenly irradiated in the width direction of the metal strip 5. Further, the intensity of the reflected light of each light at the scan line S becomes approximately the same, and when the scan line S is imaged while being scanned by the infrared / color line scan camera 21, finer imaging can be obtained and surface defects can be obtained. The detection capability is further increased.
本実施形態において、赤外・カラーラインスキャンカメラ２１は、赤外受光素子に加えてＲＧＢの受光素子を搭載したラインスキャンカメラであり、波長の異なる光情報を別々の素子によって個別に取得することが可能である。 In the present embodiment, the infrared / color line scan camera 21 is a line scan camera equipped with RGB light receiving elements in addition to the infrared light receiving elements, and individually acquires optical information with different wavelengths by separate elements. Is possible.
図２と同様に、赤外・カラーラインスキャンカメラ２１は、スキャンラインＳの直上において、スキャンラインＳを撮像可能に鉛直下向きに設置するとよく、線光源１、線光源２、線光源３、線光源２０から照射されたＲＧＢ各光とＩＲ光の反射光を均等に受光可能にするとよい。 As in FIG. 2, the infrared / color line scan camera 21 may be installed vertically above the scan line S so that the scan line S can be imaged. The line light source 1, the line light source 2, the line light source 3, and the line It is preferable that the RGB light and the reflected light of the IR light emitted from the light source 20 can be received evenly.
赤外・カラーラインスキャンカメラ２１により得られた撮像は、適宜パーソナルコンピュータ等の演算手段に転送され処理される。そして、その結果を前記演算手段に接続されたモニタ上に表示する。 The image obtained by the infrared / color line scan camera 21 is appropriately transferred to an arithmetic means such as a personal computer for processing. Then, the result is displayed on a monitor connected to the calculation means.
（金属帯表面の検査方法）
上記検査装置を用いて行う本発明の金属帯表面の検査方法では、スキャンラインＳを、それぞれ異なる方向から、赤外・ＲＧＢの各光により均等に照射し、このスキャンラインＳを赤外・カラーラインスキャンカメラ２１で撮像することで、金属帯５の表面に生じた全方向の凹凸性に対してその方向別に色情報を付与することが可能である。
(Inspection method for metal strip surface)
In the metal strip surface inspection method of the present invention performed using the above inspection apparatus, the scan lines S are evenly irradiated with infrared and RGB lights from different directions, and the scan lines S are irradiated with infrared and color. By imaging with the line scan camera 21, it is possible to give color information for each direction with respect to the concavo-convex property in all directions generated on the surface of the metal band 5.
一例として、本発明の検査方法により、図１１（ａ）に示すような断面形状の凹状欠陥１２を撮像した場合について説明する。この場合には、図１１（ｂ）のような光の情報をもった撮像（平面図）を得ることができる。 As an example, a case where a concave defect 12 having a cross-sectional shape as shown in FIG. 11A is imaged by the inspection method of the present invention will be described. In this case, imaging (plan view) having light information as shown in FIG. 11B can be obtained.
すなわち、金属帯５のバルク部（正常部）では、Ｒ光、Ｇ光、Ｂ光、ＩＲ光が反射され、これらの反射光が赤外・カラーラインスキャンカメラ２１でスキャンされるため、図１１（ｂ）の撮像では、バルク部はグレーで表示される。また、グレーのバルク部とＲ光、Ｇ光、Ｂ光、ＩＲ光の外側との輪郭の境界が金属帯表面の欠陥の形状として判別できる。 That is, in the bulk part (normal part) of the metal band 5, R light, G light, B light, and IR light are reflected, and these reflected lights are scanned by the infrared / color line scan camera 21, so that FIG. In the imaging of (b), the bulk part is displayed in gray. Further, the boundary of the contour between the gray bulk portion and the outside of the R light, G light, B light, and IR light can be determined as the shape of the defect on the surface of the metal band.
さらに、凹状欠陥１２に対し、Ｒ光は、金属帯５の上流側（図１１（ａ）の紙面左奥側）から凹状欠陥１２を照射する。当該Ｒ光は、凹状欠陥１２の紙面右手前側の壁（図１１（ｂ）の右下側）で反射され、その反射光が赤外・カラーラインスキャンカメラ２１でスキャンされる。その結果、図１１（ｂ）の撮像では、凹状欠陥１２の領域のうち右下側が赤色の領域（Ｒ領域）で示される。 Further, the R light irradiates the concave defect 12 from the upstream side of the metal strip 5 (the left rear side in the drawing of FIG. 11A). The R light is reflected by the wall on the right front side of the concave defect 12 (lower right side in FIG. 11B), and the reflected light is scanned by the infrared / color line scan camera 21. As a result, in the imaging of FIG. 11B, the lower right side of the area of the concave defect 12 is indicated by a red area (R area).
ＩＲ光は、金属帯５の上流側（図１１（ａ）の紙面右奥側）から凹状欠陥１２を照射する。当該ＩＲ光は、凹状欠陥１２の紙面左手前側の壁（図１１（ｂ）の左下側）で反射され、その反射光が赤外・カラーラインスキャンカメラ２１でスキャンされる。その結果、図１１（ｂ）の撮像では、凹状欠陥１２の領域のうち左下側がＩＲ領域で示される。 The IR light irradiates the concave defect 12 from the upstream side of the metal strip 5 (the right back side in the drawing of FIG. 11A). The IR light is reflected by the wall on the left front side of the concave defect 12 (lower left side in FIG. 11B), and the reflected light is scanned by the infrared / color line scan camera 21. As a result, in the imaging of FIG. 11B, the lower left side of the region of the concave defect 12 is indicated by the IR region.
また、Ｇ光、Ｂ光は、第１の実施形態と同様に、凹状欠陥１２を照射する。その結果、図１１（ｂ）のような色情報をもった撮像が得られる。第１の実施形態と同様、凹状欠陥１２の壁の傾斜角により、Ｒ光、Ｇ光、Ｂ光、ＩＲ光それぞれの反射強度が異なるため、凹状欠陥１２の深さ方向の傾斜角が、図１１（ｂ）の撮像のｒ方向の彩度に反映され、凹状欠陥１２の周方向の傾斜角が、図１１（ｂ）の撮像のｗ方向の色相に反映される。そのため、本発明の検査方法によれば、金属帯５表面の凹状欠陥１２を検出できるだけでなく、凹状欠陥１２の内部の形状（凹状欠陥１２の深さ、深さ方向及び周方向の凹凸形状など）まで検出することができる。 Further, the G light and the B light irradiate the concave defect 12 as in the first embodiment. As a result, imaging with color information as shown in FIG. 11B is obtained. Similar to the first embodiment, since the reflection intensity of each of the R light, G light, B light, and IR light varies depending on the inclination angle of the wall of the concave defect 12, the inclination angle in the depth direction of the concave defect 12 is 11 (b) is reflected in the saturation in the r direction, and the circumferential inclination angle of the concave defect 12 is reflected in the hue in the w direction of the imaging in FIG. 11 (b). Therefore, according to the inspection method of the present invention, not only can the concave defect 12 on the surface of the metal strip 5 be detected, but also the internal shape of the concave defect 12 (the depth of the concave defect 12, the depth direction and the uneven shape in the circumferential direction, etc.) ) Can be detected.
なお、第２の実施形態における線光源１、２、３、２０の配置は、図１２に示すように線光源のいずれか２つが、金属帯５の上方から見て金属帯５の進行方向に平行な平行照射であってもよい。図１２は、その例として線光源１（Ｒ光）と線光源２０（ＩＲ光）が、金属帯５の進行方向に平行な平行照射であり、線光源２（Ｇ光）と線光源３（Ｂ光）が金属帯５の上方から見てスキャンラインＳと同一直線上から幅方向均等にライン状に平行照射を可能とする斜方平行照射の場合である。この場合、金属帯進行方向の正面から見て線光源１と線光源２０は金属帯幅方向に対し垂直に、線光源２と線光源３は金属帯幅方向に対し斜めからそれぞれ光を金属帯幅方向に均等に平行照射する。 The arrangement of the line light sources 1, 2, 3, and 20 in the second embodiment is such that any two of the line light sources are in the traveling direction of the metal band 5 as viewed from above the metal band 5 as shown in FIG. 12. Parallel parallel irradiation may be used. In FIG. 12, as an example, the linear light source 1 (R light) and the linear light source 20 (IR light) are parallel irradiation parallel to the traveling direction of the metal strip 5, and the linear light source 2 (G light) and linear light source 3 ( B light) is oblique parallel irradiation that enables parallel irradiation in a line shape evenly in the width direction from the same straight line as the scan line S when viewed from above the metal strip 5. In this case, when viewed from the front in the metal band traveling direction, the line light source 1 and the line light source 20 are perpendicular to the metal band width direction, and the line light source 2 and the line light source 3 emit light from the metal band obliquely with respect to the metal band width direction. Irradiate evenly in the width direction.
以上、説明したように、本発明によれば、金属帯の特定幅方向（スキャン）位置に対して、各方向からそれぞれ波長の異なる光を平行照射し、その特定幅方向位置をラインスキャンカメラで撮像することで、各光のそれぞれの成分毎に異なった方向から撮像対象である表面欠陥を照射した状態の画像を得るようにしたので、凹凸や表面性状によって反射特性に変化が現れた際にその傾斜角が彩度や色相に反映されるようになり、これらの性質を含む欠陥に対してそれらの情報を付与し、より詳細かつ正確に欠陥を検出し、しかも、分別することが可能となった。 As described above, according to the present invention, light having different wavelengths is irradiated in parallel from each direction with respect to a specific width direction (scan) position of the metal strip, and the specific width direction position is detected by a line scan camera. By taking an image, an image of the surface defect that is the subject of imaging is illuminated from different directions for each component of each light, so when the reflection characteristics change due to irregularities and surface properties The inclination angle is reflected in the saturation and hue, and it is possible to provide information on defects including these properties, detect defects in more detail and accurately, and separate them. became.
１ 第１の線光源
２ 第２の線光源
３ 第３の線光源
４ カラーラインスキャンカメラ
５ 金属帯（検査対象）
６ 金属帯の進行方向
１０、１２ 凹状欠陥
１１ 凸状欠陥
２０ 第４の線光源
２１ 赤外・カラーラインスキャンカメラ
DESCRIPTION OF SYMBOLS 1 1st line light source 2 2nd line light source 3 3rd line light source 4 Color line scan camera 5 Metal strip (inspection object)
6 Traveling direction of metal strip 10, 12 Concave defect 11 Convex defect 20 Fourth line light source 21 Infrared / color line scan camera
Claims (18)
前記照射されたラインを、前記光を検出可能なラインスキャンカメラでスキャンしつつ撮像する金属帯表面の検査方法であって、
前記３つ以上の線光源は、それぞれ金属帯の幅方向に平行に設置され、前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯進行方向の正面から見て金属帯幅方向に対し斜めから光を平行照射し、
前記金属帯の表面の幅方向同一ライン上の同一点を基点とし、前記基点から光照射面までの前記３つ以上の線光源からそれぞれ平行照射された光の光路長が等しいことを特徴とする金属帯表面の検査方法。 The same line in the width direction of the surface of the traveling metal strip is irradiated in parallel with light having different wavelengths from three or more line light sources from different directions,
A method for inspecting a surface of a metal strip that images the irradiated line while scanning with a line scan camera capable of detecting the light,
The three or more line light sources are respectively installed in parallel with the width direction of the metal band, and at least two of the three or more line light sources are in the metal band width direction when viewed from the front in the metal band traveling direction. Irradiate parallel light from diagonally,
The same point on the same line in the width direction of the surface of the metal band is a base point, and the optical path lengths of light irradiated in parallel from the three or more line light sources from the base point to the light irradiation surface are equal. Inspection method of metal strip surface.
前記照射手段により照射されたラインをスキャンしつつ撮像する前記光を検出可能なラインスキャンカメラと、を備え、
前記照射手段は、それぞれ波長の異なる光を平行照射する３つ以上の線光源を有し、
前記３つ以上の線光源は、それぞれ金属帯の幅方向に平行に設置され、前記３つ以上の線光源のうち少なくとも２つの線光源は、金属帯進行方向の正面から見て金属帯幅方向に対し斜めから光を平行照射し、
前記金属帯の表面の幅方向同一ライン上の同一点を基点とし、前記基点から光照射面までの前記３つ以上の線光源からそれぞれ平行照射された光の光路長が等しいことを特徴とする金属帯表面の検査装置。 Irradiation means for irradiating light in a line shape on the same line in the width direction of the surface of the traveling metal strip,
A line scan camera capable of detecting the light to be imaged while scanning the line irradiated by the irradiation means,
The irradiating means has three or more line light sources that irradiate light of different wavelengths in parallel,
The three or more line light sources are respectively installed in parallel with the width direction of the metal band, and at least two of the three or more line light sources are in the metal band width direction when viewed from the front in the metal band traveling direction. Irradiate parallel light from diagonally,
The same point on the same line in the width direction of the surface of the metal band is a base point, and the optical path lengths of light irradiated in parallel from the three or more line light sources from the base point to the light irradiation surface are equal. Metal strip surface inspection equipment.
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