JPS60125546A - Detector for surface flaw of red heat object - Google Patents
Detector for surface flaw of red heat objectInfo
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- JPS60125546A JPS60125546A JP23296483A JP23296483A JPS60125546A JP S60125546 A JPS60125546 A JP S60125546A JP 23296483 A JP23296483 A JP 23296483A JP 23296483 A JP23296483 A JP 23296483A JP S60125546 A JPS60125546 A JP S60125546A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
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- Analytical Chemistry (AREA)
- Biochemistry (AREA)
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- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は被探傷材の表面欠陥の検出方法、とくr′JI
L##鰭浩T雅に卦りイー去凱鉾優スラブの表面疵を非
接触で検出する方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for detecting surface defects on a material to be tested, and
This invention relates to a method for non-contact detection of surface flaws on slabs.
従来例の構成とその問題点
赤熱物の表面疵検出は、接触式、非接触式の2つの方式
が提案されている。しかし、接触式は対象物体が高温で
あるため、接触部の耐熱性が要求されたり、対象物体の
平面性が問題となり、十分な検出精度が期待できない。Conventional Structure and Problems Two methods have been proposed for detecting surface flaws on a red-hot object: a contact method and a non-contact method. However, in the contact type, since the target object is at a high temperature, heat resistance of the contact part is required, and flatness of the target object becomes a problem, and sufficient detection accuracy cannot be expected.
そこで、一般に赤熱物体の表面疵の検出は、非接触で検
出する方法がとられている。Therefore, a non-contact detection method is generally used to detect surface flaws on a red-hot object.
非接触で表面疵を検出する方法は、一般に光学的方法が
とられ、従来、次の2つの方法が提案されている。Optical methods are generally used to detect surface flaws in a non-contact manner, and the following two methods have been proposed so far.
1つは、赤熱物体に対して可視あるいは紫外域の光を照
射して、これにより生ずる赤熱物体表面の陰影像を撮像
し、この映像信号から疵検出を行なうものである。One method is to irradiate a red-hot object with light in the visible or ultraviolet range, capture a shadow image of the surface of the red-hot object, and detect defects from this image signal.
もう1つは、赤熱物体の自発光によって検出する方法で
ある。これは、赤熱物体の表面と疵によって露出した赤
熱物体の内部の温度差を利用して赤外域で撮像し、この
映像信号から疵検出を行なう方法である。The other method is detection based on the self-luminescence of a red-hot object. This is a method that uses the temperature difference between the surface of a red-hot object and the inside of the red-hot object exposed by a flaw to take an image in the infrared region, and detects a flaw from this video signal.
しかし、前記2つの方法では、前者は、疵以外の凹凸が
赤熱物体表面上にあれば、これも疵と見なすといった誤
まった判断をおこしうろこと、また、後者は赤熱物体の
表面状態によって表面温度の不均一性が生じるため、本
方法のみではSN比が十分とれないといった欠点がある
。However, with the above two methods, the former may lead to a erroneous judgment that if there are irregularities other than flaws on the surface of the red-hot object, they are also considered flaws, and the latter may cause surface irregularities depending on the surface condition of the red-hot object. Since temperature non-uniformity occurs, this method alone has the disadvantage that a sufficient signal-to-noise ratio cannot be obtained.
また、前記2つの方法を1光学系で構成し、疵の種類に
応じて、おのおの別々の系統で疵を検出する方法が特開
昭49−131192で提案されている。しかし、この
方法では、前に述べた2つの光学的検出方法の欠点を含
んだままであり、本質的な改善とはならない。たとえば
、赤熱物体表面に疵でない凹凸があるとき、可視あるい
は紫外域の光の照射によって、この凹凸の陰影が生じ、
この方法ではこれを疵と判別する。また自発光による映
像信号のSN比の改善もされていない。Furthermore, Japanese Patent Laid-Open No. 131192/1983 proposes a method in which the above two methods are implemented in one optical system and each flaw is detected using a separate system depending on the type of flaw. However, this method still includes the drawbacks of the two optical detection methods described above and is not a substantial improvement. For example, when the surface of a red-hot object has irregularities that are not flaws, irradiation with light in the visible or ultraviolet region produces shadows from the irregularities.
This method identifies this as a flaw. Furthermore, the SN ratio of the video signal is not improved by self-emission.
また、特開昭和52−139482および特開昭和55
−160837においても、前記2つの検出方法のそれ
ぞれから疵の2値化信号を得、これらの信号の論理積を
とっているため前記2つの方法の欠点を含んだままであ
り、本質的な改善となっていない。Also, JP-A-52-139482 and JP-A-55
-160837 also obtains binary signals of flaws from each of the two detection methods described above, and ANDs these signals, so it still contains the drawbacks of the two methods described above, and is not an essential improvement. is not.
発明の目的
本発明は、先に述べた光学的検出方法の問題点を解決す
ることを目的とし、光学的検出手段であって、しかも高
精度で廓の検出を可能とする赤熱物体の表面疵検出装置
を提供するものである0発明の構成
本発明による装置は、赤熱物体の表面の像を1つの結像
光学系によって投影し、この投影像を2光路に分離して
、一方の通過波長域を近赤外域または可視域とし、他方
の通過波長域を上記可視域よりも短波長域とし、双方の
投影面に位置する撮像素子の光電信号のうち、一方を他
方で除算する信号処理部をもった、赤熱物体の表面疵検
出装置である。さらに本装置は上記の通過波長域のひと
つである近赤外域または可視域に分光放射をも2照明装
置をもつ。OBJECT OF THE INVENTION The present invention aims to solve the problems of the optical detection method described above, and is an optical detection means, which enables surface flaws on a red-hot object to be detected with high precision. 0 Constitution of the Invention which Provides a Detection Device The device according to the present invention projects an image of the surface of a red-hot object by one imaging optical system, separates this projected image into two optical paths, and selects one of the passing wavelengths. A signal processing unit that divides one of the photoelectric signals of the image pickup devices located on both projection planes by the other, with the wavelength range set in the near-infrared range or the visible range and the other wavelength range set as the wavelength range shorter than the visible range. This is a device for detecting surface flaws on red-hot objects. Furthermore, this device has two illumination devices that emit spectral radiation in the near-infrared region or the visible region, which is one of the above-mentioned passing wavelength regions.
上記構成により、照明によって赤熱物体の疵の陰影像を
検出するのに近赤外域もしくは可視域の長波長側を用い
、赤熱物体の自発光による検出はS/N比のよい可視域
の短波長側で行なう。With the above configuration, the long wavelength side of the near-infrared region or visible region is used to detect the shadow image of a flaw on a red-hot object by illumination, and the short wavelength side of the visible region with a good S/N ratio is used for detection of the self-emission of the red-hot object. Do it on your side.
また、このようにして得られた双方の光電出力のうち、
一方を他方で除算した商について2値化処理を行なうこ
とにより、それぞれ単独で2値化した場合に比べて、柔
軟性のある疵判別を実現することができる。Also, among the photoelectric outputs of both obtained in this way,
By performing binarization processing on the quotient obtained by dividing one by the other, more flexible flaw discrimination can be realized than when each is binarized alone.
実施例の説明
第1図は本発明の表面疵検出装置の一例を示すもので、
鉄鋼プラント、とくに連続鋳造謹備における熱間鋼片(
スラブ)の表面疵検出装置として用いられるものである
。この場合、スラブの表面温度は約800〜900℃、
内部温度は1000℃である。この装置は第1図に示す
ように、赤熱物体、すなわち熱間スラブ1を照明する近
赤外域または可視域に主な分光放射をもつ照明装置2と
、この照明装置により照明されたスラブ表面を撮像する
撮像装置3と、この撮像装置からの信号を処理中る信号
処理部10とから構成される〇この照明装置2は、たと
えば、白熱電球など赤外域にも分光放射を有する光源と
シャープカットフィルタの組み合せ等によって構成され
る。DESCRIPTION OF EMBODIMENTS FIG. 1 shows an example of the surface flaw detection device of the present invention.
Hot steel billets in steel plants, especially continuous casting facilities (
This device is used as a surface flaw detection device for slabs. In this case, the surface temperature of the slab is approximately 800-900℃,
The internal temperature is 1000°C. As shown in Fig. 1, this device includes an illumination device 2, which has spectral radiation mainly in the near-infrared region or visible region, which illuminates a red-hot object, that is, a hot slab 1, and a slab surface illuminated by this illumination device. Consisting of an imaging device 3 that captures images, and a signal processing unit 10 that processes signals from this imaging device, this illumination device 2 uses a sharp cut light source and a light source that has spectral radiation also in the infrared region, such as an incandescent light bulb, for example. It is composed of a combination of filters, etc.
撮像装置3において、4は熱間スラブ1の表面を投影す
るための投影光学系である。6は像界側にもうけたハー
フミラ−で、これにより光路を2つに分割し、結像面を
2つ形成する。7および9は上記2つの結像面に配置し
た撮像素子である。In the imaging device 3, 4 is a projection optical system for projecting the surface of the hot slab 1. 6 is a half mirror provided on the image field side, which divides the optical path into two and forms two imaging surfaces. Reference numerals 7 and 9 are image pickup elements arranged on the two imaging planes.
撮像素子9の光路には、近赤外域および可視域に感度を
有するようにシャープカットフィルタ8を配置し、撮像
素子7の光路には、可視域の短波長側に主に感度を有す
るように、赤外カットフィルタ6を配置する。A sharp cut filter 8 is arranged in the optical path of the image sensor 9 so as to have sensitivity in the near-infrared region and the visible region, and a sharp cut filter 8 is arranged in the optical path of the image sensor 7 so as to have sensitivity mainly in the short wavelength side of the visible region. , an infrared cut filter 6 is arranged.
第2図は信号処理部1oのブロックダイヤグラムを示す
もので、7,9は撮像素子、33,34は撮像素子の光
電信号の利得ならびに線形特性を調整するだめの利得調
整回路、36は利得調整回路33.34からの光電出力
の一方を他方で除算し、その商を算出するための除算回
路、37は除算回路の出力を基準電圧発生部36と比較
して、2値化するだめの2値化回路、38は2値化回路
374Cよる疵判別信号を表わす。FIG. 2 shows a block diagram of the signal processing unit 1o, in which 7 and 9 are image sensors, 33 and 34 are gain adjustment circuits for adjusting the gain and linear characteristics of the photoelectric signal of the image sensor, and 36 is a gain adjustment circuit. A division circuit for dividing one of the photoelectric outputs from the circuits 33 and 34 by the other and calculating the quotient; 37 is a division circuit for comparing the output of the division circuit with the reference voltage generating section 36 and converting it into a binary value; A digitizing circuit 38 represents a flaw determination signal from the binarizing circuit 374C.
以上のように構成された本実施例の疵検小装置において
、以下その動作を説明する。The operation of the flaw inspection device of this embodiment configured as described above will be described below.
撮像素子8は、照明装置2からの照明光によシ生じた熱
間スラブ1の陰影像を撮像する。すなわち熱間スラブ1
0表面の凹部が影となり、撮像素子の1ライン走査分に
相当する光電信号は第3図すの17に示すような形態を
とる。また撮像素子7は熱間スラブ1の自発光パターン
を撮像する。The image sensor 8 captures a shadow image of the hot slab 1 caused by the illumination light from the illumination device 2 . That is, hot slab 1
The concave portion on the surface of the photoelectric sensor becomes a shadow, and the photoelectric signal corresponding to one line of scanning of the image sensor takes the form as shown in FIG. 3, 17. Further, the image sensor 7 images the self-luminous pattern of the hot slab 1.
すなわち、第3図において熱間スラブ10表血に疵11
があると、スラブ内部14の高温部が露出するのでCに
示すような疵信号22を得ることができる。That is, in FIG. 3, there is a flaw 11 on the surface blood of the hot slab 10.
If there is, the high-temperature portion of the slab interior 14 is exposed, and a flaw signal 22 as shown in C can be obtained.
一般に、すべての物体はその自身の温度と放射率で定ま
る熱エネルギーを放射しているといえる。In general, all objects can be said to radiate thermal energy determined by their own temperature and emissivity.
この放射エネルギー量は、黒体(放射率が1)の場合、
次式で表われる。In the case of a black body (emissivity is 1), this amount of radiant energy is
It is expressed by the following formula.
Meλ=C1λ5/(@!p、!−’ 1 ) [WC
m−2/J−’ ] ・・(1)ま
ただし、Meλはスペクトル放射発散度、Tは完全放射
体の絶対温度、λは波長、C1,C2は定数で表わすこ
とができる。Meλ=C1λ5/(@!p,!-' 1) [WC
m-2/J-'] (1) where Meλ is the spectral radiation emittance, T is the absolute temperature of the perfect radiator, λ is the wavelength, and C1 and C2 can be expressed as constants.
第3図において熱間スラブの内部14の温度が1000
℃、スラブ表面13の温度が850℃として、(1)式
を図示すると、第4図に示すような分光放射分布が得ら
れる。In Fig. 3, the temperature inside the hot slab 14 is 1000.
When formula (1) is illustrated assuming that the temperature of the slab surface 13 is 850° C., a spectral radiation distribution as shown in FIG. 4 is obtained.
第1図において、撮像素子にシリコンと材料とした固体
撮像素子を用いると、この素子の感度波長域は、0.4
μm〜1.2μ、である。このため、赤外カットフィル
タ6の特性も考慮に入れた撮像素子7の感度波長域は0
.4μm〜0.7μ、となる。In Fig. 1, if a solid-state image sensor made of silicon is used as the image sensor, the sensitivity wavelength range of this element is 0.4.
μm to 1.2 μm. Therefore, the sensitivity wavelength range of the image sensor 7 is 0, taking into consideration the characteristics of the infrared cut filter 6.
.. 4 μm to 0.7 μm.
すなわち、第4図からもわかるように、スラブ疵の自発
光放射のうち、短波長側の、たとえば0.7μm以下の
可視域の放射を利用することによ一す、近赤外域に比べ
て十分なSN比をもつ光電信号を得ることができる。In other words, as can be seen from Fig. 4, among the self-luminous radiation of slab defects, it is possible to utilize radiation in the short wavelength side, for example, in the visible range of 0.7 μm or less, compared to the near-infrared region. A photoelectric signal with a sufficient SN ratio can be obtained.
また、シャープカットフィルタ8(たとえば、0.73
μ。以上の光を通過させるR−73フイルタ)の特性を
考慮した固体撮像素子9の感度波長域は、0.73μm
〜1.2μ、である。一方、照明装置のシャープカット
フィルタに上記のR−73フイルタを用いることにより
、照明光の波長帯による陰影像が、そのまま撮像素子9
でとらえられるととKなる。この場合、0.73μm〜
1.2μ工の自発光放射も同時に検出することになるの
で、照明光による光放射の出力を十分大きくとり、自発
光放射とのレベル比を10=1〜20:1程度にとるこ
とによシ自発光放射の影響を除くことができる。Also, a sharp cut filter 8 (for example, 0.73
μ. The sensitivity wavelength range of the solid-state image sensor 9 is 0.73 μm considering the characteristics of the R-73 filter that passes the above light.
~1.2μ. On the other hand, by using the above-mentioned R-73 filter as the sharp cut filter of the illumination device, the shadow image due to the wavelength band of the illumination light can be directly transmitted to the image sensor 9.
If you can catch it, it will be K. In this case, 0.73 μm ~
Since the self-luminous radiation of 1.2 μm will also be detected at the same time, the output of the optical radiation from the illumination light should be sufficiently large and the level ratio with the self-luminous radiation should be about 10 = 1 to 20:1. The influence of self-luminous radiation can be removed.
また、照明装置はハロゲン電球などの白熱電球を使用す
ることにより、検出器の走査周波数に無関係に安定した
照明光が得られ、かつ近赤外域に効率のよい照明光が得
られる。また、放電灯のような発光管内部の輝点移動に
伴なう照明光の変動がない。Further, by using an incandescent light bulb such as a halogen light bulb in the lighting device, stable illumination light can be obtained regardless of the scanning frequency of the detector, and efficient illumination light can be obtained in the near-infrared region. Furthermore, there is no fluctuation in illumination light due to the movement of the bright spot inside the arc tube like in a discharge lamp.
以上の実施例に示すように、スラブ疵の自発光成分の検
出を0.4μm〜0.7μあて行ない、照明装置による
スラブ疵の陰影像を検出するのに0.7μm〜1.2μ
、の波長域を使用することにより、両波長域ともにSN
比の良い疵信号を得ることができる。As shown in the above embodiment, the detection of the self-luminous component of the slab flaw is carried out at 0.4 μm to 0.7 μm, and the detection of the shadow image of the slab flaw by the illumination device is performed at 0.7 μm to 1.2 μm.
By using the wavelength range of , the SN of both wavelength ranges is
A flaw signal with a good ratio can be obtained.
なお、照明装置2および撮像装置3に使用しているシャ
ープカットフィルタの波長設定tio−73μ を中心
に短波長側および長波長側に移動することができ、とく
に短波長域の光量を補う場合には、0.73μ。よりも
長波長側のシャープカットフィルタを使用することによ
り、両光電信号のバランスをとることができる。Note that the wavelength setting of the sharp cut filter used in the illumination device 2 and the imaging device 3 can be moved to the short wavelength side and the long wavelength side, centering on the wavelength setting tio-73μ, especially when supplementing the light amount in the short wavelength range. is 0.73μ. By using a sharp cut filter on the longer wavelength side, it is possible to balance both photoelectric signals.
また、ハーフミラ−60代りに、赤反射ダイクルイック
ミラーを使用することにより、両受光器への光入射のク
ロストークを低減し、SN比の良い疵信号を得ることが
できる。Further, by using a red reflective dichroic mirror instead of the half mirror 60, it is possible to reduce crosstalk between light incident on both light receivers and obtain a flaw signal with a good S/N ratio.
次に、第3図にもとづき、信号処理部の動作を説明する
。第3図aのような断面の熱間スラブ1を撮像したとき
の光電信号は、前述のごとく第2図す、cに示す信号と
なる。陰影像を撮像する撮像素子9の光電信号16には
、熱間スラブ1の上の疵11による疵信号17のほかに
、熱間スラブ表面の凹部によって生ずる信号16や、熱
間スラブ表面上の高反射体および低反射体によって生ず
る信号18.19が存在する。また、自発光パターンを
撮像する撮像素子7の光電信号21には、熱間スラブ1
の上の疵11による疵信号22のほかに、スラブ表面の
不規則な温度分布によって生ずる信号23が存在する。Next, the operation of the signal processing section will be explained based on FIG. As described above, the photoelectric signal obtained when the hot slab 1 having the cross section shown in FIG. 3a is imaged becomes the signal shown in FIG. 2c. In addition to the flaw signal 17 caused by the flaw 11 on the hot slab 1, the photoelectric signal 16 of the image sensor 9 that captures a shadow image includes a signal 16 caused by a recess on the surface of the hot slab, and a signal 16 caused by a concave portion on the surface of the hot slab. There are signals 18.19 caused by high reflectors and low reflectors. In addition, the photoelectric signal 21 of the image sensor 7 that images the self-luminous pattern includes the hot slab 1
In addition to the flaw signal 22 due to the flaw 11 above, there is a signal 23 caused by the irregular temperature distribution on the slab surface.
上記2つの信号をそれぞれ個別に2値化すれば、光電信
号15では、16,17.19が、また、光電信号21
では22.23がそれぞれ疵信号としてとらえられ、こ
れらの2系統信号の論理和はいうに及ばず、論理積をと
っても、疵以外の信号たとえば19と23によって生ず
る偽信号は、容易に疵判定をうける。If the above two signals are individually binarized, the photoelectric signal 15 becomes 16, 17.19, and the photoelectric signal 21
In this case, 22 and 23 are each taken as a flaw signal, and even if you take the logical sum or logical product of these two signals, signals other than flaws, such as false signals caused by 19 and 23, are easily detected as flaws. box office.
本信号処理では、第6図に示すごとく、撮像素子7およ
び9で得られた光電信号について、疵のない部分の平均
信号電圧を基準として、利得調整回路33および34に
おいてレベル調整を行なう。In this signal processing, as shown in FIG. 6, the level of the photoelectric signals obtained by the image sensors 7 and 9 is adjusted in the gain adjustment circuits 33 and 34 based on the average signal voltage of the portion without flaws.
この利得調整回路33および34の信号は除算回路35
において一方の信号を他方で除算する。The signals of the gain adjustment circuits 33 and 34 are transmitted to the divider circuit 35.
Divide one signal by the other at .
第4図のdに示す信号出力25は、光電信号21を光電
信号15で除算した結果を示すもので、割れ疵信号27
は2つの光電信号から強調されるが、他の光電信号波形
16 、1 B 、 19 、23はすべて相殺される
。The signal output 25 shown in FIG.
is emphasized from the two photoelectric signals, but the other photoelectric signal waveforms 16, 1B, 19, and 23 are all canceled out.
上記判定方法の原理を第6図をもとに説明する。The principle of the above determination method will be explained based on FIG. 6.
第5図aは従来例に示した疵判別方法を図示したもので
、陰影光がQより減小するか、自発光がPより大きくな
ると、疵と判定される。すなわち、■の他域以外のII
、N、IVの領域で疵と判定することを示している。FIG. 5a illustrates the flaw discrimination method shown in the conventional example. When the shadow light decreases below Q or the self-emission exceeds P, it is determined that there is a flaw. In other words, II other than ■ other areas
, N, and IV are determined to be defects.
これに対し、第5図すではP/Q/ で結ぶ曲線より上
の部分、すなわち■の領域では疵と判定されず、このP
/ Q /より下の領域■、すなわち自発光による光
電出力を陰影光のそれて割るだめの除算回路の出力が一
定値以上となる場合に疵と判定することを示している。On the other hand, in Figure 5, the area above the curve connected by P/Q/, that is, the area marked ■, is not determined to be a flaw, and this P
It is shown that a defect is determined in the region (2) below /Q/, that is, when the output of the division circuit that divides the photoelectric output due to self-emission by the deflection of shadow light exceeds a certain value.
第5図のaとbを比較した場合、本発明はIQ領域中の
39.40の領域が疵なしと判定され、41の領域が逆
に疵と判定されていることを示す。A comparison of a and b in FIG. 5 shows that in the present invention, 39.40 areas in the IQ area are determined to be free of defects, and 41 areas are determined to be defective.
第4図の測定例を第5図にあてはめると、陰影光の光電
信号のうち16と19が領域39に属し、自発光の光電
信号のうち23が領域40に属することがわかり、本発
明による疵判定方法が、従来例に比べて柔軟な判定がで
きることを示している。Applying the measurement example in FIG. 4 to FIG. 5, it can be seen that 16 and 19 of the photoelectric signals of shadow light belong to region 39, and 23 of the photoelectric signals of self-emission belong to region 40. This shows that the flaw determination method is more flexible than conventional methods.
すなわち、自発光および陰影光の光電信号の利得は利得
調整回路33.〜34によって変えることができるため
、実測データに応じて、一定限度内で任意の線形特性を
もつ判定曲線p / Q /が設定でき、疵判別に際し
て柔軟なアルゴリズム形成ができる。That is, the gain of the photoelectric signals of self-emission and shadow light is determined by the gain adjustment circuit 33. .about.34, a determination curve p/Q/ having arbitrary linear characteristics within a certain limit can be set according to actual measurement data, and a flexible algorithm can be formed for defect determination.
なお、上記の実施例では、両光型信号の除算回路の出力
に対して、1つのスレッショールドで2値化しているが
、2値化回路37の代りに多値化回路方式を配置して、
疵の種類に応じて領域■の部分を分割してもよい0また
、投影光学系の汚れなどによる光電出力の低下によって
、第6図すの判定レベルが変化するのを防ぐため、利得
調整回路33.34の出力信号を適宜記憶し、この情報
をもとに基準電圧発生部36の基準電圧を自動的にシフ
トする機能をもうけることにより、長期間にわたって安
定な判定動作を維持できる。In the above embodiment, the output of the division circuit for both optical signals is binarized using one threshold, but a multi-value circuit system is arranged in place of the binarization circuit 37. hand,
The area (■) may be divided depending on the type of flaw.In addition, in order to prevent the judgment level shown in Figure 6 from changing due to a reduction in photoelectric output due to dirt on the projection optical system, etc., a gain adjustment circuit is used. By appropriately storing the output signals of 33 and 34 and providing a function of automatically shifting the reference voltage of the reference voltage generating section 36 based on this information, stable determination operation can be maintained over a long period of time.
発明の効果
本発明による赤熱物体の表面疵検出装置は、可視放射の
短波長域で赤熱物体の自発光を検出し、可視放射の長波
長域から近赤外域にかけての波長域で疵による陰影光を
とらえ、これらの2つの光電信号を、それぞれの利得調
整回路を通して除算回路に入力し、この除算回路の出力
を2値化することにより、実測の疵判定データに応じた
疵判定基準が設定でき、これにより正確かつ柔軟性のあ
る疵判定方法を提供することができ、その実用的価値は
極めて大きいものといえる。Effects of the Invention The device for detecting surface flaws on a red-hot object according to the present invention detects self-luminescence of a red-hot object in the short wavelength range of visible radiation, and detects shadow light due to flaws in the wavelength range from the long wavelength range of visible radiation to the near-infrared range. By capturing these two photoelectric signals and inputting them to a division circuit through their respective gain adjustment circuits, and binarizing the output of this division circuit, it is possible to set a flaw judgment standard according to the actually measured flaw judgment data. As a result, an accurate and flexible flaw determination method can be provided, and its practical value can be said to be extremely large.
第1図は、本発明による構成のうち、照明装置。
撮像装置および信号処理部の原理図を表わしたものであ
る。第2図は信号処理部のブロックダイヤグラム、第3
図aは熱間スラブ表面の形状、第3図b−dは前記aに
対応して得られる光電信号、第3図eは疵検比信号、第
4図は(1)式にもとづいて計算した、スラブ表面の分
光放射分布、第6図aは疵信号検出原理の従来例、第6
図すは本発明による疵検出原理図を、それぞれ表わす。
1・・・・・・熱間スラブ、2・・・・・・照明装置、
3・・・・・・撮像装置、4・・・・・・投影光学系、
5・・用ハーフミラ−17・・・・・・撮像素子、8・
・川・シャープカットフィルタ、9・・・・・・撮像素
子、1o・・・・・・信号処理部。
代理人の氏名 弁理士 中 尾 敏 男 ほか1名第3
図
第4図
5夾−&(μ川)FIG. 1 shows a lighting device among the configurations according to the present invention. 2 is a diagram illustrating the principle of an imaging device and a signal processing section. Figure 2 is a block diagram of the signal processing section, Figure 3 is a block diagram of the signal processing section.
Figure a is the shape of the hot slab surface, Figure 3 b-d are photoelectric signals obtained corresponding to the above a, Figure 3 e is the flaw inspection ratio signal, and Figure 4 is calculated based on formula (1). Fig. 6a shows the conventional example of the flaw signal detection principle.
Each figure shows a diagram of the flaw detection principle according to the present invention. 1...Hot slab, 2...Lighting device,
3... Imaging device, 4... Projection optical system,
Half mirror 17 for 5. Image sensor, 8.
-Sharp cut filter, 9...imaging device, 1o...signal processing unit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5 Kyo - & (μ river)
Claims (1)
、この照明装置によって照明された赤熱物体を投影する
だめの結像光学系と、この結像光学系から2系統の結像
面を得るための光学素子と、2系統に分割した光路上の
それぞれに別々に設けた近赤外域または可視域の放射を
通過させるフィルタおよび上記可視域よシ短波長側の可
視放射を通過させるフィルタと、上記2系統の結像面に
それぞれ位置する撮像素子と、との撮像素子からの光電
信号のうち一方を他方で除算して2値化するだめの信号
処理部とからなる赤熱物体の表面疵検出装置。An illumination device that mainly emits spectral radiation in the near-infrared or visible region, an imaging optical system for projecting the red-hot object illuminated by this illumination device, and two systems of imaging planes from this imaging optical system. an optical element for obtaining a signal, a filter that passes radiation in the near-infrared region or visible region, and a filter that passes visible radiation on the short wavelength side of the visible region, which is provided separately on each of the two divided optical paths; surface flaws on a red-hot object, which is composed of image pickup devices located on the imaging planes of the above two systems, and a signal processing unit that divides one of the photoelectric signals from the image pickup device by the other and binarizes it. Detection device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP23296483A JPS60125546A (en) | 1983-12-09 | 1983-12-09 | Detector for surface flaw of red heat object |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP23296483A JPS60125546A (en) | 1983-12-09 | 1983-12-09 | Detector for surface flaw of red heat object |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS60125546A true JPS60125546A (en) | 1985-07-04 |
JPH031619B2 JPH031619B2 (en) | 1991-01-11 |
Family
ID=16947628
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP23296483A Granted JPS60125546A (en) | 1983-12-09 | 1983-12-09 | Detector for surface flaw of red heat object |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS60125546A (en) |
-
1983
- 1983-12-09 JP JP23296483A patent/JPS60125546A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPH031619B2 (en) | 1991-01-11 |
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