DE2612482A1 - METHOD AND EQUIPMENT FOR OPTICAL OBSERVATION OF THE SURFACE OF FAST MOVING ROLLED MATERIAL - Google Patents

Description

Hoesch Werke Aktiengesellschaft, Eberhardstr. 1P, 4600 Dortmund

Method and device for the optical observation of the surface of rapidly moving rolling material

The invention relates to a method and a device for optical observation of the surface of rapidly moving rolled material, especially of sheet metal and strips in rolling mills and processing lines, in which the rolling material is flashed stroboscopically and electronically mapped and the image is saved.

Surface defects occur in the manufacture of rolled material, especially steel strips and sheets, on the one hand by the casting and the solidification of the liquid metal, in particular of the steel, on the other hand are caused by external influences, in particular damage or malfunctions on individual rollers. While the through the defects caused by the casting and the solidification are distributed more or less randomly over the material surfaces, surface defects caused by defective rollers occur periodically. Especially with fast running Processing lines, preferably hot and cold rolling mills,

Coating lines, the periodically occurring,

z. Sometimes very small errors are visually recognized very poorly

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will. Detecting these errors as early as possible is, however, of considerable importance for production of defective rolling stock to a minimum.

A device is already known for detecting the aforementioned type of error, see "Stahl und Eisen" 1974-, P. 198/200, consisting essentially of a high-speed, high-resolution television camera, a strobe flash unit and an electronic image memory (storage tube). By means of this facility However, only random samples can be taken of the moving belt surface, which on a Observation monitor displayed as a still image until the next picture is taken, i.e. H. there can only be one The part of the rolling stock surface specified by the operating conditions can be observed and assessed. In addition, the measurement chain formed by the television camera and the image memory is during observation of an image is blocked on the monitor and is only released again when the next image is on the monitor should be observed. At a rolling speed of z. B. 900 m / min and a time interval of Image to image of only 5 see therefore the rolling stock can with it the well-known, relatively complex device

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observed and assessed only at distances of about 75 m will. Faults that occur periodically on the rolling stock surface are therefore only discovered by chance.

Dex 'invention is based on the problem of the disadvantages to avoid the known device and to specify a method and a device by means of which on one ; fold way and with relatively simple means the entire surface of a fast moving rolling material can be observed and the records resulting from the observation can be evaluated, without having to interrupt the observation process.

Based on the prior art mentioned at the beginning, this object is achieved in that in each case directly successive sections of the moving rolling material surface flashed through the surface directly reflected and / or the light scattered diffusely from the surface images of the surface are recorded and the images recorded by the reflected and / or scattered light together on one Observation monitor to display or be brought to cover and evaluated together. A good opto-electronic Separation of the individual images is included

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Advantage achieved when the individual flashes through a picture .fan ^ simpuls be triggered at the beginning of the image acquisition. To determine different types of defects on the strip surface, is advantageously from the same section of the rolling material surface by alternately Flashing one image each recorded by means of the directly reflected and the diffusely scattered light.

In a further development of the method according to the invention, the are directly reflected and diffuse by means of the scattered light generated double images · in pairs or after optical and / or electronic superimposition brought to the display together in one image each. the Images captured in this way are saved during the observation and recording time retrieved moving rolling material surface, observed and evaluated. If this seems appropriate, it is of course also possible to take the pictures on Retrieve and evaluate the end of the observation and image recording time. Both in one case and in the other the images are advantageously in with parameters of the rolling train or further processing line, preferably the Speed of the rolling stock, dej length of the roll circumference, the roller peripheral speed, synchronized times or intervals.

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An operationally reliable application of the method according to the invention is given in particular when the time interval between the individual flashes is selected to be greater than the persistence of the image recording system. Advantageously, this time interval between the individual flashes when using a television display device as an observation device is given by at least two image cycles, with one image cycle being defined by a single scan of the television cathode. For a proper evaluation system in £ _if the rolling stock to ensure be portions of 1E to 100, preferably of 70 cm length of the rolling stock shown in an image. In addition, the length of these sections expediently depends on the resolution of the television camera used.

A preferred embodiment of a device for carrying out the method according to the invention is thereby characterized in that a stroboscopic light source is used to illuminate the moving rolling stock surface is arranged, whose light reflected directly from the rolling stock surface is recorded by a television camera is that the from this light source or another provided stroboscopic light source on the

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Rolled stock surface diffusely scattered light from a v / pus TV camera is recorded that the images recorded separately by the television cameras in electronic Storage units are stored and the Storage units are connected to a viewing monitor. A complete record of what is in the tape Error occurs when the stroboscopic light sources and television cameras are above and below the moving rolling stock are arranged. The stroboscopic light sources by means of an image start pulse are preferred of the television cameras can be switched on by means of a trigger control unit. The storage device is advantageous designed as a magnetic tape and / or disk storage, so that their high resolution is used can be.

The advantages of the method and the device according to the invention can be seen in particular in the fact that on simple way and with relatively simple means the whole, of course just as well only parts of the surface of a rapidly moving rolling material can be observed and those from the Observation resulting recordings can be evaluated without interrupting the observation process to have to. In particular, according to the invention

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Method also discovers those surface defects that occur periodically, e.g. B. occur due to errors in (lon rollers. Another essential advantage of the device according to the invention is the use of an observation monitor and recording cameras that are equipped with normal, commercially available television tubes.

The invention is explained in more detail in the drawing on the basis of preferred exemplary embodiments. Show it

i'-ig. 1 and 2 each have an overall arrangement and

Fig. 3 arrangements for storage and image reproduction

in a schc-uiatic way.

In Fig. 1 a below the device according to the invention z. B. aul an outlet roller table of a hot wide strip mill Hot wide strip 1 moving rapidly in the direction of arrow A is shown. Above the j WarmbreitLandes 1 is a light source 2 in the form of a

arranged stroboscopic flash lamp group, namely!

so that the light emitted from the light source 2 I

directly reflective on the surface of the Varmbreitband 1

is animalized. The j

Light rays are recorded by a television camera 5 ^]

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catch. According to its task, the television camera 3 is expediently at the same angle to the rolling stock surface as the light source ? arranged.

Another light source 4- in the form of another stroboscope! see flash lamp group is arranged next to the .Lichtquelle 2 and the television camera 3 in the direction of tape travel. The light source 4 is preferably arranged laterally next to the running hot wide strip 1, also above the strip Λ . Since only the light beams diffusely scattered by the surface of the hot wide strip 1 are to be captured by the further television camera 5, the light source 4- is arranged in an acute angle to the strip surface. The already mentioned television camera 5 is accordingly with advantage directly above the di ■ -. Light source 4-flashed band section arranged.

The light sources 2, 4 and the television cameras 3 ₅ 5 are connected to a trigger control unit 6.

The television cameras 3? 5 are each with a storage unit 7, 8, preferably a magnetic tape storage unit, in which the recorded by the cameras 3, 5 Images are saved.

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During the optical observation of the hot wide strip 1 by means of the device according to the invention, the flash lamps of the light source £ are triggered by means of the trigger control unit 6 by an image start pulse from the television camera 3. The light beams directly reflected by the double piece 9 of the hot wide strip with a length of? 0 cm are recorded by the television camera ') , and the resulting image is stored in the storage unit 7.

After the section 9 of the hot wide strip 1 has left the position below the light source 2 and the television camera 3, it arrives in the area below the television camera 5. Triggered by a pulse from the trigger control unit 6 that takes account of the time interval, the section ') is illuminated by the flash lamps of the light source 4, the light scattered diffusely from the surface is captured by the television camera 5 and the image generated is stored in the storage unit 8 saved.

By means of the directly reflected light and the diffusely scattered light from the same section 9

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on the named and stored in the storage units 7 »8 Images are overlaid and subsequently displayed in one image.

The embodiment shown in Fig. 2a under j
j differs from that in S ¹ Ig. 1 shown in that

the directly reflected and the diffusely scattered image

! of the surface section 9 can be obtained at the same time.

Above the hot wide strip 1 is for this purpose stroboskopieehe light source group 2 arranged so that the light it emits on the surface of the Hot strip 1 is reflected directly into the television camera 3 and that at the same time that of the same surface section 9 diffusely scattered light is recorded by the television camera 5. The television camera is used for this purpose 3 arranged at the same angle to the rolling stock surface as the light source 2, while the television camera 5 in one it is arranged at a substantially different angle above the strip surface.

The television cameras 3 »5 each have a storage unit 7, 8, preferably magnetic tape storage units, in which the recorded by the television cameras 3 »5 Images can be saved separately. At-

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Finally, as described in Example 1, further procedure to bring the images to the display.

Another alternative to image processing is shown in FIG. 2b. The television cameras shown in Figure 2a 3, 5 are connected to a common storage unit 7, in which the images recorded separately by cameras 3 »5 are already stored overlaid can. The already superimposed images are displayed in a display monitor according to FIG. 3.

The possibilities of the storage and image reproduction according to the invention are shown in FIG.

According to FIG. 3a, FIG. 3 shows, schematically, a magnetic tape storage device 10 is shown, are recorded by means of the television cameras 3, 5 during the passage of the hot wide strip 1 Images are stored on the magnetic tape memory 10. At the end of the recording, i. H. then when the whole When hot wide strip has run through the system, the magnetic strip 10a is rewound. According to Fig. 3b are at the following run of the magnetic tape 10a all individual images at a time interval suitable for observation, preferably at a distance of 5 see, accessed and on

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ί shown on a monitor 11. Evaluation of the images can now take place independently of the recording of the images.

j Correspondingly does not need the total number of j to be called up and displayed.

It can e.g. B. suffice, several parts or even just one

j part, preferably that of the middle part of the hot

'< band 1 corresponding part of the magnetic tape 10a in

Call up single image switching, this part of a complete development of all rollers of the Pertig-

j. line corresponds to the hot wide strip mill.

; With an arrangement according to FIG. 3. 3c is the possibility given, while the picture is being taken by the television

meras 3 _S 5 on the same side or following in the shortest possible time,

To call up individual images or individual tape sections for observation, to display them on the warning monitor 11 and evaluate. For this purpose, between the unwinding device and the winder 10 of the magnetic tape 10a a mechanical tape storage device 12 is provided, which is designed so that the entire magnetic tape 10a one Hot wide strip 1 can be stored therein.

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In addition, the observation monitor 11 is provided with a picture tube by means of which an ^{image consisting of 625 lines and 300,000 "to 2} KSO,000 image points can be produced.

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Claims (1)

Hoe sch Werke Aktiene; eseJ! .Schaft, Eberhard π tr. 12, 4-600 Dortmund ' Expectations J
A method for the optical observation of the surface of rapidly moving rolling material, in particular of sheet metal and strips in rolling mills and further processing lines, in which the rolling material is stroboscopically flashed and electronically mapped and the image is stored, characterized in that immediately successive sections of the moving rolling material surface are flashed , recorded by the directly reflected from the surface and / or diffusely scattered from the surface Lxcht images of the surface, and the images recorded by the reflected and / or dis-scattered light are brought together on an observation monitor for display or coincidence and jointly evaluated will. Method according to claim 1, characterized in that da'i the individual flashes are triggered by an image start pulse at the beginning of the image acquisition. 709840/0164 ORIGINAL INSPECTED _ ρ - Process according to Claims 1 and 2, characterized in that that from the same section of the rolled material surface by alternately flashing one image each by means of the directly reflected and de ^ diffusely scattered Light absorbed «i-rd. and recording of the moving rolling material surface can be called up, observed and evaluated. Process according to Claims 1 and 5, characterized in that that the pictures in with parameters of the rolling mill - 3 - 709840/0164 Method according to claims 1 to 3, characterized in that the means of the directly reflected and Double images created by diffusely scattered light paax * - by way of or after optical and / or electronic superimposition together v / earthed for display in one image each. 5. ■ ■ Process according to claims 1 to A-, characterized in that that the images are saved while loading or- Weittrververarbeitungiiuie synchronized lead or at intervals. Process according to Claims 1 to 4, characterized in that that d'_r time interval between the individual flashes greater than the persistence of the imaging system is chosen. 8. j Ancestors according to the preceding claims, characterized in that sections from 1ü to 100, preferred! wise of ^f / U cm length of the Valzgutoberflache can be shown in one picture. \ Device for carrying out the method according to Claims 1 to 8, characterized in that for illuminating the b.-wegenden rolling stock surface (1) a mi .: overhead light source (2) is arranged, whose Light reflected directly from the Wuxzguto. ^ ri'läche (1) is recorded by a television camera (3) that that provided by the light source (2) or another Light source i, 4) -.n the rolling stock surface (1) diffusely scattered Light from another television camera (5) 709840/0164 it is assumed that the images recorded separately by the television cameras (3, 5) are stored in electronic storage units (7, 8) and the storage units (7, 8) with an observation monitor (11) are connected. j Device according to Claim 9i, characterized in that the stroboscopic light sources (2, 4) and television cameras (3, 5) above and below the moving one 'Rolled stock are arranged. Device according to Claims 9 and 10, characterized in that that the stroboscopic light sources (2, 4) by an image start pulse of the television cameras (3, 5) can be switched on by means of a trigger control unit (6) are. Device according to claim 9 »characterized in that that the storage device (7-8) as magnetic Tape and / or disk storage is formed. 709840/0164