KR20140084612A - Strip edge monitoring system and method - Google Patents

Strip edge monitoring system and method Download PDF

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Publication number
KR20140084612A
KR20140084612A KR1020120154256A KR20120154256A KR20140084612A KR 20140084612 A KR20140084612 A KR 20140084612A KR 1020120154256 A KR1020120154256 A KR 1020120154256A KR 20120154256 A KR20120154256 A KR 20120154256A KR 20140084612 A KR20140084612 A KR 20140084612A
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South Korea
Prior art keywords
edge
defect
image
casting
unit
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KR1020120154256A
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Korean (ko)
Inventor
황석균
임지우
김윤하
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주식회사 포스코
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Priority to KR1020120154256A priority Critical patent/KR20140084612A/en
Publication of KR20140084612A publication Critical patent/KR20140084612A/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
    • B21B38/02—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring flatness or profile of strips
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/12—Accessories for subsequent treating or working cast stock in situ
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8851—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined

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  • Engineering & Computer Science (AREA)
  • Biochemistry (AREA)
  • Analytical Chemistry (AREA)
  • Pathology (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Immunology (AREA)
  • Mechanical Engineering (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Signal Processing (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

Abstract

According to an aspect of the present invention, there is provided an image forming apparatus including: a photographing unit that acquires a video image of an edge of a casting; a defect detecting unit that detects a defect of the casting edge by primary image processing of the image acquired by the photographing unit; And a processing unit for classifying defects detected by the detecting unit into predetermined defect types and converting the defects into a database.

Description

[0001] STRIP EDGE MONITORING SYSTEM AND METHOD [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a billet edge monitoring system and method, and more particularly, to a system and method for capturing an edge portion of a billet, detecting a defect,

In double-roll laminated casting equipment, the quality of the edge of the casting, which is the product, determines the amount of trimmings in the final product, which directly affects the yield rate of the product. The quality of the cast strip edge can be improved by reducing the skull formation suppression, edge scoring, bending, and fin phenomenon through adhesion of the casting roll and edge dam and edge dam vibration operation, and edge dam operation Most of the results are obtained by moving the commercialized coil to the yard and then knowing the state of the worker.

In such a case, a hold time delay of about 10 minutes, which is a time when one coil is wound, occurs. If the edge state is deteriorated, the quality of the next coil in addition to the coil becomes worse. In such a situation, the product yield is lowered. In severe cases, even if the wear rate of the edge dam is changed to the maximum, the quality of the casting edge may be irreversibly deteriorated. Therefore, it is preferable to check the casting edge condition in real time.

The edge state of the cast steel can be checked immediately after casting and at the time when the coil is wound after hot rolling. The latter method has a disadvantage in that it can not immediately check the operation state of the edge dam, There is an advantage that the edge state of the cast steel can be directly checked against defects such as edge fins, cracks, and wagging in the cast steel.

As a conventional technique relating to a method and an apparatus for inspecting the state of a cast steel in a twin roll thin plate manufacturing process, "method and apparatus for detecting a surface defect of cast steel" is disclosed in Korean Patent Application No. 10-2008-0077759. However, this conventional technique is incapable of detecting a defect within a few millimeters due to the limitation of the image acquiring apparatus, and the image processing process is delayed by several tens of seconds to generate an output. The accuracy is not guaranteed until the defect size is within several tens of um.

There is a remote inspection apparatus for the surface of a hot rolled plate as disclosed in Korean Patent Laid-open Publication No. 10-2003-0014524, which is a remote inspection apparatus for the surface of a hot rolled steel sheet. There is a problem that it is difficult to directly apply the defect detection method to a twin roll type thin plate manufacturing process.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems of the prior art, and it is an object of the present invention to detect accurate defect information for a high-speed moving piece in a twin roll type thin plate manufacturing process,

According to an aspect of the present invention, there is provided an image forming apparatus including: a photographing unit that acquires a video image of an edge of a casting; a defect detecting unit that detects a defect of the casting edge by primary image processing of the image acquired by the photographing unit; And a processing unit for classifying defects detected by the detecting unit into predetermined defect types and converting the defects into a database.

In addition, it is possible to provide a method of monitoring a billet edge to which the system is applied.

According to the present invention, it is possible to optimize the quality of the casting and the operation of the edge dam by transmitting the casting edge condition information to the operator in real time by detecting and classifying the defect through the image of the edge portion and data. In addition, the edge quality of the coiled product can be known immediately, and important information can be provided in post-processing and edge trimming.

1 is a configuration diagram of a billet edge monitoring system according to an embodiment of the present invention.
2 is an example of a screen displayed on the display unit of the billet edge monitoring system according to the embodiment of the present invention.
3 is a flowchart showing a method of monitoring a billet edge according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art can easily carry out the present invention.

In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the drawings, like reference numerals are used throughout the drawings.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to "include" an element means that it may include other elements, rather than excluding other elements, unless specifically stated otherwise.

1 is a configuration diagram of a billet edge monitoring system according to an embodiment of the present invention.

1, the billet edge monitoring system 100 according to the present embodiment may include a photographing unit 110, an illumination unit 120, a defect detection unit 130, a processing unit 140, and a display unit 150 . The billet edge monitoring system 100 according to the present embodiment can be applied to a twin roll type thin plate casting machine, in which the biaxial thin plate casting machine is provided with a casting machine for casting a thin plate by coagulating and pressing molten steel by two casting rolls rotating in the opposite direction And a discharging portion for rolling and winding the cast thin sheet. In the present embodiment, the photographing unit 110 and the illumination unit 120 can be installed in front of the take-up unit of the discharge unit of the twin roll type sheet metal casting machine.

The photographing unit 110 may be a high-quality camera capable of high-speed photographing. Since the cast piece 1 transferred from the roll bed can move at a maximum speed of 240 m / min, it is preferable that the photographing speed of the photographing unit 110 is fast to photograph the accurate image. In addition, since wave form defects are generated in the cast shape on the roll bed on which the cast strip is fed, or the cast strip edge portion is shaken up and down due to the vibration due to the high-speed feed, It is preferable that the diaphragm of the photographing lens is tightened as much as possible in order to minimize the focus change caused by the lens. Also, in order to obtain a precise expression image for a high-speed cast slab, it is preferable to tighten the aperture value to at least f5. In order to prevent image blurring due to high-speed movement of the casting, Or more.

The photographing unit 110 preferably fixes the lens direction so as to observe the same edge portion in the cast steel, and illuminates the part to be photographed by the lighting unit 120 brightly. In the present embodiment, two independent cameras can be independently operated for image processing on both edge portions of the casting.

The illumination unit 120 may irradiate a predetermined amount of light to the cast strip 1 to improve the blurring phenomenon of the image captured by the photographing unit 110. In the present embodiment, the illumination unit 120 may be an illumination device using a light emitting diode (LED). The halogen metal lamp is used as a lighting device. However, such a halogen metal lamp consumes a large amount of electric power, shortening the lifetime of the lighting device, and turning on / off there has been a synchronization problem in which the lighting device must be operated by on / off switching. In this embodiment, by using the illumination unit using LEDs to overcome the disadvantages of such a halogen metal lamp, it is possible to irradiate the surface of the cast steel with light of uniform intensity, thereby improving the accuracy in defect detection. In the present embodiment, it is preferable that the illumination unit 120 uses illumination of 70,000 lux or more in consideration of the light reflectance of the gray-silver hot-rolled steel sheet.

It is preferable that the incidence angle of light with respect to the billet in the illumination unit 120 is symmetrical in consideration of the incidence angle of the lens in the photographing unit 110. At this time, it can be assumed that the main body is placed horizontally. In order to capture the state of the edge of the cast strip at a high resolution, when the target resolution is 50 μm / pixel, the shooting unit (5000 * 3000 pixels) is installed at about 2100 mm above the casting so that the system can be protected against high- . In this case, if a large diameter lens with a minimum diameter of 200 mm or more is used, the photographing area may be about 25 cm in the conveying direction of the billet. Since the light source must be intensively irradiated to the corresponding portion of the casting film to be photographed, the lighting unit 120 is preferably installed at a distance of about 1700 mm from the billet. For this purpose, a lens having a viewing angle of less than 15 degrees can be used for the illumination unit.

It is preferable that the photographing unit 110 and the illumination unit 120 are arranged so as to be able to move horizontally by a simple operation when there is a large change in the width of the main roll.

In the present embodiment, the edge portion of the cast steel means a portion within 300 mm from the end of the cast steel.

The defect detector 130 can detect a defect that is not a normal state from the image of the billet edge portion photographed by the photographing unit 110. The defect detector 130 may first extract the edges of the main marginal area using a predetermined algorithm (Edge Detect Algorithm), and then determine whether the edge sub-line is straight or not by predetermined mathematical modeling. If the straight line does not form a certain part of the edge line, the part can be recognized as a defect.

In the processing unit 140, defects extracted from the defect detecting unit 130 can be classified into predetermined types of defects and a database can be formed. That is, when a defect is detected in the defect detector 130, it is possible to classify the defect as an edge tear, a crack, a fin fin, or a wicked defect, and form a database thereof. Since each of these defects has different feature parts, it is possible to classify the types of defects using the information. The characteristic portion that determines the type of the defect may be a color of a portion of a casting edge to be photographed, a cast average image brightness, a width and a length, a width to height ratio, an inside or outside of an edge portion, As an example of the method of classifying defect types in the processing unit 140, a predetermined reference value is inputted in advance for each feature part, and when the calculated value of the feature part photographed in the actual photographing part exceeds the reference value, A method of classifying the defect into the defect determined by the feature portion may be used.

Since a large amount of image data must be transmitted in real time from the photographing unit 110 to the defect detecting unit 130, optical module communication can be used to secure a transmission speed reduction and communication stability according to the movement distance.

The display unit 150 may display each of the defect information of the edge portions classified by the processing unit 140. Fig. 2 is a view showing an example of a display unit according to the present embodiment. The display unit 150 in the present embodiment may be a monitor disposed in a cab with an edge dam driver. The display unit 150 of the present embodiment allows the state of each frame to be selectively displayed and the edge dam operator can confirm the state of the slab of the corresponding part with a simple selection operation for each frame. Also, in the integrated system, the defective state of the product coil can be displayed as an image by receiving data from both sides.

In the twin roll type thin sheet manufacturing process using the billet edge monitoring system according to the present embodiment, the billet edge information is transmitted to the biller in real time by detecting and classifying and detecting the defect through the video image of the edge portion, Edge dam operation can be optimized. In addition, the edge quality of the coiled product can be known immediately, and important information can be provided in post-processing and edge trimming.

3 is a flowchart of a billet edge monitoring method according to another embodiment of the present invention.

A method for monitoring a billet edge according to an embodiment of the present invention includes a step S310 of obtaining a video image of an edge of a cast bill, a step S320 of detecting a billet edge defect by processing the obtained image And classifying the detected defects according to a predetermined defect type, and processing the detected defects into a database (S340).

The method for monitoring a billet edge according to the present invention is characterized in that when a defect is not detected in step S320 of detecting the defect (S330), the step S310 of obtaining the image is executed again, Monitoring can be performed.

The casting edge monitoring method may further include a step S310 of sorting the detected defects according to a predetermined defect type and forming a database in step S340 and continuing the casting in step S350 Continuous casting edge monitoring during the casting process can be performed.

The present invention is not limited to the above-described embodiments and the accompanying drawings. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

110: photographing unit 120: illuminating unit
130: Defect detection unit 140:
150:

Claims (8)

A photographing unit for acquiring a video image of the edge of the casting;
A defect detecting unit for detecting a defect of the billet edge by performing a primary image processing on the image obtained by the photographing unit; And
A processor for classifying defects detected by the defect detector into a predetermined defect type,
And a cutting edge monitoring system.
The method according to claim 1,
The billet edge monitoring system includes:
And an illumination unit
Further comprising: a cutting edge monitoring system.
The method according to claim 1,
Wherein the defect detecting unit comprises:
Wherein the edge of the casting is extracted and then mathematical modeling is performed to determine whether the edge line is straight or not.
The method according to claim 1,
Wherein,
Wherein at least one of the color of the corresponding region, the average surrounding image brightness, the horizontal and vertical sizes, the horizontal and vertical ratios, and the edge positions of the primary image processed in the primary image processing is used to classify the type of the defect, system.
The method according to claim 1,
A display unit for displaying data converted into a database by the processing unit
Further comprising: a cutting edge monitoring system.
Acquiring a video image for the edge of the casting;
Detecting a defect of a billet edge by performing a first image processing on the obtained image; And
Classifying the detected defects according to predetermined defect types,
Wherein the method comprises the steps of:
The method according to claim 6,
The billet edge monitoring method includes:
And if the defect is not detected in the step of detecting the defect, the step of acquiring the image is re-executed.
The method according to claim 6,
The billet edge monitoring method includes:
Wherein the step of acquiring the image is performed again if the casting is continued after the step of forming the database.
KR1020120154256A 2012-12-27 2012-12-27 Strip edge monitoring system and method KR20140084612A (en)

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KR1020120154256A KR20140084612A (en) 2012-12-27 2012-12-27 Strip edge monitoring system and method

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210304399A1 (en) * 2020-03-31 2021-09-30 Ngk Insulators, Ltd. Inspection method and inspection system for pillar-shaped honeycomb structure made of ceramic
CN114252504A (en) * 2021-12-20 2022-03-29 马鞍山钢铁股份有限公司 Online rapid detection method and detection device for corner cracks of continuous casting slab

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210304399A1 (en) * 2020-03-31 2021-09-30 Ngk Insulators, Ltd. Inspection method and inspection system for pillar-shaped honeycomb structure made of ceramic
US11915409B2 (en) * 2020-03-31 2024-02-27 Ngk Insulators, Ltd. Inspection method and inspection system for pillar-shaped honeycomb structure made of ceramic
CN114252504A (en) * 2021-12-20 2022-03-29 马鞍山钢铁股份有限公司 Online rapid detection method and detection device for corner cracks of continuous casting slab

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