JPH0712537A - Method and apparatus for detection of shape of steel plate in inside of continuous annealing furnace - Google Patents

Abstract

PURPOSE:To enhance the controllability and the dealing property of the apparatus by a method wherein slit-shaped light which is tilted to the advance direction of a steel plate is shone irradiated to both faces of the steel plate and the light is imaged from both side faces and judged. CONSTITUTION:Slit-shaped irradiation parts which are situated on both faces of a steel plate are tilted respectively by the same obtuse angle with reference to the advance direction of the steel plate. Pieces of data which have been imaged by image sensing devices 2, 3 on both sides are stored in a memory 21, they are taken out sequentially, images which are obtained by an image processing device 22 are binary- coded, they are made thin, an image processing operation is performed, and a pattern recognition device 23 analyzes the pattern of the images. The output of the device 23 is output to a shape-pattern output device 24. On the other hand, the output 25 of data on the length and the angle of the line of the images which have been judged by the image processing device 22 is input to an operation device 26, it is operated by the operation device 26 together with pattern data from the device 24, and it is output as essential information 27. In addition, the devices can be installed easily in positions in which the shape of the steel plate is easily changed without being restrained by the arrangement of other devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel sheet shape detecting method and apparatus in a continuous annealing furnace.

[0002]

2. Description of the Related Art Generally, in a continuous annealing furnace, an operator visually observes an image from an in-furnace monitoring camera to detect the shape of a steel sheet, or disclosed in JP-A-62-170425 and JP-A-63-62825. As disclosed,
A method of linearly radiating a laser beam in the width direction of a steel sheet, dividing the irradiated portion into multiple pieces in the width direction of the steel sheet with a TV camera, and taking a photograph, and detecting the shape of the steel sheet based on the principle of triangulation. There is.

[0003]

In the prior art, there is a problem that a laser beam irradiation unit and a device such as a television camera for photographing the laser irradiation unit are concentrated at a position facing the surface of the steel plate, and a triangle is formed. Since it is a surveying method, it is necessary to make a certain angle between the laser irradiation section and the camera imaging section. On the other hand, there is a heater device for heating or a cooling gas blowing device for cooling at a position facing the plate surface, and it is difficult to install the irradiation unit and the imaging unit in such a portion.

Therefore, when detecting the shape of the steel plate in the furnace and controlling the shape of the steel plate by using the heating device or the cooling device in the furnace, the installation position of the detection part and the operating part of the heating device etc. Therefore, the controllability is deteriorated because it is separated from the installation position. Further, the shape change occurring in the furnace is mainly in the heating part or the cooling part, and it is impossible to promptly detect the shape defect near the position where the shape is changed, so that there is a problem that the response to the shape defect is delayed.

An object of the present invention is to provide a method and apparatus for detecting the shape of a steel sheet in a continuous annealing furnace which solves the above problems.

[0006]

According to the present invention, in order to solve the above-mentioned problems, only light irradiation is performed from a position facing a steel plate surface, and a camera installation position for photographing this irradiation portion is set on a steel plate side surface. The position is opposite to. That is, the present invention irradiates the steel plate running in the continuous annealing furnace with light,
This irradiation part is imaged, the obtained image is binarized, thinned, and in the method of detecting the furnace shape of the steel sheet, slit-shaped light inclined with respect to the traveling direction of the steel sheet is irradiated on both sides of the steel sheet, It is a steel plate shape detection method in a continuous annealing furnace, characterized in that the irradiation part is imaged from both sides of the steel plate and the steel plate shape is determined from the captured image. In this case, laser light may be used as the light.

The apparatus of the present invention which can suitably carry out the above method is an irradiation apparatus for irradiating both sides of a steel sheet traveling in a continuous annealing furnace with a linear laser beam inclined with respect to the traveling direction of the steel sheet, and a steel sheet. The apparatus for detecting the shape of a steel plate in a continuous annealing furnace, comprising: cameras arranged on both side surfaces of the irradiation device for imaging the irradiation portion; and an analyzer for analyzing the captured image to determine the steel plate shape.

[0008]

According to the present invention, the laser beam applied to the steel sheet is a straight line (dotted line) in the sheet width direction which is inclined at an arbitrary angle with respect to the traveling direction of the steel sheet. It becomes a specific pattern corresponding to the steel plate shape, and the steel plate shape pattern can be detected by discriminating this pattern.

The operation of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an extracted relationship between devices of the present invention arranged with respect to a steel plate 1 passing through a furnace. Steel plate 1
The laser irradiation devices 4 and 5 are arranged so as to face both surfaces thereof, and the image pickup devices 3 and 4 are arranged at positions facing both side surfaces of the steel plate 1.

The laser irradiation devices 4 and 5 have slit-shaped irradiation portions 6 and 7, respectively, formed on both sides of a steel plate. The irradiation parts 6 and 7 are inclined by the same obtuse angle θ with respect to the traveling direction 11 of the steel plate 1. This inclination angle θ is preferably as large as possible within the limit that the entire irradiation units 6 and 7 are within the field of view of the imaging devices 3 and 4. 2 is shown in FIG.
2 is a plan view of the laser irradiation devices 4 and 5 facing both surfaces of the steel plate 1 and the imaging devices 2 and 3 in a planar relationship.

In FIG. 3, when the steel plate 1 is deformed in a plane as shown in FIG. 3A with respect to the image pickup devices 2 and 3, for example, when the steel plate 1 is deformed as shown by the steel plate 1a, the image pickup device 2 is shown. Captures the image 8a shown in FIG. On the other hand, the imaging device 3
Captures the image 9a shown in FIG. If Figure 3
In FIG. 3A, if the steel plate is deformed like the steel plate 1b as shown by the broken line, the imaging device 2 captures the image 8b shown by the broken line in FIG. 3B. On the other hand, the imaging device 3 is shown in FIG.
The image 9b of the broken line shown in (c) is photographed. Therefore, from these images, when the steel sheet 1 is simply tilted to the left and right, the direction of the tilt and the magnitude of the tilt can be analyzed.

FIG. 4 shows a state in which the steel plate 1 is deformed into a C shape. For example, as shown by the solid line in FIG.
Assuming that the steel plate 1a is deformed, the image pickup device 2 is shown in FIG.
The image 8a shown in (b) is photographed. On the other hand, the imaging device 3 captures the image 9a shown in FIG. As described with reference to FIG. 3, assuming that the steel plate is deformed like the steel plate 1b as shown by the broken line in FIG. 4A, the imaging device 2 captures the image 8b shown by the broken line in FIG. 4B. To do. On the other hand, the imaging device 3 captures the broken-line image 9b shown in FIG. From these images, when the steel plate 1 is deformed into C shape,
The direction of the deformation and the size of the deformation can be determined by analyzing the images in FIGS. 4B and 4C.

Even when the steel plate 1 is deformed into the W shape shown in FIG. 5, the deformed shape can be detected from the images of the image pickup devices 2 and 3 shown in FIGS. 5B and 5C. . Figure 6
In the case where the steel plate 1 is a deformed W shape, it can be handled in the same manner as above.

[0014]

EXAMPLE The method of the present invention was carried out by using the apparatus shown in FIG. The irradiation unit 6 formed by the laser irradiation devices 4 and 5,
No. 7 was inclined by 135 degrees with respect to the traveling direction 11 of the steel plate 1. FIG. 7 is a block diagram of the device of the present invention. The data captured by the imaging devices 2 and 3 is stored in the memory 21, sequentially taken out, and the image obtained by the image processing device 22 is binarized, thinned, and image-processed. Pattern recognition device 23
Analyzes the patterns in these images. For this pattern recognition, the analysis as described in FIGS. 3 to 6 is performed. For this analysis, for example, a neural network that has learned these pattern recognitions in advance may be configured and used. The output of the pattern recognition device is output to the shape pattern output device 24. On the other hand, the output 25 of the image line length and angle data determined by the image processing device 22 is input to the calculation device 26, and is calculated by the calculation device 26 together with the pattern data from the shape pattern output device 24 to obtain the necessary data. The information 27 is output. The information 27 can be expressed in the form of necessary information such as a shape coefficient, a shape display approximation formula, a specific dimension, and the like.

8 and 9 are views for explaining the correlation between the size on the image and the size of the line on the steel plate surface. The dimension a ′ in the x direction of the line on the image, the dimension b ′ in the y direction, the length L of the line on the steel plate surface,
The angle formed by this line with the width direction of the steel sheet is α, that is, α = (θ−90) degrees with respect to the angle θ formed with the steel sheet traveling direction.
Where β is the inclination of the image pickup device axis and k is the resolution of the image pickup device, then a = a ′ × k b = b ′ × k L = {(b / tan α) ² + a ² } ^1/2 X = a / (B / tan α) β = tan ⁻¹ X holds.

Since the apparatus of the embodiment is installed dispersedly in multiple directions on the steel sheet, it is easily installed in a portion of the annealing furnace where the shape change of the steel sheet is likely to occur, without being restricted by the arrangement of other apparatuses. Therefore, it is possible to perform useful detection regarding the defective shape of the steel sheet.

[0017]

According to the present invention, the shape of the steel sheet traveling in the continuous annealing furnace can be detected at the most appropriate position without being restricted by the cooling device and other devices.
Moreover, various shapes can be pattern-recognized and necessary information can be detected as desired data.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall arrangement of an apparatus according to an embodiment.

FIG. 2 is a plan view of an example device.

FIG. 3 is an explanatory diagram of image analysis.

FIG. 4 is an explanatory diagram of image analysis.

FIG. 5 is an explanatory diagram of image analysis.

FIG. 6 is an explanatory diagram of image analysis.

FIG. 7 is a block diagram of an example apparatus.

FIG. 8 is a diagram illustrating a correlation between a dimension on an image and a dimension of a line on a steel plate surface.

FIG. 9 is an explanatory diagram of dimensions on an image.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel plate 2, 3 Imaging device 4, 5 Irradiation device 6, 7 Irradiation part 8a, 8b, 9a, 9b Image 10 Central axis 11 Moving direction 21 Memory 22 Image processing device 23 Pattern recognition device 24 Shape pattern output device 25 Output 26 Calculation Device 27 Information

Claims (2)

[Claims] 1. A method for detecting a shape of a steel sheet in a furnace by irradiating a steel sheet traveling in a continuous annealing furnace with light, imaging the irradiated portion, binarizing and thinning the obtained image The steel sheet in the continuous annealing furnace characterized by irradiating both sides of the steel sheet with slit-shaped light inclined with respect to the traveling direction of the steel sheet, imaging the above-mentioned irradiation portion from the side surface directions of the steel sheet, and determining the steel sheet shape from the captured image. Shape detection method. 2. An irradiation device for irradiating both sides of a steel plate traveling in a continuous annealing furnace with a linear laser beam inclined with respect to the traveling direction of the steel plate, and cameras arranged on both sides of the steel plate in the lateral direction for imaging the irradiation part, A steel plate shape detection device in a continuous annealing furnace, comprising: an analysis device that analyzes a captured image to determine a steel plate shape.