JPS6338740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recognizing the two-dimensional shape of an object, and proposes a method effective for recognizing the shape of a thick plate (a steel plate with a thickness of 6 mm or more), for example.

Measures the planar shape (effective width, length, corner shape, squareness, etc.) of a steel plate during rolling in a short period of time, such as during the extra time when the rolling direction is reversed after leaving the reversing mill. Conventionally, there has been no method to do this, and for this reason, it has been impossible to reflect the planar shape during rolling in rolling control.

Conventionally, as a means of measuring the planar shape of thick plates, etc.
The following three are known as representative ones. One of these uses the self-emission spectrum of hot-worked steel, in which an optical system consisting of an infrared photomultiplier tube and a mirror is placed above the steel, and the field of view is changed by swinging the mirror. A configuration in which a steel material is scanned and the width and/or length of the steel material is determined by correlating the scanning system signal and the photomultiplier tube output, assuming that the point of sudden change in the photomultiplier tube output is at the edge of the steel material. can be,
The width and length meters manufactured by KELK are equivalent to this. However, this device performs scanning in which the longitudinal direction is the main scanning direction and the width direction is the sub-scanning direction, and scanning in which the width direction is the main scanning direction and the longitudinal direction is the sub-scanning direction. Since the width dimension at each part in the longitudinal direction is determined, the measurement target is 2 to 3.
It needs to be stopped for even seconds. Furthermore, since it uses a self-emission spectrum, it is easily affected by the surface condition and temperature of the object to be measured, and is particularly prone to errors due to scale on edges, water deposits, etc. In addition, it is extremely expensive.

Next, there is a method in which the object to be measured is photographed using near-infrared or visible television, and the shape is determined by pattern recognition. However, when this method is used to measure hot steel materials such as thick plates being rolled, the influence of temperature unevenness is significant, and errors occur if the edges are cold or covered with scale.

The third method is to use a width meter with a bottom light source. This is a method that uses this width meter to determine the width of each part in the longitudinal direction, and then measures the shape from this and the information about the transfer distance in the longitudinal direction. It can be used in places with good environments such as thick plate finishing lines. However, in a rolling line, scale and water fall into the light source at the bottom, making it unusable, and there is a limit to the transfer speed.

The present invention was developed in view of the above circumstances, and is capable of high-speed shape recognition, and is highly accurate, being almost unaffected by the surface condition and temperature of the object to be measured, and is capable of recognizing the shape of a thick plate. It is an object of the present invention to provide a two-dimensional shape recognition method that recognizes each rolling pass and can be used as control information for the next rolling pass.

The first method of the present invention is a method that can detect the edge shape in detail, and involves continuous projection of light or scanning projection of light onto the surface to be recognized. A first process of drawing striations, capturing images of these striations with a two-dimensional imaging device, and determining the position of the edge of each striation through data processing of the captured image, and specifying the position based on this position. A ray is drawn on a portion including the edge of the surface by continuous projection of light or scanning projection of light, the ray is imaged with a two-dimensional imaging device, and the shape of the edge is determined by data processing of the captured image. , and the second process is 1
It is characterized by being executed once or multiple times.

FIG. 1 is a schematic diagram showing the state of implementation of this first method. A thick plate whose shape is to be recognized leaves a reversible rolling mill (not shown), is sent in the direction of the white arrow, is stopped at a substantially fixed position, and is then sent back. 4
Reference numeral 1 is an HMD (Hot Metal Detector) that detects when the thick plate 10 reaches the stop position, regardless of whether the tip shape of the thick plate 10 is a tongue-like shape with a protruding central part or a fishtail-like shape with a concave central part. The tip of the HMD is placed in an upper position where it can be detected.
41 opens the shutters (not shown) covering the beam projection ports of the laser beam generators 11 and 21 in synchronization with the output signal that detects the thick plate 10, and also instructs the arithmetic unit 1 to start calculation. I have to. For example, the laser beam generators 11 and 21 are
It is an Ar laser device that outputs light with a wavelength in the range of 3511 to 5145 Å. This wavelength is shorter than the natural luminescence of hot slabs, which is in the red, near-red, and infrared regions. 12 and 22 are convex lenses placed in front of the generators 11 and 21 to diffuse the laser beam;
Furthermore, rotating mirrors 13 and 23 are arranged in front of these convex lenses 12 and 22, respectively. rotating mirror 1
3 and 23 are in the shape of a hexagonal prism, and have a shaft 130, 230 at the center thereof, which is the center of rotation, and rectangular plane mirrors 131, 231 on six surrounding surfaces. FIG. 2 schematically shows the internal structure of the rotating mirror 13 (23 is the same). A plane mirror 131 whose mirror surface is made by vapor-depositing aluminum or the like on a glass plate is attached to one end of a substrate 132 constituting one bottom surface of a hexagonal prism. It is pivotally supported by the
Similarly, on the substrate 133 side that constitutes the other bottom surface, claw-shaped holding members 134, 134 are attached to the peripheral edge of the substrate 133 so as to urge the plane mirror 131 toward the shaft 130 side, and the plane mirror 131 is pushed out in the centrifugal direction. In addition, the back surface of the plane mirror 131 (shaft 130
the substrate 1 facing the holding members 134, 134 on the side)
One end of the piezoelectric elements 135, 135 is attached to the end portion on the 33 side. The substrates 132 and 133 are connected by a connecting rod 136 and a shaft 130 arranged at the corners of a hexagon, and the peripheral edge of the back surface of the plane mirror 131 is brought into contact with the outer peripheral surface of the connecting rod 136 and the peripheral edge of the substrate. Comes with cushioning material to protect it. The other ends of the piezoelectric elements 135, 135 are connected to the substrate 133.
The plane mirror 131 is attached to a holder fixed to the back surface, and dimensions are determined so that the plane mirror 131 is parallel to the axis when no voltage is applied to the piezoelectric element. Two electrodes 136, 136 are fixed to each piezoelectric element 135, and each lead wire connects all the piezoelectric elements (total 12
The reflection angle control circuit 14 is connected to a common slip ring 137, 137, and is connected to the reflection angle control circuit 14 via a brush (not shown).

The rotating mirror 23 has a similar structure and is connected to the reflection angle control circuit 24. The shafts 130, 230 are connected to a motor (not shown) and rotate at high speed. The rotating mirror 13 is configured so that the laser beam emitted from the laser beam generator 11 and diffused by the lens 12 scans the longitudinal center of the thick plate 10 in the width direction to draw a light streak l ₁ of an appropriate width. In addition, the rotating mirror 23 is configured so that the laser beam emitted from the laser beam generator 21 and diffused by the lens ₂₂ scans the center of the width direction of the thick plate 10 in the longitudinal direction to draw a light streak of an appropriate width. the respective shafts 130, 23
The direction of 0 is determined.

The reflection angle control circuits 14 and 24 apply a DC voltage to the piezoelectric elements 135 and the like of the rotating mirrors 13 and 23 in accordance with signals given from the arithmetic unit 1. Piezoelectric element 1
35 contracts and expands depending on the polarity of the applied voltage to connect the substrates 133, 233 of the plane mirrors 131, 231.
The side end portions approach or separate from the shafts 130, 230, and the amount of approach or separation is determined depending on the value of the applied voltage. As a result, the position of the rays will change. In other words, the configuration is such that the position of the striations can be freely changed and adjusted based on the output of the arithmetic device.

2a is the camera head of television camera 2;
2b is a control unit. An interference filter 3 is attached to the lens surface of the camera head 2a to selectively transmit laser light of the aforementioned wavelength. Since the self-emission spectrum of the thick plate is on the longer wavelength side, the image taken by the television camera 2 clearly captures only the rays on the thick plate.
Furthermore, if a laser beam is projected onto the rollers of a roller conveyor below the plank, streaks in this area may also appear in the image, but by binarizing the video signal using an appropriate threshold, It becomes possible to make only the rays on the plank effective. The output of the control unit 2b, that is, the video signal, is input to the edge list 3, where the video signal is binarized, striations and other parts are distinguished, and the coordinate values of the edges of the striations are memorized.

In the case of this first method, the width of the striation is 10 mm.
It is determined according to the shape of the top and bottom.
The rays are used to illuminate the edges as described below, but due to the size of the irregularities and control errors, the edges do not fall within the rays, that is, they are not illuminated. It is desirable to have a certain width to prevent this from occurring, and it is also desirable to have a narrow width from the viewpoint of ease of data processing. Therefore, if the distance between the most convex part and the most concave part of the top or bottom of the thick plate is about 100 mm at most, it is better to select about 300 mm.

Figure 3 shows the captured image (however, it is binarized and shows the light streak l ₁ ,
The state in which only l ₂ appears) is shown schematically. For example, Edge List 3 has an X-
In the Y coordinate system, both vertical edges of ray l ₁
The X and Y coordinates of Yu, Yd and both horizontal edges Xl and Xr of the ray _l2 are obtained. These are a set of X and Y coordinates of pixels that constitute each edge line, but the calculation device 1 calculates the average values (Yu) and (Yd) for each Y coordinate group for edges Yu and Yd.
Find this and use this as the edge position. one edge
Regarding Xl and Xr, the average values (Xl) and (Xr) for each X coordinate group are determined, and these are taken as the edge position. The arithmetic unit 1 further calculates the intersection coordinates (Xc, Yc) of the rays l ₁ and l ₂ from the contents of the edge list 3.
seek. For this purpose, the average of the coordinate values of the four corners of the square portion formed at the intersection of the rays l ₁ and l ₂ is used.

Arithmetic unit 1 was obtained in this way (Xc,
Find the amount of streak movement from Yc), (Xl), (Xr), (Yu), and (Yd) as L ₁₁ = Xr−Xc L ₁₂ = Xl−Xc L ₂₁ = Yu−Yc L ₂₂ = Yd−Yc .

The moving amounts L ₁₁ and L ₁₂ are sequentially input to the reflection angle control circuit 14 at predetermined time intervals, and the moving amounts L ₂₁ and L ₂₂ are sequentially input to the reflection angle control circuit 24 at predetermined time intervals. Based on these input signals, the reflection angle control circuits 14 and 24 control the piezoelectric elements 135 of the rotating mirror 13 and the piezoelectric elements of the rotating mirror 24 by the above-mentioned movement amount _.
Apply a voltage of the polarity that should cause _l2 to swing. As a result, the top, one edge, bottom, and other edge of the plank are sequentially irradiated. FIG. 4 shows a captured image in which the top portion and one side edge are illuminated by the rays l ₁₁ and l ₂₁ formed by the rays l ₁ and l ₂ . Further, FIG. 5 shows a captured image in which the bottom part and the other side edge part are illuminated by the rays l ₁₂ and l ₂₂ formed by the rays l ₁ and l ₂ . In addition, the angle of inclination of each mirror surface of the rotating mirror is set to a different angle,
As shown in FIG. 7, it is also possible to simultaneously irradiate portions corresponding to four sides and obtain edges from captured images corresponding to the four sides.

In the binarized signal in Edge List 3, there are no outlines such as rays _l11 outside the thick plate, and instead, the periphery of the thick plate becomes the boundary between bright and dark. As a result, the coordinates of the peripheral edge of the thick plate are stored in the edge list 3. The arithmetic unit 1 processes this coordinate information into required shape information, outputs this to an output display device 4 such as a printer, and supplies it to a processing controller 5 for controlling the reversible rolling mill as a rolling control signal.

In the above embodiment, a laser beam generator was used as the light source, but other types may be used.A light source with a color different from the self-luminous color of the hot material is used, and the light source is passed through a slit of an appropriate width. It can also be used as a beam. Furthermore, the striations may be drawn by continuous irradiation instead of scanning. The scanning means is not limited to the above-mentioned rotating mirror, but other conventionally known means may be used. Furthermore, the means for changing the position of the striations is not limited to the piezoelectric element, but other means such as a solenoid may also be used.

Furthermore, depending on the plate size, desired resolution, etc., a plurality of television cameras may be used and the imaging portion may be shared by each television camera.

In this case, it is sufficient to use as many edge lists as there are TV cameras and unify the coordinate systems using the arithmetic unit, but the intersection of the rays l ₁ and l ₂ should be included in the field of view of each camera, The coordinate system is unified based on this.

Alternatively, the steel plate may be automatically detected using a captured image without using an HMD.

Next, a second method of the present invention will be explained. This method involves determining the width of the top and bottom, the length of the side edges, etc., and then recognizing the shape.The method involves continuously projecting light or scanning light onto the surface to be recognized. a first step of drawing two mutually non-parallel rays, capturing images of these rays with a two-dimensional imaging device, and determining the position of the edge of each ray through data processing of the captured images; Similarly, rays parallel to the rays are drawn on other parts of the surface specified based on these lengths, and the rays are imaged with a two-dimensional imaging device, and the captured image data is a second step of determining the position of the edge of each striation by processing;
It is characterized by performing the process one or more times.

This method will be explained below. The apparatus used to carry out this method is similar to that shown in FIG. 1, and the first step of drawing the striations l ₁ and l ₂ is also similar.
However, in the second method, the edge of the plate is not included within the width of the ray, so the width of the ray may be narrow, and the convex lens 1
The use of 2 and 22 can be omitted.

Then, as shown in Fig. 6, in the same way as the first method, rays l ₁ and l ₂ are drawn approximately in the center, and (Xr), (Xl),
Find (Yu), (Yd), and (Xc, Yc). Next, in this method, the ray l ₁ is sequentially moved to a position slightly closer to the center than the edges of the top and bottom parts, and the ray l ₂ is moved to a position slightly closer to the center than the edges of both sides. Move to positions sequentially. That is, the arithmetic unit 1 calculates the amount of movement as L ₁₁₁ =Xr-Xc-α ₁ L ₁₂₁ = Xl-Xc-α ₁ L ₂₁₁ = Yu-Yc-α ₂ L ₂₂₁ = Yd-Yc-α ₂ . Here, α ₁ and α ₂ are (Xr), (Yu)
etc., is the distance in the longitudinal direction and width direction that should be moved from the edge position of the striations l ₁ and l ₂ to the center,
For longitudinal directions with large irregularities, α ₁ = approximately 150 mm;
In the width direction, it is preferable to set α ₂ to be shorter than this, approximately 100 mm.

After the calculation, the calculation device 1 sends a predetermined signal to the reflection angle control circuits 14 and 24 in order to realize this movement amount.
Output to. As a result, a voltage is applied to the piezoelectric element to draw striations l ₁₁₁ , l ₁₂₁ , l ₂₁₁ , and l ₂₂₂ near the edges of the four peripheries. These rays are imaged and the coordinates of the edges of the rays are stored in the edge list 3. In this method, the computing device 1 is able to detect the longitudinal edges of the rays l ₁₁₁ and l ₁₂₁ (widthwise edges of the plate). (edge) position or the length between the edges, and also determine the position of the longitudinal edge of the rays l ₂₁₁ and l ₂₂₁ or the length between the edges.

Next, each ray is drawn at a position moved closer to the center by β (for example, 10 mm), and the position of the edge of the ray is determined in the same way.

That is, L ₁₁₂ = Xr−Xc−α ₁ −β L ₁₂₂ = Xl−Xc−α ₁ −β L ₂₁₂ = Yu−Yc−α ₂ −β L ₂₂₂ = Yd−Yc−α ₂ −β as the light l ₁ Rays away from L ₁₁₂ , L ₁₂₂ L ₁₁₂ , L ₁₂₂
, and also sequentially draw rays L ₂₁₂ and L ₂₂₂ , which are L ₂₁₂ and L ₂₂₂ away from ray L ₂ . Thereafter, the same process is repeated in increments of β, thereby recognizing the shape.

According to the method of the present invention as described above, shape recognition can be performed without being affected by the temperature, surface condition, etc. of the object to be recognized. Furthermore, since it generally takes about 1/30 second to capture one frame of image, shape recognition according to the present invention is sufficiently possible within one second, and the speed can be significantly increased. For this reason, in thick plate rolling, shape recognition can be performed quickly by reversing the conveying direction without having to stop the plate for shape recognition, and as a result, the shape can be recognized without any loss in rolling efficiency. The present invention has excellent effects, such as being able to perform recognition and use the recognition results for rolling control of the next rolling pass.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a schematic diagram showing the implementation state of the first method, and FIG.
The figure is a schematic diagram of the internal structure of the rotating mirror, Figure 3 is a schematic diagram of the captured image, Figures 4 and 5 are explanatory diagrams of the recognition principle, and Figure 6 is an illustration of the recognition principle.
The figure is an explanatory diagram of rays drawn by the second method,
FIG. 7 is a captured image diagram showing another implementation state of the first method. 1... Arithmetic device, 2... Television camera,
3... Edge list, 11, 21... Laser beam generator, 13, 23... Rotating mirror, 14, 24
...Reflection angle control circuit, 135...Piezoelectric element.

Claims (1)

[Claims] 1. Two mutually non-parallel rays are drawn on a surface to be recognized by shape by continuous projection of light or scanning projection of light, and these rays are transmitted to a two-dimensional imaging device. The first step is to obtain the position of the edge of each striation by data processing the captured image, and to continuously project light or light onto the portion including the edge of the surface specified based on this position. A second step includes drawing a striation by scanning and projecting the striation, capturing an image of the striation using a two-dimensional imaging device, and determining the shape of the edge through data processing of the captured image. A two-dimensional shape recognition method characterized by being executed once or multiple times. 2 Draw two mutually non-parallel rays on the surface to be shape recognized by continuous projection of light or scanning projection of light, image these rays with a two-dimensional imaging device, and capture the image. A first process of determining the position of the edge of each striation by image data processing, and similarly placing striations parallel to the striation on other parts of the surface specified based on these lengths. a second step in which the rays are imaged with a two-dimensional imaging device, and the position of the edge of each ray is determined by data processing of the captured image, and the second step is performed one or more times. A two-dimensional shape recognition method characterized in that the two-dimensional shape recognition method is performed twice.