JPH02194307A - Curvature shape measuring instrument for plate-like body - Google Patents

Abstract

PURPOSE:To improve the quality of a rolled product by obtaining linear images at three positions which are at intervals in the moving direction of the plate-like body simultaneously and finding the curvature shape from position information extracted from the linear images. CONSTITUTION:When a steel plate 10 which is being rolled is carried by a table roller 24, a steel plate front end detector 12 detects whether or not the front end part of the steel plate 10 enters the visual field 15 of a video camera 16. When the front end part of the steel plate 10 is detected, the detection signal of the detector 12 is inputted to a camera controller 18. Then, the controller 18 uses the detection signal as a trigger signal and inputs the video information of the camera at the front end detection time point to an image processing part 20 for edge detection as a still image. Consequently, the processing part 20 obtains a still image of the flank of the steel plate 10. Then an arithmetic processing part 22 finds the curvature of the steel plate 10 from a specific expression based upon the coordinates of three points on the surface of the steel plate in the still image inputted from the processing part 20.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a warpage shape measuring device for a plate-shaped object, and particularly,
The warpage curvature of the steel plate is measured during rolling, and the warpage curvature is used to reflect the warpage curvature in the control of the rolling mill, or to determine whether or not the steel plate comes into contact with equipment located downstream of the rolling mill. , relates to an apparatus for measuring the warp shape of a plate-shaped object, which is suitable for use in protecting equipment.

[Conventional technology]

In a rolling line, warping may occur at the tip of a steel plate, and it is necessary to measure the shape of the warp, such as the curvature of the warp and the amount of warp, from the viewpoint of rolling mill control and downstream equipment protection. Conventionally, there is a device that uses image processing to measure the warped shape of a steel plate. In this device, the tip of the steel plate is imaged from the side direction of the steel plate, and the imaged two-dimensional surface @ (2
After processing the dimensional image (@) as it is for all pixels, extract the edge coordinates of the steel plate, and from a large number of edge coordinate groups,
The warp curvature, which is one of the characteristic quantities of the warp shape, was determined.

[Problems to be Solved by the Invention] Therefore, in the shape measuring device, a large amount of data processing is required, and the image processing process takes time. It took a lot of time. Particularly, in a measuring device that extracts edge coordinates from a two-dimensional image and then uses a regression equation to determine the curvature, it typically takes several seconds to several tens of seconds. Furthermore, when image processing is performed using soft logic, it takes more time to transmit video information. Therefore, with conventional warp shape measuring devices, the processes in which they can be used online are quite limited, and in cases where it is not possible to perform control according to the warp shape of a plate-shaped object such as a steel plate in rolling mill equipment. There have been problems in that there are cases where it is not possible to sufficiently protect the equipment. To solve these problems, it is conceivable to obtain one-dimensional image information from the side surface of the plate-shaped object using a one-dimensional image sensor, and measure the warped shape from the image information. If this one-dimensional image sensor is used, the amount of data to be handled is much smaller than that of a two-dimensional image sensor, so the processing time can be significantly shortened. However, when one image sensor is used, it can be expected that the accuracy of time axis alignment according to the movement of the steel plate will be sufficient, and when three image sensors are used, there will be a gap between the image sensors. Sometimes it is difficult to synchronize the imaging timing. Therefore, in the past, even if a one-dimensional image sensor was used, measurement accuracy could not be reliably improved. Note that Japanese Patent Application Laid-Open No. 59-85903 discloses a proposal that is common to the present invention in that it photographs the edge of a steel plate and obtains image GTCM information. This publication discloses a technique for obtaining a two-dimensional still image of the edge of a steel plate using an electronic shutter, etc., but its purpose is different from that of the present invention; its purpose is to obtain a cropped shape of the edge of a steel plate; The structure is also different in that two two-dimensional cameras are used and the images obtained by them are combined. The present invention has been made to solve the above-mentioned conventional problems, and simplifies the processing contents of the image processing process, and
It is an object of the present invention to provide a warpage shape measuring device for a plate-shaped object that can reduce processing data, shorten processing time, and speed up the measurement of warp shapes while maintaining measurement accuracy. [Means for Achieving the Object] The present invention provides an apparatus for measuring the warped shape of the tip of a moving plate-like object based on image information obtained by imaging the moving plate-like object from the side direction. , means for simultaneously obtaining one-dimensional images at three locations spaced apart in the moving direction of the plate-shaped object, and means for simultaneously obtaining one-dimensional images at three locations on the upper surface or lower surface of the plate-shaped object from the obtained one-dimensional images; Based on the means for extracting location information and the extracted location information,
The above object has been achieved by providing a means for determining the warped shape.

[! @Actions and effects of Ming]

In the present invention, in the apparatus for measuring the warp shape of a plate-shaped object, first, one-dimensional images at three locations spaced apart in the moving direction of the plate-shaped object are obtained simultaneously. To obtain one-dimensional images at the same time, for example, a video camera with a high-speed shutter is used to image a plate-like object from the side, and the resulting two-dimensional still image as shown in Figure 2 below is obtained. By extracting the images on three scanning lines spaced apart in the traveling direction of the plate-shaped object as one-dimensional images, it is possible to obtain the one-dimensional images while ensuring the simultaneity between them. Next, positional information on three locations on the upper surface or lower surface of the plate-shaped object is extracted from the obtained one-dimensional image, and the warped shape, for example, the curvature shown in FIG. 3 below, is determined based on the extracted positional information. As a result, the objects of processing can be limited to the three one-dimensional images necessary for deriving the warped shape. That is, the image processing process is limited to the minimum necessary functional content to enable high-speed processing. Therefore, compared to the conventional method of processing the entire two-dimensional image and measuring the warped shape, the processing content is simplified and the amount of data to be handled is significantly reduced. However, while it took several tens of seconds,
By adopting the present invention, all processing can be completed in 1/30 seconds or less. Therefore, this technology can be applied to processes such as plate rolling, which require high-speed processing comparable to real-time measurement, which previously could not be applied due to the slow processing time despite the importance of measuring warped shapes. According to the invention, it is possible to perform rolling control that reflects the warp shape at high speed and with high precision using the warp shape measuring device. That is, the present invention can expand the applicable range of the warp shape measuring device and reliably improve the quality of rolled products. . Note that when obtaining the three one-dimensional images at the same time, using different fill lights can facilitate the extraction of side-view images of the plate-like object, and also fix the binarization amount value during image processing. Therefore, each processing time can be further shortened.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. First, a first example will be explained. In this first embodiment, as shown in FIG. 1, the curvature of a warp occurring at the tip of a steel plate 10 moving in the direction of arrow F on a rolling line is calculated using image information from the side of the steel plate 10. This is the device that was determined based on this. This embodiment device includes a steel plate tip detector 12 consisting of, for example, a hot steel detector (HMD) for detecting the tip position of the steel plate 10, and a field of view having an angle of view 15 shown in FIG. a video camera 16 with a high-speed shutter that can output a still image; a camera controller 18 that controls the shooting of the video camera 16 based on the detection signal of the steel plate tip detector 12; an edge detection image processing section 20 that processes the image obtained to detect edges on the upper surface of the steel plate 10; and an arithmetic processing section 22 that calculates a characteristic amount of warpage (in the embodiment, warp curvature) from the detected edge data. will be provided. The video camera is capable of photographing the steel plate 10 from the side, and is provided so that its scanning line is perpendicular to the direction of movement of the steel plate. In addition, in FIG. 1, the reference numeral 24 is a table roller for conveying the steel plate 10. The operation of the first embodiment will be explained below. When the steel plate 10 being rolled is being conveyed by the table rollers 24 as shown in FIG. device 12 detects. When the tip of the steel plate 10 is detected, a detection signal is input from the steel plate tip detector 12 to the camera controller 18. The camera controller 18 uses the detection signal as a trigger signal and inputs the image information of the video camera 16 at the time of detecting the tip as a still image to the edge detection image processing section 20. As a result, the image processing section 20
obtains a still image of the side surface of the steel plate 10. Here, when considering the steel plate 10 being rolled as the object to be measured, as shown in FIG. 2, due to the light emission of the steel plate 10 itself,
An image is obtained in which the steel plate 10 and the portions that reflect light from the steel plate 10 stand out. In Fig. 2, symbol A is the steel plate 1.
0, and symbols B and C are images of the table roller 24 reflecting the light from the steel plate 10. In a normal measurement environment, the background is sufficiently dark, whereas the steel plate 10 is sufficiently bright. Furthermore, since the shooting timing is based on the detection signal from the steel plate tip detector 12, the position of the steel tip on the still image is always vague due to the positional relationship between the video camera 16 and the steel plate tip detector 12. It will come into place. Therefore, the warp curvature of the steel plate can be stably determined every time from the still image of the tip obtained every time. The warp curvature is determined as follows. That is, in order to find the warp curvature of the steel plate 10, the warp is taken as a circular arc and its curvature is found. Generally, in order to find the curvature ρ of a circular arc, it is sufficient to know the coordinates Xi, X2, and X3 of three points on the circular arc, as shown in FIG. In this case, the curvature ρ is expressed by the arithmetic expression (1) of xi, x2, and X3. ρ=f (Xi, X2, X3)...(1
) In FIG. 3, R is the radius of curvature, and 0 is the center of the arc. Therefore, if you know the coordinates of the three points on the top surface of the steel plate in the input still image as shown in Figure 2 (indicated by ×1, ×2, ×3 in Figure 2), then using equation (1), The curvature of the steel plate 10 can be determined. In the embodiment, in order to obtain the coordinates x1, x2, x3 of these three points in a short time, first, three specific scanning lines of the video camera]6 (1.12 .13
), and performs binarization image processing on the one-dimensional video signals on the scanning lines 11, 12 and i3. Next, the edge coordinates of the steel material 10 (
x1, x2, x3). This obtained coordinate (×
1, ×2, ×3) into equation (1) to find the curvature ρ of the steel plate 10. Note that, as described above, since the video camera 16 can take a picture at the timing when the tip of the steel material 10 is almost at the fixed position, the necessary steel material 10 can be seen on the selected specific scanning lines 11 to 13. You can take pictures when you enter. Therefore, the coordinates of 3@ (Xi, ×2, ×
3) is guaranteed to exist. Therefore, it is possible to always accurately measure the warp curvature of the tip of the steel plate 10 that is being conveyed one after another on the line. Furthermore, in the case of rolled steel plates, the difference in brightness in the image between the background and the steel plate is large enough for practical use, so it is possible to binarize the video signal with the threshold level fixed.
Extracting edge coordinates can be done in a shorter time. Note that if the brightness difference is not sufficient, auxiliary light is irradiated to ensure the brightness difference. Next, a second embodiment of the present invention will be described. In this second embodiment, the two-dimensional video camera 1 of the first embodiment is
6, three one-dimensional video cameras 26A to 26C are installed, as shown in FIG.
It was set up so that The rest of the structure is the same as that of the first embodiment, and the same numbers are given to the same parts, and the explanation thereof will be omitted. These video cameras 26A to 26C simultaneously take pictures using the time when the steel plate tip detector 12 detects the tip of the steel plate 10 as a trigger. The photographed one-dimensional video signal is input to the edge detection image processing section 20, and image processing is performed in the same manner as in the above embodiment to obtain surface coordinates (1,111i10).
Xl, x2, x3). Next, the coordinates (x1, x2, x3) are substituted into equation (1) above to calculate the curvature ρ. In this second embodiment, since a one-dimensional video camera is used, there may be a time lag between scanning lines 11 to 13, but if a video camera with a high-speed shutter is used, such a time lag can be avoided. The warped shape of the plate-shaped object can be measured with high precision without any occurrence of warping. In addition, in the first and second embodiments, a steel plate was used as an example of the plate-shaped object, and its curvature was used as the feature quantity of the warped shape, but the feature quantity of the plate-shaped object and the warped shape is limited to this. For example, the amount of warpage can be measured as the feature amount.

[Brief explanation of the drawing]

FIG. 1 is a block diagram including a partial layout showing the overall configuration of a warp shape measuring device according to a first embodiment of the present invention, and FIG. 2 is a block diagram for explaining the operation of the embodiment. FIG. 3 is a diagram showing how to calculate the curvature, and FIG. 4 is an overall diagram of the second embodiment of the present invention. FIG. 2 is a block diagram including a partial layout diagram showing a typical configuration. 0... Steel plate (plate-shaped object), 2... Steel plate tip detector, 5... Field of view of video camera, 4A to 14C... Field of view of one-dimensional video camera, 6...
- Two-dimensional video camera, 8... Camera controller, 0... Image processing section for edge detection, 2... Arithmetic processing section, 6A, 26B, 26C... One-dimensional video camera.

Claims (1)

[Claims] (1) In an apparatus for measuring the warped shape of the tip of a moving plate-shaped object based on image information obtained by imaging the plate-shaped object from the side, the apparatus includes: an interval in the moving direction of the plate-shaped object; means for simultaneously obtaining one-dimensional images at three locations having a 1-dimensional image; and means for extracting positional information on three locations on the upper surface or lower surface of the plate-shaped object from the obtained one-dimensional images; A device for measuring a warped shape of a plate-shaped object, comprising: means for determining the warped shape based on the extracted position information.