JPH05157536A - Plate-shape measuring apparatus - Google Patents

Abstract

PURPOSE:To obtain a plate-shape measuring apparatus, which can measure the strain of a plate material highly accurately, with the simple constitution of the apparatus. CONSTITUTION:The elongations of a plate at a plurality of predetermined measuring points in the direction of the width of a plate material under movement are compared. Thus, the strain of the plate material is measured. In this plate-shape measuring apparatus, a fluorescent lamp 1, which is arranged in the direction of the width of the plate material, is used as a light source. The image of the fluorescent lamp 1, which is reflected on the surface of the plate material, is photographed with a CCD camera 3. In this measuring apparatus, the slant angle of the plate material is obtained out of a table, wherein the relationship between the image position and the slant angle is stored beforehand, based on the position of the image of the fluorescent lamp obtained at every specified sampling period. The length of the slant side is obtained based on the slant angle. The profile length of the plate material is obtained by the integration of the lengths of the slant sides. The profile lengths are measured for, e.g. five points in the width direction of the plate material. The strain of the plate is operated based on the measured result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate shape measuring device for measuring the strain of a plate material by comparing the plate elongations of a plurality of predetermined measurement points in the width direction of the transferred plate material.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring the strain of a plate material, a measuring device to which a light cutting method is applied has been known. This measuring device includes a light source that emits a laser beam, and a two-dimensional camera that captures an image of a spot formed by the laser beam from the light source striking the plate surface. Then, in this measuring device, the amount of positional deviation between the spot image obtained when there is no distortion in the surface shape of the plate and the spot image actually obtained, and the angle of the laser light flux to be applied, in the plate width direction Measure the height of the board surface at each position. The surface shape of the plate is measured by obtaining a large number of heights thus measured as the plate is transported. Since the measurement accuracy increases as the incident angle of the laser light flux decreases, the laser light source is installed far away from the two-dimensional camera (for example, 2 meters).

[0003]

However, the above conventional device has a problem that a large space is occupied because the two-dimensional camera and the laser light source need to be installed separately. Further, since a laser light source is used, there is a problem that the device configuration becomes complicated and expensive, and that there is a floating substance in the measurement environment, the laser light is scattered and measurement becomes difficult. It was

The present invention has been made to solve the above problems, and an object of the present invention is to provide a plate shape measuring device capable of measuring the strain of a plate material with high accuracy with a simple device configuration.

[0005]

In order to achieve the above object, the present invention, as illustrated in FIG. 1, compares the plate elongations of a plurality of predetermined measurement points in the width direction of the transferred plate material by comparing the plate elongations. In the plate shape measuring device for measuring the distortion of the plate material, a rod-shaped light source arranged in the width direction of the plate material above the plate material to be transferred, and a light source image which is arranged in proximity to the rod-shaped light source and is reflected on the surface of the plate material. Imaging means for imaging
A relational data storage unit that stores in advance data indicating the relation between the inclination angle of the plate surface and the position of the light source image that changes according to the inclination angle; Based on the imaged position of the image of the rod-shaped light source, an inclination angle extracting unit that obtains inclination angles of the plurality of measurement points in the width direction of the plate member, and the plate member based on the inclination angle extracted by the inclination angle extracting unit. A plate shape measuring device characterized by comprising: a plate elongation calculating means for calculating plate elongations at the plurality of measurement points in the width direction.

[0006]

In the present invention, the image pickup means picks up an image of the rod-shaped light source on the surface of the plate material, and the relational data storage means stores the relation between the inclination angle of the plate surface and the position of the light source image which changes according to the inclination angle. Is stored in advance, and the inclination angle extraction means refers to the relational data storage means to determine a plurality of predetermined measurement points in the width direction of the plate material based on the position of the image of the rod-shaped light source imaged by the imaging means. The inclination angle is calculated, and the plate elongation calculation means
The plate elongation at the plurality of measurement points in the width direction of the plate material is calculated from the tilt angle extracted by the tilt angle extraction means.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, a plate shape measuring device for measuring the shape of a continuous plate material transferred on a rolling line will be described below. First, the measurement principle of the plate shape measuring device will be described. As shown in FIG. 2A, the fluorescent lamp 1 and the two-dimensional CCD camera 3 are arranged above the plate material T,
Both of the fluorescent lamp 1 and the lens surface of the two-dimensional CCD camera 3 are set to be equal in height.

In FIG. 2A, a plate material having no distortion is shown by a solid line as a plate material T0, and a plate material having a distortion is shown as a plate material Ti by a one-dot chain line. When measuring a flat plate material T0 without distortion, the virtual image of the fluorescent lamp 1 with respect to the plate material T0 is at the position Q0. At this time, when viewed from the CCD camera 3 side, the plate material T
The image of the fluorescent lamp 1 is visible at the position P0 on the surface of 0.

On the other hand, when measuring a distorted plate material Ti, the virtual image of the fluorescent lamp 1 with respect to the plate material Ti is at the position Qi. At this time, when viewed from the CCD camera 3 side, the plate material Ti
The image of the fluorescent lamp 1 is visible at the position Pi on the surface of the. The image of the fluorescent lamp 1 is formed on the image pickup surface of the CCD camera 3, and the image forming position moves according to the distortion (tilt) of the plate material T in correlation with the tilt, as described later. Therefore,
If the relationship between the position of the image and the inclination of the plate T is measured in advance and the data is stored in the conversion table, based on the position of the image of the predetermined measurement point obtained at each predetermined sampling cycle, The inclination angle θ of the plate material at the measurement point can be extracted from the conversion table. And this inclination angle θ
Then, the elongation of the plate material at the measurement point is calculated as follows.

To calculate the elongation of the plate material, as shown in FIG. 2 (b), the length L of the inclined side (oblique side length) L is obtained from the inclination angle θ,
Then, the hypotenuse length L obtained for each sampling cycle
Is performed to obtain the contour length. here,
The contour length obtained represents the relative extension length. By setting a plurality of measurement points in the plate width direction of the plate material and comparing the plate elongations obtained at the respective measurement points, the strain of the plate material can be obtained.

The above table is created according to the following principle. As shown in FIG. 3, the fluorescent lamp 1, the CCD camera 3, and the plate material T are arranged so as to have a positional relationship similar to that of an actual plate shape measuring device. That is, the CCD camera 3 is arranged at a position 200 mm away from the fluorescent lamp 1, and the distance between these and the plate T is 2000 mm.

Then, the inclination of the plate T is changed to change the CCD.
The camera 3 captures an image (virtual image) of the fluorescent lamp on the surface of the plate T, and obtains the relationship between the center position of the image of the fluorescent lamp and the inclination angle of the plate T. In this embodiment, the peak point of the luminous intensity is set to the center of the image of the fluorescent lamp 1, but as the peak point of the luminous intensity, an intermediate point between two points where the luminous intensity curve having the peak point intersects with a predetermined threshold level. Is used approximately. That is, the midpoint between the two points where the above-mentioned luminous intensity curve and the predetermined threshold level intersect is calculated, and the calculated midpoint is taken as the peak point of luminous intensity.

FIG. 4 shows the relationship between the center position of the fluorescent lamp image thus obtained and the inclination angle of the plate material T. The horizontal axis of the graph indicates the inclination of the plate material T, and the vertical axis indicates the position of the pixel (pixel) where the luminous intensity has a peak. The fluorescent lamp image extends in the direction corresponding to the width direction of the plate material on the imaging surface of the CCD camera 3, but here, one of the plurality of measurement points in the width direction of the plate material is measured. The above measurement is carried out in. That is, the position of each pixel shown in FIG. 4 is on one straight line parallel to the direction corresponding to the transport direction of the plate material on the imaging surface.

It can be seen from FIG. 4 that there is a one-to-one correspondence between the inclination angle of the plate material T and the position of the fluorescent lamp image reflected on the plate material T. Next, the accuracy of the angle obtained by this measurement principle will be described. By placing the spacer on the flat surface, arranging the plate material T on the flat surface, and changing the height of the spacer,
The angle of the plate was slightly changed. Plate material T in this case
The following Table 1 illustrates the angle difference between the actual angle of 1 and the angle obtained based on the position of the fluorescent lamp image. In this case, unlike the above case, the CCD camera 3 is different from the fluorescent lamp 1.
It is arranged at a position separated by 125 mm from the plate material, and the distance between these and the plate material T is set to 2000 mm as in the above case.

[0015]

[Table 1]

In Table 1, the angle of the plate material T in the leftmost column is
It is the actual angle of the plate material T obtained by the geometric calculation based on the height and position of the spacer, the image position in the right column is the pixel number of the peak position of the luminous intensity, and the angle in the right column is Is an angle obtained using a conversion table created in advance under the same conditions as above.

In Table 1, the actual angle and the measured angle are in good agreement. From this, it is understood that the angle of the plate material T can be obtained with high accuracy from the center position of the fluorescent lamp image. It should be noted that when the plate material T moves in parallel in the vertical direction and the height of the plate material T changes, even if the plate material T has the same inclination angle, it is considered that images are captured at different positions. Was carried out while changing the height of the plate material T, the following results were obtained.

[0018]

[Table 2]

Table 2 shows the height of the plate T as a reference position (0 m
m), 70 mm above the reference position, 150 from the reference position
mm and above the reference position by 250 mm, and the angle of the plate material T was changed from 0 ° to 9 ° by 1 ° and measured. The numbers in the table are the numbers of pixels at the peak position of illuminance. At the reference position, the distance between the fluorescent lamp 1 and the CCD camera 3 and the plate material T is 2000 mm.
Is the position. The distance between the fluorescent lamp 1 and the CCD camera 3 was set to 125 mm as in the case of Table 1.

From Table 2, it can be seen that, if the angles are the same, the positions of the images are almost the same even if the heights of the plate materials T are different. Therefore, even when the plate material moves in parallel in the vertical direction and the height of the plate material changes, it can be seen that the inclination angle of the plate material T is uniquely determined by the position of the obtained image.

FIG. 5 shows a block diagram of the plate shape measuring apparatus of this embodiment. In FIG. 5, the plate shape measuring device includes a fluorescent lamp 1, a two-dimensional CCD camera 3, a processing device 5, and a display device 7. The fluorescent lamp 1 as a light source is arranged such that its longitudinal direction is the same direction as the width direction of the plate material T of the transport line, and is arranged, for example, 2000 mm above the plate material T.
The two-dimensional CCD camera 3 as an image pickup means is installed at a position 200 mm away from the fluorescent lamp 1. As described above, the two are set so that the height of the fluorescent lamp 1 and the height of the lens surface of the two-dimensional CCD camera 3 become equal.

The processing unit 5 is a well-known CPU 51 and ROM 5
3, an arithmetic logic operation circuit including a RAM 55, an input / output circuit 57, and the like. The two-dimensional CCD camera 3 and the display device 7 for displaying data such as results are connected to the input / output circuit 57. The ROM 53 of the processing device 5 stores various programs for measuring the surface shape, such as a contour length calculation processing routine and a program based on a known method for finally measuring the surface shape by comparing the contour lengths. It In addition, a conversion table (equivalent to the graph of FIG. 4) is stored as a relational data storage unit that indicates the relationship between the tilt amount and the amount of displacement of the image position of the fluorescent lamp 1 that changes according to the tilt angle of the surface of the plate material. There is.

FIG. 6 is a flow chart for explaining the processing of the contour length calculation routine. Next, a process of obtaining the contour length by the plate shape measuring apparatus of this embodiment will be described. In step S1, the position P of the image of the fluorescent lamp 3 at each measurement point Mi (i = 1 to 5) set in the width direction of the plate material.
i is measured, and the difference Di between the obtained image position Pi and the reference image position P0 is obtained. The difference Di is a pixel-wise distance in the direction corresponding to the plate material conveying direction on the imaging surface.

Next, in step S2, the difference Di
Based on the above, the tilt angle θi corresponding to the difference Di is extracted from the conversion table. Next, in step S3, 1 / C
OSθi is calculated to obtain the hypotenuse length Li. Next, in step S4, the hypotenuse length Li is integrated.

Next, in step S5, it is judged whether or not a certain length of the plate material T has been conveyed based on a signal sent from a sensor (not shown) provided on the conveying line, and the certain length must be conveyed. If so, the process returns to step S1. When the fixed length has been conveyed, in step S6, the result of integration of the hypotenuse length Li is set as the contour length RLi.

The plate strain is calculated by comparing the contour lengths RLi measured at five measurement points in the width direction of the plate material, and the result is displayed on the display device 7. The processes of steps S1 and S2 function as inclination angle extracting means, and the processes of steps S3 to S6 function as plate elongation calculating means.

As described above, according to the present embodiment, since the fluorescent lamp is used as the light source, it is possible to measure even in the presence of suspended matter, and the environment is better than that using the conventional laser. Less affected by. Further, since the fluorescent lamps are arranged in the width direction of the plate, the light source and the CCD may be changed depending on the plate width of the plate material.
No need to move the camera position. As a result, a mechanism for moving is not required, which facilitates maintenance. Further, from the above, the present measuring device can be manufactured at low cost.

Further, since the fluorescent lamp and the CCD camera can be arranged close to each other, the installation space can be reduced. By placing the fluorescent lamp and the CCD camera at the same height from the board surface,
Even if the plate material moves in parallel and the height of the plate material changes, the plate strain can be accurately detected.

[0029]

As described above, according to the present invention, since the rod-shaped light source is arranged in the plate width direction, it is not necessary to move the positions of the light source and the CCD camera depending on the plate width of the plate material as in the prior art. As a result, a mechanism for moving is not required, which facilitates maintenance and enables inexpensive manufacturing.

Further, since the rod-shaped light source and the image pickup means can be arranged close to each other, the installation space can be reduced. Furthermore, since it is not necessary to use a laser beam as a light source as in the conventional case, even if a suspended matter or the like exists in the measurement environment, it is possible to perform the measurement without lowering the accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a basic configuration of the present invention.

FIG. 2 is an explanatory diagram showing a measurement principle of a plate shape measuring apparatus as an embodiment of the present invention.

FIG. 3 is a schematic diagram of a measuring device that measures the relationship between the image position and the tilt angle of a fluorescent lamp.

FIG. 4 is a graph showing the measurement result of the relationship between the position of the image of the fluorescent lamp and the tilt angle.

FIG. 5 is a block diagram showing a configuration of a plate shape measuring apparatus according to this embodiment.

FIG. 6 is a flowchart showing a contour length calculation processing routine.

[Explanation of symbols]

1 ... Fluorescent lamp 3 ... CCD camera 5 ... Processing device
7 ... Display device 51 ... CPU 53 ... ROM 55 ... RAM

Claims (1)

[Claims] 1. A plate shape measuring device for measuring strain of a plate material by comparing plate elongations at a plurality of predetermined measurement points in the width direction of the plate material to be transferred, the plate material being above the plate material to be transferred. A rod-shaped light source arranged in the width direction of the plate member, an image pickup unit arranged in the vicinity of the rod-shaped light source for capturing a light source image reflected on the surface of the plate material, and an inclination angle of the plate surface and the inclination angle that changes according to the inclination angle. Based on the position of the image of the rod-shaped light source imaged by the imaging unit, referring to the relational data storage unit, the relational data storage unit that stores in advance the data indicating the relation with the position of the light source image, Inclination angle extraction means for obtaining the inclination angles of the plurality of measurement points in the width direction of the plate material, and plate elongation of the plurality of measurement points in the width direction of the plate material is calculated from the inclination angle extracted by the inclination angle extraction means. Sheet elongation calculation Plate-shaped measuring apparatus characterized by comprising: a stage, a.