JPH0552525A - Calibration device of optical plate width meter - Google Patents

Abstract

PURPOSE:To obtain a means for enabling a plate width meter to be calibrated accurately under the same conditions as on-line situations. CONSTITUTION:A magnet type screening plate 5 is fitted onto an upper surface of a light-source detection hole 4 of a side guide liner 2. An opening of a side guide 1 is changed within a detectable range of two CCD cameras. The side guide 1 is stopped at a known calibration point, thus enabling an edge position of the screening plate to be detected. Two cameras can perform calibration within a visual field to be detected, no light source exclusively for calibration is needed, a calibration time is short, and a calibration accuracy is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to a solid-state image pickup device (CC
The invention relates to a calibration device for a plate width meter that optically measures a plate width of a steel plate in an imaging camera having D).

[0002]

2. Description of the Related Art Measuring the strip width in hot rolling is extremely important for quality assurance. Conventionally, a method using an image pickup camera having a solid-state image pickup device (CCD) is generally used for measuring the plate width. In this method, the imaging camera is installed above both edges of the steel plate, a light source is provided below both edges, and both edge positions are detected based on the brightness of the imaging camera on both edges. This is a method in which the distance is used as the board width. Therefore, in the case of this method, it is necessary to regularly calibrate the measuring device in order to check whether the imaging camera is properly installed, or whether the tilt is caused by the vibration in the factory. ..

Conventionally, there are the following two methods for the calibration. (1) Calibration method for a camera self-tracking width meter As shown in FIGS. 6 and 7, a shield plate 51 having a window hole 51a is set on a surface plate 50 in which an insertion hole 50a is accurately formed. A light source (not shown) is arranged below the shielding plate, and two image pickup cameras are scanned from the outer side to the inner side in the longitudinal direction of the surface plate 50, and the image pickup camera has a visual field at the A edge position and the B edge position. The image pickup camera is moved so that the centers thereof coincide with each other, and calibration is performed based on the error between the known AB length and the actually measured AB length, and the shielding plate 51 is repositioned as necessary and then recalibrated. To be This calibration device is installed off-line on the side of the line and is used exclusively for periodic verification and camera replacement.

(2) Calibration method in the case of a board width meter using a fixed type camera The method using a fixed type camera is used in a place where installation is difficult in terms of equipment or when an inexpensive board width meter is sufficient. When calibrating, install a sample plate (shield plate) with a known plate width on the measurement line, perform verification based on the measured width value, and set the installation position for other sample plates of different widths. It is calibrated by adjusting the front-rear direction and the left-right direction of the camera while changing or moving in the lateral direction (direction orthogonal to the line).

[0005]

However, in the above method (1), it is necessary to permanently install a large light source and a surface plate between stands, which have many driving parts in an actual line, by using an existing side guide or looper. There is interference and it is impossible in terms of space, and it is difficult for a self-following type camera to follow accurately due to vertical vibration of the steel plate and the like. On the other hand, in the method of (2), it is difficult to align the center of the pass line with the center of the sample plate in the width direction, and the field of view of the camera is easily deviated due to vibration during actual operation.
When the resolution is determined by the amount of movement of the edge detection bit position with respect to the amount of movement of the sample plate in the width direction, the amount of movement of the sample plate in the width direction is visually determined, so the resolution is inaccurate, and the camera is fixed. Therefore, when the edge height of the sample plate changes, the plate width measurement value also changes, causing errors, not only taking a long time for the verification work and calibration work, but also low repeatability and low calibration accuracy. There are problems such as. Further, both the methods (1) and (2) require a dedicated light source (high-frequency fluorescent lamp) and a calibration sample plate, and have a drawback that a lot of labor and time are required for measurement.

In view of the above problems of the prior art, the present invention provides a device that does not require a dedicated light source for calibration and can calibrate easily and quickly with high accuracy by using an existing light source for measuring plate width. Is what you are trying to do.

[0007]

SUMMARY OF THE INVENTION A gist of the present invention is a side guide liner provided on both lower sides of a steel plate pass line, having a light source detection hole on the upper surface thereof, and having a lower light source therein, and the side guide liner. A distance meter provided to measure the distance between the side guides, a detachable shield plate that is mounted on the light source detection hole so that the width of the steel plate calibration plate can be adjusted, and a distance from the lower light source. Light is input through the light source detection hole, and equipped with imaging cameras provided on both sides above the steel plate pass line to measure the steel plate calibration plate width.
Calibration in which the measurement value of the imaging camera is adjusted to be the steel plate calibration plate width, and the side guide position is adjustable so that the center of the side guide is the center of the steel plate pass line by the measurement value of the distance meter. On the device.

[0008]

Operation The detachable shield plate may be of the magnet type, for example. A laser rangefinder, for example, can be used as a rangefinder for measuring the distance between the insides of the side guide liners. The edge surface of light and shadow (bright and dark parts) is always kept constant by the removable shield plate provided on the upper surface of the light source detection hole of the side guide liner so as to match the width of the steel plate calibration plate. In this state, change the side guide opening while measuring the inside distance of the side guide liner with a rangefinder, and set the side guide opening at a known calibration reference point position. By reading the number of bits that the CCD camera detects both edge positions of the plate, the difference (deviation amount) between the distance between the both shielding plates (steel plate calibration plate width) and the distance between the camera centers is detected, and the position of the camera is determined. Calibrate.

In this device, the lower light source incorporated in the side guide liner can be used as it is as a calibration light source. Since the side guide opening is changed according to a known calibration reference point, the calibration within the visual field detected by the two CCD cameras can be performed. In addition, since the calibration is based on the opening of the side guide, the center position of the opening of the side guide becomes the pass line center, and the shielding plate provided on the upper surface of the light source detection hole also moves at the same interval around the pass line center. Therefore, the alignment of the pass line center is unnecessary.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing an apparatus of one embodiment of the present invention, 1 is a side guide, 2 is a side guide liner, 3 is a side guide.
Is a lower light source, 4 is a light source detection hole, 5 is a magnet type shielding plate, 6 is a laser distance meter, 7 is a CCD camera, 8 is a controller, 9 is a meandering / width measuring device, 10 is a distance measuring device, and 11 is It is an indicator.

In FIG. 1, first, a position (calibration reference point) where the visual field centers of the two CCD cameras 7 installed above the actual line and the center of the light source detection hole 4 provided in the side guide liner 2 coincide with each other. Position the side guide 1 at. In that case, the side guide 1 is moved left and right while measuring the inner distance of the side guide liner 2 with the laser distance meter 6, and the side guide 1 is stopped at the position of the distance between the calibration reference points.

Next, the lower light source detection hole 4 and the CCD camera 7
Adjust the optical axis of. FIG. 2 is a schematic diagram showing a vertical vibration adjustment method for a CCD camera. FIG.
Analog video signal (A
When the waveform of the V signal is small, FIG. 6B shows the case where the AV signal is the optimum waveform, and FIG. 7C shows the case where the AV signal is small as in the case of FIG. That is, vertical vibration adjustment is performed so that the AV signal has the optimum waveform shown in FIG.

FIG. 3 is a schematic diagram showing a method for adjusting the parallelism between the CCD camera image sensor and the light source detection hole. Similar to the above optical axis adjustment, the AV signals detected by the two CCD cameras are confirmed and the camera rotation is performed. Adjust the axis. That is, FIGS. 9A and 9C show the case where the AV signal is defective, and FIG.
The respective cases where the V signal is optimum are shown. Therefore, AV
When the signals are as shown in FIGS. (A) and (C), the rotation axis of the CCD camera is adjusted so that the AV signal shown in FIG.

As shown in FIGS. 1 and 4, the magnet type shield plate 5 is fitted inside the center of the light source detection hole 4 of the side guide liner 2. At that time, by mounting the magnet type shield plate at the position where the light source detection hole 4 is shielded by 1/2, the edge surface of the bright and dark parts is always kept constant, and the distance between the left and right shield plates and the CCD camera center are kept. It will match the distance.

To adjust the lateral shake of the CCD camera, the controller 8 is set in a measuring state as shown in FIG. 5, and the left and right edge position outputs (the amount of deviation from the camera center) are confirmed. When it is 1.0 mm or more, the lateral vibration is adjusted.

After the above adjustment work is completed, calibration is performed. That is, the opening degree of the side guide 1 is driven in the width direction or the width direction narrower than the position of the calibration reference point to stop at the known calibration point. The stop position accuracy of the side guide 1 is determined by measuring the distance between the insides of the side guide liners with a laser range finder 6 housed in the side guide liner 2 to stop at a known position within an error of ± 0.1 mm. it can. Then, the magnet type shielding plate 5 at the above point
The amount of deviation from the camera center (edge position output) and the plate width can be measured by reading the number of bits that the CCD camera detects the edge position of. Thereafter, by changing the opening of the side guide according to a known calibration point in the same procedure as described above, it is possible to completely calibrate the visual field ranges of the two left and right CCD cameras. The measurement error caused by the height of the edge surface of the shielding plate 5 is input as the plate thickness correction value in the meandering / plate width calculation device 9 in advance, so that the measurement value is not affected. As a result, calibration can be performed under the same conditions as in the online state, and calibration accuracy and reproducibility accuracy are improved.

[0017]

As described above, according to the device of the present invention, the side guide liner light source detection hole is provided with a detachable shield plate, and the distance between both shield plates and the amount of deviation from the center between cameras (edge position output). Because you can measure
It is possible to calibrate within the field of view detected by two CCD cameras, which eliminates the error caused by the positional displacement when moving the sample plate, which has been a problem in the past, and greatly improves reproducibility and calibration accuracy. Can be improved. In addition, the stop position of the side guide can be set while automatically measuring with the range finder stored in the side guide liner, and the movement of this side guide should always be opened and closed at the same interval from the pass line center. Therefore, the calibration work can be simplified and speeded up. Further, since the lower light source can be used as it is, the method of the present invention has an excellent effect that it can be calibrated with high accuracy under the same conditions as online.

[Brief description of drawings]

FIG. 1 is a schematic view showing an apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a vertical shake adjustment method for a CCD camera in the same apparatus.

FIG. 3 is an explanatory diagram showing a method for adjusting parallelism between a CCD camera image sensor and a light source detection hole in the same apparatus.

FIG. 4 is an enlarged schematic plan view showing a mounted state of a magnet shield plate in the same apparatus.

FIG. 5 is an explanatory view showing a lateral shake adjusting method of the CCD camera in the same apparatus.

FIG. 6 is a plan view showing an example of a conventional calibration device.

FIG. 7 is a front view showing a shielding plate of the above calibration device.

[Explanation of symbols] 1 side guide 2 side guide liner 3 lower light source 4 light source detection hole 5 magnet type shield plate 6 laser distance meter 7 CCD camera 8 controller 9 meandering / width calculation device 10 distance meter calculation device

Claims (1)

[Claims] 1. A side guide liner provided on both lower sides in the width direction of a steel plate pass line, having a light source detection hole on the upper surface thereof, and having a lower light source inside, and a side guide on either one of the side guide liners. A distance meter provided to measure the distance between them, a detachable shield plate mounted on the light source detection hole so that the width of the steel plate calibration plate can be adjusted, and light from the lower light source is input through the light source detection hole. Then, it is equipped with imaging cameras provided at both ends of the steel plate pass line to measure the steel plate calibration plate width, and the measurement value of the imaging camera is adjusted so as to be the steel plate calibration plate width, and the distance meter is measured. A calibration device for an optical plate width meter, wherein the side guide position can be adjusted so that the center of the side guide becomes the center of the steel plate pass line depending on the value.