JP7481223B2 - End-piece material detection device and end-piece material detection method - Google Patents

Description

The present invention relates to an apparatus and method for detecting end pieces that are shorter than the product length and are generated when cutting multiple steel bars in a steel bar rolling facility.

In steel bar rolling facilities, the steel bars that come out of the rolling mill after being rolled to a specified diameter are longer than the specified product length (for example, around 100 m), so multiple pieces of these long products are cut together into the specified product length (fixed product length: generally around 3.5 to 12 m) using a cold shear.

However, there is variation in the length of the slab (e.g., 140mm square billet material) cast by the continuous casting machine, which is the raw material that is rolled by the rolling mill, and as a result, there is variation in the length of the steel bars obtained by rolling these slabs. Therefore, the group of steel bars obtained by shear cutting of these steel bars may contain steel bars (end pieces) that are shorter than the standard product length.

Devices for detecting such end materials include those disclosed in Patent Document 1 (JP Patent Publication 5-149718 A) and Patent Document 2 (JP Patent Publication 6,340,177 A), for example.
The devices disclosed in Patent Documents 1 and 2 detect scrap material by measuring the number of steel bars present at a given position as they are fed longitudinally in a line within the rolling equipment, based on information obtained from a sensor or image acquisition device installed above the steel bars.

Japanese Patent Application Laid-Open No. 5-149718 Japanese Patent No. 6340177

However, because multiple steel bars arranged side by side may overlap in parts, it was difficult to accurately detect end pieces using these devices.

The present invention was made to solve these problems, and provides an end-of-cut material detection device and end-of-cut material detection method that can easily and accurately detect the presence or absence of end-of-cut material.

(1) The end material detection device of the present invention is disposed in a bar steel rolling facility equipped with a conveying table on which multiple rolled bar steels are placed in one layer and conveyed in the longitudinal direction, and a cold shear which shears the multiple bar steels supplied by the conveying table together, and detects end material that does not meet a predetermined product length from a group of bar steel obtained after shear cutting,
A lighting device is provided at an outlet side of the shear in a position facing the cut surface so as to illuminate the cut surface of the steel bar immediately after the shear cutting;
an image capture device provided at an outlet side of the shear at a position facing the cut surface so as to capture an image of the cut surface illuminated by the illumination device;
an image processing device that performs image processing on the image of the cut surface obtained by the image acquisition device;
The system is characterized by comprising a calculation device configured to measure the number of the steel bars cut by the cold shear based on the image processed by the image processing device, and to use the number of the steel bars measured from images of the cut surfaces by the successive first shear cut and second shear cut to detect the end material based on the difference between the number of the steel bars cut by the first shear cut and the number of the steel bars cut by the second shear cut.

(2) Furthermore, in the above (1), the lighting device is configured to be able to project light onto the cutting surface from different positions in the width direction, which is the direction in which the steel bars are arranged.

(3) Furthermore, in the above (1) or (2), the device further comprises a display device that is capable of communicating with the arithmetic device and that displays a detection signal indicating that the end material has been detected when the detection signal is received from the arithmetic device.

(4) The end material detection method of the present invention is a method for detecting end material that does not meet a predetermined product length from a group of steel bars obtained after shear cutting in a steel bar rolling facility equipped with a conveying table on which multiple steel bars after rolling are placed in one layer and conveyed in the longitudinal direction, and a cold shear that shears the multiple steel bars supplied by the conveying table at once,
Illuminating the cut surface of the steel bar immediately after shear cutting with a lighting device;
taking an image of the cut surface illuminated by the illumination device with an image capture device;
Counting the number of steel bars cut by the first shear cutting and the number of steel bars cut by the second shear cutting by performing image processing on the images of the cut surfaces by the successive first shear cutting and the second shear cutting obtained by photographing;
Detecting the end piece based on the difference between the measured number of steel bars cut by the first shear cutting and the measured number of steel bars cut by the second shear cutting.

The accuracy of detecting the presence or absence of end material depends on the accuracy of detecting the presence or absence of steel bars at a specific position in the longitudinal direction of the steel bar, but in the present invention, by illuminating and photographing the aligned cut surfaces immediately after shear cutting from a position opposite these, an image suitable for counting the number of bars is obtained through image processing such as binarization, and the number of bars at a specific position (the position where the bar is cut by the shear) can be measured with high accuracy. This makes it possible to detect end material with high accuracy.

1 is a schematic side view of an end piece detection device according to an embodiment of the present invention. 1 is a schematic plan view of an end piece detection device according to an embodiment of the present invention; 5 is an explanatory diagram for explaining image processing in the end material detection device according to the embodiment of the present invention. FIG. 5 is an explanatory diagram for explaining a calculation process in the end material detection device according to the embodiment of the present invention. FIG.

As shown in Figures 1 and 2, the end material detection device 1 according to this embodiment is placed in a bar steel rolling facility 3 and detects end material that does not meet a predetermined product length from a group of bars obtained after shear cutting. It is equipped with a lighting device 5, an image acquisition device 7, a computer 8, and a display device 13, and the image processing device 9 and calculation device 11 of the present invention are realized by software built into the computer 8. Each component will be described in detail below.

<Steel bar rolling equipment>
The bar steel rolling equipment 3 is equipped with a conveying table 15 on which multiple rolled bars 14 are placed in one layer and conveyed in the longitudinal direction, and a cold shear 19 having a blade 17 which shears the multiple bars 14 supplied by this conveying table 15 together.
The conveying table 15 of this embodiment conveys the group of steel bars in three lines in the width direction, as shown in Fig. 2. In the present invention, the width direction means the direction in which the steel bars are arranged, and the direction perpendicular to the longitudinal direction (conveying direction) of the steel bars in a horizontal plane.
The conveying direction of the steel bar 14 is the direction indicated by the arrow in Figure 1, and a movable stopper (not shown) for receiving the steel bar 14 is installed at a predetermined position downstream of the conveying table 15, i.e., in the direction of the tip of the arrow, and the position of the stopper is determined so that the distance between the stopper and the blade 17 is the standard product length.

<Lighting equipment>
The lighting device 5 is provided at a position facing the cut surface on the exit side of the shear so as to illuminate the cut surface of the steel bar 14 immediately after it has been cut by the shear (see FIG. 1).
The lighting device 5 is preferably installed at a position where as much of the emitted light as possible is reflected by the cut surfaces of the steel bars 14 and reaches the image acquisition device 7. This is because the brighter the cut surface portion is in the image captured by the image acquisition device 7, the easier it is to identify the cut surface portion of the steel bars 14 in the image obtained by performing a binarization process (described later) on the image in the image processing device 9, thereby improving the measurement accuracy of the number of steel bars.
For this reason, the lighting device 5 is ideally installed at a position directly opposite the cut surface, but since it cannot be installed in such a position in reality, it is installed at a location where it can be installed in relation to other devices constituting the rolling equipment. Normally, there is a space on the conveying table downstream of the cold shear, so the lighting device 5 may be installed at an appropriate position in that space. For example, as in this embodiment, the lighting device 5 may be positioned so that the ratio of the horizontal distance from the shear outlet to the height based on the top surface of the conveying table is about 3:1.

Furthermore, it is preferable that the lighting device 5 illuminates all cut surfaces of the steel bars 14 constituting the group as uniformly as possible across the entire width of the steel bar group, and for this reason, in this embodiment, two line lighting devices made of light-emitting diodes (LEDs) and extending in the width direction of the conveyor table 15 are provided. Note that, as lighting capable of uniformly illuminating the entire width of the steel bar group, other than LED line lighting, for example, line lighting using other semiconductor light-emitting elements such as organic electroluminescence (EL) elements, or a configuration in which multiple floodlights using incandescent light bulbs or the like are lined up in the width direction, may also be used.
In other words, it is preferable that the lighting device 5 is configured to be able to project light onto the cut surfaces of the steel bars 14 from different positions in the width direction, which is the direction in which the steel bars 14 are arranged. For example, if floodlights using incandescent bulbs or the like are used, two floodlights can be installed at two different positions in the width direction. This makes it possible to illuminate the entire group of steel bars more uniformly than if one floodlight were installed in one location and projected light onto the cut surfaces from one point, and makes the cut surface portion brighter in the image captured by the image capture device 7.

<Image Acquisition Device>
The image capturing device 7 is provided at a position facing the cut surface of the steel bar 14 on the exit side of the cold shear 19 so as to capture an image of the cut surface of the steel bar 14 illuminated by the lighting device 5 .
2, the image capture device 7 of this embodiment is composed of three video cameras 7a installed in the width direction of the conveying table 15. The installation position of the image capture device 7 is approximately the same as that of the lighting device 5.

The reason why the image acquisition device 7 is composed of three video cameras 7a is as follows.
In this embodiment, there are three conveying lines for the steel bar group, and if one video camera is to capture the entire width of the steel bars, the video camera is placed far back (away from the cut surface). In this case, the size of each cut surface of the steel bars in the obtained image becomes small, making it difficult to count the number of steel bars by image processing. In contrast, by installing multiple video cameras 7a (three in this example), it is possible to place the video cameras 7a near the cross sections of the steel bars and capture a large image of the cut surfaces of the steel bars, making it easier to count the number of steel bars by image processing.

In this embodiment, the lighting device 5 is installed directly above the image capture device 7 so that as much of the light emitted from the lighting device 5 and reflected by the cut surface of the steel bar 14 as possible reaches the image capture device 7 (see FIG. 1). However, because the cross section of the steel bar 14 cut by the blade 17 is a shear-fractured cut surface, the illumination light is diffusely reflected by the cut surface of the steel bar 14 and reaches the image capture device 7, so the positional relationship between the image capture device 7 and the lighting device 5 does not need to be very strict.

<Image Processing Device>
The image processing device 9 is a device that performs image processing on the image of the cut surface of the steel bar 14 obtained by photographing with the image acquisition device 7 as preprocessing for measuring the number of steel bars, and in this embodiment is realized by software incorporated into a single computer 8 together with the calculation device 11 described below.
The image processing device 9 of this embodiment sequentially performs the following image processing steps (1) to (4).
(1) An image of an appropriate size including the cut surface of the group of steel bars is cut out from the image captured by the image capture device 7.
(2) To smooth out the brightness of the image, the color image is binarized.
(3) To remove minute noise, a filtering process is performed.
(4) A pruning process is performed to remove large objects.
Of these, the binarization process of (3) preferably uses a moving threshold method, and the filtering process of (4) preferably involves appropriately repeating an expansion process and an erosion process.
By carrying out the series of image processing described above, the calculation device 11 is able to count the number of steel bars 14 .

<Calculation device>
The calculation device 11 is realized by the software incorporated in the computer 8 as described above, and counts the number of steel bars 14 cut by the cold shear 19 based on the image processed by the image processing device 9. Specifically, in the image in which the image processing up to (4) has been completed, the number of white areas whose size falls within a predetermined threshold range is counted as the number of steel bars 14. At this time, if there is a white area whose size is larger than the size corresponding to the cut surface of one steel bar by a certain percentage or more, it is determined how many steel bars the area corresponds to according to the size, and the counting result (number) is corrected based on the determination result. For example, if 14 white areas are detected and the maximum width of one of the areas is about 70% larger than the size corresponding to the cut surface of one steel bar, it is determined that the area corresponds to two steel bars, and the counting result of the steel bars 14 is corrected and output as 15.
The system is configured to use the number of steel bars 14 measured from images of the cut surfaces produced by the successive first shear cut and second shear cut, and detect end pieces 14a based on the difference between the number of steel bars 14 cut by the first shear cut and the number of steel bars 14 cut by the second shear cut.
Furthermore, when the calculation device 11 detects the end piece 14a through the above calculation, it outputs to the display device 13 a detection signal indicating that the end piece 14a has been detected (hereinafter referred to as an "end piece detection signal").

<Display Device>
The display device 13 is provided to be capable of communicating with the calculation device 11 and, when it receives an end scale detection signal from the calculation device 11, displays that fact. In this embodiment, the display device 13 is a screen display device connected to the computer 8.

A method for detecting end pieces using the end piece detecting device 1 of this embodiment configured as described above will be described together with the operation of the device.
The group of steel bars transported from the upstream side on the transport table 15 is received by a stopper (not shown) and cut by the blades 17 of the cold shear 19 .
The cut surface of the steel bars 14 immediately after shear cutting is illuminated by the lighting device 5, and the cut surface illuminated by the lighting device 5 is photographed by the image capture device 7. Fig. 3(a) is a photograph of a group of steel bars photographed by the image capture device 7. It can be seen that the cut surface of each steel bar 14 in the group of steel bars is photographed as white due to diffuse reflection of light. In this photographed state, the cross section of each steel bar 14 can be detected by the image processing described above (see the frame surrounding the cut surface in the enlarged view) as shown in Fig. 3(b), making it easy to count the number of steel bars 14 in the group.

The computing device 11 measures the number of steel bars 14 cut by the cold shear 19 based on the image processed by the image processing device 9. Then, using the number of steel bars 14 measured from the image of the cut surface from the previous shear cut (first shear cut) and the number of steel bars 14 measured from the image of the cut surface from the current shear cut (second shear cut), the end material 14a is detected based on the difference between the number of steel bars 14 cut in the previous shear cut and the number of steel bars 14 cut in the current shear cut.

For example, as shown in Fig. 4, if the number of steel bars 14 measured from the image of the cut surface by the previous shear cutting is M, and the number of steel bars 14 measured from the image of the cut surface by the current shear cutting is N, then as shown in Fig. 4(a), when N = M, it is determined that the group of steel bars cut to the specified length by the previous and current shear cuttings does not include any end pieces 14a. On the other hand, as shown in Fig. 4(b), when N < M, it is determined that M-N end pieces 14a shorter than the fixed product length are mixed in the group of steel bars cut to the specified length by the previous and current shear cuttings, and an end piece detection signal is output to the display device 13.
When the display device 13 receives the end-of-length material detection signal, it displays a message to that effect on the screen to notify the operator.
In this way, by photographing the cut surface cut by the cold shear 19 and counting the number of steel bars 14, it is possible to detect whether or not end pieces 14a are present, thereby preventing end pieces from being mixed in with subsequent processes.

The accuracy of detecting the presence or absence of end material 14a depends on the accuracy of detecting the presence or absence of steel bar 14 at a specific position in the longitudinal direction of steel bar 14, but in this embodiment, illumination and imaging are performed from a position opposite the aligned cut surfaces immediately after shear cutting, thereby obtaining an image suitable for counting the number of pieces using image processing such as binarization, and the number of pieces at a specific position (cut position by the shear) can be measured with high accuracy. This makes it possible to detect end material 14a with high accuracy.

The present invention has been described above using an embodiment, but the present invention is not limited to the configuration of this embodiment. The scope of the present invention is determined based on the description of the appended claims, and within that scope, the present invention includes all configurations in which some of the components shown in the embodiment are omitted or modified, as well as improvements thereon.

For example, in the present invention, the image processing device 9 and the calculation device 11 do not have to be realized by software incorporated into a single computer 8, but may be realized by separate hardware having their respective functions.
In the above embodiment, when the arithmetic device 11 detects the end material 14a, the detection is visually indicated on the display device 13, but the display device of the present invention is not limited to this. The display device of the present invention may inform the operator that the end material 14a has been detected by, for example, a sound such as an alarm or a light such as a light being turned on.

REFERENCE SIGNS LIST 1 End piece detection device 3 Steel bar rolling device 5 Lighting device 7 Image acquisition device 7a Video camera 8 Computer 9 Image processing device 11 Arithmetic device 13 Display device 14 Steel bar 14a End piece 15 Conveyor table 17 Blade 19 Cold shear

Claims (4)

An end-piece detection device is provided in a bar rolling facility equipped with a conveying table on which a plurality of rolled steel bars are placed in one layer and conveyed in the longitudinal direction, and a cold shear that shears the plurality of steel bars fed by the conveying table together, and detects end-piece pieces that do not meet a predetermined product length from a group of steel bars obtained after shear cutting,
A lighting device is provided at an outlet side of the cold shear in a position facing the cut surface so as to illuminate the cut surface of the steel bar immediately after the shear cutting;
an image capture device provided at an outlet side of the cold shear at a position facing the cut surface so as to capture an image of the cut surface illuminated by the illumination device;
an image processing device that performs image processing on the image of the cut surface obtained by the image acquisition device;
This end material detection device is characterized by comprising: a calculation device configured to measure the number of the steel bars cut by the cold shear based on the image processed by the image processing device, and to detect the end material based on the difference between the number of the steel bars cut by the first shear cut and the number of the steel bars cut by the second shear cut using the number of the steel bars measured from images of the cut surfaces by the successive first shear cut and second shear cut. The end material detection device according to claim 1, characterized in that the lighting device is configured to be able to project light onto the cut surface from different positions in the width direction, which is the direction in which the steel bars are arranged. The end material detection device according to claim 1 or 2, further comprising a display device that is capable of communicating with the calculation device and that displays a detection signal indicating that the end material has been detected when the detection signal is received from the calculation device. A method for detecting end pieces that do not meet a predetermined product length from a group of steel bars obtained after shear cutting in a steel bar rolling facility equipped with a conveying table on which a plurality of steel bars after rolling are placed in one layer and conveyed in the longitudinal direction, and a cold shear that shears the plurality of steel bars supplied by the conveying table, comprising:
Illuminating the cut surface of the steel bar immediately after shear cutting with a lighting device;
taking an image of the cut surface illuminated by the illumination device with an image capture device;
Counting the number of steel bars cut by the first shear cutting and the number of steel bars cut by the second shear cutting by performing image processing on the images of the cut surfaces by the successive first shear cutting and the second shear cutting obtained by photographing;
and detecting the end material based on the difference between the measured number of steel bars cut by the first shear cutting and the measured number of steel bars cut by the second shear cutting.