JP2561994B2 - Optical surface inspection device for rolling rolls - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical surface inspection device for a rolling roll which is applied to the surface inspection of a rolling roll of a hot finish rolling mill in a steel plate rolling line. By capturing the surface image of the rolling roll with an imaging device and analyzing the obtained static image of the surface, it was possible to detect that the rolling roll had reached its roll replacement time due to its surface deterioration. The present invention relates to an optical surface inspection device for rolling rolls.

[0002]

2. Description of the Related Art Black skin gradually forms on the surface of a work roll (rolling roll) of a front stand in a hot finish rolling mill of a steel plate rolling line during rolling. Then, with the passage of time due to rolling, the black skin has turtle shell-like minute cracks (cracks) whose number gradually increases as a whole. After a further lapse of time, on the surface of the work roll, the black scale is partly peeled off, and thereby a crater-like depression is formed in a strip shape along the circumferential direction of the roll.
A rough skin condition called roll banding as shown in FIG. When rolling is performed by the work roll in which the roll banding occurs, the portion of the roll surface on which the dent is transferred is pressed by the work roll of the subsequent stand, and biting scale flaws occur in the steel sheet.

Therefore, the work roll is appropriately pulled out, the work roll is pulled out from the stand, and the operator directly conducts a visual inspection of the roll surface, and when the skin is rough, which may cause roll banding, the work roll is replaced. I'm trying to do. Such an inspection by direct visual inspection by the operator requires a lot of time and labor for removing and installing the work roll each time the inspection is performed.
When the rolling operation is restarted, it is necessary to warm up the work rolls, which causes a problem that productivity is lowered.

Therefore, in order to solve the above-mentioned inconveniences, the present applicant has previously proposed a stroboscopic illumination light source for irradiating the surface of the rolling roll with illumination light, and the surface of the rolling roll rotating while the roll cooling water is sprinkled. Of the image of the strobe illumination light source in synchronization with lighting, and a television camera as an image pickup device for obtaining a still image of the surface, and an image display device for displaying the image obtained by the television camera. We have proposed an optical surface inspection device for rolling rolls (Japanese Patent Application No. 3-165648).

As shown in FIG. 4 of the configuration diagram, the conventional optical surface inspection apparatus described above includes a moving device 4, a housing box 5 having a window portion, a television camera (industrial use) disposed in the housing box 5. CC as a video camera)
A D camera 6, an annular xenon lamp 7 as a stroboscopic illumination light source, which is also arranged in the housing box 5,
A water column forming nozzle 8 mounted on the front surface of the housing box 5, a control device 9, a frame memory 10 as an image storage device, and a CRT display as an image display device.
It is composed of 11. A printer 12 connected to the control device 9 is used for making a hard copy of a rolling roll surface static image.

More specifically, the rolling rolls (work rolls) W of the second stage finishing stand F2 and the rolling rolls (not shown) of the next stage finishing stand F3 of the hot finish rolling mill in the steel sheet hot rolling line. Between the feed screw shaft 1 that is provided in parallel with the longitudinal direction (roll shaft direction) of the rolling roll W and is rotated in the forward and reverse directions by a motor (not shown), and in the longitudinal direction of the rolling roll W in accordance with the rotation of the feed screw shaft 1. A moving device 4 including a moving block 2 that is moved along the moving block 2 and an air cylinder 3 provided on the upper surface of the moving block 2 is provided. A box-shaped housing box 5 in which a transparent window glass plate 5a as a window is fitted on the front surface facing the peripheral surface of the rolling roll W is attached to the rod tip portion of the air cylinder 3 of the moving device 4. . The CCD camera 6 arranged in the housing box 5 uses a CCD (Charge Coupled Device) image pickup device arranged two-dimensionally, and in order to prevent image blur due to vibration of the rolling roll W, It has a lens system with a large numerical aperture and a long focal length, and a deep focal depth.

As shown in the figure, the water column forming nozzle 8 has a water ejection port communicating with the window glass plate 5a of the housing box 5, and when the pressurized water is supplied, the window glass plate 5a.
And a surface of the rolling roll W that is rotating while the roll cooling water is being sprinkled. This prevents the window glass plate 5a from being contaminated by the roll cooling water containing dirt, and prevents the rolling roll surface static image from becoming unclear. The cylindrical water column forming nozzle 8 is made of acrylic resin that allows light to pass through and has transparency, and is attached to the front surface of the housing box 5 through a pressure water supply pipe 8a to supply a supply source (not shown). Water pressurized from is introduced inside.

The controller 9 controls the inspection start signal S1 from the outside.
In response to this, the annular xenon lamp 7 is turned on in synchronization with the vertical synchronizing signal of the CCD camera 6, and the roll surface still image signal from the CCD camera 6 is stored in the frame memory.
Captured in 10 and receiving display command signal S2, frame memory
This is a device for controlling the roll surface still image signal stored (stored) in the CRT display 11 to the CRT display 11. The control device 9, the frame memory 10, the CRT display 11 and the printer 12 are arranged in the examination room.

In the optical surface inspection apparatus having the above-described structure, the housing box 5 in which the annular xenon lamp 7 and the CCD camera 6 are arranged is arranged at a predetermined inspection position in the longitudinal direction of the rolling roll W. When it is positioned at, the control device 9 synchronously controls the synchronization signal of the CCD camera 6 and the lighting of the annular xenon lamp 7. Illumination light from the annular xenon lamp 7 is applied to the surface of the rolling roll through the window glass plate 5a and the water column by the water column forming nozzle 8. The CCD camera 6 is a window glass plate 5a
Also, an image of the surface of the rolling roll W that is rotating while the roll cooling water is being sprinkled is taken through the water column, and a static image signal of that roll surface is output. The roll surface still image signal from the CCD camera 6 is stored in the frame memory 10
Stored in. The above operation is sequentially repeated while moving the housing box 5 along the longitudinal direction of the rolling roll W by the moving device 4.

When the display command signal S2 is input to the control device 9 by the operation of the inspector after the image pickup of the surface of the rolling roll is completed, the still image signal of the roll surface stored in the frame memory 10 is changed according to the image pickup position. It is sequentially taken out for each screen and displayed on the CRT display 11 as a still image. The inspector determines the degree of roughening of the rolling roll (degree of surface deterioration of the rolling roll) by looking at the still image displayed on the monitor. FIG. 6 is a sketch of an example of a still image obtained by capturing an image of the surface of the rolling roll, and is a diagram showing a state of a hexagonal crack occurring in the black skin of the surface of the rolling roll.

[0011]

However, in the above-mentioned conventional optical surface inspection apparatus, the surface image of the rolling roll which is rotating while the roll cooling water is being sprinkled is imaged by the image pickup device, and the obtained surface stillness is obtained. Since the image is displayed on the image display device simply on the monitor, the judgment as to when to replace the rolling rolls, which is made by looking at the image displayed on the monitor, is based on the fact that there are variations among the individual operators. There is. Therefore, since roll banding may occur due to delay in roll replacement, surface deterioration progresses along with rolling of the rolling roll, that is, it is automatically detected that roughening has progressed and the replacement time has been reached. It is required to have a function.

The present invention has been made in view of the above circumstances, and is to take a surface image of a rolling roll which is rotating while the roll cooling water is being sprinkled, and analyze the obtained still image of the surface. Accordingly, an object of the present invention is to provide an optical surface inspection device for a rolling roll, which can automatically detect that the surface deterioration of the rolling roll has progressed and the roll replacement time has been reached.

[0013]

In order to achieve the above object, an optical surface inspection device for a rolling roll according to a first aspect of the present invention comprises a stroboscopic illumination light source for illuminating the surface of the rolling roll with illumination light, and roll cooling water. The image of the surface of the rolling roll which is rotating while being sprinkled is imaged in synchronization with the lighting of the strobe illumination light source, and an imaging device for obtaining the rolling roll surface still image, and an image obtained by the imaging device. It is characterized in that it comprises a determination processing means for detecting that the surface deterioration of the rolling roll has progressed and the roll replacement time has been reached based on the degree of blackening and the degree of the blue component.

An optical surface inspection device for a rolling roll according to a second aspect of the invention provides a strobe illumination light source for illuminating the surface of the rolling roll with illumination light, and an image of the surface of the rolling roll which is rotating while the roll cooling water is sprinkled. An image pickup device for picking up an image in synchronization with lighting of the strobe illumination light source to obtain a rolling roll surface still image, and an image obtained by the image pickup device
Detecting the number of hexagonal cracks in a predetermined area that occurs on the surface of the rolling roll after the value conversion, and based on the temporal change pattern of the number of hexagonal cracks detected, the surface deterioration of the rolling roll progresses and the roll replacement timing And a determination processing unit that detects that the time has reached.

[0015]

FIG. 3 is a view for explaining the operation according to the present invention, in which (a) is a view showing the temporal change of the blackening degree of the surface of the rolling roll, and (b) is the surface of the rolling roll. Is a diagram showing the temporal change in the number of hexagonal cracks occurring in the black skin of Fig. 3, and (c) is a diagram showing the temporal change in the degree of the blue component on the surface of the rolling roll.

[0016] On the surface of the rolling roll, a black scale is gradually generated and gradually becomes black with rolling, and thereafter, the black scale is partly peeled and the part is turned white. Therefore, the degree of blackening, which is the degree of blackness of the surface of the rolling roll, is as shown in FIG.
As shown in (a) of FIG. In FIG. 3, the time point A at which the degree of blackening approaches the peak indicates the time when the rolling roll needs to be replaced, and the time point B indicates the time when roll banding due to peeling of the black skin begins to occur on the surface of the rolling roll. ing. Further, the degree of the blue component on the surface of the rolling roll shows a temporal change such that its peak appears at a stage earlier in time than the above-mentioned blackening degree, as shown in FIG. 3 (c). . Therefore, the image of the surface of the rolling roll that is rotating while the roll cooling water is being sprinkled is captured by the imaging device in synchronization with the lighting of the strobe illumination light source to obtain the rolling roll surface still image, and the image obtained by the imaging device is obtained. It is possible to detect that the surface deterioration of the rolling roll has progressed and the roll replacement time has come based on the degree of blackening and the degree of the blue component.

On the other hand, the number of hexagonal cracks formed on the black scale of the surface of the rolling roll increases, as shown in FIG. 3 (b), in a relatively short period (hour) before the roll replacement time is reached. When the replacement time is reached, it tends to be almost constant once. Even in the case of the regenerated roll obtained by grinding the surface-deteriorated portion for reuse, the change in the number of hexagonal cracks shows the same tendency as described above, as indicated by the broken line in FIG. 3 (b). Therefore, the image of the surface of the rolling roll that is rotating while the roll cooling water is being sprinkled is captured by the imaging device in synchronization with the lighting of the strobe illumination light source to obtain the rolling roll surface still image, and the image obtained by the imaging device is obtained. The number of hexagonal cracks in the predetermined area generated on the surface of the rolling roll by binarization is detected, and based on the temporal change pattern of the number of hexagonal cracks detected, it is confirmed that the rolling roll has reached its roll replacement time. It can be detected automatically.

[0018]

EXAMPLES Examples of the present invention will be described below.
FIG. 1 is a view showing the arrangement of an optical surface inspection device for a rolling roll according to an embodiment of the first invention. Here, in this embodiment, the same or corresponding portions as those of the conventional optical surface inspection apparatus shown in FIG. 4 are denoted by the same reference numerals as those in FIG.

In FIG. 1, a CCD camera 6 as an image pickup device is a CCD color camera having a color filter array. Reference numeral 21 denotes a three-color component smoothing circuit having three integrators, and R for each image from the CCD camera 6 is input to the integrator and smoothed.
Memory for each color component signal of (red), G (green), B (blue) 22
Is output to Reference numeral 23 is a computer such as a microcomputer. The computer 23 reads out the three color component signals of R, G and B from the memory 22, and determines the degree of blackening and the degree of blue component of the rolling roll surface still image at each time when the CCD camera 6 captures the three color components. Calculated based on the signal, and by comparing them with a preset setting value, it is detected that the rolling roll has reached the roll replacement time due to the progress of its surface deterioration, and a signal for displaying that. Is output to the CRT display 11. The three-color component smoothing processing circuit 21, the memory 22, and the computer 23 constitute the judgment processing means 20. The control device 9 provides various timing signals to the CCD camera 6, the judgment processing means 20, the frame memory 10, and the like.

Next, the operation will be described with reference to FIG. The ring-shaped xenon lamp 7 and CCD camera 6
The housing box 5 disposed inside is prepositioned at a predetermined inspection position in the longitudinal direction of the rolling roll W, and the CCD camera 6 captures an image of the surface of the rolling roll W at predetermined time intervals. It has become so.

Each time the CCD camera 6 captures an image at each time point, the R, G, and B component signals of the rolling roll surface still image at the time of the image capture are read from the memory 22. Then, the computer 23 causes the degree of blue component FB = B · (aR + bG + cB) ⁻¹ and the degree of blackening D = for the still image of the rolling roll surface.
(AR + bG + cB) ⁻¹ is calculated based on the above-described three-color component signals. Here, a, b, and c are coefficients for weighting and normalization, respectively.

Next, the degree of the calculated blue component
FB and is compared with a preset set value FB _R is, when the degree FB of the blue component is equal to or smaller than the set value FB _R, the setting values D _R more than the calculated blackening degree D is set in advance Is determined. Then, the following set value FB _R degree FB of the blue component is set in advance, and, when blackening degree D is a preset value D _R or more, the rolling roll W is the surface degradation progresses It is determined that the roll replacement time has been reached, and a message such as "Replace the roll" is displayed on the CRT display 11 to that effect. In this way, it is confirmed that the surface deterioration (roughness) of the rolling roll W has progressed and the roll replacement time has come.
It can be detected automatically.

FIG. 2 is a diagram showing the construction of an optical surface inspection device for a rolling roll according to an embodiment of the second invention. Here, in this embodiment, the same or corresponding portions as those of the conventional optical surface inspection apparatus shown in FIG. 4 are denoted by the same reference numerals as those in FIG.

In FIG. 2, reference numeral 31 is a binarization processing section for binarizing an image obtained by the CCD camera 6 with an appropriate threshold value, and 32 is binarization processing by the binarization processing section 31. It is a memory for temporarily storing a binary image signal. 33 is a counter having a differentiator and a counter. Counting unit 33
Is 2 in a given scan line read from the memory 32.
The value image signal is differentiated and pulsed, and the pulse signal is counted to detect the number of hexagonal cracks in a predetermined area on the surface of the rolling roll, and the value is given to the computer 34 such as a microcomputer. The computer 34 analyzes the temporal change pattern of the number of hexagonal cracks to detect that the surface deterioration of the rolling roll W has progressed and the roll replacement time has been reached, and a signal for displaying this is detected. It is output to the CRT display 11. The binarization processing unit 31, the memory 32, the counting unit 33, and the computer 34 constitute the judgment processing unit 30.

Next, the operation will be described with reference to FIG. Each time the CCD camera 6 captures an image at each time, the computer 34 causes the difference between the number of hexagonal cracks C _{N (t)} detected this time and the number of hexagonal cracks C _{N (t-1)} detected last time | C _{N (t) -C N (t} -1) | is calculated, the tortoise-shell cracks number change amount | a a preset value _{ΔC N | C N (t)} -C N (t-1) Are compared. As shown in (b) of FIG. 3, the number of hexagonal cracks formed on the black scale on the surface of the rolling roll increases in a relatively short period before reaching the roll replacement timing (A), and when the roll replacement timing is reached. There is a tendency that it becomes almost constant once. Thus, computer 34, tortoise-shell cracks number change amount | when is equal to or less than [Delta] C _N after the state in which the set value [Delta] C _N or more _{continues, | C N (t) -C} N (t-1) It is determined that the rolling roll W has reached the roll replacement time, and a signal indicating this is output to the CRT display 11. As a result, a message guide such as "Exchange rolls" is displayed on the CRT display 11.
In this way, it is possible to automatically detect that the surface deterioration of the rolling roll W has progressed and the roll replacement time has come.

[0026]

According to the optical surface inspection device for a rolling roll according to the first aspect of the present invention, the rolling roll surface still image is displayed indicating that the rolling roll has undergone surface deterioration (rough skin) and has reached the roll replacement time. It can be automatically detected based on the degree of blackening and the degree of the blue component, which makes it possible to avoid delays in determining the roll replacement timing due to individual differences between operators by looking at the image displayed on the conventional monitor. It can be eliminated, and it can contribute to surely prevent the occurrence of bite scale flaws of the steel plate due to the surface deterioration of the rolling roll in the hot rolling process of the steel plate. According to the optical surface inspection device for a rolling roll according to the second aspect of the present invention, the fact that the surface deterioration of the rolling roll progresses and the roll replacement timing is reached is indicated by the temporal change pattern of the number of hexagonal cracks occurring on the rolling roll surface. Can be automatically detected based on
In the same manner as described above, it can contribute to surely prevent the occurrence of bite scale flaws of the steel sheet due to the surface deterioration of the rolling roll in the hot rolling step of the steel sheet.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an optical surface inspection device for a rolling roll according to an embodiment of the first invention.

FIG. 2 is a diagram showing a configuration of an optical surface inspection device for a rolling roll according to an embodiment of the second invention.

FIG. 3 is a diagram for explaining the operation according to the present invention, in which (a) is a diagram showing a state of temporal change of the blackening degree;
(B) is a diagram showing a temporal change in the number of hexagonal cracks, and (c) is a diagram showing a temporal change in the degree of the blue component.

FIG. 4 is a diagram showing a configuration of a conventional optical surface inspection device for a rolling roll.

FIG. 5 is a diagram for explaining how roll banding occurs on the surface of a rolling roll.

FIG. 6 is a sketch of an example of a still image obtained by capturing an image of the surface of a rolling roll, and is a diagram showing a state of a hexagonal crack occurring in the black skin of the surface of the rolling roll.

[Explanation of symbols]

1 ... Feed screw shaft 2 ... moving block 3 ... air cylinder 4 ... moving device 5 ... housing box 5a ... window glass plate 6 ... CCD camera 7 ... annular xenon lamp
8 ... Water column forming nozzle 9 ... Control device 10 ... Frame memory 11 ... CRT display 12 ... Printer 20, 30 ...
Judgment processing means 21 ... 3-color component smoothing processing circuit 22, 32 ... Memory 23, 34 ... Computer 31 ... Binarization processing unit 33 ...
Counter W ... Rolling roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 59-174204 (JP, A) JP 5-10888 (JP, A) Actual development Sho 64-15951 (JP, U) JP 5 40408 (JP, Y2)

Claims (2)

(57) [Claims] 1. A stroboscopic illumination light source for irradiating the surface of a rolling roll with illumination light, and an image of the surface of a rolling roll rotating while sprinkling roll cooling water are imaged in synchronism with lighting of the stroboscopic illumination light source, An image pickup device for obtaining the rolling roll surface still image, and based on the degree of blackening and the blue component of the image obtained by the image pickup device, the rolling roll surface deterioration progresses and the roll replacement time is reached. An optical surface inspection apparatus for a rolling roll, comprising: a determination processing unit that detects that the rolling surface is rolled. 2. A stroboscopic illumination light source for irradiating the surface of the rolling roll with illumination light, and an image of the surface of the rolling roll that is rotating while the roll cooling water is sprinkled, are imaged in synchronization with lighting of the stroboscopic illumination light source. An imaging device for obtaining the rolling roll surface static image, and the number of hexagonal cracks in a predetermined area generated on the rolling roll surface by binarizing the image obtained by the imaging device to detect the number of hexagonal cracks detected. An optical surface inspection device for a rolling roll, comprising: a determination processing unit that detects that the surface deterioration of the rolling roll has progressed and the roll replacement time has been reached based on the temporal change pattern.