JPH02259454A - Apparatus for displaying coil steel plate - Google Patents

Abstract

PURPOSE:To easily and accurately display a flaw by operating the display timing based on the flaw position data and transport speed of a cold rolled steel plate to apply marking to the surface of said steel plate. CONSTITUTION:When a flaw visually discovered is present on the surface of a fed cold rolled steel plate, this flaw is detected by a flaw inspection device 12 and the feed speed of said steel plate is detected simultaneously by a speed detector 14 and these detection signals are applied to an operation apparatus 16. Herein, the timing wherein the flaw reaches the part directly under a marking mechanism is operated from the flaw detection point of time and a marking start order is outputted. One the basis of this marking start order, a display means 18 emits an ink droplet from a nozzle. Since the marking is applied to the steel plate 10 so that a colored solution is continuously adhered to said steel plate at a definite width in the feed direction thereof, the marking can be easily automated and the position of the flaw can be clearly displayed to be easily detected on a user's side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coil steel sheet defect display device for adding an identification mark to a flaw portion on the surface of a cold rolled steel sheet that is wound into a coil. It is related to.

[Prior art] For example, on the user side such as an automobile manufacturer, during the process of unwinding a cold-rolled steel plate that has been wound into a coil, parts with surface flaws are separated as defective products, and only the parts without flaws are separated. We carry out sorting to select good quality products. To this end, it is desirable from the point of view of work efficiency that the site of the flaw is displayed in advance by the steel manufacturer as a defect indicator at the time of shipment, and that this is used for detection by the user.

As a conventional defect display means, for example, a developed view showing the location of the flaw is attached to the product, and the user identifies the location of the flaw on the surface of the steel plate while referring to the developed view. Alternatively, as described in Japanese Patent Publication No. 63-1<1784, a magnetizer causes a change in the state of the magnetic field between the flaw location and other parts, and this is shipped as a magnetic mark to indicate a defect, and the user On the other hand, magnetic mark detection bases are used to detect magnetic marks and pinpoint flaw locations.

[Problems to be Solved by the Invention] However, in the above-mentioned former method for displaying defects on coiled steel sheets, the verification work is time-consuming, resulting in poor work efficiency, and it is difficult to specify the flaw position with high precision. In addition, although the latter defect display device is superior in terms of work efficiency, when the user unwinds the steel plate after it has been rolled up, an external bending force is applied to the steel plate, resulting in a reduction in the magnetizing field and eddy current. This caused a shift in the magnetized position, making it impossible to accurately detect the flaw position. Therefore, the user also had to have a magnetizer for re-magnetizing the magnet.

The present invention has been made to solve these problems, and an object of the present invention is to provide a coil steel sheet defect display device that can easily and accurately display defects on a coil steel sheet.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides for displaying information based on flaw position information on the cold-rolled steel sheet during transportation and the conveyance speed of the cold-rolled steel sheet. The apparatus is provided with a calculation means for calculating timing, and a display means for marking the surface of the cold rolled steel plate at the paper position calculated by the calculation means.

Further, the marking is performed by applying a colored liquid continuously in a dot-like or linear form in a constant width in the conveying direction of the cold-rolled steel sheet so that defects can be easily detected by the user. is desirable.

[Operation] According to the above means, the marking mechanism is activated by the marking timing calculated based on the flaw position information detected (or visually recognized) prior to the display process and the conveyance speed of the steel plate passing through the installation position of the defect flaw indicating device. is driven, and a marking is placed on the defect to be displayed.

Additionally, by applying a colored liquid (e.g., ink) continuously over a fixed width in the direction of conveyance of the steel plate, marking can be easily automated and the location of defects can be clearly displayed. , which facilitates detection on the user side.

[Embodiment] Fig. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, Fig. 2 is an explanatory drawing explaining marking contents, and Fig. 3 is a perspective view schematically showing an example of marking means. be.

In FIG. 1, reference numeral 10 denotes a cold-rolled steel plate, which is wound into a coil after being subjected to display processing by the defect display device according to the present invention. Defect display device is steel plate 10
A flaw inspection device 12 that detects flaws on the surface of the screen prior to displaying the flaws.
A speed detector 14 that detects the conveyance speed (-winding speed) of the steel plate IO, a calculation device 16 that calculates the position to be marked based on the output signals of the speed detector 14 and the flaw inspection device 12, and the calculation It is comprised of a display means 18 that marks a specific position on the steel plate IO based on the calculation result of the device 16.

The flaw inspection device 12 is configured to use, for example, an image pickup device such as a COD (charge coupled device) as a detection sensor, and perform signal processing on the sensor output using a technique such as frequency analysis. The speed detector 14 may have a configuration in which a roller or the like is brought into pressure contact with the surface of the steel plate 10 and its rotational speed is converted into an electric signal corresponding to the conveyance speed of the steel plate 10. Also,
The calculation device gl16 is configured using a microcomputer or the like, and performs calculations by processing input data (speed detection signal and flaw detection signal) according to a software program. A marking mechanism based on the same principle as an inkjet printer, which is expected to become popular as an apparatus, is used, and marking commands corresponding to the flaw position are used to eject display ink onto the surface of the steel plate 10 for a certain period of time. The marking mechanism consists of a nozzle section consisting of a plurality of fine-diameter nozzles lined up in a row, an ink chamber that communicates with each nozzle of this nozzle section and is supplied with ink from an ink tank, and an inside of this ink chamber or nozzle passage. It is configured with an energy generating body (piezoelectric element, magnetostrictive element, heater, etc.) provided in the. Then, by driving the energy generator with a pulse signal of a predetermined frequency, ink droplets are ejected from the nozzle toward the steel plate IO.

Next, the operation of the embodiment with the above configuration will be explained.

When there is a visually detectable flaw on the surface of the steel plate IO being conveyed and this enters the detectable area of the flaw inspection device 12, the flaw inspection device 12 generates a flaw detection signal. At the same time, the speed detector 14 is detecting the conveying speed of the steel plate IO, and this speed detection signal and flaw detection signal are applied to the arithmetic unit 16.

Based on the two detection signals, the calculation device 16 calculates the timing at which the flaw reaches directly below the marking mechanism (i.e., the timing of the start of marking) from the time of flaw detection.
Output marking start command. The display means 18 discharges ink droplets from the nozzle based on a marking start command output from the arithmetic device 16. The discharge from the nozzle is not instantaneous, but is performed as indicated by the length in the conveying direction.

For example, as shown in Figure 2, 90□1 in the conveying direction of the steel plate lO
Then, from the side edge, for example, 50 mm, so that the width is 10 mm.
．． The marking 24 is performed so that , becomes the display start point. In this case, the nozzle spacing and the distance between the nozzles and the steel plate 10 are set so that the distance between the ink dots ejected by each nozzle and attached to the steel plate 10 is l step degrees. Further, dot formation in the longitudinal direction of the steel plate 10 can be arbitrarily set by adjusting the drive time and drive frequency of the nozzle.

In this way, by displaying a sufficient length in the conveying direction of the steel plate IO, even if there is an error in one display timing, this display length will include flaws, and the user will be able to When detecting a flaw display according to the invention, the flaw part can be reliably cut. In addition, by displaying with a width of 10 mm in this embodiment, the flaw portion can be easily detected by the sensor when similarly detecting the 5 flaw display. Furthermore, since the speed detection signal is incorporated into the calculation conditions, the detection accuracy of flaw indication can be increased by ±1.
．． can be kept within the range.

In the above description, an example was given in which the flaw inspection device 12 automatically detects flaws and automatically displays the flaws at the positions calculated by the arithmetic device 16, but the flaws can also be displayed manually. That is, as shown in FIG. 1, the inspector 20 visually enters the presence of a flaw on the flaw input panel 22 when a flaw on the surface of the steel plate 10 passes in front of it, and from this point on, the flaw is displayed on the display means 18. This can be done by calculating the time taken by the calculation device 16 to reach the position immediately below.

Further, when the flaw inspection device fi12 is not used and the function is limited to manual flaw display, a configuration as shown in FIG. 3 is possible. That is, as shown in FIG. 3, the display means in this case is composed of an inkjet device g12B that is driven by an inkjet control device 26 activated by turning on the activation button 30 to eject ink droplets onto the surface of the steel plate 10. . The inkjet control device 26 has a start button 30
When the button is turned on, defects are detected from the inspection position of the inspector 20 to the marking position (corresponding to the turning on of the start button 30).
A function that calculates the time it takes for the steel plate to move (can be calculated based on the transport speed of the steel plate 10 and the distance from the inspection position to the marking position), and each nozzle of the marking mechanism as described above at the timing determined by the calculation result. Drive all at once, and continue this drive for a certain period of time (Length 90□ in Figure 2)
Equipped with the ability to control the duration (time) to continue. With such a configuration, the flaw inspection device 12
Moreover, complicated calculations are no longer necessary, and the cost of the device can be reduced.

Although the invention made by the present invention has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above-mentioned Examples and can be modified in various ways without departing from the gist thereof. .

For example, although an example is shown in which an inkjet is used as the display means 18, it is also possible to provide a brush drive mechanism that allows a brush to come into contact with the steel plate 10 during marking, and to have the brush exude ink. It is desirable to use markings as shown in the figure.

Examples of excellent marking shapes shown in FIG. 2 will be described below with reference to FIGS. 4 to 9.

FIG. 4 is a block diagram showing a schematic configuration of a detection device suitable for detecting the markings shown in FIG. 2.

40 is a camera that detects the marking 24 on the surface of the rewound steel plate 10, and is constructed using an optical system such as a lens and an image sensor such as a CCD, and furthermore, it is configured with an 8-bit parallel signal to facilitate digital processing. Convert it to output the image data. 42 is an image processing device that performs image processing to be described later based on image data and recognizes defects;
CPU, built-in memory, various interface circuits.

The external storage device 9 includes a display control circuit, a power supply circuit, and the like. Further, 44 is a monitor that displays an image of the processing result by the image processing device 42.

Next, the contents of the process executed by the image processing device i42 will be explained using the flowchart in FIG. 5 and the process explanatory diagram in FIG.

When the steel plate 10 is transported and the marking 24 attached to its surface reaches directly below the camera 40, the marking 24
is imaged on the CCD via the optical system in the camera 40 (
S31), the camera 40 uses a COD having a reading capability of, for example, 51212 pixels (horizontal direction) x 512 lines (vertical direction), and a marking 24 is projected in a band shape within this image area (see Fig. 6 (Illustration)). )) Here, the reason why the marking 24 becomes a strip is that the steel plate 10 is, for example, 15
0. ,.

However, the reading speed of the CCD of the camera 40 is 33□8c, and during this reading time, the steel plate l
O is about 801. This is because the ink dots are read as connected because they move. However, steel plate l
Since the width direction of O does not move with respect to the reading direction of the CCD, the ink dots are read in a separated state. As a result, the marking 24 is imaged as a plurality of stripes.

The image signal captured by the camera 40 is converted into an 8-bit parallel digital signal, output from the camera 40, and transferred to the image processing device 42 via a high-speed bus (S32 in FIG. 5 and (b) in FIG. 6). .

Next, one-dimensional FFT processing is performed on this captured image signal, but if this is performed on all of the captured image signals for one screen, it will take a lot of processing time. This takes time and causes a delay in defect display detection. Therefore, we thinned out the ink dot array in the direction of the pitcher's force to 11n (1/4 or 1/8 in this example) (534 in FIG. 5 and (c) in FIG. 6), and applied one-dimensional FFT only to the thinned out image area. If processing is performed (S35 in Figure 5 and (d) in Figure 6), if the pixels are thinned out to 1/4, the CCD with the above specifications will target 12,828 pixels in the direction of the pitcher's force, and if the pixels are thinned out to 118. In this case, 64 pixels in the direction of the pitcher's force are targeted (the number of lines in the width direction is 512)
In this case, as shown in (d) of FIG. 6, the one-dimensional FFT processing by the CPU is performed from the line direction after corner turn processing (-vertical/horizontal conversion processing) is performed within the image processing device 14. ing.

Instead of such one-dimensional FFT processing, for example, a level slice method that performs length calculation and area calculation after binarization at the slice level can be considered, but there are problems in adopting it for the following reasons. .

■S/N ratio is low (about 2.5 to 3).

■Since it takes time (0.5 seconds) for CCD charge accumulation,
The faster the sheet threading speed is, the worse the S/N ratio becomes.

■Since the base color of the steel sheet cannot be specified, the level cannot be determined, and it is necessary to change the slice level for each product type.

For these reasons, the level slice method may not be able to perform binarization correctly, and the marking 24 may not be detected. However, as mentioned above, one-dimensional FFT
By using the frequency analysis by processing, the following processing using the processing result becomes possible, so that the marking 24 can be detected reliably and accurately.

Next, a power vector is calculated for the one-dimensional FFT result (S36 in FIG. 5 and (e) in FIG. 6).
A dimensional FFT is performed on each of the stripes of marking 24. Therefore, a power spectrum is calculated for each one-dimensional FFT result of each fringe. Then, the respective power spectra are added (S37 in FIG. 5 and (to) in FIG. 6). In other words, the spectra are superimposed at the ink dot interval (-stripe interval) in the width direction of the marking 24, so the level is calculated. is a row of ink dots (-stripes)
increases while the rest of the spectrum remains unchanged.

As a result, as shown in FIG. 7(a), the marking 24
When there is no marking 24, the power spectrum is concentrated in the DC component and low frequency component region, whereas when the marking 24 is present, the spatial frequency corresponding to the ink dot interval is concentrated as shown in FIG. 7(b). A power spectrum concentrated at f (−wavelength/length) is generated. Here, the spatial frequency f
can be obtained from the input screen as shown in FIG. That is, (number of dot marks per 1 line) = 512156 depth 10 number of dots in 1 mark = 1O (because the interval is 111 and 10.) Therefore, the spatial frequency becomes f-10 x 512156 depth 90.

Moreover, FIG. 9 is a characteristic diagram showing the relationship between the spatial frequency f and the power spectrum. Here, a case is shown in which there are m ink dot rows in a width of 200 bits.

As is clear from FIG. 9, when there is no marking 24, the power spectrum increases as the spatial frequency f decreases. This is because noise due to dust etc. is added in a long wavelength region (low frequency region). On the other hand, when the marking 24 has the same condition in the long wavelength region (low frequency region), the power spectrum becomes large in the vicinity of the spatial frequency f corresponding to the inktra 1-interval. Note that if all power spectra other than DC components and low frequency regions are marked 24, all power spectra resulting from addition processing that exceeds the level will be detected as paper, so the threshold value must be set. It is set up.

Next, the results of the power spectrum addition process for the specified band are transferred to the display control circuit or the host computer (38 in Figure 5 and (g) in Figure 6), and the recognition results of the flaw display are displayed as images on a CRT monitor, etc. (339 in Figure 5)
).

[Effects of the Invention] As is clear from the above, according to the present invention, the timing at which an indication should be attached is calculated based on the flaw position information on the cold rolled steel sheet during transportation and the conveyance speed of the cold rolled steel sheet. and a display means for marking the surface of the cold rolled steel sheet at the flaw position calculated by the calculation means, it is possible to easily and accurately display defects on the 5-coil steel sheet. can.

Furthermore, by applying the colored liquid to the markings in a dot or linear manner with a constant width in the conveying direction of the cold rolled steel sheet, it is possible for the user to detect flaws with high precision. can.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram explaining marking contents, FIG. 3 is a perspective view schematically showing an example of marking means, and FIG. Fig. 2 shows a schematic configuration of a detection device suitable for detecting markings, Fig. 5 is a flowchart showing the processing content by the image processing device shown in Fig. 4, and Fig. 6 shows the processing content of Fig. 5. An explanatory diagram showing an image, FIGS. 7(a) and (b) are waveform diagrams showing the output status of the power spectrum when there is no flaw indication, and FIG. 8 is an explanatory diagram showing the method of calculating the spatial frequency. FIG. 9 is a characteristic diagram showing the correlation between spatial frequency f and power spectrum. In the figure. 1 Discharged steel plate coil 12: Flaw inspection device 14: Speed detector 16: Arithmetic device 18: Display means 22: Flaw input panel 24: Marking 26: Inkjet control device 28: Inkjet device 30: Start button

Claims (2)

[Claims] (1) In a coil steel sheet defect display device that attaches an identification mark to a flaw portion on the surface of a cold rolled steel sheet that is wound into a coil, information on the flaw position of the cold rolled steel sheet during transportation and the cold A calculation means for calculating the timing at which a mark should be attached based on the conveyance speed of the cold-rolled steel plate, and a display means for marking the surface of the cold-rolled steel plate at the flaw position calculated by the calculation means. A coil steel sheet defect display device characterized by: (2) According to claim (1), the marking by the display means is such that a colored liquid is continuously applied in a dot shape or a line shape with a constant width in the conveyance direction of the cold rolled steel sheet. Defect display device for coil steel sheet described above