JPH0725440B2 - Plate-like seam detection method and mark detection device used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention connects plate members into a continuous strip,
The present invention relates to a method for detecting a seam portion of a plate-like body by making a mark in the vicinity of a seam portion of the plate-like body at the time of processing on a processing line, and detecting the mark, and a mark detection device used therefor.

[Prior Art] A plate-shaped steel plate is welded and joined as a continuous strip to be processed in a production line, but this joint cannot be included in a product. In addition, some equipment on the manufacturing line needs to be temporarily retracted when passing through the joints, and it is necessary to detect the joints in order to control these. For this reason, as a conventional detection method, a method has been adopted in which the vicinity of the seam portion of the steel sheet is perforated, and the amount of light transmission is optically detected when the hole passes, and a detection device according to this method has been used.

[Problems to be Solved by the Invention] In the conventional seam detection method and device thereof as described above, depending on the product, the plate width of the steel plate may be narrow or may interfere with the inner and outer surface beat cutters during welding. There is a problem in that there is a restriction on the hole diameter and the hole position, and it is not a method and device that can be easily applied to all products.

The present invention has been made to solve the above problems, and an object thereof is to obtain a joint detection method and a mark detection device that can be easily applied to all products.

[Means for Solving the Problems] A plate-shaped body seam detection method according to the present invention is a method for connecting plate-shaped bodies to form a continuous strip, which is processed near a seam of plate-shaped bodies when processed in a processing line. Of a parallel line having a predetermined width and spacing, which is oblique to the longitudinal direction of the strip, is made of a material having a reflection characteristic different from that of the parallel line. The plurality of marks are detected at the same time by a linear optical sensor that intersects with the marks made of lines, and the width and interval of the detected marks are within the respective prescribed ranges of the predetermined width and interval. This is for detecting the seam position of the shaped body.

Further, a method of detecting the seam position of the plate-shaped body described above using a fluorescent material as the material of the mark composed of the plurality of parallel lines,
The mark reception strength is increased and the reliability of mark detection is improved.

A mark detecting device according to the present invention has a field of view that extends at least in one axis direction, and is provided obliquely with respect to the longitudinal direction of a strip in which plate-like bodies are connected so as to intersect the field of view in the axial direction. A light receiver that simultaneously receives the marks formed of a plurality of parallel lines, converts the electric signal corresponding to the luminance distribution in the field of view, and outputs the electric signal, and the signal amplitude of the electric signal output from the light receiver is predetermined. The binarizing means for outputting the binarized high-level signal only when the binarized high-level signal is larger than the predetermined value, and the signal width of the binarized high-level signal output from the binarizing means falls within a predetermined range. Only when the mark width discriminating means generates a detection position signal at a predetermined position in the signal width of the high-level signal, and an interval between the detection position signals generated by the mark width discriminating means is set in advance. Within the prescribed range Only when that Tsu, those having a spacing determining means for generating a mark detection signal.

[Operation] In the plate-like body seam detection method of the present invention, when the plate-like members are connected to form a continuous strip and processed in the processing line, the reflection characteristics of the plate-like members near the joints of the plate-like members are different in advance. A material having a reflective property, which is slanted with respect to the longitudinal direction of the strip, has been subjected to a marter consisting of a plurality of parallel lines having a predetermined width and interval, and the plurality of parallel lines provided in the processing line. The plurality of marks are detected at the same time by a linear optical sensor that intersects with the marks made of lines, and the width and interval of the detected marks are within the respective prescribed ranges of the predetermined width and interval. Detect the seam position of the object.

Further, by using the material of the mark composed of the plurality of parallel lines as a fluorescent substance, the mark receiving intensity can be increased, the SN ratio (signal to noise ratio) can be improved, and the mark can be easily identified.

In the mark detecting device of the present invention, the light receiver has a field of view that extends in at least one axial direction, and is oblique with respect to the longitudinal direction of the strip in which the plate-like bodies are connected so as to intersect the field of view in the axial direction. The marks formed by a plurality of parallel lines are simultaneously received, converted into an electric signal corresponding to the luminance distribution in the visual field and output, and the binarizing means outputs the electric signal output from the light receiver. The binarized high level signal is output only when the signal amplitude is larger than a predetermined value. The mark width discriminating means determines a predetermined value in the signal width of the high level signal only when the signal width of the binarized high level signal output from the binarizing means is within a predetermined specified range. The detected position signal is generated at the specified position, and the interval determination means generates the detected mark signal only when the interval between the detected position signals generated by the mark width determination means is within a predetermined specified range. To do.

[Embodiment] Fig. 1 (a) is a view showing an embodiment of a mark shape for detecting a seam of a plate-like body of the present invention, in which 1 is a strip, 2 is a seam portion, and 3 is a mark.

In FIG. 1A, for example, the seam portion 2 of the strip 1 is used.
A mark 3 made of parallel lines having a length of about 180 mm is provided at a distance of 300 mm ahead of the strip 1 in the traveling direction in a direction oblique to the longitudinal direction of the strip 1.

FIG. 1 (b) is a diagram showing the positional relationship between the marks in FIG. 1 (a) and the light-receiving field of view, and 1-3 are the same as FIG. 1 (a). Reference numeral 10 denotes a light receiving field of the light receiver 4.

The reason why the mark 3 is slanted in the longitudinal direction of the strip 1 in this embodiment is that the mark 3 is received by the light receiver 4 even when the strip 1 rolls laterally with respect to the traveling direction.
This is because the light receiver 4 can sufficiently detect the mark 3 by preventing the mark 3 from deviating from 10. The material of the mark 3 may be any material as long as the light receiver 4 can optically distinguish the strip 1 from the mark 3, and for example, a fluorescent substance may be used. When a fluorescent substance is used as the material of the mark 3, the mark 3 can be easily identified by the difference between the reflection characteristics of the plate-shaped surface of the strip 1 and the reflection characteristic of the mark 3, and the processing line is dark. However, it also has the advantage that it can be identified. The mark 3 is provided at a distance of about 300 mm in front of the seam welded portion 2, and then the strip 1 is inserted into the processing line.

FIG. 2 is a block diagram showing an embodiment of the plate-like body seam detecting method and the mark detecting apparatus used for the same according to the present invention. 1 is a strip, 4 is a light receiver, 5 is a binarizing means, 6
Is a mark width determining means, 7 is an interval determining means, and 8 is a light projector.

FIG. 3 is a waveform diagram for explaining the operation of FIG.

2 will be described with reference to FIG. First, the projector 8 projects light onto the surface of the strip 1 at an incident angle θ ₁ . However, the light projector 8 is not always necessary, and it illuminates the visual field surface of the light receiver 4 so that the mark 3 can be reliably detected even when the processing line is dark. Therefore, it is unnecessary when the processing line is bright. When the light projector 8 is used, the surface of the strip 1 is close to the specular reflection and the mark 3
When the material of contains a diffuse reflection component, for example, mark 3
If the material is a fluorescent material, the positional relationship between the light projector 8 and the light receiver 4 is determined by the surface of the strip 1.
It is effective to improve the detection reliability by arranging the incident angle θ ₁ and the light receiving angle θ ₂ so as not to directly enter the specular reflection component of the light from the light receiver 4. As an example, the incident angle θ ₁ = 45
A stable detection signal can be obtained by setting the angle and the light receiving angle θ ₂ = 5 °. As shown in FIG. 1 (b), the light receiver 4 has a light receiving visual field 10 that spreads in a direction perpendicular to the traveling direction of the strip 1, and the luminance distribution in the visual field is optically received to obtain the luminance. It is a device that converts into a corresponding electric signal and outputs it. The light receiver 4 includes, for example, an optical system that collects light from a predetermined light-receiving field and inputs the light to a light-receiving sensor, a light-receiving sensor that receives incident light and performs optical-electric conversion, and reads an output signal from the light-receiving sensor. And a signal read amplifier circuit for amplifying the signal. The light receiving sensor used in this embodiment is generally called a one-dimensional array (or line) light receiving sensor, and includes a photodiode or a CCD (charg).
Dozens to hundreds of light receiving elements such as e coupled devices) are linearly arranged, and the light reception brightness can be individually detected for each array position of the light receiving elements. When the number of light receiving elements increases, the detection signal is usually read out in the serial shift-out form in synchronization with the read clock signal, as in the case of reading information from the analog shift register. That is, since the detection signals are read out in the order in which the light receiving elements are arranged, the number of read clock signals and the arrangement position of the read detection signals have a one-to-one correspondence. Therefore, the received light intensity information about the one-dimensional position can be read from the light receiver 4 as a time series signal. FIG. 3A shows an output signal waveform when the light receiver 4 receives the mark 3, the horizontal axis shows the range of the length L which is the light receiving range of the light receiver 4, and the vertical axis shows the background. An output signal is obtained at a position where the light receiving element detects the mark 3 in a form in which a pair of light receiving signals are superimposed on the noise level (generally referred to as background noise). The light receiver 4 transfers the output signal for this position to the binarizing means 5. In this signal transfer method, when the number of light receiving elements described above is large, the signal is transferred as a time-series signal synchronized with the read clock signal of the detection signal. That is, the information about the one-dimensional position is converted into the information about time and transferred. The binarization means 5 includes, for example, a voltage comparator and 2
It can be configured by a binarization reference voltage setting device and a binarization output circuit. That is, the time-series signal input from the photodetector 4 is input to one end of the input end of the voltage comparator, and the output voltage from the reference voltage setting device shown as the binarization level in FIG. By connecting it to the other end of the input terminal of the voltage comparator, the voltage comparator generates an output signal of 1 when the input voltage of the former exceeds the input voltage of the latter and 0 when it does not. When the output voltage of the voltage comparator is output via a binarization output circuit (for example, a data latch circuit), a binarized detection signal is output for each array position of the light receiving elements. The output signal waveform of the binarizing means 5 is shown in FIG. That is, from the reference position at the left end, distances l ₁ to l ₁ + Δ
The first output signal A _{0 at} the position of l _{1 and} the distance from the reference position
A _second output signal B ₀ is obtained and shown at the positions l ₂ to l ₂ + Δl ₂ , respectively. The binarizing means 5 supplies this output signal to the mark width determining means 6. The mark width determination means 6 is 2
It is determined whether or not the width of the mark detection signal input from the quantizer 5 is equal to or larger than a preset width. If the width is equal to or larger than the preset width, the mark signal is discriminated and a detection position signal is output. Have a function. Now, the binarizing means 5 in FIG.
Each of the first and second width of the output signal A ₀ and B ₀ of .DELTA.l ₁
And Δl ₂ and the width preset by the mark width determination means 6 is ΔL, the following equations (1) and (2) are determined.

Δl ₁ > ΔL (1) Δl ₂ > ΔL (2) When the mark width determining means 6 determines that the mark signal is a mark signal,
A signal of the detection position is generated. As an output signal of the mark width discriminating means 6 in FIG. 3C, the first output signal A ₁ is the second output signal at the position of distance l ₁ + ΔL from the reference position. An example is shown in which B ₁ is generated at a position l ₂ + ΔL from the reference position. To detect a more accurate position, the first output signal A ₁ is located at a distance l ₁ + Δl _1/2 from the reference position, and the second output signal B ₁ is located at a distance l ₂ + Δl ₂ from the reference position.
It should be generated at the positions of / 2. There are various methods for realizing the mark width determination means 6. The easiest method is to perform signal processing using the distance as time. In this case, the mark width determination means 6 keeps the input signal for a certain time so that the mark is not misread due to noise or the like.
Only when it continues for t ₁ or more, the output signal having a constant pulse width t ₂ may be generated by regarding it as a mark signal. Therefore, the mark width determination means 6 is activated by an input signal, for example, and the time width t ₁
A first monostable multivibrator which generates an output signal of and a second monostable multivibrator which is activated by an input signal after this time t ₁ and generates an output signal of a time width t ₂ You can However, since the photodetector 4 can read out the detection signal at an extremely high speed compared to the traveling speed of the plate-shaped body, the photodetector 4 scans many times within the time when the mark 3 is detected in the light receiving field. And the detection signal can be read. Therefore, if the mark width discriminating means 6 performs the signal processing (for example, correlation processing) a plurality of times instead of performing the signal processing only once, the mark width can be determined to obtain a very reliable and stable determination result. You can In this case, a data storage circuit and a correlation processing circuit are further required. The mark width judging means 6 supplies the output signals A ₁ and B ₁ to the interval judging means 7. The interval determination means 7 determines that the pair of input signal intervals is a regular mark signal and outputs a mark detection signal when the pair of signal intervals is within a predetermined range. The following equation (3) is determined by assuming that the pair of input signals is lp and the predetermined range is Lp to Lp + ΔLp.

Lp <lp <Lp + ΔLp (3) As a circuit that realizes the interval determination means 7, a physical interval can be processed as a time interval of pulse signals as in the case of the mark width determination means 6. In this case, the interval determination means 7 may generate the output signal when the interval between the two input pulse signals is within a predetermined time range. Mark width discriminating means 6 is thus for example, a first monostable multivibrator for generating a first output signal of the start time width t ₃ by the pulse signal A ₁ input, the pulse signal of the time width t ₃ Time width activated by falling waveform
a second monostable multivibrator for generating an output signal C of the t4, the second input pulse signal C of the time width t ₄
AND circuit for calculating the logical product with the pulse signal B _{1 of}
It can be constituted by a circuit with a third monostable multivibrator which is activated by an output signal of the circuit and generates an output signal D having a time width t ₅ . FIG. 3D shows a pulse signal C having the time width t ₄ used as a gate signal for interval determination.
In addition, FIG. 5E shows the output signal D of the third monostable multivibrator used as the output signal of the interval determining means 7. Further, like the case of the mark width determination means 6, the interval determination means 7 may output the detection signal based on the result of the correlation processing performed a plurality of times instead of the result of the determination performed only once.

In this way, the width of each signal of the pair of linear mark signals detected when the received light signal is binarized into a signal for a one-dimensional position and the interval between the signals are defined in advance. The mark detection signal is obtained when the value is within the range, and the malfunction is prevented.

In the above-mentioned embodiment, an example of a pair of linear marks having a constant interval is shown as an identification mark, but a plurality of linear marks of 3 or more are further provided to prevent malfunction and improve reliability. It is also possible to measure.

Further, in the embodiment of the mark width determining means 6 described above, only the lower limit value ΔL of the mark width is set in advance and comparison with the output signal width of the binarizing means 5 is performed. Is also set, and the detection position output signal is generated only when the output signal width of the binarizing means 5 is within the range of the upper and lower limit values, thereby improving the detection reliability. It is also possible.

[Effects of the Invention] As described above, according to the plate-like body joint detecting method and the mark detecting apparatus used for the same, a material having a reflection characteristic different from the reflection characteristic of the plate-like body near the joint of the plate-like body is provided. A line-shaped optic which is oblique to the longitudinal direction of the strip and has a mark made up of a plurality of parallel lines having a predetermined width and interval and which intersects with the mark made up of the plurality of parallel lines in the processing line. Since the plurality of marks are simultaneously detected by the dynamic sensor, and the mark detection signal is obtained only when the width and the interval of the detected marks are within a predetermined specified range, the plate-like body is not subject to roll. Even if there is a mark, there is no mark detection failure, and even in an environment with a lot of background noise, a mark that is not a mark is not erroneously detected, and it is possible to perform highly reliable mark detection.

Further, by using a fluorescent material as the material of the mark, the mark can be stably detected in an optically bad environment.

Further, in the mark detecting device of the present invention, since the output signal of the light receiver is binarized into a digital signal and the position information can be converted into time information, the mark width discriminating means and the interval discriminating means are all digital circuits. Since the device can be constructed on a small scale, the device can be made inexpensive, and a highly reliable device can be obtained.

[Brief description of drawings]

FIG. 1 (a) is a diagram showing an embodiment of a mark for plate-like body seam detection of the present invention, and FIG. 1 (b) is a diagram showing a positional relationship between the mark in FIG. FIG. 2 is a block diagram showing an embodiment of the plate-like body seam detecting method and the mark detecting apparatus used for the same according to the present invention, and FIG. 3 is a waveform diagram for explaining the operation of FIG. In the figure, 1 is a strip, 2 is a seam, 3 is a mark, 4 is a light receiver, 5 is a binarizing means, 6 is a mark width judging means, 7 is an interval judging means, 8 is a light projector, and 10 is a light receiving field of view. is there.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuya Suzuki, 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor, Koji Owaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Date Inside the Steel Pipe Co., Ltd. (72) Inventor Yuji Sugimoto 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Inside the Nippon Steel Pipe Co., Ltd. (56) Reference JP 62-31655 (JP, A) JP 62- 111860 (JP, A) Actual development Sho 56-68111 (JP, U) Japanese Patent Sho 48-40186 (JP, B1)

Claims (3)

[Claims] 1. A continuous strip formed by connecting plate-like bodies, and a material having a reflection characteristic different from the reflection characteristic of the plate-like bodies in the vicinity of the joint of the plate-like bodies when processed in a processing line. A mark made of a plurality of parallel lines having a predetermined width and a distance that is oblique to the line is provided, and the plurality of the plurality of parallel lines are crossed by the linear optical sensor in the processing line. A method of detecting marks at the same time, and detecting the seam position of the plate-shaped body when the widths and intervals of the detected marks are within the respective prescribed ranges of the predetermined widths and intervals. 2. The method for detecting the seam position of a plate-like body according to claim 1, wherein the mark composed of the plurality of parallel lines is made of a fluorescent substance. 3. Having a field of view extending at least in one axis direction,
Corresponding to the brightness distribution in the field of view, simultaneously receiving the mark composed of a plurality of parallel lines obliquely provided with respect to the longitudinal direction of the strip connecting the plate-shaped bodies so as to intersect the field of view in the axial direction. A light receiver for converting and outputting the converted electric signal, and a binarizing unit for outputting a binarized high-level signal only when the signal amplitude of the electric signal output from the light receiver is larger than a predetermined value. Only when the signal width of the binarized high-level signal output from the binarizing means is within a predetermined specified range, the signal is detected at a predetermined position in the signal width of the high-level signal. Mark width determining means for generating a position signal, and an interval determining means for generating a mark detecting signal only when the interval between the detected position signals generated by the mark width determining means is within a predetermined specified range. Having and That mark detection device.