JPH05187825A - Method and apparatus for measuring shape of steel bar of irregular shape - Google Patents

Abstract

PURPOSE:To quickly and highly accurately measure the size irregular and shape of a steel bar of an irregular shape immediately after the hot rolling by detecting a changing point of the diameter from the first and last black signals in the diametrical direction among the black-and-white image signals obtained by scanning the pattern of the light shielded by the steel bar. CONSTITUTION:An illuminating device 4 casts parallel beams spreading in the diametrical direction of a steel bar 1 irregular of an irregular shape. The pattern of the light shielded by the steel bar 1 is detected as black and white signals by photodetecting elements of a camera 5 aligned on a two-dimensional plane. A detecting device 7 detects coordinates values of pixels of the first and last black signals in the diametrical direction of the steel bar 1 among the black and white image signals obtained by the camera 5, operates the coordinates values in the axial direction of the steel bar 1, thereby to detect a point where the diameter of the steel bar is changed. A shape operating device 8 calculates the configuration, basic circle, knot height, knot pitch, knot shift and knot angle of the steel bar 1 with the use of the detected changing point of the diameter in the axial direction of the steel bar 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring method and a measuring apparatus for hot-rolled deformed steel bars.

[0002]

2. Description of the Related Art The rolling workability of a deformed steel bar having protrusions and ribs on the outer peripheral surface thereof is particularly difficult as compared with ordinary round bar rolling. In particular, regarding the deformed steel bar 1 for screw reinforcing bars shown in FIG. 6, since both screw reinforcing bars are connected using the coupler for coupling, the spiral of the inner surface of the coupler other than the outer diameter (D ₁ ) and the base circle diameter (D ₂ ) is used. Height (a), bush pitch (P), shift (G), and bush angle of the male screw that fits the female screw
Strict accuracy is required for the outer peripheral shape such as (θ ₂ ), and if there is misalignment, a large amount of rejected products will be generated. Therefore, when rolling this type of deformed bar steel, it is very important to control the dimensions and shape, and particularly at the time of initial rolling, it is necessary to be very careful. Conventionally, this dimensional shape adjustment at the time of initial rolling is performed by rolling once, measuring the dimensional shape of the intermediate inspection sample manually by hand, feeding it back to the next rolling, and repeating this until it is within the standard, The rolling amount, the thrust amount, and the misalignment amount of the upper and lower rolls of the rolled material are adjusted to shift to full-scale rolling.

As prior art relating to the present invention, for example, JP-A-59-141008 and JP-A-60-25.
There are techniques disclosed in Japanese Patent No. 0235, etc., but these are related to the surface defect inspection of the screw and cannot be applied to the case of detecting the size and shape as intended by the present invention.

[0004]

As described above, since the dimension and shape measurement at the time of the initial rolling of the deformed steel bar is manually performed, the measuring time is long and the measuring accuracy varies widely. There was a problem that could not be overcome. Therefore, there has been a demand for development of a technique capable of accurately detecting the dimension and shape of a deformed steel bar in a short time, that is, capable of performing automatic measurement without manual labor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method and apparatus for accurately measuring the dimension and shape of a deformed steel bar immediately after hot rolling.

[0006]

The method of the present invention is a method for measuring the shape of a deformed steel bar, wherein at least one parallel light beam having a radial spread toward a flat portion (hereinafter referred to as a rolling free surface) of the deformed steel bar. The black and white image signal is obtained by scanning the light pattern shielded by the deformed steel bar in the axial direction, and the coordinate values of the first and last black signal in the radial direction of the deformed steel bar are detected from the black and white image signal. The difference value is calculated in the axial direction of the deformed steel bar to detect the diameter change point, and the outer diameter of the deformed steel bar, the base circle diameter, the bush height, the bush pitch, and the shift deviation are detected based on the coordinate value of each of the diameter change points. And at least 1 of the bending angle
One to detect one.

Further, the apparatus of the present invention is, in the shape measuring apparatus for deformed steel bar, an illuminating device for irradiating parallel rays having a spread in the radial direction of the deformed steel bar, and a light pattern in the radial direction of the deformed steel bar shielded by the deformed steel bar. And an image pickup device that obtains the black and white image signal by scanning in the axial direction, and the coordinate values of the first and last black signals in the radial direction of the deformed steel bar of the black and white image signal are detected and the coordinate values are differentiated in the axial direction of the deformed steel bar. A signal processing device that calculates and detects a diameter change point, and detects at least one of the outer diameter, base circle diameter, bush height, bush pitch, bush shift, and bush angle of the deformed steel bar from the coordinate value of each shift point. It is a shape measuring device composed of.

[0008]

The contents of the present invention will be described in detail below with reference to the drawings. 1 to 4 are views showing the principle of shape measurement of a deformed steel bar according to the present invention. In FIG. 1, the free surface 2 of the deformed steel bar 1 is placed on the pedestal 3 with the free surface 2 of the deformed steel bar 1 being substantially vertical, and a parallel light beam is emitted from the illumination device 4 behind the deformed steel bar 1, and the camera 5 is installed to face it. The deformed steel bar 1 is photographed. As shown in FIG. 2, light receiving elements of 512 × 480 pixels are arranged in the light receiving portion of the camera 5, and the axial direction and the radial direction of the deformed steel bar 1 are set to 512 of the light receiving elements, respectively.
Images are taken in the pixel direction (X direction) and the 480 pixel direction (Y direction).

The area where the light emitted from the rear of the deformed steel bar 1 is shielded by the deformed steel bar 1 and the portion which is not shielded by the deformed steel bar 1 are detected by the light receiving elements of the camera 5 as information of different brightness, and the light having a predetermined brightness or more is detected. Is the white state of the light receiving element and the following is the black state, the shape of the deformed steel bar 1 is measured as a distribution of the white and black states as shown in FIG.

In FIG. 2, the first radial direction where light is blocked by the deformed steel bar 1 is changed from white to black, which is the first Y direction.
The position of the th black pixel is calculated in pixel units in the X direction, which is the axial direction, and the coordinate values of the respective pixels are (x ₀ , y _0n ), (x
_{1, y 1n) ··· (x} m, detected as y _mn) ···.

Similarly, the coordinates of the last black in the Y direction from black, which is the last radial portion where light is blocked by the deformed steel bar 1, to white, are set to (x ₀ , y _0n 'in the axial direction). ),
(x ₁ , y _2n ') ... (x _m , y _mn ') ...

Two arithmetic operations shown in the following equations are performed on these coordinate values to detect the radial dimension change point of the deformed pole steel 1.

The first forward difference calculation is a process of calculating a difference in Y coordinates from a certain coordinate as a starting point up to a few points in the X direction and setting the result as the Y coordinate value of the starting point. On the contrary, the backward difference calculation is a process of calculating the difference of the Y coordinate within a range starting from a certain coordinate up to several points in the X direction and setting the result as the Y coordinate value of the starting point.

[Forward Difference Calculation] (y _0n −y _1n ) + (y _0n −y _2n ) + ·· + (y _0n −y _mn ) ⇒ y _0n (y _1n −y _2n ) + (y _1n −y _3n ) + ・ ・ ＋ (y _1n −y _{(m + 1) n} ) ⇒y _1n・ ・ (y _0n '−y _1n ') + (y _0n '−y _2n ') + ・ ・ + (y _0n ' −y _mn ') ⇒y _0n ' (y _1n '−y _2n ') + (y _1n '−y _3n ') + ・ ・ + (y _1n '−y _{(m + 1) n} ') ⇒y _1n ' [Backward difference calculation] (y _mn −y _{(m-1) n} ) ＋ (y _mn −y _{(m-2) n} ) ＋ ・ ・ ＋ (y _mn −y _0n ) ⇒ y _mn (y _{(m + 1 ) n} −y _mn ) ＋ (y _{(m + 1) n} −y _{(m-1) n} ) ＋ ・ ・ ＋ (y _{(m + 1) n} −y _1n ) ⇒ y _{(m + 1) n}・ ・(y _mn '−y _{(m-1) n} ') ＋ (y _mn '−y _{(m-2) n} ') ＋ ・ ・ ＋ (y _mn '−y _0n ') ⇒ y _mn '(y _{(m +1) n} '−y _mn ') ＋ (y _{(m + 1) n} '−y _{(m-1) n} ') ＋ ・ ・ ＋ (y _{(m + 1) n} '−y _1n ') ⇒y _{(m + 1) n} '・ ・ The dimension change point in the axial direction of the deformed steel bar 1 is obtained from the point where the results of the forward difference calculation and the backward difference calculation become zero.
That is, as shown in FIG. 3, the dimensional change starting points A ₁ and A _{2 in} the axial direction of the deformed steel bar 1 are A ₁ (x ₁ , y ₁ ), A ₂ from the point where the backward difference calculation value becomes zero. (X ₃ , y ₃ ), and the dimensional change end points B ₁ and B ₂ are B ₁ (x ₂ , y ₂ ), B ₂ (x ₄ , y) from the point where the forward difference calculation value becomes zero. Detect as in ₄ ).

The shape of the deformed steel bar is measured using the dimension change point in the axial direction of the deformed steel bar thus obtained by the difference calculation.

As shown in FIG. 4, the outer diameter of the deformed steel bar 1 (D
₁ ) is obtained as D ₁ = y ₂ −y ₂ ′ from the Y coordinate value difference between the odd-numbered dimensional change end points B ₁ and B ₁ ′. or,
A ₂ from _a point B from the average value and the B ₁ 'point of Y-coordinate values of A ₂ points
If it is obtained from the difference in the average value of the Y coordinate values of the points, it is possible to measure with less variation.

The base circle diameter (D ₂ ) of the deformed steel bar is D ₂ = from the Y coordinate values of the odd-numbered dimensional change starting points A ₁ and A ₁ ′.
y ₁ −y ₁ 'is obtained. This can also be measured with a smaller variation if it is obtained from the difference between the average value of the Y coordinates from the B ₂ point to the A ₃ point and the average value of the Y coordinate values from the B ₂ 'point to the A ₃ ' point.

The bristle height (a) of the deformed steel bar is determined as a = y ₂ −y ₁ from the difference in Y coordinate value between the odd-numbered dimensional change start point A ₁ and end point B ₁ . Since this is also a measurement with a smaller variation, it can be obtained from the difference between the average value of the Y coordinate values from the B ₁ point to the A ₂ point and the average value of the Y coordinate values from the B ₂ point to the A ₃ point.

The bending pitch (P) of the deformed steel bar is the difference in X coordinate value at every four points, for example, the difference in X coordinate value between point A _{1 and} point A ₃ (P).
= Determined from x ₅ -x _1). Where A ₁ point, B ₁ point, A
Area surrounded by ₂ points and B ₂ points, A ₃ points, B ₃ points, A ₄
A smaller variation can be measured by the difference in the X coordinate value of the center of gravity of the area surrounded by the points B ₄ and B ₄ .

[0020] Fushizure variants steel bar (G) utilizes that the inclination angle of the knots (theta ₁₎ is constant, lines and A ₁ 'point extended in advance Azukara the theta ₁ angle from _a point A It is calculated from the difference in the X coordinate value between and. Even further to the small measurement variations which, A ₁ point, B ₁ point, A ₂ points, area and A ₁ 'point, B _1, A _2, B _2' surrounded by _two points B enclosed by points It may be obtained from the difference in X coordinate value of the center of gravity of the area.

The bending angle (θ ₂ ) of the deformed steel bar is A ₁
It is calculated from the angle at which the straight lines connecting the points B ₁ and A _{2 and the} points B ₂ intersect.

[0022]

FIG. 1 shows an embodiment of the shape measuring apparatus of the present invention. The apparatus is a pedestal 3 on which the free surface 2 of the deformed steel bar 1 is placed vertically, an illuminating device 4, a camera 5 arranged on the opposite side of the illuminating device 4, a camera controller 6 for camera adjustment, and an deformed steel bar from the obtained image. It comprises a diameter change point detection device 7 for calculating a diameter change point in the longitudinal direction, a shape calculation device 8 for detecting the shape of the deformed steel bar 1 using this change point, and an output device 9. The illuminating device 4 irradiates the deformed steel bar 1 with parallel rays of light spread in the radial direction. The camera 5 is a deformed steel bar 1.
The light pattern shielded by is detected as a black and white signal by the light receiving elements arranged in a two-dimensional plane in the camera 5. The camera controller 6 adjusts the field of view and the aperture of the camera 5, and adjusts the camera 5 to an optimum shooting state.
From the image signal obtained by the camera 5, the diameter change point detection device 7 detects the coordinate values of the pixels of the first and last black signals in the radial direction of the deformed steel bar of the black-and-white image signal, and determines these coordinate values in the axial direction of the deformed steel bar. And the change point of the diameter is detected. Shape calculator 8
Uses the diameter change point in the axial direction of the deformed steel bar obtained by such calculation to calculate the outer diameter, the base circle diameter, the hump height, the hump pitch, the hump shift, and the hump angle of the irregular steel bar. The measurement result, that is, each calculated value is output to the output device 9 such as a recorder or a CRT screen.

FIG. 5 shows the shape measurement results of a standard deformed steel bar by the device of the present invention. In this embodiment, 50 mm field of view / 5000 bit
The camera 5 having a resolution of 0.01 mm / bit is used. measurement

The time is about 30 seconds, and it has been confirmed that the accuracy can be measured within a required range.

As described above, according to the present invention, the shape of a deformed steel bar can be measured accurately and quickly.
It is possible to reflect the measurement result in the adjustment of the rolling mill immediately, and it is extremely effective in the industry by overcoming the two problems of reducing the dimensionally defective material and reducing the rolling stop time.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the device of the present invention.

FIG. 2 is a plan view showing a shooting screen of the camera 5 shown in FIG.

FIG. 3 is a graph showing a difference value calculated from the photographed image shown in FIG. 2 for obtaining an outer diameter change point in the axial direction of the deformed steel bar 1 shown in FIG.

FIG. 4 is a plan view showing the coordinates for calculating the shape of the deformed steel bar 1 shown in FIG. 1 on the captured image shown in FIG. 2.

5 is a plan view showing an actually measured data table by the apparatus shown in FIG.

FIG. 6 is an enlarged view showing the shape of the deformed steel bar 1.

[Explanation of symbols]

1: Deformed bar steel for screw reinforcing bars 2: Rolling free surface of deformed bar steel 3: Cradle 4: Lighting device 5: Camera 6: Camera controller 7: Diameter change point detection device 8: Shape calculation device 9: Output device

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuharu Nomura, 12 Nakamachi, Muroran City, Nittetsu Hokkaido Control System Co., Ltd. (72) Inventor, Toru Kakuhari, 12 Nakamachi, Muroran City

Claims (2)

[Claims] 1. A non-rolled surface of a deformed steel bar is irradiated with at least one parallel light beam having a radial spread.
The pattern of light shielded by the deformed steel bar is scanned in the axial direction to obtain the black-and-white image signal, and the coordinate values of the first and last black signals in the radial direction of the deformed steel bar in the black-and-white image signal are detected, and the coordinate values are detected. Is characterized by detecting the change point of the diameter by calculating the difference in the axial direction of the deformed steel bar and detecting one or more of the outer diameter, base circle diameter, bush height, bush pitch, slippage and bush angle of the deformed steel bar. Measuring method for deformed steel bar. 2. A lighting device for irradiating a parallel light beam having a spread in the radial direction of the deformed steel bar, and a pattern of light in the radial direction of the deformed steel bar shielded by the deformed steel bar is axially scanned to obtain a black and white image signal thereof. An image pickup device; and an arithmetic device for detecting the coordinate values of the first and last black signals in the radial direction of the deformed steel bar of the black and white image signal, and calculating the difference between the coordinate values in the axial direction of the deformed steel bar to detect the change point of the diameter. And a signal processing device for detecting one or more of the outer diameter, the base circle diameter, the height of the bush, the height of the bush, the shift, and the angle of the bush from the obtained change point of the shape of the deformed steel bar.