JPS6139286Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dimension measuring device that automatically measures the length of a long plate or rod. When manufacturing long plates, the rolling process or cutting process to a fixed length is skipped, but conventionally the length of a plate or bar with a length of several meters in the feeding direction is automatically measured while it is being fed. It was difficult. The present invention provides an inexpensive means for accurately and automatically measuring the length in the running direction during rolling using a camera using a photoelectric sensor, such as a photodiode linear array (solid-state scanning element), commonly known as a line sensor. This is what we provide.

When manufacturing long plates, etc., the length of several tens of meters is rolled and then fed and cut into lengths of several meters to 30 meters, but there is no way to automatically measure the dimensions after cutting. , I had no choice but to manually measure it online with a tape measure. Traditionally, the width direction has been measured using two line sensor cameras, but the movement speed in the longitudinal direction is fast, so contact-type length meters have short lifespans due to accuracy or wear. Moreover, the method of arranging cameras required several cameras to cover a measurement range of arbitrary length.

The present invention aims to eliminate the drawbacks of the conventional method by automating this process using a single camera and at low cost.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is a layout diagram of a dimension measuring device that is an embodiment of the present invention. Here, the elongated iron plate 1, which is the object to be measured, is sent in the direction of the arrow 9 by the rotation of the feed roller 2. _L1 ,
L ₂ and L ₃ are floodlights that detect the tip of the long iron plate 1 in correspondence with photoelectric sensors P ₁ , P ₂ , and P ₃ . A camera 3 incorporating a line sensor 7 detects the rear end of the iron plate 1 and detects its position and dimensions. Reference numeral 4 denotes an illumination light, which is generally a fluorescent light that serves as a line light source, such as a high-frequency flashlight. FIG. 2 is a diagram showing the principle of the device and shows the arrangement of the measurement system. In the camera 3 with a built-in line sensor 7, the iron plate 1 passes under the roller 2, and the photoelectric sensors P ₁ , P ₂ , P ₃
Which one of them is covered by the tip of iron plate 1,
When light can no longer be received, measurement begins. However, even if the iron plate 1 reaches the point of the photoelectric sensor _P1 , if the rear end of the iron plate 1 does not enter the field of view V of the camera at the position indicated by the dotted line in the figure, measurement will not be possible. In this case, when the iron plate 1 reaches the point of the photoelectric sensor P ₁ as shown in the same figure and the incident light of the photoelectric sensor P ₂ is blocked, measurement starts again, and as shown in FIG. is obtained, and the length l is measured with the camera 3 as shown in FIG. Furthermore, if the iron plate 1 is long, the measurement will be made when the tip of the iron plate 1 reaches the photoelectric sensor _P3 .

Once the length l is determined, the length A of the iron plate 1 can be determined by the following equation, assuming that the distance between the photoelectric sensor P ₂ and the camera 3 is the distance D as shown in FIG.

A=D−l However, if the moving speed of iron plate 1 is velocity v and the time required for measurement is t, then iron plate 1 moves at v during measurement.
Move by the length xt. The effect of this is that, as shown in FIG. 4, measurement starts at position _S1 and ends at position _S2 .

Therefore, the signal obtained by the line sensor 7 in the camera 3 has a bright level at the position S ₁ ' and a dark level at _the position S' ₂ as shown in FIG. Become. The horizontal axis O to N represents the number of bits of the line sensor 7, and the subordinate axis represents the output voltage of the bright/dark level. Therefore, in order to find the length l, if we set the light and dark slice levels in two places and call them SL1 and SL2, respectively, the bright level becomes the saturation level.
If SL1 is E ₁ and SL2 is E ₂ for E ₃ or less, the following relational expression is obtained from the same figure. If R ₁ and R ₂ are read as shown in Figure 3, from the geometrical relationship, E ₁ -E ₂ /R ₂ -R ₁ =E ₃ -E ₁ /R ₁ -S'
₁ Therefore, S′ ₁ =R ₁ −E ₃ −E ₁ /E ₁ −E ₂・(R ₂ −R ₁
) to find S ₁ .

Therefore, the length l can be found from this.

FIG. 5 is a block diagram of the entire apparatus, and 5 is a processing machine with a built-in computer. When any of the photoelectric sensors P ₁ , P ₂ , and P ₃ detects the tip of the iron plate 1, the camera 3 reads R ₁ and R ₂ , calculates S ₁ , and obtains the length l. At the same time photoelectric sensor
Depending on which one of P ₁ , P ₂ , or P ₃ was detected and measured,
Select one of the registers D ₁ , D ₂ , D ₃ and
The distance D between the camera 3 and the photoelectric sensor that detected the tip is determined and D-l is displayed on the display 6. The spacing between the photoelectric sensors P ₁ , P ₂ , and P ₃ for tip detection is set to be equal to or slightly narrower than the measurement range V of the camera 3 so that the measurement range of dimensions does not extend beyond the measurement range V of the camera 3.

As explained above, according to the present invention, a simple sensor is used to detect the tip of a long board, etc., and a means for accurately measuring the length of any board while traveling is provided. It is something. Moreover, it is possible to provide a dimension measuring device that has the great feature that the measurement range can be extended to any length by adding inexpensive sensors.

[Brief explanation of the drawing]

Fig. 1 is a layout diagram of dimension measurement which is an embodiment of the present invention, Fig. 2 is a diagram of the principle of the same device, and Fig. 3 is:
Figure 4 is a characteristic diagram showing the output signal of the camera of the device, and Figure 5 is a principle diagram for explaining the measurement error of the device.
The figure is a block diagram of the entire device. 1... Steel plate, 3... Camera with built-in line sensor, 5... Processing machine, 6... Display device, 7... Line sensor, P ₁ , P ₂ , P ₃ ... Photoelectric sensor,
L ₁ , L ₂ , L ₃ ... floodlight, D ₁ , D ₂ , D ₃ ... register star.

Claims (1)

[Scope of utility model registration request] a light source that illuminates the rear end of a long object to be measured;
A line sensor camera is mounted facing the light source so that the object to be measured can pass through the middle thereof, and detects a position where the irradiation light is covered by the object to be measured, and a tip portion of the object to be measured that is fed in the longitudinal direction. a tip detecting means comprising a plurality of detection means arranged in the longitudinal direction at shorter and narrower intervals than the width of the detection area of the line sensor camera; processing means for determining and displaying the length of the object to be measured based on the number of bits until the brightness level changes and the distance from the tip detection means to the line sensor camera; In this processing means, brightness and darkness of the line sensor camera and slice level are provided at two locations,
A dimension measuring device characterized in that the position of the rear end of the object being measured is calculated from the number of bits of the line sensor camera corresponding to these slice levels.