JPH0658203B2 - Object edge detection device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for detecting an end of a long or block-shaped object moving in a certain direction.

(Prior Art) Hereinafter, a case where an object whose end position is detected is a spiral steel pipe will be described as an example.

Since the spiral steel pipe is continuously manufactured by a long coil, the spiral steel pipe has a predetermined length (for example, 6 to 30.5) on the outlet side of the pipe making machine.
m) is cut by a traveling cutting machine. That is, the pipe end position detecting device is positioned at a position extending from the cutting start position of the traveling cutting machine to a predetermined cutting length. Then, the tip of the traveling steel pipe is detected to start cutting, and the steel pipe is cut to a required length with an accuracy of about ± several mm.

FIG. 1 shows an example of a pipe end detecting device developed by the present inventors. The tube end detection device 1 is arranged on the side of the moving line of the tube P, a projector 2, a television camera 3 arranged on the same side as the projector 2 and scanning the projector in parallel to the tube moving direction, and imaging. It comprises a device 4 for processing the video signal from the television camera 3.

In the tube end detection device 1 having the above-described configuration, there are cases where a sufficient distance cannot be maintained between the tube P and the television camera 3 due to space limitations. In addition, the projector 2, the TV camera 3
The TV camera 3 cannot move forward and backward (left and right in FIG. 1) because they are installed on the carriage 5 that runs on a rail extending along the tube axis. Further, as shown in FIG. 2, the pipe making machine produces pipes P _{1 to} P ₅ having various diameters, so that the distance (shooting distance) D between the pipe P and the television camera 3 greatly changes.

(Problems to be Solved by the Invention) Since the taking lens of the television camera 3 is a zoom lens, even if the taking distance D changes, the tube P can be taken at a constant magnification by changing the focal length. However, the lens is designed to have a close-up distance, and if the shooting distance is less than or equal to the close-up distance, the image plane will not be in focus. As a result, a blurred image is reproduced on the screen of the monitor TV. Further, in the video signal processing device, the ratio of the video signal of the tube and the video signal of the background becomes small, which causes an error in detecting the tube end.

The present invention solves the above-mentioned problems in the object edge detecting device, and can significantly reduce the close range of the photographing zoom lens by a simple mechanism, and the size of the detected object changes and the photographing is performed. An object of the present invention is to provide an object edge detecting device that can always obtain a sharp image signal even if the distance changes greatly and can detect the edge accurately.

(Means for Solving Problems) An object edge detection device of the present invention is a projector that irradiates an object that moves in a certain direction from the side, a television that is arranged on the same side as the projector and that images the irradiation part of the object. Consisting of a camera and a device for processing video signals from a television camera,
In an apparatus for detecting an edge of a moving object, the projector and the TV camera are installed on a carriage that can move along a moving line of the object, and the TV camera is a lens barrel fixed to a base. And a camera head including an image pickup tube or an image pickup plate are separated from each other, the camera head is attached to a base so as to be movable in the optical axis direction, and the television camera is a fine movement device for displacing the camera head in the optical axis direction. Is equipped with.

(Operation) In the apparatus configured as described above, when the object whose position is detected moves forward and the end reaches the light projecting unit, the end enters the visual field of the video camera. The signal from the video camera is compared with a preset reference voltage in the video signal processing device to determine whether the end portion has reached a predetermined position.

When the tube diameter becomes large and the distance between the surface of the tube to be photographed and the television camera becomes the shortest distance or less, the photographing lens cannot be focused on the light receiving surface of the image pickup tube or the image pickup plate. In this case, the camera head is moved forward by the fine movement device, that is, the camera head is brought closer to the photographing lens so that the light receiving surface is in focus.

In addition, the dolly is moved and the projector and the TV camera are installed at the required edge detection positions according to the length of the object.

(Example) Hereinafter, an example of the present invention will be described by taking the case of detecting the pipe end of a spiral steel pipe as an example.

Since the projector, the video signal processing device and the like are the same as those shown in FIG. 1, their description will be omitted.

The television camera 3 is equipped with a zoom lens (not shown) having a focal length of 16 to 160 mm and a close range of 1.1 m, and the image pickup device is a MOS type image pickup plate.

FIG. 3 is a plan view showing a part of the television camera 3. As shown in the drawing, the lens barrel 11 is fixed to a base 13 by a metal fitting 12. A camera head 14 having an image pickup device (not shown) inside is supported on a base 13 by a guide ring 16 so as to be movable back and forth (in the optical axis direction). The lens barrel 11 and the camera head 14 are separated from each other, and the tip portion 15 of the camera head 14 can be inserted into the lens barrel 11 by about several mm.

A fine movement device 18 is arranged behind the camera head 14.
A frame 19 of the fine movement device 18 is fixed to the base 13, and a motor 20 is attached to the frame 19. Motor 20
A gear 22 is fixed to the output shaft 21 of the. Frame again
A screw rod 23 is rotatably attached to the screw 19, and a gear 24 meshing with the gear 22 is fixed to the rear portion of the screw rod 23. The screw rod 23 is fitted to the female screw 26 of the connecting fitting 25 extending rearward from the camera head 14. Further, a guide rod 27 projects forward from the frame 19 in parallel with the screw rod 23, and penetrates a hole 28 of the connecting fitting 25.

In the television camera 3 configured as described above, a method of focusing according to the suture will be described.

As shown in FIG. ₂ , in a range E where the surfaces of the tubes P ₁ , P ₂ and P ₃ are farther than the closest point N, the front surface of the camera head 14 is separated from the rear surface of the lens barrel 11 to the surface of the image pickup plate. You can focus. On the other hand, the pipe P ₄ . In the range F where the surface of P ₅ is within the close range, the camera head 14 is attached to the lens barrel.
Get closer to 11. The shooting distance is very close (1.
If it is smaller than 1 m), even if the focusing lens is extended, the light receiving surface of the image pickup plate will not be in focus. That is, an image is formed closer to the photographing lens than the light receiving surface. Therefore, the focus can be adjusted by displacing the camera head 14 as described above. In this way, a sharp image can be obtained over the range of infinity to 800 m, and for the pipe P, the diameter of the pipe is 500 to 2250 mm.

The maximum displacement of the camera head 14 is 1.1 mm in this embodiment. As described above, since the displacement amount of the camera head 14 is small and fine adjustment is necessary, the fine movement device 18 is provided in the present invention. Press the motor 20 and push the button switch 3
When driven forward or backward by 0, 31 (see FIG. 4), the screw rod 23 rotates, and the camera head 14 moves back and forth via the connecting fitting 25. Since the guide rod 27 penetrates the hole 28 of the connecting fitting 25, the connecting fitting 25 is prevented from rotating by the rotation of the screw rod 23 and moves back and forth. The position of the camera head 14 is read by the indicator 34 which displays the voltage of the potentiometer 33 which is interlocked with the rotation of the motor 20.

FIG. 5 schematically shows a video signal. In the video signal a, H is a horizontal synchronizing signal, a ₁ is a video signal of the backboard 6 placed behind the tube P, a ₂ is a video signal of the tube body, and a ₃ is a video signal of the tube end Q. is there. The signal a ₃ is at a higher level than the signal a ₂ because the tube end Q is glossier than the tube body due to cutting. Signal a ₁
The reference voltage is set to a level R between the level A ₁ of the signal A ₂ and the level A ₂ of the signal a ₂ . In the video signal processing device 4, it is judged that the tube end has reached the predetermined position when the level of the video signal exceeds the reference voltage.

When the light receiving surface of the image pickup plate is out of focus, the signal a
The difference between the level ₃ and the reference voltage becomes small, and an error is likely to occur in detecting the tube end.

(Effect of the Invention) According to the present invention, the lens barrel and the camera head are divided so that the camera head is movable in the optical axis direction. Therefore,
A sharp image can be obtained by bringing the camera head close to the taking lens even if the taking distance is shorter than the closest distance when the two are integrated. Needless to say, the shortest distance can be shortened by designing the lens, but such a lens is a custom-made product, which is not available in the general market, and is extremely expensive. In this respect, the present invention is economical because only the lens barrel and the camera head are divided and a fine movement device for the camera head is provided.

Further, according to the present invention, since the fine movement device of the camera head is provided, accurate focusing can be performed.

Furthermore, since the trolley can be moved and the projector and the TV camera can be installed at the required edge detection position according to the length of the object, the edge can be moved over a wide range from short to long. Can be detected.

It should be noted that the present invention is not limited to pipes, as is apparent from the configuration and operation of the device, but the object whose end position is detected is not limited to pipes, but can be applied to elongated bodies such as rods or boxes or other block-shaped objects. Further, the present invention can be applied to a place where the presence or absence of an object is determined.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an example of a tube end detecting device, FIG. 2 is a drawing for explaining the relationship between a tube diameter and a shooting distance, and FIG. 3 is an example of the present invention. FIG. 4 is a plan view showing the parts, FIG. 4 is an explanatory view of a driving part of the fine movement device shown in FIG. 3, and FIG. 5 is a drawing schematically showing a video signal. 1 ... Tube end detection device, 2 ... Projector, 3 ... Television camera, 11 ... Lens barrel, 13 ... Base, 14 ... Camera head, 18 ... Fine movement device, 20 ... Motor, 22 , 24 …… Gear, 2
3 …… Screw rod, 25 …… Connecting metal fittings.

Claims (1)

[Claims] 1. A light projector for laterally illuminating an object moving in a fixed direction, a television camera arranged on the same side as the light projector for capturing an image of an illuminated portion of the object, and a device for processing a video signal from the television camera. In a device for detecting an edge of a moving object, the projector and the TV camera are installed on a carriage that can move along a moving line of the object, and the TV camera is a lens fixed to a base. A lens barrel and a camera head including an image pickup tube or an image pickup plate are separated, the camera head is attached to a base so as to be movable in the optical axis direction, and the television camera displaces the camera head in the optical axis direction. An object edge detection device comprising a fine movement device.