JPS61221607A - Detector for end part of body - Google Patents

Abstract

PURPOSE:To obtain an invariably definite image signal and to detect and part accurately by separating a lens barrel and a camera head and moving the camera head freely in directions of an optical axis. CONSTITUTION:This detector consists of a projector, the telecamera 3, a device which processes a video signal from the camera 3, etc. The camera 3 has the lens barrel 11 fixed to a base 13 and the camera head 14 separately, and the head 14 is fitted to the base 13 movably in the directions of the optical axis. Further, the camera 3 is equipped with a jogging device 18 which displaces the head 14 in the directions of the optical axis. The signal from the camera 3 is compared with a reference voltage preset by a video signal processor to judge whether the end part reaches a specific position or not. Further, when the diameter of a tube increases and the distance between the surface of the tube and camera 3 becomes short, a photographic lens becomes out of focus on the photodetection surface of an image pickup tube or image pickup plate. In this case, the lens in put in focus on the photodetection surface by the device 18.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for detecting the end of a long or block-shaped object that is moving in a fixed direction.

(#Hiro of Subui) Hereinafter, a case where the object whose end position is detected is a spiral steel pipe will be described as an example.

Spiral steel pipes are manufactured continuously using long coils, so they are rolled to a predetermined length, for example 6 to 30 mm, at the exit side of a pipe making machine.
5m) by a traveling cutting machine. That is, the tube end position detecting device is positioned at a position extending from the cutting start position of the traveling cutter to a predetermined cutting length. Then, the tip of the traveling steel pipe is detected and cutting is started, and the steel pipe is cut to the required length with an accuracy of about 11 degrees.

FIG. 1 shows an example of a tube end detection device developed by the present inventors. The tube end detection device 1 includes a light projector 2 disposed on the side of the movement line of the tube P, a television camera 3 disposed on the same side as the light projector 2, which scans the light projector in parallel to the direction of tube movement to take an image, and It consists of a device 4 for processing video signals from a television camera 3.

In the tube end detection device I configured as described above, there are cases where a sufficient distance cannot be maintained between the tube P and the television camera 3 due to spatial restrictions. In addition, the floodlight 2. TV camera 3
Since the TV camera 3 is installed on a trolley 5 that runs on a rail extending along the tube axis, the television camera 3 cannot be moved back and forth (left and right in FIG. 1). Furthermore, since the pipe making machine produces pipes P1 to P5 of various diameters as shown in FIG. 2, the distance D between the pipe P and the television camera 3 (photographing distance) varies greatly.

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

This invention solves the above-mentioned problems in object edge detection devices, and uses a simple mechanism to significantly shorten the close-up distance of the photographing zoom lens. It is an object of the present invention to provide an object edge detection device that can always obtain a sharp image signal even when the distance changes greatly and can accurately detect the edge.

(Means for Solving the Problems) The object end detection device of the present invention is a light projector placed on the side of the movement line of an object moving in a fixed direction.

It consists of a television camera that is placed on the same side as the light projector and that scans the light projector in parallel to the object movement direction to take an image, and a device that processes the video signal from the TV camera.

In the television camera, a lens barrel fixed to a base and a camera head including an image pickup tube or an image pickup plate are separated, and the camera head is attached to the base so as to be movable in the optical axis direction. Furthermore, the television camera is equipped with a fine movement device that displaces the camera head in the optical axis direction.

(Operation) In the apparatus configured as described above, when an object whose end position is to be detected moves forward and the end reaches the light projecting section, the end enters the field of view of the video camera.

The signal from the video camera is compared with a preset reference voltage in a video signal processing device to determine whether the end has reached a predetermined position.

If the diameter of the tube increases and the distance between the tube surface to be photographed and the television camera becomes less than close range, the photographing lens will no longer be focused on the light-receiving surface of the image pickup tube or 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 brought into focus.

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

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

The television camera 3 is equipped with a zoom lens (not shown) with a focal length of 16 to 1601 cm and a close distance of 11+s.
The imaging device consists of a MOS type imaging plate.

As shown in FIG. 3, which is a plan view showing a part of the television camera 3, the lens barrel 11 is fixed to a base 13 with a metal fitting 12. A camera radar 14 equipped with an imaging device (not shown) inside is supported on a base 13 so as to be movable back and forth (in the optical axis direction) by a guide ring 1B. The lens barrel 11 and the camera head 14 are separated, and the distal end 15 of the camera head 14 can fit into the lens barrel 11 in several layers.

A fine movement device 18 is arranged behind the camera radar 14. In the fine movement device 18, a frame 18 is fixed to the base 13, and a motor 20 is attached to the frame 19. A gear 22 is fixed to the output shaft 21 of the motor 20. Further, a threaded rod 23 is rotatably attached to the frame 19, and the gear 22 is attached to the rear of the threaded rod 23.
A gear 24 that meshes with the other is fixed.

The threaded rod 23 is fitted into a female thread 26 of a connecting fitting 25 extending rearward from the rad 14 to the camera. moreover,
A guide rod 27 projects forward from the frame 18 in parallel with the threaded rod 23 and passes through a hole 28 in the connecting fitting 25.

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

As shown in FIG. 2, in the range E where the surfaces of the tubes Pt +P2 and P3 are far from the closest point N, the camera focuses on the surface of the image pickup plate with the front surface of the radar 14 being further away from the rear surface of the lens barrel it. can be done. On the other hand, tube P4. In the range F where the surface of Ps is within close range, the camera head 14
is brought closer to the lens barrel 11. When the photographing distance becomes smaller than a close distance (1.1 m in this embodiment), even if the focusing lens is extended, it will not be focused on the light receiving surface of the image pickup plate. That is, the image is formed closer to the photographing lens than the light receiving surface. Therefore, focusing can be achieved by displacing the camera head 14 as described above. In this way, sharp images can be obtained over a range of imaging distances from infinity to 800 m, and in the case of the tube P, over a range of tube diameters of 500 to 2250 and intestinal layers.

Camera head! In this example, the maximum displacement of 4 is 1 i
It is the s layer. As described above, the amount of displacement of the camera head 14 is small and requires minute adjustments, so the present invention includes a fine movement device 18. When the motor 20 is driven in forward or reverse rotation by the pushbutton switch 30.31 (see Figure 4), the threaded rod 23 rotates and the connecting fitting 2
5, the camera head 14 moves back and forth. Since the guide rod 27 passes through the hole 2B of the connecting fitting 25, the connecting fitting 25 is prevented from rotating due to the rotation of the threaded rod 23, and moves back and forth. The position of the camera head 14 is the motor 20
is read by an indicator 34 that displays the voltage of a potentiometer 33 that is linked to the rotation of the .

FIG. 5 schematically shows a video signal. In the video signal a, H is a horizontal synchronizing signal, ill is a video signal of the backboard 6 placed on the rear side of the tube P, a2 is a video signal of the tube body, and a3 is a video signal of the tube end Q. The reason why the signal a3 is at a higher level than the signal a2 is because the tube end Q is more glossy than the tube body due to the cutting. The reference voltage is set to a level H between the level Al of the signal al and the level A2 of the signal a2. In the video signal processing device 4, it is determined that the tube end has reached a predetermined position when the level of the video signal exceeds this reference voltage.

When the light receiving surface of the image pickup plate is not in focus, the signal a
The difference between the level No. 3 and the reference voltage becomes small, which tends to cause errors in detecting the tube end.

(Effects of the Invention) In the present invention, the lens barrel and the camera head are separated and the camera head is made movable in the optical axis direction. therefore,
Even if the shooting distance is smaller than the close distance when both are combined, a sharp image can be obtained by bringing the camera head closer to the shooting lens. Of course, the close distance can be shortened by lens design, but such lenses are custom-made, unavailable on the general market, and extremely expensive. In this respect, the present invention is economical because the lens barrel and camera head are separated and only a fine movement device for the camera head is provided.

Furthermore, since the present invention is provided with a fine movement device for the camera head, accurate focusing can be performed.

As is clear from the configuration and operation of the device, the object whose end position is detected is not limited to a tube, but can also be applied to a long object such as a rod, or to a block-shaped object such as a box. Furthermore, the present invention can also be applied to determining the presence or absence of an object.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing an example of a tube end detection device, and FIG. 2 is a diagram illustrating the relationship between tube diameter and photographing distance. FIG. 3 shows an example of the present invention. FIG. 4 is a plan view showing a part of a television camera, FIG. 4 is an explanatory diagram of the drive section of the fine movement device shown in FIG. 3, and FIG. It is a drawing schematically shown. l...Tube end detection device, 2...Floodlight, 3...TV camera, 11...Camera barrel, 13...Base, 1
4...Camera head, 1st...Fine movement device, 20...
・Motor, 22.24...Gear, 23...Threaded rod,
25...Connecting metal fittings.

Claims (1)

[Claims] A projector placed on the side of the movement line of an object moving in a fixed direction, a television camera placed on the same side as the projector and which captures an image by scanning the projector parallel to the direction of object movement, and a video signal from the television camera. In the television camera, a lens barrel fixed to a base and a camera head including an image pickup tube or an image pickup plate are separated, and the camera head is movable in the optical axis direction. 1. An object edge detection device, which is attached to a base, and further includes a fine movement device for displacing the camera head in the optical axis direction of the television camera.