JPH0131349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to visual functions of a device that utilizes mechanical automatic visual information for inspection, inspection, or monitoring of, for example, nuclear reactors, power plants, chemical plants, and general production plants. This is related to the improvement of.

In practice, it is used as a visual system using an improved image processing method for a robot for inspecting the inside of a reactor containment vessel, which monitors the environment and equipment inside the reactor containment vessel using a television camera.

Alternatively, it can also be used in imaging systems such as portable television cameras attached to video devices that are becoming popular in households.

2. Description of the Related Art Conventionally, there have been robots called reactor containment vessel inspection robots that inspect or monitor the inside of a reactor containment vessel while collecting visual information about the environment and equipment inside the reactor containment vessel using a television camera. This robot is loaded with a television camera, which is pulled by a trolley chain installed inside the rail along the trajectory of a guide rail attached to a structure inside the reactor containment vessel. Patrol inside the containment vessel.

The guide rail and trolley chain are attached in advance to a structure within the reactor containment vessel. However, depending on how it is installed, objects such as structures and equipment that are designed and installed with the vertical direction in mind,
It is generally difficult to properly photograph with a television camera using the vertical direction as a reference, and it is impossible to obtain a uniform and reliable normal photographed image over the entire guide rail area. To do this, the subject was supposed to be photographed standing vertically, but in reality, the subject's image was taken on a monitor screen normally placed with the vertical direction as a reference, and the subject was not standing vertically, but rather on either the left or right side. It's leaning. This is due to the inclination of the imaging surface of the television camera and the fact that the scanning direction for decomposing the image into time-series information is constant with respect to the television camera frame.

Here, using the attached drawing, a television camera whose scanning direction for decomposing an image into time-series information is fixed with respect to the frame, is tilted left and right around the optical axis with the vertical direction as a reference, for example, in the vertical direction. I will explain in detail what kind of problems occur when photographing a standing subject.

In FIG. 1, a subject placed in the vertical direction on the left is indicated by reference numeral 1, and a television camera 2 having a camera lens 2 is shown between the monitor television 4 and the subject 1 on the right; It is connected to the camera 2 by a transmission line 9 that sends time-series video signals. The monitor television 4 has a screen 5, and an arrow _8a indicating the vertical direction on the subject surface, an arrow _8b indicating the vertical direction on the camera imaging surface, and an arrow _8c indicating the vertical direction on the screen 5. Indicated by a dashed line. The subject image 6 as a normally photographed image on the screen 5 is indicated by the arrow mark 8.
_c , and the subject image 7 has an inclination of an angle φ with respect to the arrow mark 8 _c . A camera 2, Place the TV 4 normally with the vertical direction as a reference. In this normal state, a normal image 6 of the subject 1 on the screen 5 of the television 4 will be aligned with the arrow mark _8c . From this normal state, without moving the television 4, only the camera 2 is tilted to the left by an angle φ around the optical axis with reference to the arrow _8b . At this time screen 5
The image of the subject 1 above changes from the state of the image 6, which coincides with the arrow mark 8 _c , to the state of the image 7, which is tilted to the right by an angle φ when viewed from the screen side with respect to the arrow mark 8 _c . When the camera 2 is tilted to the right with reference to the arrow mark _8b , the image on the screen 5 is tilted to the left, contrary to the above. Therefore, if you do not properly photograph a subject that exists in the vertical direction with a television camera that has its imaging surface correctly placed relative to the vertical direction, the image of the subject that is transmitted from the television camera will be
Since the monitor TV screen tilts left and right,
The image is very difficult for observers to see. In reality, when moving on the guide rail, the television camera moves with a non-uniform inclination to the left and right with respect to the vertical direction, so the image of the subject oscillates left and right in accordance with the movement of the television camera. This causes the inconvenience that the image becomes even more difficult to see.

Conventionally, the tilt of the image of the subject was determined using a digital computer system or a dedicated image processing device.
The tilt angle is detected and corrected. However, not only are these devices complicated and expensive, but if they are to be made more economical, the image processing time becomes longer, creating the problem that real-time processing becomes difficult.

On the other hand, this problem can be solved if the camera imaging surface can be controlled so that it always has the correct posture in the vertical direction, but it is preferable to keep it at a relatively low temperature in order to suppress dark current, and it must also be protected from radiation. It was not easy to control the attitude of a heavy camera body with an imaging photoelectric conversion surface.

An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art, and to provide an imaging system that decomposes and reproduces images in time series, in which the vertical direction of the subject is positioned normally on the screen of a monitor system with respect to the vertical direction. An object of the present invention is to provide an imaging device having an inexpensive image supplementing device using a simple optical information processing supplementary method so that a normal subject image aligned in the vertical direction can always be obtained as a monitor image.

In order to achieve this objective, the present invention takes advantage of the axial symmetry of the optical system, arranges an image transmission fiber optic system with sufficient flexibility between the optical system imaging plane and the imaging plane, and By controlling the attitude of only the side end face of the system around the optical axis using an inexpensive gravity control system,
Even if the camera imaging surface, whose position relative to the fiber bundle end face is fixed, is extremely tilted with respect to the vertical direction, the image tilt can be automatically and instantaneously corrected due to the properties of the image transmission fiber optic system itself. We were able to obtain an imaging device.

Embodiments based on the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an optical fiber bundle forming an image transmission fiber optic system which is the key to the construction of the present invention. In a general light transmission fiber bundle, the relative position of each fiber on both end faces is undefined, whereas in the well-known optical fiber bundle for image transmission used in the present invention, the relative position of each fiber on both end faces except for the middle part is The positions match exactly. Therefore, it is possible to transmit an image mechanically tilted by the angle θ according to the phase difference angle θ between the end faces. The image-transmitting optical fiber bundle 11 shown is flexible and can be sufficiently bent and twisted. The left end face has an entrance end 16 in contact with the optical system imaging surface, and the right end face has an exit end 17 in contact with the imaging surface. Since the optical system is originally axially symmetrical around the optical axis, no matter how tilted the camera body is, the object image 12 on the optical system imaging plane will remain unchanged.
is not tilted at all. On the other hand, the scanning direction on the imaging plane is constant with respect to the camera frame, and as the camera tilts, the scanning direction becomes tilted, resulting in a tilted monitor image. Here, if the image transmission function having the phase difference angle θ between both end faces of the fiber bundle 11 is utilized, the inclination in the scanning direction on the imaging plane can be offset. That is, if the phase difference angle θ and the tilt angle of the camera imaging surface are always made to match, the tilt of the image can be corrected very easily. To do this, the relative position is fixed so that the vertical component of the subject image 13 at the output end 17 and, for example, the scanning direction of the imaging surface are at right angles, while the entrance end 16 is always kept from tilting. Just leave it there. Specifically, as will be described later, a weight is fixed to the outer periphery of the fiber bundle 11 near the input end 16 to provide a rotational moment about the optical axis, so that this part can freely rotate about the optical axis. It goes without saying that the fiber bundle 11 is set so that when the tilt angle of the camera is 0, the phase difference angle θ is also 0. Even if the camera is tilted by the angle θ at this time, the phase difference angle between the entrance end 16 and the output end 17 is θ, and a subject image 14 tilted by the angle θ is obtained on the imaging plane, and automatic image correction is performed. It will be done.

FIG. 3 is a configuration diagram showing an embodiment according to the present invention. The fiber bundle 11 used in FIG. 2, the entrance end 16,
The same reference numerals for the output end 17 and the like are used in FIG. 3 as well. The TV camera 18 on the right end is connected to the output end 17 of the fiber bundle 11 similar to that shown in the second diagram via an adapter 19, and is connected to the input end 1 of the fiber bundle 11.
6 faces the imaging plane of the optical system 24 inside the lens frame 23. The fiber bundle 11 inside the frame 23 is held by a cylindrical shaft 21 and can freely rotate around the optical axis relative to the frame 23 by rolling bearings 20 and 22. A weight 28 is attached to the cylindrical shaft 21 via rods 25 and 26, and the fiber bundle 1
The entrance end 16 of 1 is always kept not tilted with respect to the vertical direction. These outer parts 36 and 37 are mounting screws for fixing the fiber bundle 11 to the cylindrical shaft 21, and 4
0 is a chain line indicating both the optical axis and the photographing direction, 39 is an arrow indicating the direction in which the rod 25 rotates around the axis 40, and 38 is an arrow indicating the direction in which the rod 26 rotates around the axis 27. .

As shown in the figure, the optical system 24 and the optical axis of the fiber bundle 11 are adjusted so as to coincide with each other. As a result, the optical information of the object enters the television camera 18 through the optical fiber bundle 11. Rolling bearings 20 and 22 are provided between the frame 23 and the cylindrical shaft 21 to minimize contact friction between the bearings. The cylindrical shaft 21 is in a state where it easily rotates with a rotational moment that exceeds the minimum torsional moment of the optical fiber bundle 11.

Since the rotational moment is generated by the rods 25 and 26, the weight 28, and the action of gravity, it always moves in the opposite direction with respect to the vertical plane including the optical axis 40 with respect to the inclination direction of the frame 23. When the frame 23 is hung so that the optical axis 40 is horizontal, the rods 25 and 26 quickly turn due to the action of gravity so that their respective center lines coincide with the vertical direction.

At this time, if the optical information of the subject placed in the vertical direction enters the television camera 18, the adapter 19 is loosened so that the optical information of the subject placed in the vertical direction is aligned with the vertical direction on the normally placed monitor screen. Edge 1
7 and the television camera 18 (positional relationship around the optical axis).

From this state, even if the frame 23 rotates leftward or rightward about the optical axis with respect to the vertical direction, the cylindrical shaft 21 can maintain its original orientation regardless of the rotation of the frame 23. Cylindrical shaft 21
The center lines of the rods 25 and 26 connected to the optical axis 40 are always controlled to coincide with the vertical plane containing the optical axis 40 due to the rotational moment due to the action of gravity. Therefore, the cylindrical shaft 21 has substantially no horizontal inclination with respect to the vertical direction. Therefore, the subject around the optical axis 40 and the incident end 1 of the fiber bundle 11 fixed inside the cylindrical shaft 21
The positional relationship with 6 remains unchanged. Furthermore, since the optical information of the subject that enters the photoelectric conversion surface of the camera 18 through the fiber bundle 11 is not substantially changed, normal photographing of the subject can be ensured regardless of the movement of the frame 23.
In addition, it is clear that no matter how the camera body is moved, a normal monitor image without tilt can be obtained due to the function of the image transmission fiber optic system itself.

Such a configuration is particularly advantageous when it is desired to change the photographing direction by remote control. That is, since the optical system is separated from the heavy camera body and there is sufficient flexibility between the two, it is easy to change the shooting direction by moving only the optical system.

FIG. 4 shows an embodiment of the present invention applied to a robot for inspecting the inside of a nuclear reactor containment vessel.
A guide rail 3 is attached to a structure inside the reactor containment vessel, and a trolley chain 31 that moves inside the guide rail 30 has a traction hook 32.
The television camera 18 shown in the third figure and the frame 23 shown in the third figure are attached and towed via the towing hook 35.

Regardless of the installation state of the guide rail 30, trolley chain 31, towing hooks 33 and 34, and frame 23, and the turning state of the horizontal and vertical turning mechanism 34, the centers of the rods 25 and 26 shown in FIGS. 3 and 4 The line pivots relative to the frame 23 to coincide with a vertical plane containing the optical axis 40 due to the rotational moment due to gravity, counteracting the oscillation of the frame 23.
As a result, it is obvious that a normal monitor image without tilt can always be obtained as described above. Furthermore, the imaging device, which has a complicated shape and is heavy, can be separated from the optical system attached to the photographing direction conversion device, and can be reliably attached in a stable state. The photographing direction changing device is small and lightweight, operates reliably, and improves economic efficiency.

As described above, according to the present invention, an image transmission fiber optic system having sufficient flexibility is provided between the optical system imaging surface and the imaging surface, and the output end surface is fixed to the imaging surface. The entrance end face is also supported rotatably around the optical axis, and a simple weight is used to prevent the entrance end face from tilting, thereby providing an inexpensive imaging device that can instantaneously and easily correct the tilt of an image. It is possible to achieve the intended purpose well and achieve high economic effects.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining problems with the prior art, FIG. 2 is an explanatory diagram of an optical fiber bundle forming an image transmission fiber optical system, which is the key to the configuration of the present invention, and FIG.
The figures are configuration diagrams showing one embodiment of the present invention, in which a is a side view of the optical system, b is a front view, and FIG. It is a diagram. DESCRIPTION OF SYMBOLS 11... Optical fiber bundle forming an image transmission fiber optical system, 16... Input end of optical fiber bundle, 19... Adapter, 17... Output end of optical fiber bundle, 21... Cylindrical shaft, 18... Television camera , 20, 22...Rolling bearing, 23...Optical system frame, 24...
Optical system, 25, 26... rod, 28... weight.

Claims (1)

[Claims] 1. In an imaging device that has an optical system that forms an optical image of a subject, and an imaging means that has a constant screen scanning direction for exchanging optical image information of the subject into a time-series video signal, the optical system An image transmission line optical system having sufficient flexibility is disposed between the imaging surface and the imaging surface of the imaging means, with both end surfaces of the image transmission line optical system being arranged at positions that coincide with the optical axes of the two surfaces, respectively, and the imaging surface of the imaging means. The end surface in contact with the imaging surface is fixed in its relative position with the imaging surface, while the end surface in contact with the imaging surface of the optical system is attached so as to be freely rotatable around the optical axis. An imaging device that corrects the tilt of an image, characterized in that it is equipped with a gravity system control means that provides a rotational moment that corrects the tilt of the device.