JPH06241760A - Cylinder inner face state inspection camera device - Google Patents

Abstract

PURPOSE:To provide a cylinder inner face state inspection camera device capable of deploying a cylinder inner wall into a flat plane at a uniform density and capable of obtaining an image suitable for an automatic inspection by a computer as well as a visual inspection. CONSTITUTION:A conical mirror 6 and a lens system 5 arranged so that the center axis coincides with the optical axis 4 of a television camera 1 convert the image of a cylinder inner wall into a circular belt-like image and form the image on the CCD image pickup element 3 of the television camera 1. An image array converting device 10 receives the circular image from the circular belt-like image of the television camera 1, converts it into a linear image, outputs it to a display control device 11, and displays it on a monitor 13 as required for an automatic inspection by a computer 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a camera device for inspecting the inner surface condition of a cylinder. It is used for a cylindrical inner surface condition inspection camera device that images and inspects the inner wall of a tunnel and the inner surface of a water pipe in a highly precise, seamless and flat state.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing an arrangement state in a cylinder and an observation result of a conventional cylinder inner surface state inspection camera device.

Conventionally, a cylindrical inner surface condition inspection camera device has obtained an observation result by arranging and observing the device in a cylinder as shown in FIG. It was pointed out that it is necessary to take a highly accurate image of the inner surface of the cylinder and inspect it for cracks and corrosion, and to take necessary measures. A method has been used in which a camera is inserted and the state of the inner wall is observed using a lens having a relatively short focus.

FIG. 5A shows the arrangement of the cameras. Since the photographing range is wide, the center of the inner wall and the tube can be seen far away as shown in FIG. 5B.

[0005]

However, in such a conventional cylindrical inner surface condition inspection camera device, it is impossible to uniformly focus from a short distance to a long distance. Therefore, there are drawbacks such that the shape of fine flaws cannot be accurately observed, and it is difficult to accurately measure the size and position of the object because the inner wall is not developed on a flat surface.

The present invention solves the above-mentioned drawbacks. The focus is accurately adjusted, the shape can be correctly recognized, the position can be grasped, the inner wall of the cylinder is developed on a plane, and the density is completely uniform. It is an object of the present invention to provide a camera device for inspecting the inner condition of a cylinder, which can be deployed by means of and can obtain an image suitable for not only visual inspection but also automatic inspection by computer.

[0007]

According to the present invention, there is provided a cylindrical inner surface condition inspection camera device having a television camera inserted in a cylinder to be imaged, the central axis being aligned with the optical axis of the television camera. It is equipped with a conical mirror.

In the present invention, another lens system may be arranged between the lens of the television camera and the conical mirror.

Further, the present invention can include an image array conversion circuit for converting a circular band-shaped output image of the television camera into a rectangular band-shaped image.

[0010]

With the conical mirror arranged so that its central axis coincides with the optical axis of the TV camera, the image of the inner wall of the cylinder is converted into a circular band image and given to the TV camera, whereby the image is oblique to the object. do not become. Therefore, the inner wall of the cylinder can be expanded into a circular plane. Furthermore, by converting a circular band image into a rectangular band image, the inner wall of the cylinder can be developed into a flat surface with uniform density, which is suitable not only for visual inspection but also for automatic inspection using image analysis by computer. You can get the video.

[0011]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a cylindrical inner surface state inspection camera device according to an embodiment of the present invention. In FIG. 1, a cylindrical inner surface state inspection camera device includes a television camera 1 inserted in a cylinder to be imaged, and the television camera 1 includes a lens 2 for converting an input image into an electric signal and a CCD (charge coupled device) image pickup device 3. including.

The feature of the present invention is that the television camera 1 is provided with a conical mirror 6 arranged so that the central axis 7 coincides with the optical axis 4.

Another lens system 5 is arranged between the lens 2 of the television camera 1 and the conical mirror 6.

Further, an image array conversion device 10 for converting a circular output image of the television camera 1 into a linear image,
A display control device 11 that stores the output image of the image array conversion device 10 and performs display control, a monitor 13 that displays the output of the display control device 11, and a computer 12 that analyzes the output of the display control device 11 are provided.

Further, as an example, the conical mirror 6 has a right conical body whose side surface is mirror-plated with metal and has an apex angle of 9.
A 0 ° mirror is used, and the conical mirror 6 and the lens system 5 are attached to the television camera 1 by a transparent acrylic fixture 8.

The operation of the cylindrical inner surface state inspection camera device having such a configuration will be described.

FIG. 2 is a diagram showing an arrangement state in the cylinder of the camera apparatus for inspecting the inner surface state of the cylinder and an observation result according to the present invention. FIG. 3 is a diagram showing an image in which a cylindrical inner wall image of the cylindrical inner surface state inspection camera device of the present invention is developed on a plane. FIG. 4 is a diagram showing the arrangement of CCD image pickup devices of the cylindrical inner surface state inspection camera device of the present invention.

FIG. 2A shows a state in which a conical mirror 6, a lens system 5 and a television camera 1 are arranged on the optical axis 4 in a cylinder. FIG. 2B shows a state in which the image on the inner wall is converted into parallel rays by the conical mirror 6, and FIG.
Shows a circular strip image in which parallel rays are formed. This circular band-shaped image is obtained by converting a certain range in the longitudinal direction of the inner wall of the cylinder.

This image is further transferred to the CCD of the TV camera 1.
Since it is possible to form an image on the image pickup element 3, it means that the inner wall taken up from the entire circumference in the vertical direction is developed into a circular plane. However, in this state, the density becomes higher toward the center of the circle and lower toward the periphery, which is not common. Therefore, a completely uniform plane can be obtained by converting the data as follows.

First, this circular band-shaped image is formed on the CCD image pickup device 3, and the pixels on the capture line of FIG.
Take out in a row. The signal in a line is the same as the one obtained by cutting the inner wall of the cylinder into slices.

When a device in which the conical mirror 6 and the television camera 1 are integrated is moved along the center of the cylinder, a large number of sliced signals can be obtained. When a large number of signals are displayed on the display control device 11 of the television camera 1 as shown in FIG.
The inner wall of the cylinder is developed in a plane with perfect density. The pixel density is determined by the number of pixels of the CCD image pickup device 3 of the television camera 1 and the moving speed.

Considering a specific example, when the CCD image pickup device 3 of 1000 × 1000 pixels is used as shown in FIG. 4, about 3000 pixels can be obtained along the capture line. If the cylinder is a tunnel having a diameter of 3.5 m, for example, the circumference of the inner wall is about 11 m, and therefore 3.6 mm per pixel, which can be used for crack inspection.

Further, in the traveling direction, if the time for making one take-in line is 1/30 seconds, and if it advances by 3.6 mm every 1/30 seconds, it will be about 6.5 km / h.

As described above, in this embodiment, the state of the inner wall of the cylinder is converted into a plane circular light beam by the conical mirror, and this is converted into an electric signal by the television camera 1. Further, the image array conversion device 10 converts the circular data into serial data, which is displayed on the display control device 11, and the output of the display control device 11 is displayed on the monitor 13 as necessary, so that the computer 1
The analysis is performed in 2. As a result, the inner wall of the cylinder can be completely flattened on a flat surface and can be automatically inspected by a computer.

In this embodiment, the apex angle of the conical mirror has been described as 90 °, but it is not limited to 90 ° and may be adjusted by a lens system so as to form parallel rays. Also, instead of the transparent acrylic mount, the conical mirror and lens system may be mounted by a narrow support that does not block light rays from the inner wall of the cylinder.

[0027]

As described above, the present invention is excellent in that the inner wall of a cylinder can be developed on a flat surface with a uniform density, and an image suitable for not only visual inspection but also automatic inspection by a computer can be obtained. effective.

In other words, it is possible to take a uniform focus from a short distance to a long distance. It is possible to take an image perpendicularly to the wall surface, so that the shape of fine flaws can be accurately observed. Since it is deployed at a density, it has the effect of being able to accurately measure the size and position of the object.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a cylindrical inner surface state inspection camera device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement state in a cylinder and an observation result of a camera device for inspecting a cylinder inner surface state of the present invention.

FIG. 3 is a view showing an image in which a cylindrical inner wall image of the cylindrical inner surface state inspection camera device of the present invention is developed on a plane.

FIG. 4 is a diagram showing an arrangement of fixed image pickup elements of a cylindrical inner surface state inspection camera device of the present invention.

FIG. 5 is a view showing an arrangement state in a cylinder and an observation result of a conventional cylinder inner surface state inspection camera device.

[Explanation of symbols]

 1 TV camera 2 lens 3 CCD image sensor 4 optical axis (TV camera) 5 lens system 6 conical mirror 7 central axis (conical mirror) 8 transparent acrylic mount 9 cover 10 image array converter 11 display controller 12 computer 13 monitor

Claims (3)

[Claims] 1. A cylindrical inner surface state inspection camera device including a television camera inserted in a cylinder to be imaged, comprising a conical mirror arranged such that a central axis thereof coincides with an optical axis of the television camera. A cylindrical inner surface condition inspection camera device. 2. The cylindrical inner surface condition inspection camera device according to claim 1, wherein another lens system is arranged between the lens of the television camera and the conical mirror. 3. The cylindrical inner surface state inspection camera device according to claim 1, further comprising an image array conversion circuit for converting a circular output image of the television camera into a linear image.