JPH06109645A - Device for inspecting inner surface of pipe - Google Patents

Abstract

PURPOSE:To prevent the unevenness of lamp illumination, by diffusively reflecting rays from a light emitting source with a reflection angle variable diffuse reflector for lighting up an inside subject of a pipe. CONSTITUTION:A TV camera 3 is provided to a camera head 2 installed in a bogie 1 for travelling through a pipe, perpendicularly to the inner surface of the pipe, or at a certain angle in the radial direction, and a plurality of lamps 4 for illumination is provided to an end part of the head 2, toward the front. A diffuse reflector 7 is pivotally attached rotatably to a reflector fitting jig 8 projected and set up to the head 2 in the pipe axis direction, for example. with a screw pin 9, and the tilt angle is made variable. In inspecting the inner surface of the pipe, the reflector 7 is tilted so that whole the field of the inside subject of the pipe for the camera 3 is lighted up by the lamps 4. Lighting rays are diffused and scattered on a semi-spherical convex part of the reflector 7 surface, reflected in the inner surface direction of the pipe and lights up whole the field of the camera 3 in even illumination. Therefore, a good image of the inside subject of the pipe without light and shade unevenness is projected on an outer monitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the inner surface inspection of steel pipes,
The present invention relates to a pipe inner surface inspection device applied to maintenance inspection of gas and water pipes.

[0002]

2. Description of the Related Art Inspection of the inner surface of pipes for gas, water pipes, etc.
It is common to observe using an image projection device such as a camera. As an example, there is a visual inspection apparatus for pipes described in Japanese Utility Model Laid-Open No. 61-178454. This device has a T that has its field of view centered on the tube axis in the tube axis direction.
By using a V camera, a reflector in front of the TV camera and an illuminating device provided on the tube axis so that the entire circumference of the inside of the tube can be viewed at the same time, and the entire circumference of the inside surface of the tube can be visually inspected at the same time. However, in the case of this device, if the distance between the reflector and the inner surface of the tube is large, the illumination becomes dark, the projected image becomes unclear, and it becomes difficult to accurately inspect the inner surface subject. It was limited to small diameter pipes and could not be applied to large diameter pipes. For this reason, an inner surface inspection apparatus of a system that partially displays an image of the inner surface of the pipe is used for the inner surface inspection of the large diameter pipe.

As an inner surface inspection device for a large-diameter pipe, a TV head 3 is mounted on a camera head 2 mounted on a pipe traveling carriage 1 so that the TV camera 3 can be viewed sideways, as shown in FIG.
In general, the system for inspecting the inner surface of the pipe 10 to be inspected is a system in which the in-pipe traveling vehicle 1 is driven by a self-propelled or external insertion means. That is, in this type of inner surface inspection apparatus, the TV head 3 and the illuminating lamp 4 are attached to the camera head 2 so as to face the inner surface of the tube as image projection means of the inner surface of the tube. The camera head 2 is rotated while the field of view is illuminated to capture an image of the subject inside the tube, and a monitor 6 is provided via an external signal processor 5.
The method of projecting is adopted.

[0004]

However, in the case of the above-described tube inner surface inspection apparatus, as shown in FIG. 6, a plurality of illumination lamps 4 are arranged around the TV camera 3, and therefore, as shown in FIG.
As shown in, the illuminance is highest on the central axis of the lamp, and the illuminance decreases as the distance from the central axis increases. That is, TV
Since the central axis of the camera is dark and the surrounding area is bright, the range in which defects can be determined is limited due to this unevenness of illuminance, and it is not possible to improve the inspection speed. There was a problem in that the image displayed on the screen had light and dark, and defects such as flaws could not be accurately determined. Even if a mechanism for adjusting the illumination direction is provided for each of the plurality of illumination lamps 4 in order to reduce the unevenness of the illuminance, the unevenness of the illuminance varies depending on the inner diameter of the tube.
A new problem arises that the adjustment takes a lot of time.

The present invention has been made in order to solve the problem of the conventional image projecting means as described above, and prevents the uneven illuminance caused by the lamp illumination, and produces a good image of the inner surface of the tube without light and dark. An object of the present invention is to provide a pipe inner surface inspection device using an illuminating means capable of projecting.

[0006]

According to the present invention, there is provided a tube inner surface inspection apparatus comprising a tube inner surface illuminating means and a means for projecting an image of the tube inner surface object, and means for preventing uneven illumination caused by lamp illumination. As a result, by adopting a method of indirectly illuminating the inner surface of the tube using a diffuse reflector,
The purpose of this is to eliminate the uneven illuminance of the subject in the tube within the field of view of the camera, and the gist thereof is to use, as the illumination means, a diffuse reflection plate with a variable reflection angle for diffusing and reflecting the light from the light emitting source to illuminate the subject inside the tube. The pipe inner surface inspection apparatus is characterized by

[0007]

In the tube inner surface inspection apparatus according to the present invention, the TV camera for photographing the tube inner surface object is installed in the camera head vertically or at a certain angle to the tube diameter direction. An illumination lamp, which is a light emitting source on the inner surface of the tube, is arranged at the tip of the camera head toward the front in the tube axis direction. The diffuse reflector is attached to the camera head in front of the illuminating lamp with a variable reflection angle by an appropriate means. Illumination light from the illumination lamp is reflected by this diffuse reflector to illuminate the subject inside the tube. The diffuse reflection plate has a hemispherical convex portion formed on its reflection surface so that the illumination light from the illumination lamp is scattered and reflected. Therefore, the illuminating light from the illuminating lamp is scattered and reflected by the diffuse reflector, and the subject in the tube is illuminated with a uniform illuminance. Since the TV camera photographs the subject in the tube illuminated with this uniform illuminance, an image of uniform brightness is displayed on the monitor as a whole. The reason why the inclination angle of the diffuse reflection plate is variable is that it can easily cope with a change in the inner diameter of the tube to be inspected.

[0008]

1 is a schematic side view showing an example of a pipe inner surface inspection apparatus according to the present invention, FIG. 2 is a vertical sectional front view taken along the line AA of FIG. 1, and FIG. 3 is a reflection surface of a diffuse reflection plate in the same apparatus. FIG. 4 is an enlarged plan view of FIG. 4, and FIG. 4 is a vertical sectional side view taken along the line BB in FIG.

That is, in the pipe inner surface inspection apparatus according to the present invention, the TV camera 3 is attached to the in-pipe traveling carriage 1 and is rotatably driven by the power of a motor or the like. Or, they are installed at a certain angle, and a plurality of them are attached to the tip of the camera head 2, here 4
The individual illumination lamps 4 are attached to the front in the tube axis direction. The diffuse reflection plate 7 is rotatably attached to a reflection plate attachment jig 8 provided on the camera head 2 so as to project in the tube axis direction, for example, by a screw pin 9, and the tilt angle is made variable with this pin as an axis. ing. As shown in FIGS. 3 and 4, the diffuse reflection plate 7 has a hemispherical convex portion 7-1 formed regularly on the reflection surface. This hemispherical convex portion 7-1 has, for example, a vertical and horizontal 5
A 3 mmφ hemisphere is formed at a mm pitch by press working from the back side.

In the tube inner surface inspection apparatus having the above structure, when inspecting the tube inner surface, the diffuse reflection plate 7 is tilted at a predetermined tilt angle so that the entire field of view of the tube inner surface subject of the TV camera 3 is illuminated by the illumination lamp 4. Let Lighting lamp 4
The illumination light emitted in the tube axis direction by the
Simultaneously with the hitting, the hemispherical convex portion 7-1 on the surface diffuses and scatters the light and reflects it toward the inner surface of the tube, and illuminates the entire field of view of the inner surface object of the TV camera 3 with uniform illuminance. Since the TV camera 3 shoots the subject on the inside of the tube illuminated with this uniform illuminance, a good image of the subject on the inside of the tube without light and shade is displayed on the external monitor. When the inside diameter of the tube 10 to be inspected changes, the optimum image can be easily obtained by adjusting the inclination angle of the diffuse reflection plate 7 after aligning the center of the camera head 2 with the tube axis.

[0011]

As described above, according to the device of the present invention, the illumination for photographing the inner surface of the tube is indirectly performed by using the diffuse reflection plate having the variable reflection angle.
Since the subject inside the tube can be illuminated with a uniform illuminance, it is possible to always display a good image without light and shade, and it is possible to easily and accurately determine the flaws on the inside of the tube. Furthermore, since the device of the present invention can adjust the angle of the diffuse reflection plate according to the pipe diameter, it can be easily applied to the inner surface inspection of all pipes from small diameter pipes to large diameter pipes, and the inspection accuracy and efficiency of various pipe inner surfaces can be improved. It has a great effect on the improvement.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of a pipe inner surface inspection device according to the present invention.

FIG. 2 is a vertical sectional front view taken along the line AA of FIG.

FIG. 3 is an enlarged plan view showing a reflection surface of a diffuse reflection plate in the same apparatus.

FIG. 4 is a vertical sectional side view taken along the line BB in FIG.

FIG. 5 is a schematic side view showing an example of a conventional pipe inner surface inspection device.

FIG. 6 is an enlarged plan view taken along the line AA of FIG.

FIG. 7 is an enlarged front view taken along the line BB in FIG.

[Explanation of symbols]

 1 In-pipe traveling vehicle 2 Camera head 3 TV camera 4 Lighting lamp 5 Signal processing unit 6 Monitor 7 Diffuse reflection plate 8 Reflector mounting jig 9 Screw pin 10 Pipe to be inspected

Claims (1)

[Claims] 1. A tube inner surface inspection apparatus comprising illumination means for a tube inner surface subject and means for projecting an image of the tube inner surface object, wherein the illumination means diffuses and reflects light from a light emitting source to produce a tube inner surface object. A pipe inner surface inspection apparatus characterized by using a diffuse reflection plate having a variable reflection angle for illuminating a pipe.