JPH03103753A - Color in-tube inspecting device - Google Patents

Abstract

PURPOSE:To reduce the size, weight, and power consumption of the inspecting device by converting LED light beams of the primary colors on the surface of the internal wall of a tube and detecting intensity distributions of reflected light beams of the respective LED light beams which are reflected by the internal wall as rotary motion is carried out. CONSTITUTION:The respective light beams of the primary colors, i.e. red, green, and blue emitted by LEDs 21 - 23 of a light source part 20 are converged on one point on the internal surface of the steel pipe 10 through a movable beam scanning part 30. The scanning part 30 scans the internal wall of the steel pipe 10 through its rotary motion. A fixed photodetection part 10 detects the quantity of reflected light which is incident from the internal wall of the steel pipe 10 and outputs its intensity distribution as defect information on the inter nal wall of the steel pipe 10. The color in-tube inspecting device of this constitu tion is movable in the steel pipe 10 and mounted on, for example, a self-runing robot to gather reflection factor information on the internal wall of the steel pipe 10. Therefore, the device can operates with a small amount of electric power, so only the electric power of a secondary battery is required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inside pipe inspection device for inspecting the condition of the inner wall of a small-diameter pipe or steel pipe that cannot be inspected by entering the pipe.

In particular, we emit a focused, small-diameter light beam into the tube using an LED (light emitting diode) that supports three primary colors as a light source, monitor the amount of light reflected from the inner wall, and monitor the changes in reflectance for each color (
This invention relates to a color tube inspection device that detects the inner wall condition by detecting the intensity distribution (intensity distribution).

[Conventional technology]

Conventional pipe inspection equipment is equipped with a television camera at the tip of a drive machine (hereinafter referred to as a "self-propelled robot") that can self-propel within the pipe, and displays color images of the inner wall condition (defects, defects, etc.) inside the pipe.
The system was designed to ascertain the size of the defects, the number of defects, and the color of the defects. Therefore, based on the video information, the person in charge
Determined the type of defect, necessity and possibility of repair.

[Problem to be solved by the invention]

However, since conventional pipe inspection equipment uses a television camera, a lighting device (light source) for photographing needs to have a fairly high output.

Therefore, the temperature inside the tube tends to rise, which may accelerate the deterioration of the imaging equipment.

In addition, self-propelled robots have to drag thick electric wires to supply power to the light source, making it difficult to inspect over long distances and requiring a design with high driving force. Furthermore, securing a power supply for high-output light sources has become essential at work sites.

In particular, when obtaining color images, an increase in the amount of electricity used for lighting and other equipment is unavoidable, which leads to the increase in the size of inspection equipment including photographic equipment, which is difficult to operate and actually hinders efficient pipe inspections. ．． On the other hand, in addition to these challenges,
Although it would normally be sufficient to have data on only the defective area, conventional pipe inspection equipment using television cameras captures information on the entire inner wall surface as video data, resulting in a huge amount of data. This hindered improvements in operability and efficiency.

As described above, conventional pipe inspection devices have many problems with operability, and are therefore used only in special cases, such as when rust is visible within a steel pipe. Therefore, inspection of the inside of the pipe is often omitted except in such cases, and the cable may be carelessly laid inside the pipe without inspection, causing damage to the cable jacket and shortening its lifespan.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color tube inspection device that is compact, lightweight, and low-power, and that can selectively obtain positional information on a defective site and information indicating a defective state.

[Means to solve the problem]

The present invention provides an in-pipe inspection device that moves inside a pipe and inspects defects on the inner wall of the pipe.
A light source section that emits light and each LED that is emitted from the light source section
A movable light beam scanning section that changes the optical path of the light and focuses it on the surface of the inner wall, and scans the inner wall with its rotational movement, and a movable light beam scanning section that captures the reflected light of each LED light reflected on the inner wall, and the intensity distribution of the reflected light. It is equipped with a light detection section that detects the [Function] The light source section emits each of the three primary colors of LED light to the movable light beam scanning section.

In the movable light beam scanning section, the optical axes of the respective LED lights are aligned and focused on the inner wall surface, and the inner wall surface is scanned with rotational movement. Note that when the scanning of each LED light and the movement of the pipe inspection device are synchronized, the inside of the pipe is scanned in a spiral pattern, and when the pipe inspection device is stopped, scanning is performed in a two-dimensional direction within the same plane. be exposed.

The light detection unit detects the intensity distribution of the reflected light reflected on the inner wall of the tube and outputs it as inner wall defect information.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a diagram showing the main structure of an embodiment of the present invention. In this embodiment, the block configuration of the pipe inspection device is shown, and the self-propelled robot on which it is mounted and other details are omitted.

In the figure, reference number lO is a part of the steel pipe that is the object to be inspected, and an inside pipe inspection device consisting of a light source section 20, a movable light beam scanning section 30, and a fixed light detection section 40 is inserted inside. This is the cross-sectional force in the state.

The light source unit 20 is fixed, and includes three types of LEDs (light emitting diodes>21:22, 23) that emit LED light in the three primary colors of red, green, and blue, and converts the LED light into parallel light (light beam).
This is effected by the collimator lens 25 for the purpose of

The movable light beam scanning unit 30 includes a mirror 3l that emits the light beam incident from the light source unit 20 in a predetermined direction, and a light beam direction changing prism 33 that changes the direction of the light beam.
It is composed of an objective lens 35. The movable light beam scanning unit 30 is held by a guide 37 and rotated by a motor 39 connected to one end thereof, and the emitted light beam is irradiated along the inner circumference of the steel pipe 10.

By the way, each LED light is randomly polarized and does not have a specific plane of polarization. Therefore, the amount of light beam emitted in the circumferential direction by the rotational movement of the movable light beam scanning section 30 is constant, and data correction depending on the direction is not necessary.

The fixed light detection unit 40 includes a filter 41 that selects reflected light from the light beam emitted from the movable light beam scanning unit 30 and reflected on the inner wall of the steel pipe IO, and a cylindrical photodetector 43 that detects the selected reflected light. It is structured by Note that the broken lines shown in FIG.
The optical path from 22 and 23 to the fixed light detection section 40 is shown.

The fixed light detection unit 40 has a sufficient size to absorb fluctuations in the incident position of reflected light in response to minute changes in the inner diameter of the steel pipe 10, and detects the amount of incident reflected light. ,
The structure is such that the intensity distribution is output as defect information on the inner wall of the steel pipe 10.

Note that the optical axes of the three primary color light beams of red, green, and blue emitted from the light source section 20 are aligned so that they are focused on one point on the inner wall surface of the steel pipe IO via the movable light beam scanning section 30. The optical information of that one point can be obtained by the fixed light detection section 40. A color image of a defective site on the inner wall of a steel pipe can be obtained by combining this optical information.

By the way, in this case, geometrical optical behavior is assumed, and the images of the light emitting parts of each LED 2 1, 22, 23 will be imaged on the inner wall surface, and a beam spot of about 100ξcm will be obtained. .

The color pipe interior inspection device having such a configuration is movable inside the steel pipe 10, which is the object to be inspected, and is mounted on, for example, a remotely controllable self-propelled robot, to collect reflectance information on the inner wall of the steel pipe.

Therefore, because it can operate with a small amount of electricity, the electricity from a secondary battery such as a NiCd battery is sufficient, and there is no need to supply electricity using an external power cable, and a self-propelled robot equipped with it can operate with a small amount of electricity. The impact on exercise performance can be minimized.

In addition, by linking the traveling motor of the self-propelled robot and the rotating motor 39 of the movable light beam scanning unit 30, or by using the same motor, it is possible to move within the pipe, irradiate the light beam, and use the reflected light. It is possible to easily adjust the timing of data collection. That is, it is possible to easily set a spiral or two-dimensional scanning pattern inside the tube.

In addition, in the color tube internal inspection device of the present invention, the inspection data collected as the intensity distribution of reflected light is transmitted as an analog signal or The signal is transmitted as a digital signal, received by a receiver installed at a predetermined position (for example, a manhole) in the steel pipe 10, and sent to a data processing device.
By performing predetermined processing on the input data, the data processing device can determine the position and size of the defective portion within the steel pipe 10 and display the defective portion as an image.

Inspection data that can be retrieved externally has a much smaller amount of information than video data, so it is easier to send, receive, and process data, and comprehensive information about defects inside the control pipe is limited. Moreover, since it becomes possible to handle them all at once, efficient judgment work can be performed.

Figure 2 shows the inside of a steel pipe with defects using a color pipe inspection device that uses LEDs in the three primary colors of red, green, and blue as light sources.
It shows the intensity distribution of reflected light obtained by scanning with monochromatic light of any of the primary colors.

That is, FIG. 2 shows a pattern of decrease in reflectance obtained according to the defect site by intra-tube scanning. Here, the distance between the lines was 1 mm, and the size of the measured defect could be estimated to be approximately 15 mm x 20 mm.

Figure 3 shows the results of fine color scanning of the defective area using three primary colors, and the information corresponding to each color is transferred to the CRT.
Here is the example shown above.

Figure 3(a) is a display example of the intensity distribution of reflected light corresponding to red (red information), and (in Figure 3) is a display example of the intensity distribution of reflected light corresponding to green (green information). , Figure 3 (
C) is a display example of the intensity distribution of reflected light corresponding to blue (blue information), and it can be seen that defective parts can be detected in each case. Furthermore, it can be seen that the defect type can be determined from the information corresponding to each color.

〔Effect of the invention〕

As mentioned above, the color pipe inspection device of the present invention allows
It becomes possible to reduce the size, weight, and power consumption, making it possible to inspect the inside of the pipe easily and effectively. Furthermore, since defect information within the steel pipe can be obtained as color image digital data, the determination work can be facilitated.

Therefore, there is no need to omit the inspection process, which is troublesome as in the past, and the condition of the inner wall inside the pipe can be easily inspected, minimizing defective cable installation work caused by obstructions inside the pipe. It can be suppressed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main structure of an embodiment of the present invention. FIG. 2 is a diagram showing a pattern of decrease in reflectance obtained according to the defect site by intra-tube scanning. FIG. 3 is a diagram showing an example of displaying information corresponding to each color for a defective part on a CRT. 10... Steel pipe, 20... Light source part, 2l, 22, 23
...LED, 25...Collimator lens, 30...
・Movable light beam scanning unit, 3l...Ler, 33...
Light beam direction polarizing prism, 35...objective lens, 3
7...Guide, 39...Motor, 40...Fixed light detection unit, 4l...Filter, 43...Photodetector.

Claims (1)

[Claims] (1) A pipe inspection device that moves inside a pipe and inspects defects on its inner wall, which includes a light source unit that emits LED light of three primary colors of red, green, and blue, and an optical path of each LED light emitted from the light source unit. a movable light beam scanning unit that changes and focuses the light on the surface of the inner wall and scans the inner wall with its rotational movement; A color tube inspection device comprising: a light detection section that detects distribution.