JPH04301706A - Hollow body internal wall surface inspecting device - Google Patents

Abstract

PURPOSE:To obtain an internal wall surface inspecting device of a hollow body which enables easy measurement of a circumferential dimension of a membrane body affixed onto the internal wall surface of the hollow body irrespective of the material or the color of the membrane even when the inner diameter of the hollow body is below tens of a millimeter. CONSTITUTION:There is provided a photographing optical system 2 of which field of vision is a membrane body affixed onto an internal wall surface of a hollow body 3, and at the same time, an illuminating system 6 to irradiate the light on this membrane body is provided so that the intensity of the reflected light at the side end of the membrane body may be larger than the intensity of the ambient reflected light when seen from this photographing optical system 2. The photographing signals output from the photographing optical system 2 are processed by means of an image processing device 9, and the coordinates of the side end part are calculated, then the circumferential dimension of the membrane body is calculated from these coordinates. The illuminating system 6 is preferably comprised of an optical fiber 7 one end of which is opposite to an inclined surface of the membrane body at a specified angle and by a light source 8 which is connected to the other end of the optical fiber 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the inner wall surface of a hollow body for measuring the circumferential dimension of a film of paint or the like adhered to the inner wall surface of the hollow body.

0002

2. Description of the Related Art Hollow bodies such as pipes manufactured by continuous welding in the axial direction must be protected with paint at the welded parts depending on the type of fluid to be passed inside. In addition, as a special example, when applying paint to the inner wall surface of a hollow body with an inner diameter of several tens of millimeters, this hollow body is moved at several hundred meters per minute, so even during such high-speed movement, the inner wall surface is coated. There was a need to inspect it.

As described above, as a conventional apparatus for inspecting the inner wall surface of a hollow body, for example, as shown in Japanese Patent Application Laid-Open No. 56-54410, an eyepiece is attached to the base end of the cylinder, and an eyepiece is attached to the distal end. By attaching a fisheye lens to each of the cylinders, embedding multiple optical fibers along the axis of the outer cylinder of the cylinder, and connecting the base ends of these optical fibers to a light source, the inner wall surface of the bottomed cylinder There is a suitable device for inspecting whether or not there are any flaws. Also, JP-A No. 62-298703
As shown in the publication, two laser beam transmitting/receiving sections for transmitting and receiving laser beams are provided at the base end through a reflecting mirror attached to the tip of the rod, and the receiving and receiving signals of these two laser beam transmitting/receiving sections are There is a device that calculates the position and shape of substances attached to the inner wall surface. Furthermore, as another internal wall surface inspection device, a light guide is attached in a ring shape around an image handle with a diameter of 1.8 mm.
MY SCOPE” (registered trademark, manufactured by Sumita Optical Glass Co., Ltd.).

0004

Problems to be Solved by the Invention Among the conventional inspection devices mentioned above, Japanese Patent Laid-Open No. 56-54410 and Japanese Patent Laid-open No. 62
The devices shown in each publication of No. 298703 had a large diameter and were difficult to apply to a hollow body with an inner diameter of several tens of millimeters. On the other hand, since "MY SCOPE" has a relatively small diameter, it is possible to inspect the inner wall of a hollow body with an inner diameter of several tens of millimeters. However, since scattered light was used for illumination, it was not possible to measure the width of the colorless and transparent paint. That is, since there is no difference in the surface condition between the peripheral part and the middle part of the paint, it was impossible to measure the width thereof.

The present invention has been made to solve the above problems, and even if the inner rectangular dimension of the object to be inspected is several tens of millimeters or less, the film attached to the inner wall surface of the hollow body can be It is an object of the present invention to provide an inner wall surface inspection device for a hollow body that can easily measure the circumferential dimension regardless of the material and color of the membrane body.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a hollow body inner wall surface inspection device for measuring the circumferential dimension of a membrane attached to the inner wall surface of a hollow body.
an imaging optical system whose field of view is the film body; and an imaging optical system that irradiates the film body so that, when viewed from the imaging optical system, the intensity of reflected light at the side edge portion is greater than the intensity of reflected light at a portion other than the side edge portion. An image in which coordinates of the side end portion are calculated by processing video signals output from an illumination system arranged at a position and the imaging optical system, and a circumferential dimension of the membrane body is calculated from these coordinates. It is equipped with a processing device. In this case, it is convenient to use an illumination system consisting of an optical fiber whose one end faces the inclined surface of the film body at a predetermined angle, and a light source connected to the other end of this optical fiber.

[0007]

[Operation] As shown in FIG. 4, it is assumed that paint is applied to protect the axially welded portion 3a of the cylindrical hollow body 3 extending in the axial direction. In order to confirm whether this paint has a sufficient protective function, it is necessary to measure the thickness t and width W of the paint film 11. In this case, the thickness t is not directly related to the present invention, so its explanation will be omitted, but the inner diameter D
is a fraction of the width W for the hollow body 3 of several tens of millimeters.
Measurements with millimeter accuracy may be required.

In this case, the coating film 11 usually has an inclined surface 11a at its side end, although there are differences in the material of the coating material and the coating method.
has. The present invention utilizes this inclined surface 11a to measure the width of the coating film 11, and as shown in FIG. 5, an imaging optical system 2 whose visual field is the coating film 11 as a film body is provided,
The position P1 is set so that the intensity of reflected light at the side end is greater than the intensity of reflected light around the side edge when viewed from the imaging optical system 2.
, P2 is provided to illuminate the coating film 11. A coating film 11 is formed by processing the video signal output from the imaging optical system 2.
The circumferential dimension of , that is, the width W is calculated. Here, considering that the imaging optical system 2 occupies a large area at the center of the hollow body 3, the space around it becomes extremely narrow. Therefore,
If a light source is placed outside the hollow body 3, the light is introduced through an optical fiber, and the coating film 11 is irradiated from positions P1 and P2, even from such a narrow space, the side edges can be illuminated. The inclined surface 11a can be conveniently irradiated. As a result, even if the inner diameter of the hollow body 3 is several tens of millimeters or less, the circumferential dimension of the coating film 11 can be easily measured regardless of the material of the film body.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of an embodiment of the present invention. In the figure, the processed part 1 is formed in a cylindrical shape,
The hollow body 3 circumscribes the processing portion 1 and moves at high speed in the axial direction indicated by the arrow X so that the axis coincides with this. The hollow body 3 is initially a flat plate-like object, and as it approaches the left end of the processing section 1, it is rounded into a cylindrical shape, and when it reaches the processing section 1, it becomes a completely cylindrical object. First, welding of the incision is performed using this processed portion 1, and then, as shown in FIG. 4, a resin coating film 11 is applied so as to cover the welded portion 3a on the inner wall surface of the hollow body 3. The basic configuration of the processing section 1 itself is the same as the conventional one, so it will not be described in detail. An imaging optical system 2 having a cylindrical outer diameter is attached to the right end of the processing section 1 in the figure, and is attached so that the coating film 11 of the hollow body 3 is the field of view.

Here, a long hole 1a is formed in the center of the processing section 1, and a power line and a signal line of the imaging optical system 2 and a light beam having a diameter of 1 mm constituting the illumination system 6 are connected to the long hole 1a. Fiber 7 (Mitsubishi Rayon Esca (registered trademark) SK40
) has been passed. A light source 8 such as a halogen lamp, which also constitutes the illumination system 6, is coupled to the base end of the optical fiber 7, and the tips of these optical fibers 7 are coated with a coating film, as shown in FIG. The angle at which the reflected light intensity on the inclined surface 11a of No. 11 is maximum, for example, the coating film 1 with a width of 8 mm.
For 1, the inclination is α = 33.5 degrees, △X = 10 mm in the horizontal axis direction and △Y = 10 mm in the vertical axis direction from the welding part 3a.
They are attached to the imaging optical system 2 so as to face each other at a distance.

Further, as shown in FIG. 1, when the hollow body 3 is removed, photoelectric switches 4 and 5 are provided which are activated by receiving the light projected from the tip of the optical fiber 7. The switch 4 outputs an inspection start signal when light is interrupted, and the other photoelectric switch 5 outputs an inspection end signal when it receives light. These photoelectric switches 4 and 5 are connected to an image processing device 9 together with the above-mentioned imaging optical system 2. This image processing device 9 processes the video signal of the imaging optical system 2 that is input from the time when the signal to start the inspection of the photoelectric switch 4 to the time when the signal to finish the inspection from the photoelectric switch 5 is received. Measure the width B,
The measurement results are passed to the computer 10. The computer 10 is configured to determine the quality of the measurement results for the width B, and to display an alarm if the measurement results exceed the permissible range.

The operation of this embodiment configured as described above will be explained with reference to FIG. 3 as well. The hollow body 3 is the imaging optical system 2
If they are separated from each other, light is projected from the tip of the optical fiber 7, and the photoelectric switches 4 and 5 receive these lights. Now, if the hollow body 3 is moved in the direction of the X arrow in FIG. 1 to the state shown in FIG. 1, the light projected from the optical fiber 7 will be blocked. The image processing device 9 starts image processing when the incident light of the photoelectric switch 4 is interrupted. and,
When the hollow body 3 is further moved in the direction of the X arrow, the photoelectric switches 4 and 5 receive the projected light from the optical fiber 7 again. The image processing device 9 finishes image processing when the photoelectric switch 5 receives light.

During image processing by the image processing device 9, the light projected from the tip of the optical fiber 7 illuminates the coating film 11 applied to the inner wall of the hollow body 3, and the imaging optical system 2 photographs this and records it. The video signal is sent to the image processing device 9. In this case, Figure 3
As shown in (a), the imaging optical system 2 photographs a region A in the width direction of the coating film 11. At this time, the tip of the optical fiber 7 is placed at a position where the intensity of reflected light on the inclined surface 11a is greater than the intensity of reflected light around the inclined surface 11a, as viewed from the imaging optical system 2. Therefore, as shown in FIG. 3(b), the output signal level of the imaging optical system 2 is maximum at the portion corresponding to the inclined surface 11a as the side edge portion, and is higher at the center portion corresponding to the welded portion 3a. It forms a slightly small and symmetrical mountain shape.

When such a video signal is sent, the image processing device 9 binarizes it using a rectangular wave symmetrical to the welding part 3a as a threshold as shown in the figure, and generates a binary signal as shown in FIG. 3(c). Obtain valued data. Next, run-length encoding processing is performed on these data to determine the combinations of start and end points (s1, e1) and (s2, e2) whose levels change.
) and calculate the width B of the coating film 11 from these data.

Then, the width B calculated by the image processing device 9
Data regarding is sequentially sent to the computer 10,
It is used to control the coating film 11 in the processing section 1, and displays an alarm so that necessary measures can be taken when the width is inappropriate. By the way, about 10
It was possible to measure the width of millimeter paint with an accuracy of a fraction of a millimeter.

Thus, according to this embodiment, the tip of the optical fiber 7 is placed at a position where the intensity of the reflected light on the inclined surface 11a is greater than the intensity of reflected light on other surfaces, as viewed from the imaging optical system 2. Therefore, even if the paint is colorless and transparent, the width of the coating film 11 can be reliably measured regardless of its material.

Further, an imaging optical system 2 is fixed to the tip of the processing section 1, and the power line and signal line of the imaging optical system 2 and the optical fiber 7 constituting the illumination system 6 are connected to the processing section 1. Since it passes through the elongated hole 1a formed in the axial center, even if the hollow body 3 has an inner diameter of several tens of millimeters, the hollow body 3 can move at high speed (several hundred meters/minute) in the axial direction. However, the width of the coating film 11 can be measured.

Furthermore, by arranging the optical fiber 7 so as to irradiate the coating film 11 so that the intensity of reflected light at the side end is greater than the intensity of reflected light at the surrounding area, and by image processing the video signal, the width can be adjusted. could be measured with an accuracy of a fraction of a millimeter.

Although the above embodiment shows an example of measuring the width of the coating film applied to the inner wall surface of the hollow body 3, the inner wall surface inspection apparatus of the present invention is not limited to this, and the width of the coating film applied to the inner wall surface of the hollow body 3 is measured. The width of any membrane other than a membrane, such as liquid, gel, rubber, etc., can be measured with high precision in the same way as long as it is attached to the inner wall surface of a hollow body. .

[0020]

As is clear from the above description, according to the present invention, an imaging optical system whose field of view is a film attached to the inner wall surface of a hollow body is provided, and when viewed from the imaging optical system, An illumination system is provided that illuminates the film body from a position where the intensity of reflected light at the edge is greater than the intensity of reflected light at the surrounding area, and the video signal output from the imaging optical system is processed to determine the circumferential dimension of the coating film, that is, the width. is calculated, the effect is that even if the inner diameter of the hollow body is several tens of millimeters or less, the circumferential dimension of the membrane can be easily measured regardless of the material of the membrane.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a detailed configuration of main elements of an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the relationship between an imaging position and a video signal in order to explain the operation of an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a hollow body to which the present invention is applied.

FIG. 5 is an explanatory diagram showing the state of light reflection for explaining the principle of the present invention.

[Explanation of symbols]

1 Processing department 2 Imaging optical system 3 Hollow body 6. Lighting system 7 Optical fiber 8 Light source 9 Image processing device 10 Computer 11 Coating film

Claims (2)

[Claims] 1. A hollow body inner wall surface inspection device for measuring the circumferential dimension of a film attached to the inner wall surface of a hollow body, comprising: an imaging optical system with the film as a field of view; and an illumination system disposed at a position such that the intensity of reflected light at the side edge is greater than the intensity of reflected light at a portion other than the side edge when viewed from the imaging optical system; an image processing device that processes a video signal of the membrane body to calculate the coordinates of the side end, and calculates the circumferential dimension of the membrane body from these coordinates. Device. 2. The hollow body according to claim 1, wherein the illumination system comprises an optical fiber whose one end faces the inclined surface of the film body at a predetermined angle, and a light source connected to the other end of the optical fiber. Internal wall surface inspection device.