JP2962125B2 - Illumination method for cylindrical object surface image inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical object surface image inspection apparatus for inspecting the surface of a cylindrical object such as a steel pipe for defects such as scars, dirt and defective shapes, which is displayed on a television receiver. The present invention relates to an illumination method capable of making the entire luminance of a cylindrical object surface almost uniform.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional cylindrical object surface image inspection apparatus. In this method, a steel pipe 1, which is an example of a cylindrical object, is placed on a rotary roller 2, and the rotary roller 2 is driven to rotate, thereby rotating the steel pipe 1 about its axis O. The steel tube 1 was photographed by a television camera 4 while being entirely illuminated by a lighting device 3, and was projected on a television receiver 5 shown in FIG. 5 via the television camera 4 and an image processing device (not shown). The presence or absence of the scar 6 on the surface of the steel pipe 1 is inspected based on the image.

[0003]

In the above-mentioned conventional configuration,
Since the steel pipe 1 is simply illuminated entirely by the lighting device 3 provided at the rear, the image of the television receiver 5 that projects the steel pipe 1 shows the top 1a of the surface of the steel pipe 1 and its side edge 1b. And a significant difference in luminance occurs between the top and the top 1a, which appears to cause halation and shine.
The side edge 1b looks dark. Therefore, as it is,
It is difficult to inspect the presence or absence of the scar 6 on the surface of the steel pipe 1. Therefore, the image processing apparatus performs so-called difference processing of removing a dark color with reference to the previous screen to easily find the scar 6, but this requires a long image processing time and tends to be a bottleneck in online processing. .

[0004] In view of the above problems, the present invention provides an illumination method in a cylindrical object surface image inspection apparatus that can make the luminance of the entire surface of a cylindrical object such as a steel pipe projected on a television receiver substantially uniform. It is intended to provide.

[0005]

In order to achieve the above object, the present invention is to rotate a cylindrical object such as a steel pipe around its axis, and to illuminate the cylindrical object entirely from above with a lighting device.
While illuminating physically, the cylindrical object is
And shoot the TV camera and image processing device from directly above.
Through the top of a cylindrical object projected on a television
And the surface of the cylindrical object based on the image including the side edges.
Cylindrical object surface image inspection system for inspecting for scars
At a long distance along the axis of the cylindrical object.
Light source, and an arc-shaped mirror surface behind the light source
The light is collected by reflecting the light emitted from the light source with a mirror surface.
By irradiating the intermediate, the side edge of the cylindrical object is
It is characterized by lighting from obliquely above .

[0006]

In the above construction, when inspecting the surface of a cylindrical object such as a steel pipe for scars or the like, the cylindrical object such as a steel pipe is rotated about its axis, and the cylindrical object is illuminated. While illuminating with a condensing light, the cylindrical object is photographed by a television camera, and a scratch on the surface of the cylindrical object based on an image projected on a television receiver via the television camera and the image processing device. The presence or absence may be checked.

In this case, the side edges of the cylindrical object are intensively illuminated by the condensing light, and the brightness of the top and side edges of the cylindrical object projected on the television receiver is made substantially uniform. Since the halation at the top and the dark color at the side edges can be erased, the image processing time by the image processing device can be greatly reduced, and the presence or absence of scars on the surface of the cylindrical object can be efficiently inspected. It can promote online.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a steel pipe (cylindrical object) surface image inspection apparatus according to one embodiment of the present invention, in which a pair of condenser lights 8 are provided on both sides of a television camera 4. Since the configuration other than the above is almost the same as the conventional example shown in FIG.
The same portions are denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 2, the condensing light 8 includes a light source 8b such as a halogen lamp or a fluorescent lamp attached to a lamp house 8a, and an arc-shaped mirror surface 8c provided behind the light source 8b. The light emitted from the light source 8b is reflected by the mirror surface 8c, and the side edge 1b of the steel pipe 1 can be illuminated intensively.

Further, since the light source 8b extends long along the axis O of the steel pipe 1, it can illuminate the side edge 1b of the steel pipe 1 over a wide range, and as shown in FIG. 5, the entire side edge portion 1b of the steel pipe 1 can be almost uniformly and brightly illuminated.

In the above configuration, the scar 6 on the surface of the steel pipe 1
When inspecting the presence or absence of the above, the steel pipe 1 is rotated about its axis O by rotating the rotating roller 2, and the steel pipe 1 is illuminated by the illumination device 3 and the condensing light 8. That is, the lighting device 3 holds the steel pipe 1 at least from above.
Illumination is performed entirely in the radial direction, and the condensing light 8 is
b. The light emitted from the halogen lamp is reflected by a mirror surface.
By irradiating intensively, the side edge 1b of the steel pipe 1 is
Illuminate diagonally from above. In this state, the steel pipe 1 is photographed by the television camera 4, and based on an image projected on the television receiver 5 via the television camera 4 and an image processing device (not shown), a scratch 6 on the surface of the steel pipe 1 is formed. The presence or absence may be checked.

In this case, the side edge 1b of the steel tube 1 is intensively illuminated by the condensing light 8, and the brightness of the top portion 1a and the side edge 1b of the steel tube 1 projected on the television receiver 5 is substantially equalized. And the halation of the top 1a and the side edge 1b
Since the dark color can be eliminated, the time required for image processing by the image processing apparatus can be greatly reduced, and the presence or absence of the scar 6 on the surface of the steel pipe 1 can be efficiently inspected.

[0013]

According to the present invention, the converging light illuminates the side edge of a cylindrical object such as a steel pipe in a concentrated manner, and the top and side edges of the cylindrical object projected on a television receiver are illuminated. The brightness of the image can be almost equalized, and the halation at the top and the dark color at the side edges can be eliminated. Inspections can be performed online, and onlineization can be promoted.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a cylindrical object surface image inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the condensing light.

FIG. 3 is a front view of an image displayed on the television receiver.

FIG. 4 is a schematic explanatory view of a conventional example.

FIG. 5 is a front view of an image projected on the television receiver.

[Description of Signs] 1 steel pipe (cylindrical object) 3 lighting device 4 TV camera 5 TV receiver 6 scar 8 condensing light O axis of steel pipe

Claims (1)

(57) [Claims] 1. A cylindrical object such as a steel pipe is rotated around its axis, and the cylindrical object is entirely turned from above by an illumination device.
While illuminating physically, the cylindrical object is
And shoot the TV camera and image processing device from directly above.
Through the top of a cylindrical object projected on a television
And the surface of the cylindrical object based on the image including the side edges.
Cylindrical object surface image inspection system for inspecting for scars
At a long distance along the axis of the cylindrical object.
Light source, and an arc-shaped mirror surface behind the light source
The light is collected by reflecting the light emitted from the light source with a mirror surface.
By irradiating the intermediate, the side edge of the cylindrical object is
An illumination method in a cylindrical object surface image inspection apparatus, wherein illumination is performed diagonally from above .