JPH07146255A - Can flange part camera - Google Patents

Abstract

PURPOSE:To achieve a detection of fine flaws and cracks of a can flange easily with one camera by setting a conical mirror with a slant side thereof concave at the center of the top of a can to take a reflection expanded light image of a flange by a camera means arranged at the upper end thereof through a cylinder. CONSTITUTION:An empty can 1 is conveyed right under a can flange part camera with a CCD camera 5 at the top of a cylinder 3 and with a conical reflection mirror 7 at the lower end thereof and lighted from above by a ring- shaped lighting means 8 to photograph a flange part 2 of the can 1. As the slant side of the reflection mirror 7 is formed concave, the image of the flange part 2 is turned inside out to make an image expanded diametrically, which allows increase in the number of pixels per unit area of the flange part 2 to enable the detection of a fine flaw or the like even with one camera 5. An image data thus taken is sent to an image processor to judge the propriety thereof automatically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for inspecting the appearance of a ring-shaped object such as a can flange portion by image pickup.

[0002]

2. Description of the Related Art Canned beer is manufactured by filling an empty can having a horizontal ring-shaped flange with a width of about 3 mm with the beer, placing a lid, and tightly winding the flange and the lid together. It If there is a crack or a flaw on this flange, the sealing will be poor, so inspection is necessary. This inspection is performed by taking a light image of the flange with a CCD camera and automatically calculating data of pixels constituting this image.

[0003]

However, the CCD
In the image of the entire flange taken by one camera, the number of pixels per unit area of the flange is small, so there is a problem that it is difficult to identify small cracks or scratches. Further, if the flange is divided into, for example, four parts and each of them is enlarged and imaged by four cameras, the above problem can be solved, but four cameras are required, which is uneconomical.

The present invention has been made in view of the above-mentioned conventional circumstances, and one camera can easily detect small cracks and scratches on the flange of a can, which can obtain an image that solves the above problem. It is an object of the present invention to provide an imaging device capable of performing the above.

[0005]

An image pickup device for a can flange portion of the present invention is provided at one end of a cylinder and has an image pickup means for taking an optical image of the can flange portion through the inside of the cylinder, and an optical axis of the image pickup means. It is concentrically provided on the other end of the cylinder and comprises a reflection means for reflecting the optical image of the flange portion toward the imaging means, the reflection means is a conical mirror and the slope of the cone is concave. It is characterized by

[0006]

Since the reflected light image is taken by the mirror, the outer side of the flange is regarded as the inner side and the inner side as the outer side. Since the surface of the mirror is concave, not only the outer side and the inner side of the flange are inverted, but also the outer side of the flange is regarded as a smaller circle. That is, the image is enlarged in the radial direction. Since this increases the number of pixels per unit area of the flange, it is possible to easily identify small cracks or scratches.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a sectional structure of a can flange image pickup device according to one embodiment of the present invention. The empty can 1 is transported to a position right below the imaging device 5 by a transport device (not shown). The can flange portion 2 to be inspected is illuminated from above by the illumination means 8. The image pickup device includes a cylinder 3 and an image pickup means 5 such as a CCD camera for picking up an optical image of the can flange portion 2 through the cylinder 3. Further, a reflecting means 7 is provided at the other end of the cylinder 3 concentric with the optical axis 6 of the image pickup means 5 and reflects the optical image of the can flange portion 2 toward the image pickup means 5.

Here, the reflecting means 7 is a conical mirror surface, and the slope of the cone is concave. This conical mirror surface is manufactured by, for example, cutting a metal material such as aluminum so that the inclined surface of the cone becomes a concave surface, and performing mirror surface processing.

FIG. 2 shows an image of the can flange portion taken by the image pickup means 5. (A) is an image obtained by directly photographing the can flange portion by the conventional image pickup means,
(B) is a photo image of the can flange portion 2 taken by the image pickup means 5 via the reflection means 7. Can flange part 2
The illumination means 8 illuminates its upper surface brightly, and the image pickup means 5 captures the optical image reflected by the reflection means 7 through the transparent portion 10 between the cylinder 3 and the reflection means 7.
Here, since the reflecting means 7 is a conical mirror and the slope of the cone is concave, the can flange portion 2 has the inside and the outside of the circumference reversed as shown in FIG. The image is enlarged in the direction.

The inspection of the can flange for cracks and scratches is carried out by automatically calculating the data of the pixels forming this image by an image processing device (not shown). The arithmetic processing is performed by converting the brightness of the pixel into a digital signal and comparing the brightness data of two or three points that are close to each other. Therefore, in the image of the can flange portion enlarged by using the reflecting means shown in (B), the number of pixels is remarkably increased as compared with the conventional method shown in (A). Therefore, it becomes possible to easily detect small scratches and cracks that were difficult to detect in the past.

An enlarged image of the can flange portion can be arbitrarily obtained by the concave pattern of the conical slope of the conical mirror. As described above, various modifications can be made without departing from the spirit of the present invention.

[0013]

As described above, according to the present invention, it is possible to easily detect fine scratches and cracks on the can flange portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a can flange portion imaging device according to an embodiment of the present invention.

2A and 2B are explanatory views of an image of a can flange portion, in which FIG. 2A is based on a conventional direct imaging method, and FIG. 2B is based on the reflection means of the above-described embodiment.

[Explanation of symbols]

 1 can 2 can flange part 3 cylinder 5 imaging means 6 optical axis 7 reflecting means 8 illuminating means 10 transparent part

Claims (1)

[Claims] 1. An image pickup means provided at one end of a cylinder for taking an optical image of a can flange portion through the inside of the cylinder, and the flange portion provided at the other end of the cylinder concentrically with an optical axis of the image pickup means. And a reflecting means for reflecting the optical image of the light toward the image pickup means, wherein the reflecting means is a conical mirror, and the slope of the cone is concave.