JPH03225264A - Method for inspecting inside of container - Google Patents

Abstract

PURPOSE:To attain highly accurate inspection by arranging plural image pickup devices on the upper oblique part of a container, arranging plural spot light sources for irradiating light from the upper oblique direction like a circular arc and picking up the image of the container so as to divide it into plural areas. CONSTITUTION:Plural television(TV) cameras 2 are arranged on the upper oblique part of the container 1 and plural spot light sources 3 consisting of fibers are arranged on the upper oblique part of the container 1 like an approximately circular arc to pick up the image of the inside of the container 1. In the case of dividing the container 1 into three areas each of which is a 120 deg. area and picking up the images of respective areas, three cameras 2 are to be arranged. On the other hand, irradiating light from the spot light sources 3 is projected from the upper oblique direction of the container 1 to the inside of the container which is opposite side to the visual field of the cameras 2 and the inside face and bottom of the container 1 which are the visual field of the cameras 2 are diffusibly irradiated with the diffused and reflected light of the spot light. Image signals from respective cameras 2 are processed by an image processor and the validity/invalidity of respective processed results is totally decided. Since the number of image pickup devices, their angles and illuminating conditions are respectively deviced, the lower part of the inside of the container can be highly accurately inspected.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention automatically inspects the inner surface (inner surface and bottom surface) of a container whose side surface is cylindrical or similar to the cylindrical shape for abnormalities such as foreign matter, dirt, unevenness, etc. Regarding inspection methods for

[Conventional technology]

Conventionally, most of these types of inspections have been performed by taking images from directly above, as shown in Figure 6, and in many cases the illumination has been uniformly illuminated with, for example, fiber optic illumination (spot illumination) (for example, (Refer to Japanese Utility Model Application Publication No. 62187841, etc.)
. In FIG. 6, 1 indicates the container, 2A the camera focal point, 4A the camera viewing angle, 5 the bottom view, and 6 the side view.

[Problem to be solved by the invention]

Conventionally, images are taken from directly above using a single television camera, and the inside surface of the container is inspected only from the viewing angle, so the detection rate at the lower side of the container is extremely low compared to other parts. The problem arises.

Therefore, an object of the present invention is to provide an inspection method that can accurately inspect the lower side of a cylindrical container.

[Failure to solve the problem]

When performing image processing to detect defects on the inner surface (inner surface and bottom surface) of a container whose side surfaces are cylindrical or similar in shape and whose inner surface is made of a material that reflects light, an imaging device that images the inner surface of the container is used. In order to divide the plane containing the container into a plurality of regions and take images, a plurality of devices are arranged at different positions and diagonally above the container, and are directed toward the inner wall on the side opposite to the imaging field of the imaging device. A plurality of spot light sources that emit light obliquely from above are arranged in a substantially arc shape around the container, and the container is inspected by integrating image signals obtained from each imaging device.

In addition, the spot light source is arranged diagonally above the container opening and the angle at which the container is irradiated is selected to be an angle that allows the detection of paris-like defects, or the cross-sectional shape of the spot light source is elliptical. Alternatively, when forming an oval shape, the longitudinal direction of its diameter should match the longitudinal direction of the side surface of the container.

[Effect]

By devising the number, angle, illumination conditions, and angle of the imaging devices as described above, it is possible to accurately inspect the lower side of the cylindrical container.

〔Example〕

The first leap is a schematic diagram for explaining the invention in detail, and the second
3 is a schematic diagram for explaining the inspection area according to the present invention, FIG. 3 is a schematic diagram for explaining the imaging method according to the present invention, FIG. 4 is a schematic diagram for explaining the illumination method according to the present invention, FIG. 5 is a schematic diagram for explaining the primary irradiation spot in this invention.

In Fig. 1, ■ is a container, 2 is an imaging device (television camera), and 3 is an optical fiber as a light source (spot light tj
) and 4 respectively indicate the camera field of view.

That is, in the case shown in FIG.
In addition, a plurality of spot light sources 3 made of fibers are arranged diagonally above the container 1 in a substantially arc shape to image the inner surface of the container, for example, at 120 degrees as shown in Fig. 2 (A). If the image is to be divided into three regions 11 to 13, three television cameras 2 (four if the ?iI region is divided into four regions) are arranged as indicated by the dotted lines in the figure.

However, this is an example assuming that the container does not move, and when the container is transported by a conveyor, etc. as shown in FIG. 2 (b), the television camera 2 (21 to 23) They will be placed at different positions so that they can be imaged effectively.

At this time, since the TV camera 2 is tilted at an angle of 20° to 30° with respect to the vertical direction of the container as shown in FIG. can. In other words, if the size of the foreign object is L, if the television camera is placed in the vertical direction of the container as shown in Fig. 6, the size of the foreign object will be statically imaged as L sin θ. As shown in the figure, an image of 1.5 inches (θ+20° to 30°) is captured larger than before, and detection accuracy is improved.

On the other hand, the illumination at this time is, for example, as shown in Fig. 4, where the irradiation light from the spot light source 3 is applied diagonally from above to the inner surface of the container on the side facing the camera field of view, and the diffused reflected light is used to illuminate the container, which becomes the camera field of view. Diffuse irradiation of the inner surface and bottom surface. In other words, since diffused light has a spread, it is possible to provide averaged light over a wider area. FIG. 5 shows an example of the primary irradiation subbot, and when the fiber is circular, it becomes an ellipse (see reference numeral 3A) as shown in the figure. Therefore, the cross section of the fiber does not necessarily have to be circular, and may be elliptical or oblong in some cases, but in that case, it is desirable that the longitudinal direction of its diameter coincides with the longitudinal direction of the container.

Additionally, the light irradiated from the fiber may only be tilted slightly from the horizontal plane, but this makes it difficult to detect if the foreign object to be inspected is a metallic burr (microscopic protrusion). In this case, it is desirable to be able to detect this by considering the inclination of the irradiated light from the horizontal plane. This is because by tilting the irradiated light from the fiber to a certain degree from the horizontal plane, it becomes possible to capture foreign objects such as the above-mentioned Paris as shadows using the light reflected from the bottom surface.

Note that the image signals from each television camera are processed by an image processing device that is not disclosed, and the results of each process are combined to determine the quality. Additionally, if the illuminance is insufficient, it can be dealt with by adding a fiber light source.

〔Effect of the invention〕

According to this invention, since the number, angle, and illumination conditions and angles of the imaging devices are devised as described above, the inspection of the lower part of the inner surface of the container can be performed with higher precision than in the conventional method. is brought about.

[Brief explanation of drawings]

Figure 1 is a schematic diagram for explaining the invention in detail;
3 is a schematic diagram for explaining the imaging method according to the present invention. FIG. 4 is a schematic diagram for explaining the illumination method according to the present invention. FIG. 5 is a schematic diagram for explaining the primary irradiation spot in this invention, and FIG. 6 is a schematic diagram for explaining the conventional inspection method. Description of symbols 1...Container, IA...Top of the container, IB...Bottom of the container, LC...Side side of the container, 2...Imaging device (TV camera), 2A...Camera focus, 3...・Optical fiber (spot light source), 3A...-Next irradiation sbot, 4.
... Camera field of view, 4A... Camera viewing angle, 5... Bottom view, 6... Side view, 11-13... Inspection area.

Claims (1)

[Claims] 1) In detecting defects on the inner surface (inner surface and bottom surface) of a container having a cylindrical side surface or a shape close to the cylindrical shape and made of a material whose inner surface reflects light by image processing: The imaging devices that take images of the inner surface are placed at different positions in order to divide the plane containing the container into a plurality of regions and take the images.
In addition, a plurality of spot light sources are arranged diagonally above the container, and a plurality of spot light sources emit light from diagonally above toward the inner wall on the side opposite to the imaging field of the imaging device in a substantially arc shape around the container. A method for inspecting the inner surface of a container, characterized in that the inner surface of the container is inspected by integrating image signals obtained through the respective imaging devices. 2) The spot light source is arranged obliquely above the container opening and the angle at which the container is irradiated is selected to be an angle that allows detection of burr-like defects.
) The method for inspecting the inner surface of a container as described in . 3) The container according to claim 1) or 2), wherein when the cross-sectional shape of the spot light source is made into an ellipse or an oval shape, the longitudinal direction of the diameter thereof is made to match the longitudinal direction of the side surface of the container. Internal inspection method.