JPH04309850A - Inspection of defective of glass cylindrical body - Google Patents

Abstract

PURPOSE:To detect the defective such as the crack and cut which exist in a transparent glass cylindrical body. CONSTITUTION:Light is irradiated to the side surface at one edge part of a transparent glass cylindrical body 1, and the light which transmits through the inside of the wall of the glass cylindrical body and radiates from the surface of the opened port at the other edge of the glass cylindrical body is taken photograph by a CCD camera 6, and the photographed image is binary- converted, and the good or defective of the glass cylindrical body is judged from the magnitude of the defective image which appears in the image region corresponding to the dark part of the glass cylinder body where light does not radiate. Accordingly, visual inspection can be made automatic, and the reduction of inspection cost and the prevention for the supply of the defective articles can be achieved effectively.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting transparent glass cylinders for defects using image processing.

0002

[Prior Art] The conventional inspection method is
As described in ``Inspection method for bottles'' in Publication No. 839, illumination light was incident on the opening of a transparent bottle from both sides, and the reflection pattern from the opening surface was detected using a line sensor. .

0003

[Problems to be Solved by the Invention] Since the above-mentioned prior art makes a judgment by capturing the reflected light from the opening surface of the bottle,
Although it is effective for identifying defects such as cracks that occur near the surface of the opening, it does not take into account defects such as cracks that occur inside the glass cylinder, and it is also difficult to inspect the inside of the cylinder. There was no effective way to do this, so we had to rely on visual inspection. An object of the present invention is to provide a defect inspection method for a glass cylinder that automatically detects minute cracks existing inside a transparent glass cylinder, as well as deformations and chips at the end of the tube, using image processing. There is a particular thing.

0004

[Means for Solving the Problems] In order to achieve the above object, the method for inspecting defects in a glass cylinder according to the present invention provides a method for inspecting defects in a glass cylinder, in which a transparent glass cylinder is formed on the side surface of one end of the glass cylinder at approximately right angles to the axis of the glass cylinder. Spot lights are irradiated in opposing directions, the transmitted light passing through the wall of the glass cylinder is imaged by a CCD camera placed opposite to the opening at the other end of the glass cylinder, and the captured image is image-processed. It is characterized by

[0005] Of the binarized image obtained by binarization processing as image processing, the area perpendicular to the direction of the opposing spotlight is defined as a defect determination area, and the white appearing on the black background of the defect determination area is The area is determined as an image defect image and pass/fail is determined. The area of the defect image can be determined by counting the number of pixels that form a white image among the pixels of the CCD camera that correspond to the defect determination area. Alternatively, the defect image may be determined by inverting the black background of the defect determination area and the black and white of the white image.

[0006]

[Operation] Light irradiated as a spot light onto the side surface of one end of the transparent glass cylinder passes through the wall of the glass cylinder and is emitted from the open surface of the other end of the glass cylinder. When this synchrotron radiation is imaged by a CCD camera and the captured image is binarized, the image area corresponding to the spot irradiated area becomes a white screen with high brightness, and the image area corresponding to the dark area not illuminated by the spotlight becomes a white screen with high brightness. A binary image with a black screen is obtained. If there is a defect such as a crack, deformation, or chipping in a wall portion through which light passes, the light is refracted there, and an image of the defect appears as a white screen within a black screen. The glass cylinder is rotated by a certain angle to obtain a binary image of each part, and the size of the defect is determined by calculating the total area of the white screen that appears on the black screen, and the acceptability of the glass cylinder is determined. The area of the defect image, that is, the area of the white screen within the black screen, can be easily and quickly determined by counting the number of white pixels among the pixels of the CCD camera that correspond to the defect area. Note that it is obvious that a black screen and a white screen can be reversed in image processing.

[0007]

Embodiments Examples of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 is a diagram showing the configuration and arrangement of an apparatus for carrying out a method for inspecting defects in glass cylinders according to an embodiment of the present invention. The object to be examined is a transparent cylindrical glass tube as a glass cylinder. As shown in Fig. 1, a cylindrical glass tube 1 is a test object.
The illumination devices 2a and 2b are arranged to face each other so that the
a and 3b are irradiated onto one end of the cylindrical glass tube 1 from a direction substantially perpendicular to the axis of the cylindrical glass tube 1. The irradiated light passes through the inside of the glass tube 1 as shown by the transmitted light arrow 4, and at this time, a part of the light is refracted by an internal crack 5a or a chip 5b at the end of the tube, and is transmitted to other parts of the glass tube 1. The image is input as an image to a CCD camera 6 placed opposite to the end. This video is binarized and analyzed by the image processing device 10.

FIG. 2 shows a binary image obtained by binarizing an image captured by a CCD camera using an appropriate threshold value, and shows that the glass tube 1 is defect-free and is a good product. Since the side irradiated with the spot lights 3a and 3b transmits a large amount of light, that portion appears as white images 7a and 7b. Then, another area shifted by 90 degrees from the white image portion becomes the determination area 8.

FIG. 3 shows an internal crack 5a in the glass tube 1.
A binary image is shown when there is a defect such as a chip 5b at the end of the tube. Since the transmitted light 4 passing through the glass tube 1 is refracted by the defect and input to the CCD camera 6, a defect image 9 corresponding to the defect appears in the determination area 8. The number of pixels of this defect image 9 is counted, and based on the count value, it is determined whether the glass tube is acceptable or not. In this way, the determination can be made simply by counting the number of pixels in the defective image, so the determination process can be performed easily and at high speed.

Other embodiments are shown in FIGS. 4 to 7.

FIG. 4 shows an inspection method in which illumination lights 3a and 3b are incident on both ends of the bottom of a transparent glass container 11 with a bottom. The incident light propagates inside the glass container 11 as a waveguide, and the light emitted from the open end is input to the CCD camera 6 due to defects 5 in the waveguide of the glass container 11.
If there are a and 5b, the transmitted light 4 is blocked or refracted and input to the CCD camera 6. This input light is decomposed by the image processing device 10 and the presence or absence of a defect is determined.

FIG. 5 shows a transparent glass container 12 that is not straight but rounded. Since the transmitted light 4 propagates using the thick glass part of the container as a waveguide, there are defects 5a in the waveguide.
, 5b, it is possible to determine the presence or absence of a defect in the same manner as described above. Further, the illumination devices 2a and 2b may be tilted as shown in FIG. 5 as long as they do not directly irradiate the CCD camera 6 with light.

FIGS. 6 and 7 show examples of binary images when the cross-sectional shape of the container is quadrangular and triangular, respectively. By detecting the defect image 9 in the defect determination area 8, It is possible to determine the presence or absence of

[0015]

Effects of the Invention According to the present invention, a method for inspecting defects in a glass cylinder is implemented by irradiating light onto the side surface of one end of a transparent glass cylinder, transmitting light through the wall of the glass cylinder, and detecting defects in the glass cylinder. The light emitted from the aperture surface at the other end is imaged by a CCD camera, and the captured image is binarized, so the image area corresponding to the part irradiated with light becomes a high-brightness white screen, and the dark area that is not hit A binary image with a black screen is obtained for the image area corresponding to , and there are cracks, deformations, and
If there is a defect such as a crack, the light is refracted there and appears as a white screen within the black screen, and therefore the defect can be easily detected by the white screen within the black screen.

[0016] From this, the visual inspection, which was conventionally performed by skilled inspectors, can be automated, which is highly effective in reducing inspection costs and preventing shipment of defective products.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration and arrangement of a device that implements an embodiment of the present invention.

FIG. 2 shows a binary image of a defect-free glass cylinder.

FIG. 3 is a diagram showing a binary image of a glass cylinder with defects.

FIG. 4 is a diagram showing a state in which a glass container with a bottom is being inspected.

FIG. 5 is a diagram showing a state in which a round glass container is being inspected.

FIG. 6 is a diagram showing a binary image of a cylindrical body with a rectangular cross section.

FIG. 7 is a diagram showing a binary image of a cylinder with a triangular cross section.

[Explanation of symbols]

1 Cylindrical glass tube 2a, 2b Lighting device 3a, 3b Spot light 4 Transmitted light 5a Crack 5b Kake 6 CCD camera 7 White image 8 Defect determination area 9 Defect image 10 Image processing device 11 Glass container 12 Glass container

Claims (4)

[Claims] Claim 1: A spot light is irradiated on the side surface of one end of a transparent glass cylinder in a direction substantially perpendicular to the axis of the glass cylinder, and the transmitted light that passes through the wall of the glass cylinder is directed to the side surface of the glass cylinder. 1. A method for inspecting defects in a glass cylindrical body, the method comprising capturing an image with a CCD camera disposed opposite to an opening at the other end, and subjecting the captured image to image processing. 2. Of the binarized image obtained by binarization processing as image processing, an area perpendicular to the direction of the opposing spotlight is defined as a defect determination area, and a black background of the defect determination area is Claim 1 characterized in that the appearing white image is used as a defect image and the area of the defect image is determined to determine pass/fail.
The described method for inspecting defects in a glass cylinder. 3. The defect inspection method for a glass cylinder according to claim 2, wherein the area of the defect image is determined by counting the number of pixels forming a white image among the pixels of the CCD camera that correspond to the defect determination area. 4. The method for inspecting a glass cylinder for defects according to claim 2, wherein the black background of the defect determination area and the black and white of the white image are reversed.