JP2001004348A - Method and device for inspecting roughness on outer peripheral surface of glass vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow high-precision and rapid rough inspection on the outer peripheral surface of a glass vessel by projecting the image of vertical parallel lines on the outer peripheral surface of glass vessel, and judging a part of the image with wider interval between parallel lines to be a recessed part while a part with narrow one to be a protruding part. SOLUTION: An inspection signal is inputted with a glass vessel 1 set on a stage, and an image processing means clicks the shutter of an imaging means so that the picture of an image 2 of the outer peripheral surface of the glass vessel 1 is taken in for binarization. An image 2 of the slit is parallel when the outer peripheral surface of the glass vessel 1 has no rough, or normal case, while the image 2 is enlarged if a recessed part 13 is present and the interval of the image 2 of slit is enlarged. If a protruding part is present, the image 2 is reduced to narrower the interval of image 2 of the slit. The process is repeated until the glass vessel 1 is rotated once, and after one rotation, a maximum value and minimum value are selected from all measurement values, acquiring a difference. When the difference is smaller than a pre-set tolerable value, the external peripheral surface of the glass vessel 1 is judged to be good, while it is judged to be defective if the difference is larger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for inspecting a glass container such as a glass bottle or a glass cup for detecting a defective product having irregularities on a smooth outer peripheral surface.

[0002]

2. Description of the Related Art In glass containers, slight irregularities may occur on the outer peripheral surface due to defective molding or the like. Such defective products are not only unfavorable in appearance, but also when air bubbles are sealed between the label and the outer peripheral surface of the container when the label is applied, or when the printing is performed on the outer peripheral surface of the container, the printing is blurred. There's a problem. For this reason, irregularities on the outer peripheral surface of the glass container must be inspected to eliminate defective products.

[0003] A conventional inspection of the irregularity of the outer peripheral surface of a glass container is performed by bringing the tip of an arm urged in the direction of the container into contact with the outer periphery of the rotating glass container, and checking whether the arm moves with the rotation of the container. I was That is, if there is a concave portion on the outer peripheral surface of the container, the arm slightly moves toward the container at that portion, and if there is a convex portion, the arm slightly moves away from the container.

[0004]

The above-described conventional inspection of the outer peripheral surface of the glass container has the following problems. Inspection is possible only for containers whose cross section is close to a perfect circle. A stable inspection cannot be performed because it cannot follow minute irregularities. It is difficult to accurately align the center of the glass container with the rotation axis, and thus the inspection accuracy is poor. The higher the speed of rotation of the container, the worse the inspection accuracy becomes.

An object of the present invention is to perform a high-speed inspection of irregularities on the outer peripheral surface of a glass container with high accuracy.

[0006]

SUMMARY OF THE INVENTION The present invention projects an image having vertical parallel lines on the outer peripheral surface of a glass container. When there is a portion where the distance between the parallel lines of the image is large, a concave portion is formed. An unevenness inspection method for an outer peripheral surface of a glass container, wherein it is determined that a convex portion exists when there is an existing and narrowed portion.

Since the irregularities appearing on the outer peripheral surface of the glass container have a smooth curved surface, it can be considered that the concave portion is a concave mirror and the convex portion is a convex mirror. In other words, the image shown in the concave portion appears as large as the image shown in the concave mirror, and the image shown in the convex portion appears as small as the image shown in the convex mirror. The method and apparatus of the present invention make use of this principle. When an image having vertical parallel lines is projected on the outer peripheral surface of the glass container, if there is no unevenness, as shown in FIG. 2, the projected image becomes a normal parallel line, and there is a concave portion 13 therein. And FIGS. 1, 3
As shown in FIG. 4, the parallel line spreads only at that portion, and conversely, if there is a convex portion, the interval between the parallel lines becomes narrow only at that portion, as shown in FIG. That is, an image having vertical parallel lines is projected on the outer peripheral surface of the glass container, and it is possible to determine whether there is unevenness by observing the interval between the parallel lines of the image.

Although the determination based on the parallel lines can be made by visual observation, an image projected on the outer peripheral surface of the glass container is captured by the image capturing means, and the captured image is processed by the image processing means to determine the interval between the parallel lines. The measurement can be made automatically by measuring at a plurality of locations in the vertical direction. The more measurement locations of the interval, the more accurate the determination.

There are several determination methods for the determination by the image processing means. First, there is a method in which a regular interval and a permissible value of the parallel line are set in advance in the image processing means, and when the difference between the measured interval and the regular interval is larger than the permissible value, it is determined that the image is defective. There is also a method in which a predetermined number of times is further set, and when the number of times exceeds an allowable value is larger than the set number of times, it is determined to be defective.

Next, an allowable value of the difference between the maximum value and the minimum value is set in the image processing means, the maximum value and the minimum value of the measured value are obtained, and if the difference is larger than the allowable value, it is determined that the image is defective. There is a way to do that.

The unevenness inspection is performed at a plurality of different positions in the circumferential direction of the glass container. In this case, it is convenient to hold the glass container on a base that rotatably holds the glass container, and to capture a plurality of images at a plurality of positions while rotating the glass container. In the plurality of images captured in this way, a defective product may be determined for each image. However, when the determination is made based on the difference between the maximum value and the minimum value, measurement values of all images are recorded. The difference between the maximum value and the minimum value can be obtained and compared with a predetermined allowable value.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a glass container 1 on which an image 2 having parallel lines is projected, FIGS. 2 to 4 are images obtained by imaging the image 2 by an image pickup unit, FIG. 2 shows a normal case, and FIG. In this case, FIG. 4 is an explanatory view showing a case where there is a convex portion, FIG. 5 is a side view of the unevenness inspection device 3 of the embodiment, FIG. 6 is a top view of the unevenness inspection device 3, and FIG. 8 is a flowchart showing an example of image processing in the image processing means.

The projection / inspection apparatus 3 of the embodiment includes a projection unit 4,
It comprises an imaging means 10, a base 11, an image processing means (not shown), and the like. As shown in FIG. 7, the projection means 4 has a light emitting surface of a diffusing surface light source 5 and a mask 6 having two vertical slits 7 opened. Light enters the light incident portion of the diffusion surface light source 5 from a halogen lamp 8 as a light source via a fiber 9, and the incident light is diffused inside the diffusion surface light source 5 and irradiated from the light emitting surface as a substantially uniform surface light source. Is done. The mask 6 is a thin plate having a light-shielding property, and the material is metal, plastic, or the like. Light emitted from the light emitting surface of the diffusion surface light source 5 reaches the outer peripheral surface of the container 1 through the two opened slits 7 and forms images 2 of the two vertical slits. The diffusion surface light source 5 is fixed to the stand 12 toward the container 1 on the base 11.

The projection means shown here is merely an example, and it is essential that the projection means be capable of projecting a desired image on the outer peripheral surface of the glass container. Although various shapes of an image having vertical parallel lines are conceivable, two parallel slits as in the embodiment are the simplest and the image processing is simple.

The imaging means 10 is a CCD camera, and the stand 1 faces the image 2 projected on the container 1 by the projection means 4.
It is fixed to 2. The captured image is sent to image processing means (not shown), and it is determined whether the outer peripheral surface of the glass container has irregularities.

The base 11 is rotated by rotating means (not shown), and the glass container 1 is held on the base 11 and rotates. The imaging unit 10 releases the shutter a plurality of times while the container 1 makes one rotation, and sends a plurality of images to the image processing unit.
Therefore, images 2 are captured at a plurality of different positions in the circumferential direction of the glass container. The pedestal 11 is provided with a tachometer that generates a pulse each time it rotates by a certain angle, and this pulse is sent to the image processing means to determine whether the container has made one rotation.

The image processing and the pass / fail judgment method in the image processing means will be described with reference to FIG. In the initial setting, a reference value when the image is binarized, an allowable value of a difference between the maximum value and the minimum value of the width of the parallel line of the image 2 and the like are set. G
T is for confirming whether a test signal has been input. When the glass container 1 is set on the base 11 and the inspection preparation is completed, an inspection signal is input. When the inspection signal is input, the image processing means releases the shutter of the imaging means 10 to capture the image of the image 2 on the outer peripheral surface of the glass container 1 and performs binarization processing. The binarization process is a process of erasing a portion darker than a preset reference value, whereby only the image 2 becomes a “bright” image and the other portions become “dark” images. Next,
The interval x of the slit image 2 ′ of the binarized image is measured at a plurality of locations at predetermined intervals from the top to the bottom by the number of pixels, and the measured value is recorded.

When the outer peripheral surface of the glass container has no irregularities and is normal, as shown in FIG. 2, the slit image 2 'is parallel and the interval x is constant. If the concave portion 13 is provided on the outer peripheral surface of the glass container, the image of that portion is enlarged like an image reflected on a concave mirror, and therefore, as shown in FIG. It is the maximum value.
If there is a convex portion on the outer peripheral surface of the glass container, the image of that portion is reduced like an image reflected on a convex mirror, and therefore, as shown in FIG. It becomes the minimum value.

Measurement of parallel line spacing from image capture
The recording operation is repeated until the glass container makes one rotation. That is, the unevenness inspection is performed on a plurality of portions in the circumferential direction of the container. When the glass container 1 makes one rotation, the maximum value and the minimum value are selected from all the measured values in the plurality of images, and the difference is calculated. If the difference is smaller than a preset allowable value, the outer peripheral surface of the glass container has no irregularities and is determined to be a good product.If the difference is larger than the allowable value, a concave portion or a convex portion is provided on the outer peripheral surface of the glass container. It is determined to be present and defective, and an exclusion signal is output.

When this apparatus is used for inspection of unevenness in the manufacturing process of a glass bottle, the apparatus can be mounted on a well-known handling machine on which various inspection apparatuses can be mounted, and the inspection can be performed automatically. In this case, the inspection signal is input from the handling machine. In addition, the reject signal can be output to a sorting device downstream of the handling machine to automatically reject defective products.

[0021]

According to the present invention, the irregularities on the outer peripheral surface of the glass container are inspected optically, not mechanically, so that the inspection can be performed at high speed and with high accuracy. Further, not only circular containers but also containers having various shapes such as an elliptical shape can be inspected.

[Brief description of the drawings]

FIG. 1 is a perspective view of a glass container 1 on which an image 2 is projected.

FIG. 2 is an explanatory diagram of a normal case of an image captured by an imaging unit.

FIG. 3 is an explanatory diagram in a case where there is a concave portion of an image captured by an imaging unit.

FIG. 4 is an explanatory diagram in a case where there is a convex portion of an image captured by an imaging unit.

FIG. 5 is a side view of the unevenness inspection device 3 of the embodiment.

FIG. 6 is a top view of the unevenness inspection device 3.

FIG. 7 is an explanatory diagram of the projection means 4.

FIG. 8 is an explanatory diagram illustrating an example of image processing in an image processing unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass container 2 Image 3 Irregularity inspection apparatus 4 Projection means 5 Diffusion surface light source 6 Mask 7 Slit 8 Halogen lamp 9 Fiber 10 Imaging means 11 Stand part 12 Stand 13 Concave part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA49 AA53 AA61 BB22 CC00 DD03 DD06 FF04 FF44 GG02 GG18 HH02 HH06 JJ03 JJ26 LL02 LL50 QQ04 QQ25 2G051 AA11 AA12 AB02 AB20 BA20 BB17 CA03 EA04 EB07 EA07

Claims (7)

[Claims] 1. An image 2 having vertical parallel lines is projected on the outer peripheral surface of a glass container 1. When there is a portion where the interval between the parallel lines of the image 2 is large, a concave portion exists and becomes narrow. Detecting an unevenness on the outer peripheral surface of a glass container, wherein it is determined that a convex portion is present when there is a portion that is in contact 2. An image 2 having a vertical parallel line is projected on the outer peripheral surface of the glass container 1, and the interval between the parallel lines of the image 2 is measured at a plurality of locations extending in the vertical direction. A concave portion is present when there is a wider portion and a convex portion is present when there is a narrow portion. 3. An image 2 having vertical parallel lines is projected on the outer peripheral surface of the glass container 1, and the interval between the parallel lines of the image 2 is measured at a plurality of locations in the vertical direction, and the maximum value and the minimum value are measured. Determining the presence of a concave portion or a convex portion when the difference is larger than a predetermined value. 4. An image 2 having a vertical parallel line is projected on the outer peripheral surface of the glass container 1, and the interval between the parallel lines of the image 2 is measured at a plurality of locations in the vertical direction. Repeated at a plurality of different positions in the circumferential direction, the maximum value and the minimum value are obtained from all the measured values, and when the difference is larger than a predetermined value, it is determined that there is a concave portion or a convex portion. Inspection method for irregularities on the outer surface of a glass container 5. A projecting means 3 for projecting an image 2 having a vertical parallel line on an outer peripheral surface of a glass container 1, an image sensing means 10 for sensing the image 2, and a process for processing an image sensed by the image sensing means 10. Image processing means for measuring the interval between the parallel lines of the captured image at a plurality of locations in the vertical direction, and when there is a portion where the interval is wider than a predetermined interval, a concave portion is present. An unevenness inspection device for an outer peripheral surface of a glass container, wherein it is determined that a convex portion exists when there is a narrow portion. 6. A projecting means 3 for projecting an image 2 having a vertical parallel line on an outer peripheral surface of a glass container 1, an imaging means 10 for taking the image, and processing an image taken by the imaging means 10. Image processing means, the image processing means measures the interval between the parallel lines of the captured image at a plurality of locations in the vertical direction to determine the difference between the maximum value and the minimum value, the difference is greater than a predetermined value An unevenness inspection apparatus for an outer peripheral surface of a glass container, which determines that a concave portion or a convex portion exists when the size is large. 7. A base 11 for rotatably holding a glass container 1, a projecting means 3 for projecting an image 2 having a vertical parallel line on an outer peripheral surface of the glass container 1, and an imaging device for imaging the image 2. Means 10 and image processing means for processing an image picked up by the image pick-up means 10, wherein the image pick-up means 10 has images of the glass container 1 rotating on the base 11 at a plurality of different circumferential positions. 2, the image processing means measures the interval between parallel lines at each of a plurality of locations in the vertical direction for each of the plurality of captured images, obtains a maximum value and a minimum value from all the measured values, and determines a difference between them by a predetermined value. An unevenness inspection apparatus for an outer peripheral surface of a glass container, wherein it is determined that a concave portion or a convex portion exists when the value is larger than the value.