JPH08285791A - Visual inspection apparatus for inner surface of deep object - Google Patents

Abstract

PURPOSE: To enhance accuracy in the visual inspection of the inner surface of a deep object. CONSTITUTION: The image of the inner surface of a cap C is passed through a concave lens 11 and a half mirror 13 before being picked up means of a first camera 14 disposed immediately above. The bottom face part is masked and the image of side face is stored in a memory. The image reflected on the half mirror 13 is enlarged through a convex lens 15 and reflected on a mirror 16 before being picked up by means of a second camera 17. The side face part is masked and the image of bottom face is stored in a memory and flaw or contamination on the inner surface of cap are detected based on the respective images.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for inspecting the inner surface of deep-bottomed articles such as paper or plastic cups, and more particularly to a technique for improving inspection efficiency while ensuring inspection accuracy.

[0002]

2. Description of the Related Art By visually observing the inner surface of a deep-sealed article such as a cup made of paper or other material, minute holes, dirt, flaws, dent wrinkles,
Inspecting for defects such as tears and molding defects (hereinafter simply referred to as defects) causes severe eye strain and results in reduced efficiency if a long-term inspection is performed, leading to a reduction in inspection accuracy and unfavorable health. .

Therefore, an automatic visual inspection method is conceivable, in which an imaging device such as a camera is used to image and analyze the inner surface of a deep-sealed article.

[0004]

However, in the conventional one in which one camera is used to inspect with one image obtained by imaging the entire inner surface of the deep-bed article from above the deep-bed article, It is difficult to secure a depth of field that covers the side surface and the bottom surface, and when either one of the images is focused, the other image is greatly out of focus and the inspection accuracy is reduced. Even if the focus is set in the middle of the two, an average focus error occurs and the inspection accuracy is unavoidable. In order to obtain a clear image of both, it is necessary to refocus on the side surface and the bottom surface of the deep-bed article, and the inspection speed is greatly reduced due to the loss of time for refocusing. .

A combination of a fixed camera equipped with a CCD line sensor and a rotary optical system that rotates relative to the deep-deep article about its axis continuously scans the side surface and the bottom surface to CC.
Method for imaging on D line sensor (Japanese Patent Application No. 3-2200)
No. 14), etc., but they were expensive and required time for imaging. Therefore, it is conceivable that the side surface and the bottom surface of the deep-sealed article are inspected at the same time by two cameras that are in focus.

However, in the method in which the side surface and the bottom surface of the deep-bottomed article are simultaneously imaged by two cameras, it is necessary to lay out the two imaging systems (including the optical system) without mutual interference. However, in order to ensure inspection accuracy, it is necessary to take images of approximately the same size for defects of the same size that occur on the curved side surface and the flat bottom surface, respectively. Was requested.

The present invention has been made in view of such a conventional situation, and the inner surface of a deep-sealed article can be divided by using a plurality of image pickup means to obtain an image while ensuring good accuracy, respectively. It is an object of the present invention to provide a visual inspection device for an inner surface of a deep-bottomed article, which enables high inspection accuracy to be obtained without reducing the inspection speed.

[0008]

Therefore, the invention according to claim 1 is, as shown in FIG. 1, a visual inspection apparatus for inspecting the inner surface of a deep-bottomed article having a bottom surface and an opening, at a predetermined inspection position. A concave lens is disposed above the opening of the deep-deep article set in, and a half mirror is disposed above the concave lens, and an image of the inner surface of the deep-deep article transmitted or reflected by the half mirror is captured. No. 1 image pickup means, second image pickup means for picking up an image of the inner surface of the deep bottom article reflected or transmitted through the half mirror through a convex lens, and inner surface of the deep article picked up by the first image pickup means. To obtain an image of the side surface by applying a predetermined mask to the image of, and to apply an image of the inner surface of the deep bottom article imaged by the second imaging means to the image of the side surface to obtain an image of the bottom surface and the side surface in the vicinity thereof. The mask processing is performed by the first and second imaging means. And performing visual inspection of deep article inner surface on the basis of the image.

Further, the invention according to claim 2 is characterized in that the first image pickup means and the second image pickup means are mounted so as to be movable in the optical axis direction and for focus adjustment. Further, the invention according to claim 3 comprises a carrying means for carrying the deep-bed article, and a position detecting means for judging whether or not the deep-bed article carried by the carrying means is located at the predetermined position. It is characterized in that it is configured to include.

The invention according to claim 4 is characterized in that an annular illumination means is provided on the outer peripheral side of the concave lens for illuminating the inner surface of the deep-bottom article to be inspected.

[0011]

The virtual image of the inner surface of the deep article obtained by the concave lens located above the opening of the deep article becomes smaller as the distance from the concave lens increases, so that the virtual image closer to the bottom than the direct view image without passing through the concave lens. Is relatively small, and becomes relatively larger as it approaches the opening.

Therefore, in the image of the inner surface of the deep article which is taken by the first camera as it is, the image transmitted or reflected by the half mirror through the concave lens, the side surface portion has a relatively large area ratio to the bottom surface portion. It is captured as an image that has. On the other hand, the image of the inner surface of the deep article taken by the second camera after the image passing through the convex lens after being reflected or transmitted by the half mirror is the bottom image reduced by the concave lens and the image of the side surface in the vicinity thereof. An image is magnified by the convex lens.

In this way, the image of the side surface obtained by applying the predetermined mask with the first camera and the bottom surface obtained by applying the predetermined mask with the second camera. And the image in the vicinity of the same scale, and
Since each of them can be focused and picked up with a high image quality, it is possible to uniformly and highly accurately inspect the inner surface of the deep article for stains, scratches and the like.

Further, it is possible to make a compact layout without interfering with each other between the two image pickup systems, which are the optical systems corresponding to the first and second cameras. According to the second aspect of the present invention, the first image pickup means and the second image pickup means can independently pick up an image while focusing on a central portion of each image pickup area.

Further, according to the third aspect of the invention, while the deep-deep article is being carried by the carrying means, the position detecting means detects that the article has arrived at a predetermined position, so that imaging and inspection are performed. A large number of deep-bed articles can be inspected efficiently. According to the invention of claim 4, since the inner surface of the deep-sealed article is uniformly illuminated and a bright image is obtained, the inspection accuracy can be improved because it is an imaging inspection.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the overall schematic configuration will be described with reference to FIG. 1. The appearance inspection apparatus for deep-bed articles according to the present embodiment is a deep-bed article that is an object to be inspected, specifically, a cup made of paper or plastic. Positioning / conveying section (conveying means) for conveying the cup C to a predetermined position while positioning the cup C, and an imaging section (imaging means) for imaging the inner surface of the inspection object at the predetermined position
And an inspection unit for inspecting the inner surface for defects based on the imaging result, and an ejection unit for ejecting a defective product based on the inspection result.

Next, a series of operations will be described. The mass-produced cups C are sequentially placed on the conveying flat belt 1 at equal pitch intervals and conveyed at a predetermined speed (about 40 m / min). On the upstream side of the conveying path, a pair of positioning belts 2 driven by two pulleys are provided at predetermined positions on both sides of the conveying flat belt 1.
A and 2B are installed, and these positioning belts 2A and 2B
By transporting the cups C while sandwiching them between the Bs, the cups C are aligned and transported in a line while being positioned at the central portion of the transport flat belt 1 in the width direction.

Positioning belts 2A, 2B on the conveying path
A passage sensor 3 that detects passage of the cup C is installed at a predetermined position on the downstream side. The passage sensor 3 is composed of, for example, a set of a light emitter 3A and a light receiver 3B, and when the light emitted from the light emitter 3A is blocked by the cup C and is not received by the light receiver 3B, the cup C moves to a predetermined position. A signal indicating that it is passing is output to the detection unit.

An image pickup unit is installed above the cup C at a predetermined position where the passage sensor 3 detects the cup C. The image pickup unit will be described in detail later, but the cup C
Is detected at the predetermined image pickup position by a signal from the passage sensor 3 and the side surface of the cup C is imaged by the first camera 14 located directly above the cup C. The camera 17 captures an image of the bottom surface of the cup C. In this case, when the first and second cameras are equipped with an area sensor (CCD area element) as an image pickup element as described later, the cup C is stopped at the predetermined position for a predetermined time required for the image pickup at the time of image pickup. Intermittently, the line sensor (CCD
When a line element) is mounted, the predetermined position is continuously moved and passed.

The signals picked up by the first camera 14 and the second camera 17 are output to the inspection section shown in the chain line in the figure. The inspection unit uses the A / D converter 51 for each image pickup signal.
A / D conversion is performed in A and 51B, and preprocessing including mask processing described later is performed in preprocessing circuits 52A and 52B, and then the memory
Temporarily store in 53A, 53B. And each memory 53
The defect data is analyzed by the analyzer 55 for the image of the side surface of the cup C and the image of the side surface of the cup C and the side surface in the vicinity thereof, which are selectively taken out from the A and 53B by the selector 54, and the reference data prepared in advance. The discriminator 4, which will be described later, outputs a discharge signal for determining whether the product is a good product or a defective product by comparison with the discharge control circuit 56 and discharging the cup C determined to be a defective product.
Output to. In addition, the cup C stored in each of the memories
The original image and the analysis and judgment results by the analyzer 55 are selectively displayed on the monitor 58 through the selector 57, and at the same time, the analysis and judgment results are output to the totaling circuit 59 and are totalized and recorded. The timing of each processing described above is performed by the timing control circuit 60.

At a predetermined position on the downstream side of the image pickup section, a discriminator 4 is installed which is driven by receiving a discharge signal when it is determined that the defective product is present. Although it is placed on the belt 1 and conveyed to a predetermined position and moves to the subsequent process, the arm 4a of the discriminator 4 is swiveled to move the cup C to a flat position for the cup C judged to be defective. The belt 1 is sandwiched and discharged to the opposite side, and is dropped and stored in the defective product storage box 5.

Next, the structure and operation of the image pickup section will be described in detail with reference to FIGS. An illuminating lamp for arranging a concave lens 11 on the outer peripheral side of the concave lens 11 such that the optical axis and the cylindrical central axis of the cup C set at a predetermined position detected by the passage sensor 3 coincide with each other. Twelve are arranged.
The illuminating lamp 12 may be installed at a plurality of places around the luminaire, but if a circular line fluorescent lamp or a circular optical fiber is used, the inner surface of the cup can be uniformly illuminated in the circumferential direction.

A half mirror 13 is provided above the concave lens 11.
Is provided, and the image passing through the concave lens 11 on the inner surface of the cup C is separated into an image that passes through the half mirror 13 and an image that reflects and changes the direction by 90 degrees. CCD directly above the half mirror 13
A first camera 14 incorporating an area element or CCD line element is provided.

On the other hand, a convex lens 15 is disposed on the side of the half mirror 13, and a mirror 16 is disposed on the outer side of the half mirror 13 with the reflection surface facing upward and inclined by 45 degrees. A second camera 17 incorporating an area element or CCD line element is provided. The first camera 14 and the second camera 17 include an arm 19 protruding from the adjusting table 18,
The arms 19 and 20 are supported by the end portions of 20, and the movable portions 21 and 22 are freely adjustable in the vertical direction along the guide rails formed on the adjusting table 18 in correspondence with the vertical positions thereof. , Can be fixed to the base 23 of the adjustment table 18 with screws 25 and 26. Thereby, the position of each camera is adjusted, and the focus is adjusted by adjusting the lens.

Next, the operation of the image pickup section will be described. The inner surface of the cup C set at a predetermined position is illuminated by the illumination lamp 12. By passing through the concave lens 11, the illuminated image of the inner surface of the cup C reduces the entire image area as compared with the direct-view image that does not pass through the concave lens, but the image of the bottom surface of the side image is reduced. The image has a relatively increased ratio to.

The image passed through the concave lens 11 is a half mirror.
The image transmitted through 13 and the reflected image are separated. The image transmitted through the half mirror 13 passes through the hollow portion 24 of the arm 20 and is captured by the first camera 14 immediately above. Where the first
The camera 14 adjusts the position of the arm 19 of the adjusting table 18 so that the center of the cup C is centered at 2/3 from the top. As a result, the C built in the first camera 14
An image is formed on the entire inner surface of the cup C on the CD area element, and in particular, a high image quality is obtained by the focus adjustment while increasing the ratio of the image area on the side surface.

On the other hand, the image reflected by the half mirror 13 in the horizontal direction by 90 degrees is magnified by the convex lens 15 and then reflected by the mirror 16 and bent upward, so that the second camera
Imaged at 17. Here, in the second camera 17, the position of the arm 20 of the adjusting table 18 is adjusted so that the bottom surface of the cup C is in focus via the convex lens 15. As a result, the image of the bottom surface of the cup C and the side surface in the vicinity thereof, which has been reduced by the concave lens 11, is enlarged by the convex lens 15,
An image is formed on a CCD area element built in the second camera 17 with a sufficient image area, and a high image quality is captured by the focus adjustment.

The image picked up by the first camera 14 is projected from the top surface of the cup C by masking the bottom surface of the cup C and a portion having a height of 1/3 from the bottom surface by the preprocessing circuit 52A.
Only the side surface portion having a height of / 3 is stored in the memory 53A, while the image captured by the second camera is the preprocessing circuit 52.
By masking the upper two-thirds portion of the side surface portion of the cup C by B, only the bottom surface and the lower side surface portion (one-third height portion from the cup bottom surface) are stored in the memory 53B (see FIG. 3).

By this method, two clear images of the side surface and the bottom surface which are substantially in focus can be obtained. And
The bottom and bottom side images captured by the second camera 17 are magnified by the convex lens 15, so that the size of the center image 2/3 high from the top of the cup C and the scale of the bottom image can be reduced. It can be almost matched.

Therefore, this operation makes it possible to detect stains, scratches, and the like adhering to the inner surface of the cup with a clear image regardless of where they are in the cup and at substantially the same scale. The inspection accuracy can be increased as much as possible. Further, the two image pickup systems including the optical systems corresponding to the first and second cameras, respectively, can be laid out compactly without mutual interference.

[0031]

As described above, according to the first aspect of the present invention, the image of the inner surface of the deep-sealed article is picked up by the first camera after increasing the ratio of the image pickup area of the side surface through the concave lens. Then, since the image of the bottom surface of the deep-sealed article reduced by the concave lens and the side surface in the vicinity thereof is enlarged by the convex lens and then captured by the second camera, the image of the side surface and the image of the side surface in the vicinity thereof are obtained. Since it is possible to take high-quality images at substantially the same scale while focusing on each, the appearance inspection for dirt, flaws, etc. on any part of the inner surface of the deep article is performed uniformly and with high accuracy. be able to.

Further, since the two cameras can simultaneously image the side surface and the bottom surface of the deep-bottomed article and the side surface in the vicinity thereof, a large number of deep-bottomed articles can be image-inspected efficiently in a short time. . Furthermore, the two image pickup systems including the optical systems corresponding to the first and second cameras, respectively, can be laid out compactly without mutual interference.

According to the invention of claim 2, the first
The image pickup means and the second image pickup means can independently pick up an image by focusing on a central portion of each image pickup area. According to the third aspect of the present invention, it is possible to detect that the deep-sealed article has reached a predetermined position while conveying the image,
Since the inspection is performed, a large amount of deep-bottomed articles can be efficiently inspected.

According to the invention of claim 4, the inner surface of the deep-sealed article is evenly illuminated and a bright image is obtained, so that the inspection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a configuration of an image pickup unit according to the above embodiment.

FIG. 3 is a direct-view image of a deep-bed article that does not pass through a concave lens, a virtual image that passes through a concave lens (image captured by the first camera), and a virtual image that passes through a convex lens (image captured by the second camera). The figure which compared and was shown.

[Explanation of symbols]

 1 Transport flat belt 2A, 2B Positioning belt 3 Pass sensor 11 Concave lens 12 Illumination lamp 13 Half mirror 14 First camera 15 Convex lens 16 Mirror 17 Second camera 18 Adjusting stand 19 Arm 20 Arm

Claims (4)

[Claims] 1. A visual inspection apparatus for inspecting an inner surface of a deep bottom article having a bottom surface and an opening, wherein a concave lens is disposed above the opening of the deep bottom article set at a predetermined inspection position, and the concave lens is provided. A first mirror for arranging a half mirror above and capturing an image of the inner surface of the deep article which is transmitted or reflected by the half mirror; and an image of the inner surface of the deep article which is reflected or transmitted by the half mirror. A second image pickup means for picking up an image of a deep side article through a convex lens, and a side face image obtained by applying a predetermined mask to the image of the inner surface of the deep article taken by the first image pickup means. A predetermined mask is applied to the image of the inner surface of the deep-bottomed article captured in to obtain an image of the bottom surface and the side surface in the vicinity thereof, and a deep image is obtained based on the masked images captured by the first and second imaging means. Characterized by performing a visual inspection of the inner surface of the bottom article A visual inspection device for the inner surface of deep-seated articles. 2. The inner surface of the deep-sealed article according to claim 1, wherein the first image pickup means and the second image pickup means are mounted so as to be movable in the optical axis direction and to be freely adjusted in focus. Appearance inspection device. 3. Conveying means for conveying a deep-sealed article, and position detection means for determining whether or not the deep-sealed article conveyed by the conveying means is located at the predetermined position. The visual inspection apparatus for the inner surface of a deep-sealed article according to claim 1 or 2, wherein 4. The annular illumination means for illuminating the inner surface of the deep-sealed article to be inspected is provided on the outer peripheral side of the concave lens, according to any one of claims 1 to 3. Appearance inspection device for the inner surface of deep-bed articles.