JP2002365231A - Square paper cup visual inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect shape fault and cracks in the flange of a square paper cup by one inspection station. SOLUTION: The square paper cup visual inspection apparatus inspects the appearance of the flange in a square paper cup, and has a reflection mirror, an area sensor camera, and a processing section. The reflection mirror is arranged to show the surface of the corner of the flange to the area sensor camera. The area sensor camera images the flange from a horizontal direction to the surface, at the same time divides the imaging region and at the same time images the surface of the corner being shown on the reflection mirror for outputting an imaging signal, and simultaneously inspects the horizontal property in the flange and the presence or absence of cracks based on the imaging signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of automatically performing a visual inspection of a square paper cup. In particular, the present invention relates to a square paper cup appearance inspection apparatus for inspecting the horizontality of a flange of a square paper cup and the presence or absence of cracks at the corner.

[0002]

2. Description of the Related Art Major defects in a square paper cup include dirt and foreign matter adhered to the inner surface of the square paper cup, poor bonding between the bottom paper and body paper on the bottom surface, poor shape in the flange, cracks, and the like. In particular, it is difficult to form a flange in a square paper cup, and it is essential to inspect for defects generated during the molding.

In a conventional square paper cup appearance inspection apparatus, these defects are inspected by dividing them into a plurality of inspection stations suitable for detecting the respective defects. For example, as shown in FIG. 6, (A) horizontality inspection station, (B) crack inspection station,
(C) Three inspection stations of an inner surface and an outer surface inspection station are provided. The shape defect at the flange of the square paper cup is performed at (A) the horizontality inspection station, and the crack at the flange is performed at (B) the crack inspection station.

[0004]

However, providing a plurality of inspection stations in this manner not only increases the cost of the square paper cup appearance inspection apparatus, but also increases the square paper size so that they operate well. The burden of adjusting and maintaining according to the cup increases. In addition, it is often impossible or difficult to secure a space when incorporating them into a square paper cup molding device.

The present invention has been made to solve such a problem. The purpose is to enable a single inspection station to inspect for shape defects and cracks in the flange of the square paper cup.

[0006]

The above object is achieved by the present invention described below. That is, a square paper cup appearance inspection apparatus according to claim 1 of the present invention is a square paper cup appearance inspection apparatus that inspects the appearance of a flange of a square paper cup, and includes a reflecting mirror, an area sensor camera, and a processing unit. The reflecting mirror is arranged so as to project a surface of a corner of the flange to the area sensor camera, and the area sensor camera images the flange in a horizontal direction with respect to the surface and divides the imaging region. And simultaneously image the surface of the corner projected on the reflector and output an imaging signal, and the processing unit simultaneously inspects the horizontality of the flange and the presence or absence of a crack in the corner based on the imaging signal. Is performed.

According to the present invention, the surface of the corner of the flange is arranged so as to be projected on the area sensor camera by the reflecting mirror, and the flange is imaged from the area sensor camera in the horizontal direction with respect to the surface, and the imaging area is obtained. The surface of the corner projected on the reflector is imaged at the same time, and an imaging signal is output. The processing unit performs a process of simultaneously inspecting the horizontality of the flange and the presence or absence of a crack at the corner based on the imaging signal. It is. Therefore, the inspection for the shape defect and the crack in the flange of the square paper cup can be performed in one inspection station.

According to a second aspect of the present invention, there is provided a square paper cup appearance inspection apparatus according to the first aspect, wherein the area sensor cameras are provided one for each corner of the flange. It is intended to be. ADVANTAGE OF THE INVENTION According to this invention, a mechanism which rotates a square paper cup and performs imaging several times is not required, a mechanism is simplified, and imaging of the whole range can be performed by one imaging. Time can be reduced.

According to a third aspect of the present invention, there is provided a square paper cup appearance inspection apparatus according to the first or second aspect, wherein the reflecting mirror is a concave mirror. ADVANTAGE OF THE INVENTION According to this invention, the part which is easy to generate a crack can be imaged by enlarging, and inspection precision can be improved.

[0010]

Next, an embodiment of the present invention will be described. FIG. 1 is a perspective view showing an example of the configuration of an imaging unit (inspection station) in the square paper cup appearance inspection apparatus of the present invention. In FIG. 1, 1a, 1b, 1c, 1
d is a camera, 2a, 2b, 2c and 2d are mirrors, 100 is a square paper cup, and 101 is a flange.

The cameras 1a, 1b, 1c, 1d are area sensor cameras having a two-dimensional imaging area. For example, cameras 1a, 1b, 1c, and 1d each include a CCD (charge coupled device) in which light receiving elements (pixels) are two-dimensionally arranged.
e) Sensor, its driving circuit, imaging optical system (lens),
And the like. When an image of an object to be imaged is formed on the sensor via the image forming optical system, light and dark occur on each light receiving surface of the light receiving element. The amount of charge stored in the light receiving element changes according to the brightness. Cameras 1a, 1b, 1
c and 1d scan the light receiving element to generate and output a time-series voltage waveform (imaging signal) determined by the charge amount.

As shown in FIG. 1, an example of a square paper cup 1 is shown in FIG.
00 is a square paper cup having four corners.
Each of the four cameras 1a, 1b, 1c, 1d is arranged to face each of the corners of the four flanges of the square paper cup 100. Cameras 1a, 1b, 1c, 1
Each of d captures a portion of the flange in a horizontal direction with respect to its surface. Also, the cameras 1a, 1b, 1c, 1d
Image the periphery of the flange about each of the corners of the flange, and mirror 2a, 2b, 2
Each of c and 2d is arranged so as to be included in the imaging region.

Each of the mirrors 2a, 2b, 2c, 2d
The angle of the reflection surface is set so that each of the four corners of the flange of the square paper cup 100 is projected on each of the cameras 1a, 1b, 1c and 1d. Therefore, each of the cameras 1a, 1b, 1c, and 1d captures an image of the flange in the horizontal direction with respect to the surface thereof, and simultaneously divides the imaging region into mirrors 2a, 2b, and 2d.
The surface of the corner of the flange shown in c and 2d can be imaged.

As the mirrors 2a, 2b, 2c, 2d, plane mirrors are usually used, but convex mirrors or concave mirrors may be used. When a convex mirror is used, even a small mirror can project a wide range. When a concave mirror is used, a small area can be enlarged and projected. In particular, the square paper cup 10
A concave mirror is often suitable for enlarging the corners of the four flanges at 0 to reflect fine cracks.

As shown in FIG. 1, the configuration of the above-mentioned imaging unit is such that the rectangular paper cup 100 is imaged from four directions. Each of the configurations in these four directions has a similar configuration. Here, one of them is shown in FIG.
This will be further described with reference to a side view. In FIG.
1a is a camera, 1b is a mirror, 50 is a captured image, 60 is a mirror image, 100 is a square paper cup, 101, 101a, 101
b is a flange, 110 is a crack. FIG. 4 shows an enlarged view of the captured image 50 shown in FIG.

The upper portion of the square paper cup 100 has a flange 10
It is 1. Because the paper cup 100 has a lid on top, the surface of the flange 101 needs to be flat, ie, lie in one plane, to match the flat surface of the lid. One of the purposes of the camera 1a is to capture an image for inspecting whether or not the flange 101 is flat. As shown in FIG. 2, the camera 1a captures an image of the flange 101 in a horizontal direction with respect to the surface thereof. Therefore, the flange 101
Is flat, the image of the flange 101 is taken in a substantially straight line. 2 and 4, the flange 101a of the captured image 50 indicates this.

The four corners of the flange 101 of the square paper cup 100 have one of the defects, "crack".
This is a place where the occurrence is easy. One of the purposes of the camera 1a is
At four corners of the flange 101, an image for inspecting the presence or absence of a crack is taken. Mirror 2a
Are arranged at a reflection angle such that the corner surface of the flange 101 is projected on the camera 1a. The mirror 2a exists in the imaging area of the camera 1a. Therefore,
The camera 1a captures an image of the corner surface of the flange 101 projected on the mirror 2a. 2 and 4, a captured image 5
The mirror image 60 at 0 shows the contour of the mirror 2a, the projected flange 101b and the cracks 110 present therein.

Next, FIG. 3 is a block diagram showing an example of the configuration of the processing unit in the square paper cup appearance inspection apparatus of the present invention. In FIG. 3, 1a is a camera, 1b is a mirror, 20 is a processing unit, 21 is an image input unit, 22 is an inspection processing unit, and 23 is a result output unit. The processing unit 20 can be configured by hardware and software of a data processing device such as an image processing device and a personal computer. The processing unit 20 performs a process of simultaneously inspecting the horizontality of the flange 101 of the square paper cup 100 and the presence / absence of a crack at a corner of the flange 101 based on the imaging signal.

The image input unit 21 in the processing unit 20 outputs from the camera 1a. An imaging signal is input and A / D (anal
og-to-digital conversion to generate a captured image 50 (see FIGS. 2 and 4).

The inspection processing section 22 in the processing section 20 performs a process of extracting a defect based on the captured image. Further, a process of determining whether or not the range is an allowable range based on the type, quantity, size, etc. of the extracted defect, that is,
A process is performed to determine whether the square paper cup 100 is a good product or a defective product.

The result output unit 23 in the processing unit 20 is a square paper cup 100 to be determined by the inspection processing unit 22.
Is OK or OK or NG (no goo
d) An output that distinguishes whether " Result output unit 2
On the basis of the output of 3, for example, an alarm device, a defect removing device, a work volume counting device, and the like are operated. Result output unit 23
Serves as an interface to those devices.

In the above-described configuration of the imaging unit and the processing unit,
Next, an example of the operation of the inspection processing unit 22 in the square paper cup appearance inspection apparatus of the present invention will be described with reference to FIGS. The inspection processing unit 22 performs the imaging 5 shown in FIG.
At 0, inspection area 1 and inspection area 2 are set. The captured image 50 itself can be used for this setting.
For example, the contours of the flanges 101a and 101b are extracted by performing vertical differentiation at appropriate locations (plural locations) of the captured image 50 and extracting horizontal segments. Based on the outline, a predetermined range is set for the inspection area 1 and the inspection area 2.

The processing for detecting the horizontality of the flange 101a in the inspection area 1 and the processing for detecting the flange 1a in the inspection area 2
The same processing method can be applied to the processing of detecting a crack at the corner of 01b. FIG. 5 shows the process. First, in step S1 in FIG. 5, horizontal differentiation is performed on the inspection region 1 or the inspection region 2 to obtain a horizontal differential image. In the horizontal differential image, the line segments in the horizontal direction are deleted, and the line segments in the other directions are thinned by the horizontal component ratio. In other words, a vertical line segment is extracted.

Next, in step S2, the horizontal differential image is binarized with a predetermined threshold to obtain a binarized image. In the binarized image, only line segments having a large degree of deviation from the horizontal direction are left. The degree can be adjusted by a threshold value. Thereby, the flange 101b
Is extracted from the horizontality in. Further, a cracked portion of the flange 101a is extracted.

Next, in step S3, the number of pixels of the line segment remaining in the binarized image is counted, and the number of pixels is compared with a predetermined threshold value to determine the magnitude. When the number of pixels is smaller than the predetermined threshold, the square paper cup 100 to be determined is determined to be non-defective. On the other hand, when the number of pixels is larger than the predetermined threshold, the square paper cup 100 to be determined is determined to be defective.

[0026]

As described above, according to the square paper cup appearance inspection apparatus according to the first aspect of the present invention, the inspection for the shape defect and the crack in the flange of the square paper cup is performed in one inspection station. be able to. Further, according to the square paper cup appearance inspection apparatus according to the second aspect of the present invention, the mechanism is simplified, and the imaging of the entire range can be performed by one imaging, so that the imaging time can be reduced. Further, according to the square paper cup appearance inspection apparatus according to the third aspect of the present invention, it is possible to magnify and image a portion where cracks easily occur, thereby improving inspection accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of a configuration of an imaging unit (inspection station) in a square paper cup appearance inspection apparatus according to the present invention.

FIG. 2 is a side view illustrating an example of a configuration of an imaging unit (one of four imaging directions) in the square paper cup appearance inspection apparatus of the present invention.

FIG. 3 is a block diagram illustrating an example of a configuration of a processing unit in the square paper cup appearance inspection apparatus according to the present invention.

FIG. 4 is an enlarged view of a captured image.

FIG. 5 is a diagram showing a process common to a process of detecting horizontality of a flange and a process of detecting a crack.

FIG. 6 is a view showing a plurality of inspection stations in a conventional square paper cup appearance inspection apparatus.

[Explanation of symbols]

 1a, 1b, 1c, 1d Camera 2a, 2b, 2c, 2d Mirror 50 Captured image 60 Mirror image 100 Square paper cup 101, 101a, 101b Flange

Continuing on the front page (72) Shozo Kinoshita, Inventor 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Hideto Sakata 1-1-1, Ichigaga-cho, Ichigaya-cho, Shinjuku-ku, Tokyo No. F term in Dai Nippon Printing Co., Ltd. (Reference) 2F065 AA47 AA49 AA51 BB08 CC00 DD06 FF04 FF42 JJ03 JJ05 JJ08 JJ09 JJ26 LL12 QQ07 QQ13 QQ21 RR05 RR06 SS09 TT03 2G051 AA21 AB03 AB05 BB11 CA01 EA01 CB01 CA12 CA16 CE12 DA03 DB02 DC02

Claims (3)

[Claims] 1. A square paper cup appearance inspection device for inspecting the appearance of a flange of a square paper cup, comprising: a reflecting mirror, an area sensor camera, and a processing unit, wherein the reflecting mirror has a surface of a corner of the flange. The area sensor camera is arranged to project the flange from the horizontal direction with respect to the surface thereof, and the area sensor camera divides the imaging region and simultaneously projects the reflection mirror. Imaging the surface of the corner and outputting an imaging signal, wherein the processing unit performs a process of simultaneously inspecting the horizontality of the flange and the presence or absence of a crack at the corner based on the imaging signal. Square paper cup appearance inspection device. 2. The square paper cup appearance inspection apparatus according to claim 1, wherein one of said area sensor cameras is provided at each of the corners of said flange. 3. The square paper cup appearance inspection apparatus according to claim 1, wherein said reflecting mirror is a concave mirror.