JPH05120412A - Outside surface inspecting method and system for cylindrical can - Google Patents

Abstract

PURPOSE:To automatically inspect an entire can and details at a high speed. CONSTITUTION:The cylindrical longitudinal/direction of a standard can in a constant speed rotating state is line-scanned along an entire width by a one- dimensional scanning camera, and the entire video data are stored in a memory incorporated in an image processor 5. The specific details of the surface of the can in a rotation stopping state is face-scanned by a two-dimensional scanning camera, and the data are stored in the memory incorporated in an image processor 13. The can to be inspected is set at a can constant speed rotating device 1 by a can moving device. The entire video data of the stored standard can are compared with those of the new can to be inspected by the comparison discriminating circuit of the image processor 5, so that the presence or absence of the difference of the entire can to be inspected can be recognized. Then, the specific detail data of the stored standard can are compared with those of the new can to be inspected by the comparison judging circuit of the image processor 13, so that the difference of the specific details of the outside surface of the can to be inspected can be calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer surface of a standard can cylindrical can having a pattern containing characters printed thereon and an outer surface of a cylindrical can to be inspected having the same pattern printed and taken out during the manufacturing process. The present invention relates to a method and an apparatus for inspecting an outer surface of a cylindrical can for performing a comparative inspection by photographing. In the present specification, "pattern" is replaced with "character"
Used to include.

[0002]

2. Description of the Related Art Can manufacturing factories for canning are required to ship products which have no printing defects in the pattern provided on the outer circumference. Therefore, in the conventional manufacturing line,
Alternatively, after manufacturing, the product is taken out at any time and visually inspected each time. At this time, partial loss of the pattern, stains adhered with ink, scratches, abnormalities in the brightness and chromaticity (hue and saturation) of the pattern,
A method of inspecting the enlarged or reduced adhesion of printing ink and the presence or absence of errors in the relative printing positions between each pattern, eliminating defective cans from time to time, and fine-tuning the printing machine based on experience. It was common to take.

This also applies to a two-piece can which is composed of a bottomed cylindrical can and a can lid that closes the upper opening of the can. In that case, the cylindrical can is stamped from a single metal plate in a circular shape, drawn and redrawn or drawn and ironed to form the upper end, and the inner and outer surfaces of the can are washed, and then the cylindrical part. Print a design on the outer surface and bake it, then
It is manufactured by spray painting the inner surface. In order to increase production efficiency, surface printing of the outer part of the cylindrical can is performed by ink treatment of multiple colors at once. Minimal production of cylindrical cans with print defects, among others, is unavoidable. Usually, inspections for finding print defects are conducted visually by making use of many years of experience.

[0004]

In such a conventional surface inspection, it is difficult to promptly deal with a case where the setting of the printing machine is wrong from the beginning, and since printing is performed at a high speed, there is a slight error. There is a problem that a large number of defective products are generated in a short time.

The detection of printing defects in cans relies on the human eye, or human sense, even in the case of two-piece cans. Close inspection requires a lot of manpower. In addition, if a defective product is generated and the degree of the defectiveness of the setting of the printing press is judged from the degree of the defective product to adjust the equipment of the production line, highly skilled knowledge is required. Therefore, there has been a demand for automation of can pattern inspection, labor saving, and speedup, but almost no specific method has been proposed.

The present invention has been made to solve the above-mentioned problems, and provides a method and apparatus for inspecting an outer surface of a two-piece can, which can effectively detect the occurrence of defective printing during the production line. With the goal.

[0007]

A method and apparatus for inspecting an outer surface of a cylindrical can according to the present invention, which has been made to achieve the above object, will be described with reference to FIGS.

The method for inspecting the outer surface of a cylindrical can according to the present invention is a standard canned cylindrical can with a pattern printed thereon (hereinafter referred to as "standard can").
0a and an inspected cylindrical can 20b (hereinafter referred to as "inspected can") 20b which is printed from the middle of the manufacturing process by printing the same pattern, and its outer surface is photographed for comparative inspection.
The standard can 20a is rotated at a constant speed, the cylinder length direction is linearly scanned over the entire width by a one-dimensional scanning camera, and the entire image data of the surface is stored in a memory built in the image processing device 5, while the rotation is stopped. The specific details of the surface are surface-scanned by the two-dimensional scanning camera, and the specific details image data is stored in the memory built in the image processing device 13. Inspected can 20b
Are sequentially extracted from the middle of the manufacturing process to obtain the whole image data of the inspected can 20b in the same manner as in the case of the standard can 20a, and the entire image data of both the stored standard can 20a and the new inspected can 20b are imaged. The comparison / discrimination circuit of the processing device 5 compares and recognizes whether there is an overall difference. Similar to the case of the standard can 20a, the specific detail image data of the inspected can 20b is obtained, and the specific detail data of both the standard can 20a and the new inspected can 20b stored are compared and discriminated by the image processing device 13. To calculate the difference in specific details.

The first outer surface inspection device for a cylindrical can according to the present invention photographs the outer surface of a standard can 20a having a pattern printed thereon and an inspected can 20b that has been extracted from the manufacturing process by printing the same pattern. It is a device for comparison inspection. Transfer device 16 for sequentially extracting the can constant speed rotating device 1 for a cylindrical can and the inspected can 20b from the manufacturing line and installing the can in the constant speed rotating device 1
And the cylindrical cans 20a, 2 that rotate by the can constant speed rotation device 1.
0b is line-scanned over the entire width in the cylinder length direction to obtain whole image data of the outer surface, and a one-dimensional scanning camera (line sensor camera) 8 is surface-scanned for specific details on the outer surface of the cylindrical cans 20a, 20b. Two-dimensional scanning camera (CCD color camera) 11 for obtaining specific detail image data, and each scanning camera 8, 11
And image processing devices 5 and 13 for receiving and comparing the video data from the device and performing a comparative inspection. The image processing devices 5 and 13 have a memory for storing the video data of the standard can 20a, compare the video data sequentially sent by each scanning camera 8 and 11 with the stored video data, A discriminating circuit for recognizing whether or not there is an overall difference in the inspected can 20b and calculating the difference in the specific details of the inspected can 20b and / or the difference in the specific details from the specific detail image data is additionally provided.

A second cylindrical can outer surface inspection apparatus according to the present invention.
Is a standard can 20a on which a pattern including the barcode 21 is printed.
And the same pattern including the barcode 21 is printed to manufacture
Take an image of the outer surface of the inspected can 20b taken out from the middle
This is a device for comparison inspection by shadowing. Cylindrical can can rotating at constant speed
Device 1 and inspected can 20b are sequentially withdrawn from the production line.
And a transfer device 16 installed on the can constant speed rotating device 1,
Of the cylindrical cans 20a, 20b that rotate with the can constant speed rotating device 1 of
Scans barcode 21 and generates a read timing signal
It rotates with the bar code reader 3 and its can constant speed rotation device 1.
The cylindrical cans 20a and 20b running along the length of the cylinder run across the entire width.
Checked and rotated by a certain angle after receiving the read timing signal
A one-dimensional scanning camera that obtains entire video data starting from a position
8 and can be fixed after a fixed time from the reception of the read timing signal
The stop mechanism 9 for stopping the rotation of the high speed rotation device and the rotation stop
Two-dimensional scanning camera for surface-scanning the details of the surface of a rotating can.
Image data from the scanning camera 8 and 11
And image processing devices 5 and 13 for comparative inspection.
It The image processing devices 5 and 13 are the images of the standard can 20a.
Each scanning camera 8 and 1 has a memory to store data.
1 sends the video data sent sequentially and the stored video data
Compared, and the inspected can 20 from the whole image data
Recognizing the overall difference in b, the specific detail image data is
Data or / and specific details of the inspection can 20b
It also has a discriminator circuit that calculates the difference.

[0011]

In the method and apparatus for inspecting the outer surface of the cylindrical can of the present invention, since the one-dimensional scanning camera 8 performs line scanning over the entire width in the cylinder length direction of the rotating cylindrical cans 20a and 20b,
Patterns, scratches and the like can be inspected over the entire surface of the inspected can 20b. Therefore, the comparison / determination circuit of the image processing apparatus 5 can compare the inspected can 20b with the standard can 20a to determine the quality of the entire inspected can 20b. Furthermore, since the specific details of the stopped cylindrical can surface are photographed by the two-dimensional scanning camera 11, the image processing apparatus 13 can determine the quality of the specific details of the outer surface of the inspected can 20b. That is, with the device of the present invention, inspection of the entire can and inspection of details can be performed in a short time.

Particularly in a can with the bar code 21 printed thereon, the bar code reader 3 is caused to read from a certain direction when the bar code 21 passes through an angle as the can rotates, and the timing signal at that time is received. The video data can be compared by adjusting the start point at a position rotated by a certain angle from time to time.

[0013]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an outer surface inspection device for a cylindrical can to which the present invention is applied, and FIG. 2 is a perspective view of the outer surface inspection device for a cylindrical can, showing a pattern including a bar code 21. The state which is observing the printed standard can 20a is shown.

In FIG. 2, 1 is a can constant speed rotating device for setting a cylindrical can, 2 is a pulse motor for driving the can, and 3 is a bar code 21 on the can body of a cylindrical can on the can constant speed rotating device 1. A bar code reader, 7 is a lens, and 8 is a lens with a lens 7 and the can barrel of a cylindrical can on the can constant-speed rotation device 1 is viewed C
CD (charge-coupled device) line sensor camera, 1
Reference numeral 0 is a microscope lens barrel, 11 is a two-dimensional scanning CCD color camera that includes the microscope lens barrel 10, and covers a partial range of the can body of the cylindrical can on the can constant-speed rotation device 1, and 12 is a camera. Elevator, 16 is a can transfer robot that is a can transfer device, 1
A pulse motor 7 drives the camera lift 12.

In FIG. 1, reference numeral 4 denotes a control personal computer which stores an inspection program for inspecting a cylindrical can on the can constant speed rotation device 1. Reference numeral 5 denotes an image for processing an image signal of a line sensor camera 8. First with built-in frame memory
Image processing device, 6 is a clock oscillating circuit for issuing a clock signal to the first image processing device 5 and the line sensor camera 8, and 9 is the first pulse motor 2 of the can constant speed rotation device 1 and the first of the camera elevators 12. The pulse motor controller 13 controls the pulse motor 17 of 2 separately, and also serves as a stopping mechanism of the can constant speed rotation device, and 13 is the CCD color camera 11.
A second image processing device having a built-in image frame memory for performing image processing of the image signal of (1), and 15 is a can carrying sequencer for operating the can carrying robot 16.

The outer surface inspection apparatus of this embodiment is a bar code 2.
The outer surface of the standard can 20a printed with a pattern including 1 and the inspected can 20b having substantially the same pattern is photographed,
This is an apparatus for inspecting the outer surface of the inspected can 20b by comparing both on an image signal. This device is the first standard can 20a
The external appearance is scanned and the standard pattern is memorized, and then the external appearance is sequentially scanned for the inspected cans 20b which are provided with substantially the same pattern and flow through the production line, and the standard cans 20a and the inspected cans are scanned each time. The appearance of 20b is compared on a pixel-by-pixel basis, and a defect in the appearance pattern of the can is found from the difference.

<External scanning of standard can 20a>
The appearance scanning of the standard can 20a is performed as follows.

The can constant speed rotating device 1 is rotated. When the barcode reader 3 detects the barcode 21 due to the rotation, it sends a reading timing signal to the control personal computer 4. The control personal computer 4 causes the pulse motor controller 9 to count a predetermined number of pulses at a fixed angle from the time when the reading timing signal is received, and adjusts the shooting start point in the direction of the objective lens 7 of the line sensor camera 8. A clock signal is sent from the clock oscillation circuit 6 to the line sensor camera 8. The line sensor camera 8 uses the clock signal as a synchronizing signal, and performs a main scan by periodically performing line scanning over the entire width in the cylinder length direction of the standard can 20a from the shooting start point, and the constant speed rotation of the can constant speed rotation device 1. Subscan the can with. Line sensor camera 8 is standard can 2
The entire circumference of 0a is photographed, and an analog image signal which is the whole video data is sent to the first image processing device 5.

On the other hand, the clock signal is also sent from the clock oscillation circuit 6 to the first image processing device 5, and the first image processing device 5 shapes the analog image signal to convert it into a digital signal, and converts it. The whole image data is stored in the image frame memory.

The standard can 20a is the first image processing device 5
The personal computer 4 stops the rotation of the constant velocity rotating device 1 through the pulse motor controller 9 after one rotation on the image.

Next, the CCD color camera 11 scans a specific inspection area or areas for fine inspection of details. Positions of one or more inspection areas are programmed in the personal computer 4 with the number of pulses of the first pulse motor 2 based on the barcode 21. Further, the set height of the CCD color camera 11 in that case is also programmed by the number of pulses of the second pulse motor 17. These one or more inspection areas also include a small registration mark that allows the presence or absence of relative printing position error between patterns of different colors, that is, the misregistration of the pattern to be directly identified. The control personal computer 4 designates each inspection area to the pulse motor controller 9 in order of positional proximity, and adjusts the rotation angle of the can constant speed rotation device 1 and the height of the CCD color camera 11. The lens barrel 10 of the microscope focuses each inspection area on each of the above inspection areas, and
The color camera 11 magnifies and photographs each inspection area of about 4 mm square. At this time, the CCD color camera 11 separates the image information for each pixel into red, green and blue, and sends it to the second image processing device 13 as an analog signal related to the specific detail video data.

The second image processing device 13 converts the analog signal into a digital signal, thereby obtaining the microscope data of each inspection area, that is, the specific detail image data as a digital signal, and storing it in the built-in image frame memory.

<Appearance scanning and inspection comparison of the inspected can 20b> The can conveying robot 16 is driven in accordance with the sequencer 15 which is interlocked with the control personal computer 4.
The can transfer robot 16 goes through a printing pattern printing process,
The inspected cans 20b of the same type having substantially the same pattern as the standard cans 20a are sequentially withdrawn from the middle of the production line and installed in the can constant speed rotating device 1.

As in the case of the standard can 20a, the bar code reader 3 detects the bar code 21, and the line sensor camera 8 makes the entire circumference of the inspected can 20b from the same predetermined photographing start point as the standard can 20a. Is photographed, and the first image processing device 5 digitizes the analog image signal.

The first image processing apparatus 5 is a standard can 20a.
Recall the video data of the entire circumference from the memory. Next, the image data of the entire circumference of the standard can 20a and the image data of the entire circumference of the can 20b to be inspected, where the image capturing start points are coincident with each other, are stored in line information at the same rotation angle from the barcode 21. The first comparison / discrimination circuit built in the first image processing device 5 is used for matching.

The data is compared with the standard can 2 for each pixel.
0a and the to-be-inspected can 20b are searched for the difference in brightness. The first image processing device 5 includes a standard can 20a and an inspected can 20.
The presence / absence of a pixel whose brightness difference with respect to b exceeds a threshold value is recognized, and the number of pixels is sent to the personal computer 4.

When the signal processing in the first image processing device 5 is completed, the control personal computer 4 then operates one or more predetermined inspection areas according to the program in the same manner as in the case of the standard can 20a. Sequentially specify to 9.

The pulse motor controller 9 changes the rotation angle of the can constant speed rotation device 1 and the height of the CCD color camera 11 for each inspection area. CCD color camera 11
Captures analog images of each inspection area sequentially, and the second image processing device 13 digitizes and obtains the specific detailed video data of each inspection area.

The second image processing apparatus 13 has a second comparison / discrimination circuit, and stores the previously stored specific detailed video data of the standard can 20a and the newly acquired specific detailed video data of the inspected can 20b. The pixels at the same coordinate position are sequentially matched with each other in each inspection area.

Before the matching, the displacement of the image position is corrected. Specifically, for the patterns on the pixel coordinates that appear two-dimensionally, the respective pattern positions are calculated based on the coordinate axes, and the patterns are overlaid. Positioning is performed for each inspection area.

The digital signals are matched and the chromaticity is measured. Obtain the average value of red, blue and green and convert it to the L ^* a ^* b ^* chromaticity value. These pieces of information are sent to the control personal computer 4.

If the pattern width of the inspected can 20b is recognized to be enlarged, the expansion width is calculated, and if reduction is recognized, the contracted width is calculated. The register mark is provided for each type of ink used for pattern decoration. If there is a displacement of the register mark on the inspected can 20b, the distance is measured. All of these calculation results are sent to the control personal computer 4.

The personal computer 4 displays the above inspection results for abnormalities in lightness and chromaticity, missing print, scratches on the surface, stains, enlargement adhesion of printing ink, reduction adhesion, and misregistration. Is converted into a predetermined signal, or converted into a feedback signal for correction of manufacturing conditions and output.

In the above-mentioned embodiment, the cylindrical can which has been printed and then subjected to the baking process is inspected. However, the cylindrical can before the baking process may be inspected.

[0036]

As described above in detail, the method or apparatus for inspecting the outer surface of a cylindrical can according to the present invention automatically shortens the inspection of the entire can and the inspection of details, which were conventionally performed by human eyes. It can be done in time. Since the inspection does not rely on human eyes, it can be performed objectively and does not require skill. Since the inspection result is obtained as an electric signal, it can be used by converting it into a signal for displaying the inspection result or a feedback signal for correcting the manufacturing conditions.

If the control direction of the production line is such that defective products may be generated, automatic correction is possible. Skills are not required for inspection and modification of manufacturing conditions,
Once the conditions are set, automatic processing is possible.

Particularly, the outer surface inspection device for a cylindrical can using a bar code has high utility value because almost all bar products are printed on a recent can product.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an outer surface inspection device for a cylindrical can according to the present invention.

FIG. 2 is a perspective view of an embodiment of an outer surface inspection device for a cylindrical can according to the present invention.

[Explanation of symbols]

1 is a can constant speed rotation device, 3 is a bar code reader, 4 is a personal computer for control, 5 is a first image processing device, 8 is a line sensor camera, 11 is a CCD color camera to which a microscope lens barrel is connected, 13 is a second image processing apparatus, 16 is a can carrying robot, 20a is a standard can, and 20b is a standard can.
Is an inspected can and 21 is a bar code.

Claims (7)

[Claims] 1. A standard standard cylindrical can is used for comparative inspection of the outer surface of a standard standard cylindrical can with a pattern including characters printed on it and an inspected cylindrical can with the same pattern printed on it during the manufacturing process. Rotate at a constant speed, scan the length of the cylinder linearly over the entire width with a one-dimensional scanning camera, store the entire image data of the surface in memory, while stop rotation, identify the surface with a two-dimensional scanning camera. The surface is scanned for details and the specific detail image data is stored in the memory, and the inspected cylindrical cans are sequentially withdrawn from the middle of the manufacturing process to obtain the entire inspected image data of the inspected cylindrical cans in the same manner as the standard cylindrical cans. The comparison and discrimination circuit compares the stored whole image data of both the standard canned cylinder and the new inspected cylindrical can to recognize whether or not there is an overall difference. Identification of inspection cylindrical cans A cylindrical can characterized by obtaining detailed video data and comparing the stored specific standard data of both the standard cylindrical can and the new inspected cylindrical can stored in a comparison / discrimination circuit to calculate the difference in specific details. Outer surface inspection method. 2. The method for inspecting the outer surface of a cylindrical can according to claim 1, wherein the comparison / discrimination circuit recognizes the presence or absence of a pattern, stain, or scratch on the entire inspected cylindrical can from the entire image data. A method for inspecting the outer surface of a cylindrical can. 3. The method for inspecting the outer surface of a cylindrical can according to claim 1, wherein the lightness and chromaticity of the pattern printed on the surface of the cylindrical can to be inspected by the comparison / determination circuit from the specific detail data, and the printing ink. The method for inspecting the outer surface of a cylindrical can, wherein at least one of the enlarged adhesion, the reduced adhesion, and the error of the relative printing position is calculated. 4. The method for inspecting the outer surface of a cylindrical can according to claim 1, wherein the comparison / discrimination circuit recognizes the presence / absence of a pattern, stains, or scratches from the whole image data, and the specific detail image data. From the above, a method for inspecting the outer surface of a cylindrical can, wherein at least one of the lightness and chromaticity of the pattern, the enlarged or reduced adhesion of the printing ink, and the error of the relative printing position is calculated by the comparison / discrimination circuit. 5. A device for performing a comparative inspection by photographing the outer surface of a standard canned cylinder having a pattern printed thereon and an inspected cylindrical can having the same pattern printed thereon and taken out during the manufacturing process. A can constant-speed rotating device, a transfer device that sequentially removes the inspected cylindrical can from the manufacturing line and installs it on the can constant-speed rotating device, and a cylindrical can rotating by the can constant-speed rotating device over the entire width in the cylinder length direction. One-dimensional scanning camera that obtains the entire image data of the outer surface by line scanning, two-dimensional scanning camera that obtains the specific detail image data by surface-scanning the specific details of the outer surface of the cylindrical can, and the image data from each scanning camera And an image processing device for comparing and inspecting the image data, the image processing device having a memory for storing the image data of the standard cylindrical can, and the image data sent sequentially by each scanning camera and the stored image data. Compare and screen From the data recognizing the overall differences in the inspected cylindrical can, from a specific details image data data specific details of the test cylindrical can or /
And an outer surface inspection device for a cylindrical can, which is provided with a discriminating circuit for calculating a difference in the specific details. 6. A comparison is made by photographing the outer surface of a standard standard cylindrical can with a printed pattern including a bar code and an inspected cylindrical can printed with the same pattern with a bar code and taken out during the manufacturing process. It is a device to inspect, a can constant speed rotating device for cylindrical cans, a transfer device that sequentially extracts the inspected cylindrical cans from the manufacturing line and installs them on the can constant speed rotating device, and rotates with the can constant speed rotating device. When a bar code reader that reads a bar code on a cylindrical can and generates a read timing signal and a can that rotates at a constant speed rotating device is line-scanned over the entire length in the cylinder length direction and a read timing signal is received. A one-dimensional scanning camera that obtains the entire image data starting from a position rotated by a certain angle, a stop mechanism that stops the can constant speed rotation device after a fixed time from the reception of the read timing signal, and a circle that has stopped rotation. It is equipped with a two-dimensional scanning camera for surface-scanning the details of the surface of the can and an image processing device for receiving and comparing the image data from each scanning camera, and the image processing device stores the image data of the standard cylindrical can. It has a memory and compares the video data sent sequentially by each scanning camera with the stored video data.
A discriminating circuit that recognizes the entire difference of the inspected cylindrical can from the entire image data and calculates the specific detail data of the inspected cylindrical can and / or the difference of the specific details from the specific detail image data An outer surface inspection device for a cylindrical can, characterized by: 7. The outer surface inspection device for a cylindrical can according to claim 5, wherein the two-dimensional scanning camera is a color camera, and the chromaticity of a pattern printed on the outer surface of the cylindrical can is good or bad. An outer surface inspection device for a cylindrical can, which is characterized by being able to determine