JPH0815163A - Visual inspecting apparatus for cylindrical object - Google Patents

Abstract

PURPOSE:To reduce the inspecting cost by qualitatively and rapidly inspecting the external appearance of a cylindrical object. CONSTITUTION:A plurality of light sources 3 are developed separately at both the sides of a conveying passage 1 in a circumferential direction on the way of the passage 1, and all inclined with respect to the axis of a cylindrical object 2. A plurality of cameras 6 are provided between the sources 3. When the object 3 reaches a predetermined reference point C, a plurality of banded optical images are projected on the periphery of the object 2, and imaged by the cameras 6. Accordingly, the presence or absence of a defect can be judged by measuring the lightness changes of the vicinities of both the sides of the images 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the appearance of a cylindrical object suitable for inspecting the surface of a cylindrical object such as a beer can.

[0002]

2. Description of the Related Art As a tubular material, various cans and containers are known in addition to beverage cans for filling various beverages such as beer and juice. Generally, these cylindrical objects are shipped after being visually inspected for the presence of scratches or dents on the surface.

Since the naked eye is highly sensitive to a momentary differential reaction and the information processing ability of the brain is extremely high, a trained inspector, according to a trained inspector, can detect minute scratches or dents from a cylindrical object during high-speed transportation. It is also possible to detect the defective product that it has, and it is possible to quickly make a high-level judgment in the limit region between the good product and the defective product. However, the visual inspection work, which is monotonous but requires a feeling of tension, causes a great deal of fatigue to the inspector, and in some cases defective products with remarkable appearance defects may be overlooked. The inspection accuracy varies depending on the degree. Further, not only is it difficult to train and secure skilled workers, but it can also be an obstacle to reducing manufacturing costs.

In view of this, there is a system for automating the visual inspection as described above, for example, Japanese Patent Laid-Open No. 1-206242.
It is known from the official gazette. In the technique described in this publication, a linear light image that is inclined with respect to the axis is formed on the surface of the cylindrical object by using a special linear light source, and the linear light image of the linear object during rotation of the cylindrical object is formed. The quality is judged based on the degree of deformation. That is, if the product is a good cylindrical product, the linear optical image is not deformed, but if it is a defective product having defects such as scratches and dents,
Since the optical image is distorted and deformed at that portion, it is possible to judge pass / fail by detecting this deformation amount.

[0005]

However, in the one described in the above-mentioned publication, since the cylindrical object is rotated and inspected, it is necessary to provide a rotary stage for visual inspection in the middle of the transfer line, Mechanical configuration is significantly complicated.
Moreover, since the image is taken by a single camera while rotating the cylindrical object, the inspection time required for each one becomes long. Further, rotating the cylindrical object may give a new defect.

On the other hand, there are various possible causes of defects in the appearance of the tubular product. In recent years, however, automation in each process is progressing, and vibration and heat are more likely to occur than sudden failure due to human factors. There is a higher possibility that the appearance quality will be deteriorated as a result of the mechanical adjustment or the like being misaligned. in this case,
Since defective products are continuously generated, if they can be detected at an early stage of generation, it is possible to maintain a certain appearance quality by reinspecting only the lot. Therefore, regardless of whether it is a fully automatic unmanned line, it is not always necessary to strictly and quantitatively inspect the cylindrical object over the entire circumference, and the inspection cost increases due to the close inspection, and the cylindrical object is manufactured. The cost increases.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an appearance inspection apparatus capable of quickly inspecting the appearance of a cylindrical object. Another object of the present invention is to reduce the inspection cost by qualitatively inspecting the appearance defect of the cylindrical object in the high-speed conveyance state.

[0008]

SUMMARY OF THE INVENTION Therefore, a tubular object appearance inspection apparatus according to the present invention is provided with a conveying path for conveying a cylindrical object and a space around the conveying path, and the cylindrical object is provided. A plurality of light sources for forming a band-shaped optical image on the surface of the, a plurality of imaging means for imaging the surface of the cylindrical object on which the band-shaped optical image is formed in a transport state, among the images captured by each of these imaging means. The brightness measuring means for measuring the brightness and the determining means for judging the presence or absence of a defect based on the brightness change measured by the brightness measuring means are included.

Further, according to a second aspect of the present invention, there is provided a conveying path for conveying the cylindrical object and a plurality of conveying paths provided around the conveying path so as to be spaced apart from each other so as to form a band-shaped optical image on the surface of the cylindrical object. A light source, a plurality of image pickup means for picking up the surface of the cylindrical object on which the band-shaped light image is formed in a transport state, and a lightness measurement for measuring the lightness in the vicinity of both sides of each band-shaped light image picked up by each of these image pickup means. And a determining means for determining the presence or absence of a defect based on the change in brightness measured by the brightness measuring means.

Further, according to a third aspect of the present invention, a transport path for transporting the tubular material, a transport path which is spaced apart from the transport path, and is inclined by a predetermined angle with respect to the axis of the tubular material. A plurality of band-shaped light sources that form a band-shaped optical image on the surface of the cylindrical object, a plurality of imaging means that images the surface of the cylindrical object on which the band-shaped optical image is formed in a transport state, and each of these imaging means It includes lightness measuring means for measuring the lightness in the vicinity of both sides of each band-shaped light image captured by, and judging means for judging the presence or absence of a defect based on the lightness change measured by the lightness measuring means.

Furthermore, it is preferable that the scanning direction of the image pickup means is arranged parallel to the longitudinal direction of the band-shaped optical image.

[0012]

When the cylindrical object is conveyed by the conveying path and reaches the predetermined position, the light rays from the respective light sources are incident on the surface of the cylindrical object and reflected, whereby a band-shaped optical image is projected. And
When the imaging means images the tubular object in which the plurality of band-shaped light images are reflected at a predetermined timing while being in the transport state,
The determination means determines the surface defect of the cylindrical object based on the change in brightness in the captured image.

According to the second aspect of the present invention, the determining means determines the presence or absence of the surface defect of the cylindrical object based on the change in brightness near both sides of each strip-shaped optical image measured by the brightness measuring means. be able to. That is, when there is a defect in the part where the band-shaped optical image is formed, the optical image is disturbed according to this defect,
The brightness is increased near both sides of the band-shaped light image. Further, when there is no defect in the region where the band-shaped optical image is formed and defects are generated only in the vicinity of both sides of the region, light from the light source is reflected by the defect, so that the brightness of the defective portion becomes high. Therefore, it is possible to effectively detect even a defect that does not affect the shape or linearity of the band-shaped optical image.

Further, according to the third aspect of the invention, since the band-shaped optical image is arranged at a predetermined angle with respect to the axis of the cylindrical object, the reflection due to the defect can be amplified and the inspection accuracy can be improved. You can

On the other hand, if the scanning direction of the image pickup means is arranged parallel to the longitudinal direction of the band-shaped optical image and the directions of both are aligned,
It is possible to accurately and promptly detect the linearity of the band-shaped optical image.

[0016]

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

First, FIG. 1 is a structural explanatory view showing the overall construction of a cylindrical appearance inspection apparatus according to a first embodiment of the present invention. The plurality of tubular objects 2 are placed in an upright state with being separated from each other, and are conveyed in the direction of arrow A toward the next step such as the filling step and the packing step. Here, the “cylindrical object” as used in the present specification is a concept including not only a cylindrical shape and a rectangular cylindrical shape but also a conical shape, and is not limited to a hollow cylindrical shape but a solid cylindrical shape. Also included are. For example, the tubular product 2 includes various tubular containers and members such as aluminum cans and steel cans of beer and juice, bottles, cups, pipes, rings and the like.

A plurality of light sources 3 are provided in the middle of the conveying path 1 and are spaced apart from each other in the circumferential direction around a predetermined reference point C.
More specifically, each of the light sources 3 is, for example, a straight tube type fluorescent lamp housed in a tubular casing, and five light sources are deployed in a semicircular shape on both sides of the transport path 1 in the traveling direction, so that the light sources of the other party are opposed to each other. 3 in the diametrical direction.

Further, as shown in the layout explanatory view of FIG. 2, each light source 3 is inclined by a predetermined angle θ ₁ from an axis line X ₁ -X ₁ parallel to the axis line X-X of the tubular body 2. This tilt angle θ ₁ is
Although it is determined according to the type and size of the defect to be inspected, it is set in the range of 30 to 60 °, for example. When the predetermined angle θ ₁ is set in the range of 40 to 50 °, the reflection at the defect can be effectively amplified. More preferably, it should be set to about 42 to 46 °. Here, each light source 3 is not specially formed as a so-called slit light source, but is not limited to this, and the end portion of the optical fiber may be linearly arranged, or the light emitting diode may be linearly arranged. Alternatively, each light source 3 may be formed as a slit light source by providing a slit plate on the fluorescent lamp. When a fluorescent lamp is used, the brightness in the vicinity of the electrodes is lower than that in the central portion, so it is desirable to use a fluorescent lamp that is several times longer than the height dimension of the tubular member 2 for illumination.

When each of the light sources 3 emits light by being supplied with electric power from the illumination power source 4 shown in the functional block diagram of FIG. 3, the light is reflected by the peripheral surface of the tubular body 2 and thereby the tubular shape is obtained. Band-shaped reflected light image 5 (band-shaped light image 5) on the peripheral surface of the object 2.
Are spaced apart in the circumferential direction.

On the outer peripheral side of the reference point C, which is the center of the inspection stage, a plurality of cameras 6 as image pickup means are provided at intervals in the circumferential direction. Each of these cameras 6 is configured as a random shutter CCD camera using, for example, a CCD device (charge coupled device), and two cameras are provided on each side of the transport path 1 so that the cameras 6 of the other party can receive each other.
And diametrically opposite. Further, as shown in FIG. 2, each camera 6 is provided between the light sources 3, and the lens 7 at the tip thereof is located substantially on the same plane as the light source 3. In other words,
The camera 6 and the light source 3 are the cylindrical object 2 (reference point C
Are installed so that the distances from the tubular object 2) located at are substantially equal to each other. The camera 6 is a CCD
Not limited to the element, an image pickup tube or the like may be used.

Further, as will be described later with reference to FIG. 5, each camera 6 is arranged so that its scanning direction is parallel to the longitudinal direction of the band-shaped optical image 5, that is, the band-shaped optical image 5 is substantially aligned with the axis of the cylindrical object 2. When they are formed in parallel, they are arranged at an angle of about 90 ° so as to be orthogonal to the axis of this cylindrical object 2, and the optical system is arranged so that, for example, four band-shaped optical images 5 are accommodated in the visual field. (Lens 7) is set. Then, each of these cameras 6 electronically releases the shutter by a predetermined trigger signal, so that the peripheral surface of one cylindrical object 2 is imaged from four directions.

The control unit 8 for image processing is
For example, it is configured as a microcomputer system including an arithmetic circuit such as a CPU, a storage circuit such as a ROM and a RAM, an input / output circuit, and the like, and is connected with a monitor 9 and a keyboard (none of which are shown). Referring to FIG. 3, the control unit 8 includes a multi-valued image memory (frame memory) 10 for storing the A / D converted video signal from each camera 6, and each image memory 10.
And a window setting section 12 for setting a window 17 (inspection area) described below for each image memory 10 selected by the switching section 11.
And a measurement line setting unit 13 for measuring the lightness on the lightness measurement lines S ₁ and S ₂ which will be described later and set in the window 17, and whether the appearance is good or bad based on the change in lightness measured by the measurement line setting unit 13. The determination unit 14 for determining the Further, in the middle of the transport path 1, a trigger sensor 15 including a photoelectric switch, a proximity switch, etc. corresponding to the reference point C is provided.
The trigger sensor 15 is connected to a synchronizing circuit 16 which supplies an external synchronizing signal to the camera 6. Then, the trigger sensor 15 detects the tubular object 2 that has reached the reference point C, so that each camera 6 takes an image.

Next, the operation of the apparatus according to this embodiment will be described in detail with reference to FIGS.

When the cylindrical object 2 is conveyed by the conveying path 1 and reaches the reference point C in the inspection stage where each light source 3 is developed, the trigger sensor 15 detects this and outputs a trigger signal to the control unit 8. To do. Then, the light rays from the respective light sources 3 are incident on and reflected by the peripheral surface of the cylindrical object 2, and as a result, as shown in FIG. 4, a total of 10 strip-shaped optical images 5 are formed on the peripheral surface of the cylindrical object 2. They are formed so as to be separated in the circumferential direction (only four are shown in the figure).

Here, each light source 3 is tilted by a predetermined angle θ _{1 with} respect to the axis of the cylindrical object 2 as described above, but the tilt angle of the band-shaped optical image 5 reflected on the peripheral surface with respect to the axis. θ
₂ is small, for example, about 5 ° or less. Therefore, although the width of the band-shaped optical image 5 is expanded by tilting the light source 3 by the angle θ ₁ , the band-shaped optical image 5 itself is substantially parallel to the axis of the cylindrical object 2.

By the way, this tubular member 2 is a good product, and has scratches, dents,
When there is no defect such as buckling, the light rays of the respective light sources 3 are normally reflected, so that the band-shaped optical image 5 reflects the shape of the light source 3 composed of the straight tube fluorescent lamp and is reflected in a straight line.

Each camera 6 picks up an image of the cylindrical object 2 in response to the trigger signal from the synchronizing circuit 16. Here, since each camera 6 is tilted at a substantially right angle so as to be perpendicular to the axis of the tubular object 2, its scanning direction is relative to the longitudinal direction of the band-shaped optical image 5, as shown in FIG. Parallel to each other. As a result, the horizontal scanning direction (reading direction) of the image memory 10 is also along the longitudinal direction of the band-shaped optical image 5. It should be noted that the term “parallel” as used herein is a concept that includes not only perfect parallelism but also substantially parallel relationship.

The image data thus captured in each image memory 10 is sequentially sent to the subsequent circuit via the switching section 11 and subjected to necessary processing. That is, the multi-gradation image data is first sent to the window setting section 12, and the window setting section 12 sets slit-shaped windows 17 around each band-shaped optical image 5, as shown in FIG. It

Next, in the measurement line setting unit 13, as shown in an enlarged view in FIG. 6, a straight line is formed on both sides of the band-shaped optical image 5 in the image data cut out in the window 17 with a predetermined pixel spacing. The brightness measurement lines S ₁ and S ₂ are set, and the brightness of the pixels along these brightness measurement lines S ₁ and S ₂ are read out. Here, although the band-shaped optical image 5 is slightly inclined with respect to the axis of the cylindrical object 2 by an angle θ ₂ , it can be regarded as being substantially parallel to the axis of the cylindrical object 2. The lightness measurement lines S ₁ and S ₂ are set apart from the band-shaped optical image 5 so as to be parallel to the axis of the cylindrical object 2.

When the cylindrical object 2 is a good product, the band-shaped optical image 5 extends linearly along the axis of the cylindrical member 2, so that the band-shaped optical image 5 is obtained.
The brightness of the pixel corresponding to is high. However, FIGS.
As shown in, the lightness of the pixels along the lightness measurement lines S ₁ and S ₂ to which the light from the light source 3 does not directly reach becomes low, and becomes substantially constant over the entire range.

On the other hand, in the case where the tubular member 2 is a defective product having defects such as scratches and dents on the peripheral surface, the defect causes a change in the brightness in the image memory 10, as shown in FIG. Considering three types of defects, a defect 18A having a relatively large dent, a defect 18B having a relatively small dent, and a defect 18C having a minute puncture, the defects 18A and 18B are considered.
Are present on the band-shaped optical image 5, these defects 18A, 18
The band-shaped optical image 5 is disturbed by B and linearity is lost, and a part of the optical image crosses the respective brightness measurement lines S ₁ and S ₂ . However, since the other defect 18C is distant from the band-shaped optical image 5 and has a small size, it hardly affects the band-shaped optical image 5 and only the portion corresponding to the defect 18C is bright in spot. It just becomes.

Therefore, as shown in FIG. 10, the defective cylindrical article 2 having these defects 18A, 18B, and 18C is taken into the image memory 10 through the camera 6, and as shown in FIG.
When the lightness measurement lines S ₁ and S ₂ are set as shown in FIG. 12, the lightness of the pixels along these lightness measurement lines S ₁ and S ₂ are
It changes as shown in FIG.

This change in brightness will be described in detail. Since the defects 18A and 18B substantially located on the band-shaped light image 5 cause a part of the band-shaped light image 5 to cross the first lightness measurement line S ₁ , this lightness is changed. As shown in FIG. 12, the brightness of the pixel along the measurement line S ₁ is locally brightened only in the portions corresponding to the defects 18A and 18B.

On the other hand, due to the relatively small defect 18B located on the band-shaped optical image 5, a part of the band-shaped optical image 5 crosses the second lightness measuring line S ₂ and light is reflected by the minute defect 18C. As for the brightness of the pixels along the brightness measurement line S ₂ , only the portions corresponding to the defects 18B and 18C are locally bright, as shown in FIG.

Therefore, the judging section 14 determines the defects 18A, 18B, and 18B based on the change in the brightness of the brightness measuring lines S ₁ and S ₂ .
The presence / absence of 18C is detected and a pass / fail judgment signal is output.

Various kinds of judgment processing can be considered. First, for example, in the case where the brightness of a predetermined level or more is detected over a plurality of dots in each of the brightness measurement lines S ₁ and S ₂ , It is possible to determine that there is a defect and output a defective signal. This can be understood as so-called one-stage on / off control.

Secondly, a plurality of lightness measurement lines are set on both sides of the band-shaped optical image 5, and it is detected which measurement line has a lightness of a predetermined level or higher, and the size of the defect is stepwise. Can be determined. That is, in the case of a large defect, a local bright portion is generated up to the outer lightness measurement line distant from the band-shaped light image 5, and in the case of a small defect, only the inner lightness measurement line close to the band-shaped light image 5 is generated. Since no bright part is generated, it is possible to rank defects. This can be understood as multistage on / off control.

As described above, when the determination section 14 determines a defect, the control unit 8 turns on a warning or the like based on the determination output, or excludes the defective cylindrical object 2. To do. Further, it is also possible to statistically analyze the defect detection result and to analyze in which of the upper part, the central part and the lower part many defects occur.

According to the present embodiment configured as described above,
The following effects are obtained.

First, a plurality of light sources 3 are developed in the circumferential direction in the middle of the conveying path 1, the cylindrical object 2 in the middle of conveying is imaged in the non-rotating state in the conveying state, and inspection is performed based on this image data. Due to this configuration, unlike the technique described in the above publication, the entire mechanical configuration can be greatly simplified, and the appearance inspection can be performed quickly. In addition, the online inspection can be performed without the risk of new defects due to rotation.

Secondly, since a plurality of band-shaped optical images 5 are formed on the peripheral surface of the cylindrical object 2 and each of the band-shaped optical images 5 is picked up by a plurality of cameras 6 for inspection, the cylindrical object is formed. The appearance quality of No. 2 can be qualitatively and promptly evaluated. As a result, it is possible to detect a defect occurrence tendency at an early stage, adjust the manufacturing machine, and reduce the inspection cost to reduce the manufacturing cost of the tubular article 2.

Thirdly, the linearity of the band-shaped optical image 5 itself, that is, the deformation of the band-shaped optical image 5 is not directly detected to determine the presence or absence of a defect, but is set near both sides of the band-shaped optical image 5. Since the defect inspection is performed by measuring the lightness along the lightness measurement lines S ₁ and S ₂ , the inspection range can be expanded and the inspection accuracy can be significantly improved.

If the inspection is performed based on the change in brightness of the band-shaped optical image 5 itself, the defects 18A, 18 affecting the shape of the band-shaped optical image 5 can be detected, but the shape of the band-shaped optical image 5 is changed. No defect 18C can be detected.
Of course, if the number of light sources 3 is increased and a large number of band-shaped optical images 5 are formed, the chance of detecting such defects 18C can be increased, but the entire structure is complicated and the cost is increased accordingly. On the other hand, in the present embodiment, since the inspection is performed based on the change in brightness near both sides of the band-shaped light image 5, at least the first
It is possible to extend the inspection range to between the lightness measurement line S ₁ and the second lightness measurement line S ₂ . Therefore, according to the present embodiment, it is possible to set a large inspection range without increasing the number of light sources 3, and it is possible to significantly improve the inspection accuracy and efficiently perform online inspection.

Fourthly, since the light source 3 is arranged so as to be inclined with respect to the axis of the cylindrical member 2 by an angle θ ₁ , reflection due to a defect can be increased and inspection accuracy can be improved.

Fifth, the scanning direction of the camera 6 is changed to the band-shaped optical image 5
Since it is set to be parallel to the longitudinal direction of, the data processing time can be shortened and the appearance inspection can be performed more quickly. In addition to this, since the brightness measurement lines S ₁ and S ₂ are set parallel to the axis of the tubular body ₂ , the longitudinal direction and the scanning direction of each of the brightness measurement lines S ₁ and S ₂ are set. Can be substantially matched, and data processing can be efficiently performed.

Sixth, in the present embodiment, since the light source 3 which is simply a straight tube fluorescent lamp is used instead of using a special slit light source, the overall structure is relatively simple,
The manufacturing cost of the device can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS. 14 and 15. In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals,
The description will be omitted. The feature of this embodiment is that the cylindrical object 2 conveyed by the tube-shaped conveying path is inspected.

That is, the transport path 21 according to this embodiment is formed in a long tube shape from a translucent material such as acrylic resin, and the tubular member 2 flows in the transport path 21 due to air pressure or the like. It is transported by physical strength. The light sources 3 are spaced apart from each other in the circumferential direction so as to surround the transport path 21.
Two of them are arranged and are inclined by the angle θ _{1 with} respect to the axis of the tubular member 2. Similarly, the camera 6
Is also provided between the light sources 3 so as to surround the transport path 21, and the lens 7 thereof is located substantially on the same plane as the light source 3.

Thus, in this embodiment having the above-described structure, the same effect as that of the first embodiment described above can be obtained. In addition to this, in the present embodiment, since the plurality of light sources 3 and the camera 6 are arranged on the outer periphery of the tubular transport path 21, the defect detection accuracy (detection probability) can be further improved.

Although the numbers of the light sources 3 and the cameras 6 are specifically illustrated in each of the above-described embodiments, the present invention is not limited to this, and various aspects such as the outer dimensions of the cylindrical object 2 and required inspection accuracy can be obtained. It can be set as appropriate in consideration of the conditions.

In each of the above embodiments, the case where the light source 3 is tilted by the angle θ _{1 with} respect to the axis of the cylindrical object 2 has been described, but the present invention is not limited to this, and the light source 3 is changed to the cylindrical object 2. You may arrange | position parallel to the axis line of.

Further, in each of the above embodiments, the lightness measurement lines S ₁ and S ₂ are set near both sides of the band-shaped light image 5, and the lightness of the pixels along these lightness measurement lines S ₁ and S ₂ is at a predetermined level. It has been described as an example where the CPU 51 determines "Yes defect" when it reaches the above, the present invention is not limited thereto, and detects the brightness level change of the brightness measurement lines S _1, S _2, waveform analysis It is also possible to make a positive determination. That is, the changes (peaks) appearing on the brightness measurement lines S ₁ and S ₂ are analyzed based on the height, the width, the ratio of the width to the height, the angle of inclination, and the like, and the actual defect type and size. It is also possible to judge the defect in more detail by associating with the above.

[0054]

As described in detail above, according to the apparatus for inspecting the appearance of a tubular article according to the present invention, the surface defects of the tubular article can be inspected quickly and qualitatively, and the overall mechanical The structure can be simplified and the inspection cost can be reduced.

Since the defect is not judged based on the change in brightness of the band-shaped light image itself but is judged based on the change in brightness near both sides of the band-shaped light image, the inspection range can be widened. The inspection accuracy can be improved.

Furthermore, since the scanning direction of the image pickup means is arranged parallel to the longitudinal direction of the band-shaped optical image and the directions of both are aligned, the data processing time can be shortened and the inspection can be carried out more quickly. .

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing an overall configuration of a cylindrical appearance inspection device according to a first embodiment of the present invention.

FIG. 2 is an arrangement explanatory diagram showing an arrangement of a light source, a camera and the like in FIG.

FIG. 3 is a functional block diagram of a control unit and the like shown in FIG.

FIG. 4 is an explanatory diagram showing a raw image in which a band-shaped optical image is formed on the peripheral surface of a cylindrical object.

FIG. 5 is an explanatory diagram showing a multi-valued image stored in an image memory.

FIG. 6 is an explanatory diagram showing an enlarged brightness measurement line and the like.

FIG. 7 is a characteristic diagram showing changes in brightness of pixels along a first brightness measurement line.

FIG. 8 is a characteristic diagram showing a change in brightness of pixels along a second brightness measurement line.

FIG. 9 is an explanatory view similar to FIG. 4, showing a raw image when a band-shaped optical image is formed on a defective cylindrical object.

FIG. 10 is an explanatory diagram similar to FIG. 5, showing a multi-valued image of a defective tubular product stored in the image memory.

FIG. 11 is an explanatory view similar to FIG. 6, showing the relationship between the band-shaped optical image and the brightness measurement line in a defective cylindrical object.

FIG. 12 is a characteristic diagram showing a change in brightness of pixels along a first brightness measurement line.

FIG. 13 is a characteristic diagram showing a change in brightness of pixels along a second brightness measurement line.

FIG. 14 is a configuration explanatory view showing the overall configuration of a tubular-body appearance inspection apparatus according to a second embodiment of the present invention.

15 is a sectional view taken along line XV-XV in FIG.

[Explanation of symbols]

1, 21 ... Conveyance path 2 ... Cylindrical object 3 ... Light source 5 ... Camera (imaging means) 13 ... Measurement line setting section (brightness measuring means) 14 ... Judgment section (judging means) S ₁ , S ₂ ... Brightness measurement line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuhiko Sato 318 Nishikawara-machi, Moriyama-ku, Nagoya, Aichi Asahi Breweries, Ltd. Nagoya factory (72) Katsumi Kato 318 Nishikawara-cho, Moriyama-ku, Aichi, Nagoya Asahi Breweries, Ltd. Nagoya Factory (72) Inventor Ryuta Namba 318 Nishikawara-cho, Moriyama-ku, Nagoya, Aichi Prefecture Asahi Breweries Ltd.Nagoya Factory (72) Inventor Yasuro Motoyama 2-13-1, Omorikita, Ota-ku, Tokyo Asahi Biru Co., Ltd. Liquor Development Laboratory

Claims (4)

[Claims] 1. A transport path for transporting a tubular object, a plurality of light sources which are provided around the transport path and are spaced apart from each other, and which form a band-shaped optical image on the surface of the tubular object, and the band-shaped optical image. A plurality of image pickup means for picking up an image of the surface of the formed tubular object in a transport state, a lightness measuring means for measuring the lightness in an image picked up by each of these image pickup means, and a lightness change measured by the lightness measuring means. An appearance inspection apparatus for a cylindrical object, comprising: a determination unit that determines the presence or absence of a defect based on the determination. 2. A transport path for transporting a cylindrical object, a plurality of light sources which are provided around the transport path and are spaced apart from each other, and which form a band-shaped optical image on the surface of the cylindrical object, and the band-shaped optical image. A plurality of image pickup means for picking up an image of the surface of the formed tubular object in a transport state, a lightness measuring means for measuring the lightness in the vicinity of both sides of each strip-shaped optical image picked up by each of these image pickup means, and the lightness measuring means. An appearance inspection apparatus for a cylindrical object, comprising: a determination unit that determines the presence or absence of a defect based on the measured change in brightness. 3. A conveying path for conveying a cylindrical object, and a conveying path which is spaced apart from the circumference of the conveying path and is provided at a predetermined angle with respect to the axis of the cylindrical object, and is provided on the surface of the cylindrical object. A plurality of band-shaped light sources that form a band-shaped optical image, a plurality of imaging means that images the surface of the cylindrical object on which the band-shaped optical image is formed in a transport state, and a band-shaped optical image captured by each of these imaging means. A visual inspection device for a cylindrical object, comprising: a brightness measuring means for measuring the brightness in the vicinity of both sides; and a judging means for judging the presence / absence of a defect based on the brightness change measured by the brightness measuring means. 4. The appearance inspection of a tubular article according to claim 1, wherein a scanning direction of the image pickup means is arranged parallel to a longitudinal direction of the band-shaped optical image. apparatus.