JP7500960B2 - Transparent tube inspection device and transparent tube inspection method - Google Patents

Description

The present invention relates to a transparent tube inspection device and a transparent tube inspection method.

The manufacturing process for glass tubes used in fluorescent lamps, pharmaceutical containers such as ampoules and vials, and a variety of other applications is as follows. First, a continuous glass tube drawn in a furnace is roughly cut to create the original glass tube. Next, if the tube end of the final product is an open end, it is re-cut at the position that will become that tube end and subjected to a mouth-hardening process (Patent Document 1). Also, if the tube end of the final product is a closed end, it is subjected to a closing process by melting at the position that will become that tube end (Patent Document 2).

A glass tube inspection device has been proposed to inspect glass tube products manufactured through such processes for the presence or absence of abnormalities such as remaining scratches such as cracks caused by cutting, or the presence of cutting debris or other foreign matter (Patent Document 3).

JP 2013-147405 A Patent No. 5872119 Patent No. 3428172

In the conventional glass tube inspection device of Patent Document 3, a large number of cameras are installed to increase the efficiency of the inspection, while from the viewpoint of inspection reliability, the camera and lighting fixture are arranged to face each other on the optical axis of the camera, and a through-lighting configuration is adopted. However, it is desirable for the glass tube inspection device to be able to detect scratches such as cracks and the attachment of foreign matter more reliably. One aspect of the present invention focuses on the above problem, and aims to realize an inspection device for transparent tubes such as glass tubes that can more reliably detect scratches such as cracks and foreign matter.

To solve the above problem, a transparent tube inspection device according to one aspect of the present invention comprises a first camera that captures an image of a first region of a transparent tube, including one end of the transparent tube, a lighting fixture equipped with an illumination unit, and an image processing unit that processes the image captured by the first camera and detects defects in the transparent tube, the illumination unit being disposed behind the first region as viewed from the first camera, and the image processing unit further comprising a configuration that determines whether the brightness of the illumination unit in the image is within a predetermined range.

To solve the above problem, a transparent tube inspection method according to one aspect of the present invention includes the steps of: setting up a first camera that captures an image of a first region of a transparent tube, including one end; and a lighting fixture that is provided with an irradiation unit and that is positioned behind the first region as viewed from the first camera; determining whether the brightness of the irradiation unit in the image captured by the first camera is within a predetermined range; and processing the image to detect defects in the first region of the transparent tube.

The transparent tube inspection device according to one aspect of the present invention and the transparent tube inspection method according to one aspect of the present invention make it possible to realize an inspection device for transparent tubes such as glass tubes that can more reliably detect flaws such as cracks and foreign objects.

1 is a schematic configuration diagram showing a glass tube inspection device according to an embodiment of the present invention, viewed from a horizontal direction perpendicular to the central axis of a glass tube. 1 is a schematic configuration diagram showing a glass tube inspection device according to an embodiment of the present invention, viewed in a direction parallel to the central axis of a glass tube. 1 is a schematic configuration diagram showing a glass tube inspection device according to an embodiment of the present invention, viewed vertically from above. 1 is a schematic cross-sectional view showing a configuration of an illumination device of a glass tube inspection device according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing the configuration of a light control sheet used on an irradiation surface of a lighting fixture of a glass tube inspection device according to an embodiment of the present invention. FIG. FIG. 2 is a block diagram showing the functional configuration of an image processing unit of the glass tube inspection device according to the embodiment of the present invention. FIG. 2 is a diagram showing a glass tube inspection flow by the glass tube inspection device according to the embodiment of the present invention. FIG. 2 is a diagram showing an image captured by a first camera by the glass tube inspection device according to the embodiment of the present invention, and is an example of an image captured of a first tube end formed as an open end. FIG. 2 is a diagram showing an image captured by a first camera by the glass tube inspection device according to the embodiment of the present invention, and is an example of an image captured of a first tube end formed as a closed end. 1 is a diagram for explaining an illumination illuminance inspection using an image captured by a first camera by a glass tube inspection device according to an embodiment of the present invention. FIG. 1A to 1C are diagrams for explaining full length inspection using an image captured by a first camera by a glass tube inspection device according to an embodiment of the present invention. 1A to 1C are diagrams for explaining tube end shape inspection, linear defect inspection, and foreign object (small) inspection using an image captured by a first camera by a glass tube inspection device according to an embodiment of the present invention. 1A to 1C are diagrams for explaining a tube end sealing inspection using an image captured by a first camera by a glass tube inspection device according to an embodiment of the present invention. FIG. 2 is a diagram for explaining inspection of a tube end thick portion using an image captured by a first camera by the glass tube inspection device according to the embodiment of the present invention.

[Embodiment]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The shapes and dimensions (length, width, height, etc.) of the components shown in the drawings in this application do not necessarily accurately reflect the actual shapes and dimensions, and have been appropriately changed for the sake of clarity and simplification of the drawings.

<Overall configuration of glass tube inspection device>
In the glass tube inspection device 1 (transparent tube inspection device) according to this embodiment, a plurality of glass tubes 9 (transparent tubes) to be inspected are arranged horizontally with their respective central axes 9C parallel to one another. Then, in the glass tube inspection device 1, inspections are carried out in parallel on these plurality of glass tubes 9. As a specific example of this embodiment, a case is shown in which the number of glass tubes 9 arranged in the glass tube inspection device 1 is 12. However, this is merely an example, and the application of the present invention is not limited to this number.

Figures 1 to 3 are schematic diagrams showing the configuration of the glass tube inspection device 1. Figure 1 is a view from a horizontal direction perpendicular to the central axis 9C of the glass tube 9. Figure 2 is a view from a direction parallel to the central axis 9C of the glass tube 9. Figure 3 is a view from above the glass tube inspection device 1 in a vertical direction. Note that in each of Figures 1 to 3, components are omitted as appropriate to make the structure easier to understand.

As shown in FIG. 3, in the glass tube inspection device 1, when inspection is performed, a plurality of glass tubes 9 are arranged in parallel such that the first tube end 9X, which is one end of the glass tube 9, and the second tube end 9Y, which is the other end, are approximately aligned in the position in the direction of the central axis 9C. As shown in FIG. 1 to FIG. 3, the glass tube inspection device 1 includes an image processing unit 10, a first camera 20A, a first lighting fixture 30A (lighting fixture), a second camera 20B, a second lighting fixture 30B, and a rotating unit 40.

<Camera and lighting arrangement>
A plurality of first cameras 20A are provided corresponding to the respective glass tubes 9 arranged in parallel, and in the specific example of this embodiment, 12 cameras are provided. As shown in Fig. 1, the first camera 20A photographs a first region 9A near an end of the glass tube 9 including the first tube end 9X (one end) from above. The first lighting device 30A has an upwardly facing irradiation surface 31 (irradiation section) that is a flat surface, and illuminates the first region 9A in a transmissive manner when photographing with the first camera 20A.

The detailed arrangement of the first camera 20A, the first lighting fixture 30A, and the glass tube 9 is as follows. The first camera 20A photographs the first region 9A from a position directly above the first region 9A, tilted slightly outward in the direction of the central axis 9C of the glass tube 9. In other words, the angle θ between the direction from the first tube end 9X (one end) toward the inside of the glass tube 9 along the central axis 9C of the glass tube 9 and the photographing direction 21A of the first camera 20A is slightly smaller than 90°. Preferably, the angle θ is in the range of 75°±5°.

When viewed from the first camera 20A, the first lighting device 30A is behind the first region 9A of the glass tube 9, and is installed so that its irradiation surface 31 is located directly below the first region 9A. The irradiation surface 31 of the first lighting device 30A, which is a flat surface, faces the first camera 20A directly. In other words, the shooting direction 21A of the first camera 20A is perpendicular to the irradiation surface 31. This is to ensure that the brightness of the irradiation surface 31 is uniform in the captured image 22A described below.

A plurality of second cameras 20B are provided to correspond to each of the glass tubes 9 arranged in parallel, and in a specific example of this embodiment, 12 cameras are provided. As shown in FIG. 1, the second camera 20B photographs the second region 9B near the end of the glass tube 9, including the second tube end 9Y (the other end), from above. The second lighting device 30B has an upwardly facing irradiation surface 31 (irradiation section) that is a flat surface, and illuminates the second region 9B in a transmitted manner when photographing with the second camera 20B. The details of the positional relationship between the second camera 20B, the second lighting device 30B, and the glass tube 9 are as follows.

The second camera 20B photographs the second region 9B from a position directly above the second region 9B, at a position slightly tilted outward in the direction of the central axis 9C of the glass tube 9. In other words, the angle between the direction from the second tube end 9Y toward the inside of the glass tube 9 along the central axis 9C of the glass tube 9 and the photographing direction 21B of the second camera 20B is slightly smaller than 90°. Preferably, the angle is in the range of 75°±5°.

The second lighting device 30B is installed behind the second region 9B of the glass tube 9 when viewed from the second camera 20B, with its irradiation surface 31 located directly below the second region 9B. The irradiation surface 31 of the second lighting device 30B, which is a flat surface, faces the second camera 20B directly. In other words, the shooting direction 21B of the second camera 20B is perpendicular to the irradiation surface 31. This is to ensure that the brightness of the irradiation surface 31 is uniform in the captured image 22B described below.

<Configuration for supporting glass tube>
Next, a method of supporting the glass tubes 9 in the glass tube inspection device 1 will be described. Focusing on one glass tube 9, the glass tube 9 is supported by a pair of rollers 41 provided closer to the first tube end 9X from the center in the direction of the central axis 9C, and a pair of rollers 42 provided closer to the second tube end 9Y. Each roller in the pair (roller 41 or roller 42) is offset in a direction perpendicular to the central axis 9C of the glass tube 9, and is arranged so as to partially overlap when viewed in the direction of the central axis 9C of the glass tube 9.

One side of each of the 12 glass tubes 9 is supported by 13 rollers 41 arranged from the center of each glass tube 9 in the direction of the central axis 9C toward the first tube end 9X. The 13 rollers 41 are arranged in two rows, staggered so as not to interfere with each other. Each row is aligned along a direction perpendicular to the central axis 9C of the glass tube 9 in a horizontal plane.

The other side of each of the 12 glass tubes 9 is supported by 13 rollers 42 arranged from the center of each glass tube 9 in the direction of the central axis 9C toward the second tube end 9Y. The 13 rollers 42 are also arranged in two rows, staggered so as not to interfere with each other. Each row is aligned along a direction perpendicular to the central axis 9C of the glass tube 9 in a horizontal plane. Rollers 41 and 42 are of the same material, shape, and size.

These rollers 41 and 42 make up the rotating section 40. All of the rollers 41 and 42 rotate in the same direction. In FIG. 2, all of the rollers 41 and 42 rotate counterclockwise. As a result, the glass tubes 9 supported by the rollers 41 and 42 are all rotated clockwise around their central axis 9C, as shown by the arrow in FIG. 2.

Although not shown, the glass tube inspection device 1 is appropriately provided with a transport mechanism for setting multiple glass tubes 9 on a rotating section 40 consisting of multiple rollers 41 and 42, and for removing them after the inspection is completed.

<Lighting fixture configuration>
The following description will be given of the first lighting fixture 30A, but the second lighting fixture 30B has a similar structure. Fig. 4 is a cross-sectional view showing the internal structure of the first lighting fixture 30A. A substrate 32 is disposed near the bottom inside the first lighting fixture 30A. A number of light sources 33 are mounted on the upper surface of the substrate 32. The light sources 33 are preferably LEDs (Light Emitting Diodes).

Moreover, it is more preferable that each light source 33 is not a white LED, but a monochromatic LED, for example, a blue LED. Monochromatic LEDs such as blue LEDs have a narrower emission spectrum distribution than white LEDs. Among various light sources, monochromatic LEDs have relatively excellent monochromaticity. By using monochromatic LEDs, it becomes easier to obtain contrast due to defects in the images captured by the first camera 20A and the second camera 20B. In addition, it becomes easier to identify the shape and outline of the glass tube 9.

Two light control films (light control film 34, light control film 35) are arranged on top of each other on the irradiation surface 31 (irradiation section) on the top surface of the first lighting device 30A. The light control film has the function of suppressing the transmission of light rays that are inclined in one direction (restriction direction) within the film plane among the light that is about to pass through. Figure 5 is a schematic diagram for explaining the structure of the light control film 34. The light control film 34 (Light Control film) has a four-layer structure consisting of a non-glare layer 341 (anti-glare layer), a base layer 342, a light restricting layer 343, and a base layer 344.

The non-glare layer 341 is preferably disposed on the light source 33 side. The light restricting layer 343 is a layer having a louver structure. The light restricting layer 343 is composed of a number of louvers 345 that do not transmit light, and a number of transparent portions 346 sandwiched between the louvers 345. The louvers 345 are disposed close to each other and parallel to each other so as to extend in a direction perpendicular to the restricting direction within the plane of the light control film 34.

Along the restriction direction (left-right direction in FIG. 5), louvers 345 and transparent portions 346 are arranged alternately and repeatedly within the light restriction layer 343. Of the light rays attempting to pass through the light control film 34, light ray L1 inclined in the repeating direction of the louvers 345 is absorbed by the louvers 345 and is difficult to transmit. On the other hand, light ray L2 perpendicular to the repeating direction of the louvers 345 (restriction direction of the light control film 34) is not impeded by the louvers 345 and transmits. As a result, the transmission of light rays inclined in the light restriction direction of the light control film 34 is restricted.

The light control film 35 has a similar structure to the light control film 34. On the irradiation surface 31 of the first lighting device 30A, these films are arranged overlapping each other so that the limiting direction of the light control film 34 and the limiting direction of the light control film 35 are perpendicular to each other. This limits the transmission of light rays other than those emitted in a direction approximately perpendicular to the irradiation surface 31. As a result, within the first lighting device 30A, of the light emitted in various directions from the light source 33, only the light emitted in a direction approximately perpendicular to the irradiation surface 31 is extracted from the irradiation surface 31, and the light emission angle from the irradiation surface 31 is shifted to a direction perpendicular to the irradiation surface 31.

In this way, in the first lighting device 30A, the light emission from the irradiation unit 31 in a direction inclined from a direction perpendicular to the irradiation unit 31 is reduced, making it easier to obtain contrast due to defects in the images captured by the first camera 20A and the second camera 20B. When defects such as cracks in the glass tube 9 are minute, contrast changes due to the defect appear only in light rays near a specific direction. Therefore, if an image is formed with a mixture of light rays from various directions, it becomes difficult to obtain contrast due to minute defects. In addition, the shape and contour of the glass tube 9 can be easily identified.

<Configuration of image processing unit>
6 is a block diagram showing the functional configuration of the image processing unit 10. A first camera 20A and a second camera 20B, which respectively capture images of a first region 9A and a second region 9B of a certain glass tube 9, are connected to the same image processing unit 10. In a specific example of this embodiment, one image processing unit 10 corresponds to two glass tubes 9.

In other words, two sets of first cameras 20A and second cameras 20B are connected to one image processing unit 10. Therefore, in a specific example of this embodiment, the glass tube inspection device 1 is equipped with six image processing units 10 for twelve glass tubes 9. However, these numbers are examples, and the number of corresponding glass tubes 9 can be changed appropriately depending on the processing performance of the image processing units 10 relative to the inspection speed.

The image processing unit 10 is provided with a camera interface section 11, a camera control section 12, an image acquisition section 13, an integrated control section 14, an image processing section 15, an instruction section 16, a display section 17, a recording section 18, and a communication section 19. The camera interface section 11 is a communication interface for connecting the first camera 20A and the second camera 20B. The camera control section 12 is a functional block that sets the shooting conditions of the connected first camera 20A and the second camera 20B and controls the camera, including shooting, through the camera interface section 11.

The image acquisition unit 13 is a functional block that imports images captured by the connected first camera 20A and second camera 20B through the camera interface unit 11. The integrated control unit 14 is a control block that controls each functional block in the image processing unit 10, performs various information processing, and coordinates the execution of required operations by the image processing unit 10. The image processing unit 15 is a functional block that executes the required image processing instructed by the integrated control unit 14 on the images acquired by the image acquisition unit 13.

The instruction unit 16 is a functional block that accepts instructions, such as commands from a user for the image processing unit 10 and settings of operating conditions. The instruction unit 16 itself may have a user interface that accepts instructions from the user. An appropriate input device may also be connected to the instruction unit 16. The display unit 17 is a functional block that notifies the user of various types of information. The display unit 17 itself may have a user interface that notifies the user of information. An appropriate output device may also be connected to the display unit 17.

In FIG. 6, an example is presented in which a display 171 is connected to the display unit 17, but the display 171 may be a touch panel display, and the instruction unit 16 may receive input from the user via the touch panel. Other known devices such as a keyboard or a mouse may be used as input devices.

The recording unit 18 is a memory that holds various information. The information held by the recording unit 18 may include information on the inspection items and inspection conditions set by user instructions, data on the inspection results, and execution programs for realizing each part as a functional block of the image processing unit 10. The communication unit 19 is an interface that enables the image processing unit 10 to communicate with external devices. Examples of connected external devices may include a higher-level system that controls the image processing unit 10 and a database that stores the inspection results.

<Inspection process example>
Fig. 7 shows an example of an inspection flow for inspecting one end of a specific glass tube 9, which is performed by the glass tube inspection device 1. The glass tube inspection device 1 increases its processing capacity by performing the inspection flow shown in Fig. 7 in parallel for the first area 9A and the second area 9B of each of the 12 glass tubes 9. At this time, the first lighting device 30A and the second lighting device 30B are turned on.

At the same time, the rotating unit 40 rotates the glass tube 9 at a predetermined constant speed. The glass tube inspection device 1 executes the inspection flow shown in FIG. 7 multiple times while the glass tube 9 rotates once. For minute defects such as minute cracks and minute foreign bodies, contrast cannot be obtained depending on the observation direction. Therefore, in order not to overlook defects, the inspection flow is executed multiple times from different angles in this manner for a specific glass tube 9. It is preferable that the number of times per rotation of the inspection flow in FIG. 7 is at least 8 times or more, and more preferably 16 times or more.

Next, each step of the inspection flow in FIG. 7 will be described. Below, the image 22A of the first area 9A captured by the first camera 20A will be described, but the image 22B (not shown) of the second area 9B captured by the second camera 20B is also processed in the same manner. The integrated control unit 14 controls each functional block to cause the image processing unit 10 to perform the operation of each of the following steps.

In addition, as appropriate, under the control of the integrated control unit 14, the display unit 17 displays the captured image 22A and the inspection results on the display 171, and the recording unit 18 records the inspection results. At each step, the image processing unit 15 performs the judgment described below by appropriately combining various image processing methods and judgment functions that are provided in industrial image processing devices.

Step S1 (photographing): The camera control unit 12 causes the connected first camera 20A to perform photographing via the camera interface unit 11. The first camera 20A photographs the first area 9A near the end including the first tube end 9X (one end) of the glass tube 9. The image acquisition unit 13 acquires the photographed image 22A by the connected first camera 20A via the camera interface unit 11.

Figure 8 is a diagram showing a schematic example of a captured image 22A. The captured image 22A shows the first region 9A of the glass tube 9 and the illuminated surface 31 of the first lighting device 30A in the background. As described above, the first camera 20A captures the vicinity of the first tube end 9X from a position slightly tilted outward in the direction of the central axis 9C of the glass tube 9 from a direction perpendicular to the central axis 9C. Therefore, the end face of the first tube end 9X is captured in the captured image 22A. Figure 8 is an example of a capture in which the first tube end 9X is the open end 9O. Thus, in the captured image 22A, the opening at the first tube end 9X appears bright, and the thick part (glass part) appears dark.

Figure 9 is a schematic diagram of another example of the captured image 22A. Figure 9 is an example of a capture in which the first tube end 9X is a closed end 9S. In this case, in the captured image 22A, the end face of the first tube end 9X is entirely made of glass and appears dark. Note that the fine lines drawn on the glass tube 9 in the captured images 22A of Figures 8 and 9 are schematic representations of shadows (darkness in the image) (the same applies to Figures 10 to 14).

Step S2 (checking for the presence or absence of glass tube): The image processing unit 15 judges whether the glass tube 9 is present in the captured image 22A. If the deviation in brightness within the entire captured image 22A is less than a predetermined threshold, the image processing unit 15 stops the inspection, determining that the glass tube 9 is not present. This applies when the glass tube 9 is not placed in the specified position due to a transport error and the entire captured image 22A is the illuminated surface 31, or when the first lighting device 30A is not lit and the entire captured image 22A is dark. The image processing unit 15 makes an OK judgment if the deviation in brightness is equal to or greater than the threshold.

Step S3 (illumination illuminance inspection): The image processing unit 15 judges whether the brightness of the area in the captured image 22A where the irradiated surface 31 is directly observed is within a predetermined range. In FIG. 10, this area is shown as area Pi. The image processing unit 15 makes an NG judgment if the average brightness of area Pi is not within the predetermined range. This applies to cases where the illuminance of the first lighting device 30A has changed due to deterioration over time or a sudden event such as a malfunction. The image processing unit 15 makes an OK judgment if the average brightness of area Pi is within the predetermined range.

Step S4 (total length inspection): The image processing unit 15 detects the end position Pe of the glass tube 9 in the captured image 22A and obtains the length Pg (total length) of the glass tube 9 in the captured image 22A. Figure 11 shows the end position Pe and length Pg of the glass tube 9 in the captured image 22A.

The integrated control unit 14 further obtains the inspection results for the first region 9A and the second region 9B of a particular glass tube 9 from the image processing unit 15. The integrated control unit 14 calculates a value L by adding the length Pg for the first region 9A to the length Pg for the second region 9B. If the calculated value L is not within a predetermined range, the integrated control unit 14 determines that the total length of the glass tube 9 is not within the specified range and makes an NG judgment, but if it is within the range, makes an OK judgment.

Step S5 (positioning): The image processing unit 15 determines the position of the glass tube 9 in the captured image 22A. This is because the overall length of the glass tube 9 may deviate from the specified range, and because the glass tube 9 may shift in the direction of the central axis 9C when it is placed at the inspection position by transportation. The position of the glass tube 9 determined here is used in the following steps S6 to S11.

Step S6 (Tube end shape inspection): The image processing unit 15 assumes an ellipse that corresponds to the outer edge of the first tube end 9X in the captured image 22A. The ellipse is assumed from the product shape of the glass tube 9. The image processing unit 15 then compares the ellipse with the outer edge of the first tube end 9X that was actually captured (which appears darker than the surrounding area). If there are burrs on the outer edge, chips Pc such as the example shown in Figure 12, or other deformations, the comparison results in a mismatch. If there is a mismatch, the image processing unit 15 makes an NG judgment, and if there is a match, an OK judgment.

Step S7 (Tube End Sealing Inspection): This step is an inspection item for the closed end, and is not performed and is skipped if the tube end is an open end. Figure 13 shows a photographed image 22A in which the first tube end 9X is not sufficiently blocked at the closed end 9S, resulting in a hole Ph. As can be seen by comparing with Figure 9, which shows the photographed image 22A of a normal closed end 9S, the hole Ph is observed as an area brighter than the surrounding area on the end face of the first tube end 9X.

The image processor 15 judges whether or not there is a hole on the end face of the first tube end 9X (within the ellipse corresponding to the outer edge) in the captured image 22A. If there is a bright area within the ellipse that is different from the surrounding area, the image processor 15 judges it as NG, and if there is not, it judges it as OK.

Step S8 (Linear defect inspection): The image processing unit 15 judges whether or not the glass tube 9 in the captured image 22A has a linear defect Pd, an example of which is shown in FIG. 12. If the image processing unit 15 finds a linear defect Pd, it makes an NG judgment, and if not, it makes an OK judgment.

Step S9 (inspection for small foreign bodies): The image processing unit 15 judges whether the glass tube 9 in the captured image 22A has any defects other than linear defects, such as foreign bodies Pf and stains Ps, examples of which are shown in FIG. 12. In this case, the image processing unit 15 performs size filtering to extract only small defects. If a small defect is extracted, the image processing unit 15 makes an NG judgment, and if no small defect is extracted, it makes an OK judgment.

Step S10 (Large foreign body inspection): The image processing unit 15 judges whether or not there is a non-linear defect such as a foreign body or dirt in the glass tube 9 in the captured image 22A. In this case, the image processing unit 15 performs size filtering to extract only large defects that were not subject to detection in step S9. If a large defect is extracted, the image processing unit 15 makes an NG judgment, and if not, it makes an OK judgment.

Step S11 (Tube end thick section inspection): This step is an inspection item for the open end, and is not performed and is skipped if the tube end is a closed end. The image processing unit 15 evaluates the wall thickness at the first tube end 9X by utilizing the fact that in the photographed image 22A of the open end 9O, the opening at the end face is displayed bright and the thick section (glass part) is displayed dark. Figure 14 shows the wall thickness Pt in the photographed image 22A detected by the image processing unit 15. The image processing unit 15 judges the detected wall thickness as NG if it is not within a specified range, and judges it as OK if it is within the specified range.

When the above inspection flow is executed multiple times during one rotation of the glass tube 9, the integrated control unit 14 performs an overall judgment on a specific glass tube 9 based on the multiple inspection results for one rotation of that glass tube. If there is an NG judgment in any of the inspection results for the first region 9A, the inspection results for the second region 9B, and the full length inspection results for each shot, the overall judgment is an NG judgment. In all other cases, the overall judgment is an OK judgment. Note that when the overall judgment is an NG judgment, the glass tube 9 may be discarded.

<Action and Effects>
The following describes the actions and effects of the glass tube inspection device 1 according to this embodiment. In the following, the image 22A of the first region 9A captured by the first camera 20A will be described, but the same applies to the image 22B of the second region 9B captured by the second camera 20B.

According to the glass tube inspection device 1 of this embodiment, when performing the detection of various defects, the first lighting device 30A is arranged as a transmissive lighting device. The illuminated surface 31 is captured in the same captured image 22A together with the first region 9A near the end of the glass tube 9. The brightness of the illuminated surface 31 is checked in the captured image 22A itself used in the inspection for defect detection (each inspection item from step S6 to step S11).

Of defects such as cracks, scratches, foreign matter (cutting debris and the like) and dirt on the glass surface, foreign matter and dirt inside the glass, voids in the glass, and holes at closed ends, particularly small defects are difficult to contrast in the captured image 22A. Therefore, unless the shooting conditions of the first camera 20A and the illuminance of the lighting are kept in a matched state, it becomes difficult to detect such small defects from the captured image 22A.

In the glass tube inspection device 1, the brightness of the irradiated surface 31 is checked using the captured image 22A itself, and if the illuminance of the lighting is not appropriate, an NG judgment is presented in the lighting illuminance inspection (step S3). This prevents minute defects from being overlooked due to conditions that are not met due to changes over time in the state of the first lighting device 30A or the first camera 20A or sudden changes in the state. In this case, since the lighting illuminance is checked using the captured inspection image 22A itself, no dedicated equipment is required for the check. This also makes it possible to respond to sudden changes in the state, such as a malfunction of the lighting device 30A.

In the glass tube inspection device 1 of this embodiment, the light emission angle from the irradiation surface 31 of the first lighting device 30A may be configured to be biased toward a direction perpendicular to the irradiation surface 31, compared to the various light emission angles from the light source 33 inside the device. As a result, only light from limited directions illuminates minute defects present in the glass tube 9, and light from various directions is prevented from mixing in the captured image 22A, resulting in a lack of contrast. Therefore, by further rotating the glass tube 9 and capturing images from various directions, even minute defects can be reliably detected.

On the other hand, when using the first lighting fixture 30A with such a limited light emission angle, it becomes necessary to precisely adjust the output of the first lighting fixture 30A. In the glass tube inspection device 1, the brightness of the irradiated surface 31 can be checked using the captured image 22A of the first camera 20A. Thus, the user can easily make the above adjustments while referring to the results of the illumination illuminance inspection displayed on the display 171. Furthermore, even if the glass tube inspection device 1 is equipped with multiple first cameras 20A and second cameras 20B, adjustments can be made.

The glass tube inspection device 1 of this embodiment may be configured to capture an image of the first region 9A near the first tube end 9X from slightly outside the direction of the central axis 9C, particularly at the above-mentioned specific angle θ. Therefore, the end face of the first tube end 9X is captured in the captured image 22A in a state in which its shape can be recognized. Therefore, in a series of inspections using the specific captured image 22A, inspection items related to the end face, such as tube end shape inspection, tube end sealing inspection in the case of a closed end, and tube end wall thickness inspection in the case of an open end, can also be performed, enabling efficient inspection. In addition, in order to perform these inspection items, there is no need to provide an inspection device in the inspection process that is separate from the inspection device that performs inspection items such as linear defect inspection or foreign object inspection.

The glass tube inspection device 1 of this embodiment may be equipped with a second camera 20B that images the second tube end 9Y (the other end) in addition to the first camera 20A that images the first tube end 9X (one end). This allows inspection of both ends of the glass tube 9 to be performed in parallel, enabling efficient inspection. Furthermore, the entire length of the glass tube 9 can also be inspected from the image 22A captured by the first camera 20A and the image 22B captured by the second camera 20B, enabling efficient inspection.

＜Other＞
If the result of the illumination illuminance inspection by the image processing unit 10 is NG, the glass tube inspection device 1 may be configured to notify a warning to the user. Alternatively, the image processing unit 10 may be configured to control the lighting device 30A to adjust the illuminance on the irradiation surface 31 based on the brightness value of the irradiation surface 31 in the captured image 22A detected by the image processing unit 10.

The above has been a specific explanation of the case where the transparent tube to be inspected is a glass tube. However, the material of the transparent tube is not limited to glass, and it may be ceramic, inorganic crystal, plastic, etc., as long as it is transparent enough to allow for through-viewing when formed into a tubular shape.

[Software implementation example]
The functional blocks of the image processing unit 10 (in particular, the camera interface unit 11, the camera control unit 12, the image acquisition unit 13, the integrated control unit 14, the image processing unit 15, the instruction unit 16, the display unit 17, and the communication unit 19) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or by software.

In the latter case, the image processing unit 10 includes a computer that executes instructions of a program, which is software that realizes each function. This computer includes, for example, one or more processors, and a computer-readable recording medium that stores the program. The object of the present invention is achieved by having the processor in the computer read and execute the program from the recording medium.

The processor may be, for example, a CPU (Central Processing Unit). The recording medium may be a "non-transitory tangible medium" such as a ROM (Read Only Memory), as well as a tape, a disk, a card, a semiconductor memory, or a programmable logic circuit. The device may further include a RAM (Random Access Memory) for expanding the program.

The program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or broadcast waves). One aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

〔summary〕
A transparent tube inspection device according to aspect 1 of the present invention comprises a first camera that images a first area of a transparent tube including one end, a lighting fixture provided with an illumination unit, and an image processing unit that processes the image captured by the first camera and detects defects in the transparent tube, wherein the illumination unit is positioned behind the first area as viewed from the first camera, and the image processing unit is further configured to determine whether the brightness of the illumination unit in the image is within a predetermined range.

The transparent pipe inspection device according to aspect 2 of the present invention may be configured in the above aspect 1 such that the irradiating unit is a flat surface. The transparent pipe inspection device according to aspect 3 of the present invention may be configured in the above aspect 2 such that the lighting fixture reduces light emission from the irradiating unit in a direction inclined from a direction perpendicular to the irradiating unit. The transparent pipe inspection device according to aspect 4 of the present invention may be configured in the above aspect 2 or 3 such that the irradiating unit faces the first camera directly.

The transparent tube inspection device according to aspect 5 of the present invention may be configured in any one of aspects 1 to 4 above such that the angle between the direction from the one end toward the inside of the transparent tube along the central axis of the transparent tube and the shooting direction of the first camera is within the range of 75°±5°. The transparent tube inspection device according to aspect 6 of the present invention may be configured in aspect 5 above such that the image processing unit determines the presence or absence of a hole at the one end from the image.

The transparent tube inspection device according to aspect 7 of the present invention may be configured in the above aspect 5 such that the image processing unit determines the wall thickness of the transparent tube at the one end from the image. The transparent tube inspection device according to aspect 8 of the present invention may be configured in any one of the above aspects 1 to 7 such that it further includes a rotating unit that rotates the transparent tube around a central axis, and the first camera takes images multiple times for the image processing unit to detect defects while the transparent tube is rotated once by the rotating unit.

The transparent tube inspection device according to aspect 9 of the present invention may be configured in the above aspect 8 such that the image processing unit determines whether or not the brightness of the irradiated portion is within a predetermined range in each of the images captured multiple times. The transparent tube inspection device according to aspect 10 of the present invention may be configured in any of the above aspects 1 to 9 such that it further includes a second camera that captures an image of a second region of the transparent tube on the opposite side to the one end, including the other end.

The transparent tube inspection device according to aspect 11 of the present invention may be configured in the above aspect 10 such that the image processing unit detects the position of the one end in an image captured by the first camera and the position of the other end in an image captured by the second camera to determine the length of the transparent tube. The transparent tube inspection device according to aspect 12 of the present invention may be configured in any one of the above aspects 1 to 11 such that the device includes a plurality of the first cameras and performs inspections of a plurality of transparent tubes in parallel.

The transparent tube inspection method according to aspect 13 of the present invention includes the steps of: setting up a first camera that captures an image of a first region of a transparent tube, including one end; and a lighting fixture that is provided with an irradiation unit and that is positioned behind the first region as viewed from the first camera; determining whether the brightness of the irradiation unit in the image captured by the first camera is within a predetermined range; and processing the image to detect defects in the first region of the transparent tube.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the specification. Furthermore, new technical features can be formed by combining the technical means disclosed in the specification.

1. Glass tube inspection equipment (transparent tube inspection equipment)
REFERENCE SIGNS LIST 10 Image processing unit 11 Camera interface section 12 Camera control section 13 Image acquisition section 14 Integrated control section 15 Image processing section 16 Instruction section 17 Display section 18 Recording section 19 Communication section 171 Display 20A First camera 22A Captured image (image)
20B Second camera 22B Photographed image 30A First lighting device (lighting device)
30B Second lighting device 31 Irradiation surface (irradiation part)
32 Substrate 33 Light source 34, 35 Light control film 341 Non-glare layer 342, 344 Base layer 343 Light limiting layer 345 Louver 346 Transparent part 40 Rotating part 41, 42 Roller 9 Glass tube (transparent tube)
9A First region 9B Second region 9C Central axis 9X First tube end (one end)
9Y Second pipe end (other end)
9O Open end 9S Closed end

Claims (13)

a first camera for capturing an image of a first region of the transparent tube, the first region including one end of the transparent tube;
A lighting fixture provided with an irradiation unit;
an image processing unit that processes an image including the first region of the transparent tube captured by the first camera and detects defects in the transparent tube;
The illumination unit is disposed behind the first area as viewed from the first camera,
the image processing unit, when detecting a defect in the transparent tube as a result of processing the image, determines a result of inspection of the transparent tube based on the image as being NG;
The image processing unit further determines whether the brightness of the irradiated portion in the image is within a predetermined range;
If the result is negative, the result of the inspection of the transparent tube based on the image is judged as NG, regardless of whether a defect in the transparent tube is detected or not . The transparent tube inspection device according to claim 1, characterized in that the irradiation unit is a flat surface. 3. The transparent tube inspection device according to claim 2, wherein the lighting device reduces light emission from the irradiation unit in a direction inclined from a direction perpendicular to the irradiation unit. The transparent tube inspection device according to claim 2 or 3, characterized in that the irradiation unit faces directly toward the first camera. The transparent tube inspection device according to any one of claims 1 to 4, characterized in that the angle between the direction from the one end toward the inside of the transparent tube along the central axis of the transparent tube and the shooting direction of the first camera is within the range of 75°±5°. The transparent tube inspection device according to claim 5, characterized in that the image processing unit determines the presence or absence of a hole at the one end from the image. The transparent tube inspection device according to claim 5, characterized in that the image processing unit determines the wall thickness of the transparent tube at the one end from the image. A rotating unit that rotates the transparent tube around a central axis is further provided,
The transparent tube inspection device according to any one of claims 1 to 7, characterized in that the first camera takes images multiple times for the image processing unit to detect defects while the transparent tube is rotated once by the rotating part. The transparent tube inspection device according to claim 8, characterized in that the image processing unit determines whether the brightness of the irradiated portion is within a predetermined range for each of the images captured multiple times. The transparent tube inspection device according to any one of claims 1 to 9, further comprising a second camera for photographing a second area of the transparent tube opposite the one end, the second area including the other end. The transparent tube inspection device according to claim 10, characterized in that the image processing unit detects the position of the one end in the image captured by the first camera and the position of the other end in the image captured by the second camera to determine the length of the transparent tube. The transparent tube inspection device according to any one of claims 1 to 11, characterized in that it is provided with a plurality of the first cameras and performs inspections of a plurality of transparent tubes in parallel. a first camera for capturing an image of a first region of the transparent tube, the first region including one end of the transparent tube;
a lighting fixture having an illumination unit disposed behind the first area as viewed from the first camera;
a first step of processing an image captured by the first camera, the image including the first region of the transparent tube, to detect defects in the first region of the transparent tube;
a second step of determining whether or not the brightness of the irradiated portion in the image is within a predetermined range;
a third step of judging the result of the inspection of the transparent tube based on the image as NG if a defect is detected in the first region of the transparent tube in the first step, and judging the result of the inspection of the transparent tube based on the image as NG if a defect is detected in the second step, regardless of whether or not the defect was detected in the first step .

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