DEVICE AND METHOD FOR INSPECTING CONTAINERS

Description

[0001] The invention is based on a device and a method for inspecting containers according to the preamble of the independent claims. A generic device is known from US 7,560,720 B2. There, containers are fed to different transport wheels via a feed and a conveyor screw. Finally, the containers to be inspected enter a carousel, in the center of which several cameras are arranged. Reflectors are suitably arranged so that the cameras can inspect the containers. Alternatively, two cameras can be provided to inspect different areas of a single container. WO 94 / 08230 A1 discloses a method for inspecting transparent containers and the liquids contained therein. Light sources radiate through the container transversely or parallel to the longitudinal axis of the container. Prior art of this type is also shown in JP H0792108 A.

[0002] The invention is based on the object of further improving the system.

[0003] This problem is solved by the features of the independent claims. Advantages of the invention

[0004] The device and method according to the invention for inspecting containers according to the features of the independent claims have the advantage of increasing the accuracy of the inspection. Firstly, the inspection duration is extended. Furthermore, the error rate caused by illumination interference between neighboring systems is reduced by synchronizing the phase change of neighboring inspection systems. By using different types of illumination, foreign particles can be detected even more reliably. Thus, according to the invention, an additional light source is added, which reliably detects, in particular, reflective foreign particles and is referred to as reflected light.Because the reflected light is arranged in such a way that its beam path hits the container at a different angle than the beam path of the transmitted light, the foreign particles can be detected with a higher probability based on the reflections caused in this way. According to the invention, at least one partial image comprising the surface of a first container and a further partial image comprising the surface of a second container are extracted from at least one image recorded by the camera at a specific time. This makes it possible to create image sequences for two containers with just one camera. The partial images can be assigned to the image sequences using image processing software, for example in conjunction with the container contour or based on known movement sequences of the container.

[0005] In a practical development, it is provided that the reflected light and the transmitted light are switched on at different times, preferably alternately. This can reduce mutual interference, which further increases the accuracy of the device. Particularly preferably, the lighting or the camera of different inspection modules can be switched on at different times. This can reduce interference caused, for example, by reflections on the device. It could happen, for example, that light from one station unintentionally hits the camera sensor of another station, either directly or through reflections on various machine surfaces, and thus impairs the image of the other stations. This is avoided.For example, the image acquisition of the individual stations that could potentially influence each other is synchronized in strobe mode so that the images of these stations are always recorded with a time delay. This eliminates any interference without, for example, having to use mechanical light shielding for each individual station. According to the invention, the reflected light and the transmitted light are configured so that at least two containers can be illuminated simultaneously. The inspection resolution can be doubled, for example, from 50 µm to 25 µm.

[0006] In a practical further development, the container holder and / or the rotating means are designed such that the container is set in rotation before inspection by the camera and is decelerated at the time of inspection. This sets any foreign particles in the product in motion, which can then be more reliably detected in both transmitted and reflected light.

[0007] In a suitable further development, the angle of the transmitted light is essentially 90° and / or the angle of the reflected light is in a range of 25° to 50°. In these angle ranges, particularly reliable detection of foreign particles is possible with different types of illumination.

[0008] Particularly preferably, the container holder is designed to be movable relative to the camera and / or a reflector. In an expedient development, at least one additional wheel is provided for feeding or removing at least one container to or from the container holder. This allows inspections to be carried out at high speed.

[0009] Further useful developments arise from further dependent claims and the description. drawing

[0010] An embodiment of the device and method for inspecting containers is shown in the drawing and is described in more detail below.

[0011] They show: The Figure 1 a perspective view of the overall device in which the device is used for inspection, the Figure 2 a schematic side view of the device during an inspection in transmitted light, the Figure 3a schematic side view of the device during an inspection in reflected light and the Figure 4 a schematic representation of the different steps in the inspection.

[0012] In Figure 1a perspective view of an overall device 1 is shown, which comprises a device 10 for inspecting containers 12. The overall device 1 comprises at least one feed 14, via which the containers 12 to be inspected are fed. The feed 14 is, for example, a feed belt that continuously brings sufficient containers 12 into the detection range of a first wheel 22. The containers 12 can, for example, be pharmaceutical containers such as ampoules, vials, bottles, cartridges or syringes. In principle, however, other containers 12 are also possible. The containers 12 each reach a first wheel 22, which, as a transport wheel, receives the containers 12 fed from the feed 14 on the outside of the wheel 22 and feeds them to further stations or transport wheels. A pre-inspection 2 can optionally be carried out in the first transport wheel 22 at the same time.For this purpose, for example, in addition to at least one lighting system, a camera is arranged stationary above the containers 12 to be inspected and performs suitable, for example, optical, inspections. Only containers 12 found to be acceptable during the preliminary inspection 2 are transferred to a third wheel 24. Otherwise, they can be discharged at this point via a second wheel 23 into a first storage area 31.

[0013] The first wheel 22 rotates continuously and transfers the removed containers 12 via the further wheel 24 to the device 10 for inspecting containers 12. Between the pre-inspection 2 and the device 10 for inspecting containers 12, at least one further inspection module 3 could be provided on the third wheel 24. This inspection module 3 could, for example, perform a so-called cosmetic inspection of the container 12. This further inspection module 3 could also be based on optical principles using lighting and a camera, for example. Further inspections are possible as needed.

[0014] The device 10 is designed, for example, as an inspection carousel. The device 10 is essentially cylindrical and rotates clockwise in the exemplary embodiment. In the device 10, the inspection of the supplied containers 12 takes place using a specific lighting 18, 19, 20 and one or more cameras 15, which is described in the following. Figures 2 to 4will be explained in more detail below. The device 10 moves the containers 12 clockwise from the detection range of a first illumination 18, 19, 20 into the detection range of an optional additional illumination 18', 19', 20'. Here, a verification of the previous inspection sequence can be carried out. The device 10 comprises a rotating inspection table which is disc-shaped and on which the containers 12 are held. In the center of the device 10 there is / are at least one camera 15 and / or at least one reflector 11 which is / are arranged stationary opposite the inspection table.

[0015] The inspected containers 12 are fed by the device 10 via further wheels or transport wheels (not specifically designated) to different storage areas 31 - 35 depending on the detected condition of the container 12.

[0016] In Figure 2The device 10 for inspecting containers 12 is shown in more detail. The container 12 to be inspected is located in a container holder 21, preferably a turntable, wheel, or star wheel. The container holder 21 mechanically receives containers 12 as part of a transport process. After the optical inspection has been completed, the container holder 21 continues to move or rotate, so that the next container 12 to be inspected enters the detection range of a camera 15.

[0017] The container receptacle 21 at least partially encloses the container 12, for example, in the region of the head. A receiving means 9 is located at the bottom of the container 12. For example, this receiving means 9 can rotate the container 12 located thereon about the rotation axis or container axis 7 of the container 12, preferably a rotation by a multiple of 360°, especially during high-speed rotation.

[0018] The container 12 is preferably rotationally symmetrical. The container 12 has a container axis 7. The container axis 7 preferably runs parallel to the rotational axis of a rotationally symmetrical container 12 or parallel to the longitudinal axis of a container 12, wherein the longitudinal axis runs from the top to the bottom of the container 12. The container 12 is translucent. It contains a product 8, preferably a liquid or a liquid pharmaceutical. A foreign particle 13 is shown schematically. The product 8 located in the container 12 is to be examined for its proper condition, for example, to ensure that it does not contain any impermissible foreign particles 13. For this purpose, the product 8 is illuminated with various light sources 18, 19, 20, the resulting image is recorded by a camera 15 and subsequently evaluated.Due to a rotation of the container 12 around its axis 7 and a sudden stop of the rotation, the product 8 and thus also the foreign particle 13 continue to move – while the container 12 remains stationary – as indicated by a corresponding arrow. Such a foreign particle 13, among others, is to be detected as described below.

[0019] Above the container 12, but slightly offset to the side, a camera 15 with a lens 17 is arranged. The camera 15 has an optical axis 6 that runs parallel and spaced from the container axis 7. The optical axis 6 of the camera 15 runs approximately through the center of the lens 17. The camera 15 is positioned such that the optical axis 6 meets the center of a reflector 11. The reflector 11 is arranged at an angle to the optical axis 6, preferably by 45°. It serves to forward a beam path of a transmitted light 19 to the camera 15. The reflector 11 is used in particular to redirect the beam path of the lens 17 with a relatively large working distance and thus to accommodate the optical structure on the inspection carousel in a space-saving manner.

[0020] The transmitted light 19 generates a beam path directed substantially perpendicular to the optical axis 6 and / or container axis 7 at an angle α, i.e., it is directed laterally toward the container 12. The transmitted light 19 preferably extends parallel to the container axis 7 along the container 12 in order to reliably illuminate the entire area of ​​the container 12 from the side. In the exemplary embodiment, the transmitted light 19 is arranged outside the container receptacle 21 at the level of the reflector 11, with the container 12 being arranged between the transmitted light 19 and the reflector 11. This allows the transmitted light 19 to reliably illuminate the entire volume of the container 12.

[0021] In addition, at least one reflection light 18 is provided as a further light source. In the exemplary embodiment, a further reflection light 20 is arranged. The one reflection light 18 is arranged slightly above the container 12 such that the generated beam path is inclined at a certain angle β with respect to the container axis 7 and / or with respect to the beam path of the transmitted light 19, for example by 45° with a suitable bandwidth. The further reflection light 20 is arranged slightly below the container 12 such that the generated beam path is also inclined at a certain angle β with respect to the container axis 7 and / or with respect to the beam path of the transmitted light 19, for example approximately 30° to the horizontal. The essential factor in the arrangement of the reflection light 18, 20 is that both lighting sources optimally illuminate the liquid or the product 8.For this purpose, for example, the lower reflection light 20 should be arranged such that the corresponding beam path runs directly above the receiving means 9 or the container holder 21. At the same time, the beam path of the upper reflection light 18 should well illuminate the bottom of the container 12. Furthermore, both reflection lights 18, 20 should not unnecessarily obscure the beam path of the transmitted light 19.

[0022] The width of the reflection lights 18, 20 is selected so that the entire long side of at least the body of the container 12 is illuminated as in Figure 3is indicated. The beam path of the reflected light 18, 20 is selected such that it does not hit the reflector 11 and is also not directly imaged by the camera 15. Normally, the container 12 appears dark in a reflected image. If, on the other hand, the reflected light 18, 20 hits a possibly present reflective foreign particle 13 (or the meniscus area of ​​the liquid), the foreign particle 13 (or the meniscus) reflects the light or the reflected light 18, 20 in all directions, i.e., also in the direction of the camera 15. The foreign particle 13 (or the meniscus) appears in the image as a bright object on a dark background. A foreign particle 13 could possibly now also reflect the reflected light 18, 20 in the direction of the reflector 11, which the camera 15 records as an image for further analysis. The reflection lights 18, 20 are arranged so that they are not in the beam path of the transmitted light 19.The reflected light 18, 20 is arranged such that the beam path of the reflected light 18, 20 differs from that of the transmitted light 19 (with a different angle of incidence β on the container 12). The reflected light 18, 20 illuminates the container 12 in such a way that a dark-field image is generated, which the camera 15 captures. In this image, a possible foreign particle 13 appears as a bright object against a dark background. This improves the reliability of the system.

[0023] The described device 10 for inspection works as follows: The transparent containers 12 filled with liquid or product 8 - hereinafter Figure 4At least three containers - shown as examples 12.1, 12.2, 12.3 - enter the inspection carousel. There, they are held in an upright position by the respective container holder 21 by holding the tip and / or the bottom of the container 12. Each container 12 is rotated either clockwise or counterclockwise at a high speed according to a predefined rotation profile. This also sets possible foreign particles 13 in motion with the product 8, as both the liquid or product 8 and possible foreign particles 13 rotate together with the container 12. The container 12 is abruptly braked so that by the time the container 12 enters a field of view 17 of the camera 15, the container 12 is no longer rotating, while the liquid or product 8 contained therein, together with any foreign particles 13, still rotates at high speed.

[0024] In this state, a sequence of images of the container 12 is taken under alternating lighting conditions as in Figure 4 shown when the container 12 continues to move within the field of view of the camera 15. In the first step, raw images are captured in full-screen format, in which several containers 12.1, 12.2 are simultaneously imaged. At least two image sequences 31, 32 are then formed from each raw image, as described below.

[0025] These images are analyzed for the presence of possible foreign particles 13 or other defects using appropriate image processing software. For example, foreign particles 13 could be detected as dark spots in transmitted light, and foreign particles 13 could be detected as bright spots in reflected light. Further checks are also possible by comparing the consecutively acquired images with respect to the respective container 12. If foreign particles 13 or defects are detected, the corresponding containers 12 are classified as unacceptable; otherwise, they are classified as accepted.

[0026] Accordingly Figure 4The field of view 17 of the camera 15 is rectangular. The field of view 17 has a size such that at least a section of approximately two machine divisions (this is the distance between two adjacent containers 12.1, 12.2) or three adjacent containers 12 can be reliably captured. This allows the inspection period to be extended. The containers 12 are Figure 3 shown as an example from left to right through the field of view 17 of the camera 15 through the inspection carousel or the associated container holder 21. Figure 4shows by way of example the acquisition of two complete image sequences 31, 32 with respect to containers 12.1, 12.2. A third image sequence 33 of a third container 12.3 has been started but not yet completed. By way of example, an image sequence 31, 32, 33 each comprises four images of the same container 12, two images in transmitted light 19, two images in reflected light 18, 20.

[0027] At time t1, a first container 12.1 to be inspected is brought into the field of view 17 of the camera 15. At time t1, the transmitted light 19 is activated. The reflected light 18, 20 remains switched off. At time t1, the container 12.1 is in a first position 41. At this time t1 or in this position 41, the camera 15 captures a first image for the first sequence 31, which concerns the first container 12.1. A partial image, which exactly encompasses the area of ​​the container 12.1, is extracted from this image and inserted into the first sequence 31 at the first position 41.

[0028] The containers 12 continue to move from left to right. With each subsequent step or subsequent image, the containers 12.1, 12.2, 12.3, 12.n are moved evenly from left to right and come into the image one after the other. Continue. At time t2, the reflected light 18, 20 is switched on. The transmitted light 19 is switched off. The camera 15 takes another image. Again, a partial image encompassing the area of ​​the container 12.1 is extracted and inserted into the first sequence 31 at the second position 42. As a partial image, for example, a rectangle whose size approximately corresponds to the size of the container 12.1 is cut out and inserted into the first sequence 31.

[0029] The containers 12.1, 12.2, 12.3 continue to move from left to right. At time t3, in addition to the first container 12.1, a second container 12.2 is also located in the field of view 17 of the camera 15. At time t3, the transmitted light 19 is switched on and shines through both containers 12.1, 12.2. The reflected light 18, 20 is switched off. The camera 15 takes an image. A partial image comprising the first container 12.1 is inserted into the first sequence 31 at a third position 43. A partial image comprising only the second container 12.2 is inserted into the second sequence 32 at the first position 41.

[0030] At time t4, the reflected light 18, 20 is switched on. The transmitted light 19 is switched off. The camera 15 captures an image. A partial image comprising the first container 12.1 is inserted into the first sequence 31 at a fourth position 44. This is the last partial image of the first sequence 31 before the first container 12.1 leaves the field of view 17 of the camera 15. A partial image of the second container 12.2, extracted from the captured image, is inserted into the second sequence 32 at the second position 42.

[0031] At times t5, t6, tn, the steps are repeated accordingly and inserted into the corresponding sequences 32, 33. A third container 12.3 is indicated here, which enters the field of view 17 of the camera 15 at time t5.

[0032] Particularly preferably, the lighting 18, 19, 20; 18', 19', 20' or the camera 15 of different inspection modules 2, 3, 10 can be switched on at different times. This can reduce interference caused, for example, by reflections on the device. For example, it could happen that light from one station unintentionally hits the camera sensor of another station, either directly or through reflections on various machine surfaces, and thus impairs the image of the other station. This is avoided. Thus, the image acquisition of the individual stations 2, 3, 10, which could potentially influence each other, is synchronized in stroboscopic mode so that the image acquisition of these stations 2, 3, 10 is always delayed. This eliminates any disruptive influence without, for example, having to use mechanical light shields for each individual station 2, 3, 10.

[0033] The device and method for inspecting containers 12 are particularly suitable in the pharmaceutical industry for inspecting liquid or solid pharmaceuticals filled into containers 12. However, the use is not limited to this. Other products packaged in containers 12, such as packaging bags, tubular bags, cartons, or the like, such as foodstuffs, etc., could also be inspected in the described device 10 and using the described method.

Claims

1. Device for inspecting containers (12), the device comprising at least one camera (15) for visually inspecting at least two containers (12), wherein each container (12) has a container axis (7), at least one container receptacle (21) for mechanically receiving and transporting the containers (12) to be inspected, at least one transmitted light (19) for transilluminating the containers (12) to be inspected with a beam path at an angle (α) relative to the container axis (7), wherein the camera (15) records at least one image of the containers (12) transilluminated by transmitted light (19), wherein, in addition to the transmitted light (19), at least one reflected light (18, 20) is provided for illuminating the containers (12) to be inspected, wherein the reflected light (18, 20) is positioned such that a beam path thereof impinges on the relevant container (12) at an angle (β), relative to the container axis (7), which differs from the angle (α) of the transmitted light (19), characterized in that the device is configured to extract at least one partial image comprising the surface of a first container (12.1) and a further partial image comprising the surface of a second container (12.2) from at least one image recorded by the camera (15) at a specified time (t1, t2, ... tn), wherein the reflected light (18, 20) and the transmitted light (19) are configured such that at least two containers (12.1, 12.2) can be illuminated simultaneously.

2. Device according to claim 1, characterized in that the reflected light (18, 20) and the transmitted light (19) are switched on at different times (t1 to Tn), preferably alternately.

3. Device according to any of the preceding claims, characterized in that the reflected light (18, 20) is positioned such that the containers (12) illuminated by the reflected light (18, 20) are captured by the camera (15) as a dark image and, in this image, a possible foreign particle (13) in the containers (12) appears as a bright object on a dark background.

4. Device according to any of the preceding claims, characterized in that the camera (15) records at least one image at one time (t1, t3, t5) when either the transmitted light (19) or the reflected light (18, 20) is switched on.

5. Device according to any of the preceding claims, characterized in that the container receptacle (21) and / or the rotation means (9) is designed such that the containers (12) were set in rotation prior to an inspection by the camera (15) and are slowed down at the time of the inspection.

6. Device according to any of the preceding claims, characterized in that at least one further illumination (18', 19', 20') is provided, which is switched on at a different time from the reflected light (18, 20) or the transmitted light (19).

7. Device according to any of the preceding claims, characterized in that the angle (α) of the transmitted light (19) is substantially 90° and / or the angle (β) of the reflected light (18, 20) is in a range of 25° to 50°.

8. Method for inspecting containers (12), wherein at least one camera (15) for visual inspection records at least one image of at least two containers (12), wherein each container (12) has a container axis (7), wherein at least one container receptacle (21) mechanically receives and transports the containers (12) to be inspected, wherein at least one transmitted light (19) transilluminates the containers (12) to be inspected with a beam path at an angle (α) relative to the container axis (7), wherein the camera (15) records at least one image of the containers (12) transilluminated by transmitted light (19), wherein at least one reflected light (18, 20) is positioned such that a beam path thereof impinges on the relevant container (12) at an angle (β), relative to the container axis (7), which differs from the angle (α) of the transmitted light (19), characterized in that at least one partial image comprising the surface of a first container (12.1) and a further partial image comprising the surface of at least one second container (12.2) are extracted from at least one image recorded by the camera (15) at specified times (t1, t2, ... tn).

9. Method according to the preceding method claim, characterized in that the reflected light (18, 20) and the transmitted light (19) are switched on at different times (t1 to tn), preferably alternately.

10. Method according to any of the preceding method claims, characterized in that the camera (15) produces at least one image of at least two containers (12.1, 12.2), at least in transmitted light (19) and at least in incident light (18, 20).

11. Method according to any of the preceding method claims, characterized in that at least two containers (12.1, 12.2) are moved into a field of view (17) of the camera (15), in that the containers (12.1, 12.2) are illuminated either by transmitted light (19) or by reflected light (18, 20), and in that the camera (15) records at least one image of the illuminated containers (12.1, 12.2).

12. Method according to any of the preceding method claims, characterized in that the containers (12.1, 12.2) are moved further and are illuminated with reflected light (18, 20) and / or transmitted light (19) and the camera (15) records at least one further image.