Method and apparatus for inspecting cylindrical containers
By using area scanning cameras and fixing devices, the problem that the line scanning method can only check one container is solved, and the ability to check multiple containers simultaneously is realized, the inspection efficiency and accuracy are improved, and the interference of the moving mechanism is avoided.
Patent Information
- Application Number
- CN202380040836.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-19
- Filing Date
- 2023-04-04
- Publication Date
- 2025-01-03
AI Technical Summary
Existing line scanning methods can only check one container at a time and require complex moving mechanisms, which are prone to interference, errors and inaccuracies.
Two-dimensional image capture is performed using an area scanning camera. By fixed area scanning cameras and transportation devices, multiple rotatably symmetric containers can be checked simultaneously, avoiding the use of the moving mechanism and image distortion.
The ability to check multiple containers simultaneously is realized, the inspection efficiency is improved, image distortion is reduced, and the accuracy and efficiency of detection results are enhanced.
Smart Images
Figure CN119256223A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for inspecting cylindrical containers having the features of claim 1 , and to a device for inspecting cylindrical containers having the features of claim 10 . Background Art
[0002] When inspecting cylindrical containers, a line scan method can be used. In this case, a line scan camera is used. The line scan camera can capture rows of pixels aligned with the object. A pixel row can be represented by individual pixels arranged next to each other along a straight line. A pixel row can be described as a (pixel) vector. A pixel row can be considered as a one-dimensional row. Using pixel rows, the dimensions of an object can be captured or displayed. The container to be inspected moves in the transport direction and rotates in the process. The containers pass in front of the line scan camera so that the line scan camera can capture one of the containers.
[0003] The line scan camera moves together with the container detected by the line scan camera from an initial position in the transport direction. The line scan camera acquires a plurality of pixel rows of the container one after another. The row images are then combined to form a (two-dimensional) row image. For example, in the case of a cylindrical container, such a row image corresponds to the unfolded side surface of the cylindrical container.
[0004] In such a line image, possible damage to the container and / or foreign objects in the container can be better displayed or recognized. One of the reasons for this is that optical distortions in the (one-dimensional) pixel line (e.g. due to the round shape of the container to be measured) are minimal compared to conventional (two-dimensional) surface images.
[0005] Once the line scan camera has captured enough images (or rows of pixels), the line scan camera moves back to its starting position, where it can capture the next container. The line scan camera must then move along with the next container in the direction of transport and then back to its starting position again. This process is repeated for each container to be inspected.
[0006] Therefore, the line scan camera must be moved back and forth in the transport direction. For this purpose, various motion mechanisms can be used.
[0007] Alternatively, movable mirror optical elements can be used to track the movement of the transport container. Here, different motion mechanisms can also be used.
[0008] In this case, the disadvantage is that only one container can be inspected at a time using a line scan camera. In addition, it requires a motion mechanism, which can be a source of interference, errors, inaccuracies, etc. Summary of the invention
[0009] It is therefore an object of the present invention to provide a method and a device for inspecting cylindrical containers in which the above-mentioned disadvantages are eliminated.
[0010] The above object is achieved by a method for inspecting a cylindrical container having the features of claim 1. The container can be a rotationally symmetrical container, such as a bottle, a vial, an ampoule or a syringe. The container can be designed to be transparent, in particular transparent to the human eye.
[0011] The method comprises the following steps:
[0012] An area scan camera with a coverage is provided. The area scan camera is in particular a camera with a two-dimensionally arranged recording medium. The area scan camera can include a sensor (e.g. a CCD sensor) with a pixel (image pixel) matrix, which allows a two-dimensional (surface) image capture using only one exposure cycle. The coverage is in particular two-dimensional. The coverage can be designed as a (in particular rectangular) inspection plane.
[0013] Provide container (to be inspected).
[0014] The containers are transported through the coverage of the area scan camera along a transport direction. The transport direction may correspond to a straight line and / or at least partially to a circular or elliptical path. The containers may be transported sequentially or stepwise.
[0015] When a container is located within the coverage area of the area scan camera, the container and / or the liquid contained therein is rotated in a rotational direction about a longitudinal axis of the respective container while the container is located within the coverage area of the area scan camera.
[0016] At least one sequence of pixel rows is captured (read out) using an area scan camera. The pixel rows are aligned with a specified area of the container. In this case, in particular, the liquid in the container is rotating, while the container itself is not rotating. The containers can be set to rotate before the coverage area. Before the containers are moved into the coverage area, their rotational movement can be stopped so that they no longer rotate. However, in this case, the liquid continues to rotate in the container. This allows the container to be transported through the coverage area, where the container does not rotate in the coverage area, but the liquid in the container is rotating.
[0017] Alternatively, the pixel row is aligned with the specified area of the container from different rotational positions of the container. In this case, in particular, the container (including liquid) can rotate when passing through the coverage area.
[0018] In particular, each captured row of pixels corresponds to a one-dimensional image.
[0019] A pixel row may be formed by individual pixels arranged adjacent to each other along a straight line (pixel row). It is also conceivable that a pixel row may be formed by two or more adjacent pixels arranged adjacent to each other along a straight line (two or more adjacent pixel rows).
[0020] As the container moves within the coverage of the area scan camera, a sequence of pixel rows may be created (captured) for each container. In this case, the pixel rows may be captured sequentially in time. Thus, for example, a first pixel row may be captured at a first point in time, while a second pixel row adjacent to the first pixel row may be captured at a second point in time after the first point in time.
[0021] In other words, the first pixel row can be captured at a first point in time. The second pixel row can be captured at a second point in time. The third pixel row can be captured at a third point in time, and so on. In this case, the first, second, and third pixel rows can represent sequential pixel rows (in time), respectively. In other words, the pixel rows can be captured sequentially in time. The first pixel row, the second pixel row, and the third pixel row can be adjacent pixel rows (in space), or can be represented by adjacent pixels (in space).
[0022] Rows of pixels can be captured sequentially in time and space.
[0023] Thus, the container can be tracked as it is transported through the coverage area of the area scan camera. To do this, the area scan camera does not have to move with the container.
[0024] According to one development, at least two sequences of pixel rows can be at least partially captured (read out) simultaneously by means of an area scan camera. Each sequence of pixel rows can be aligned with a specified area of a different container. Each sequence of pixel rows can be aligned with a specified area of a different container from different rotational positions of the respective container.
[0025] This allows multiple containers to be tracked as they are transported through the coverage area. This means that multiple containers can be inspected at once (simultaneously) using the same area scan camera.
[0026] According to one development, the designated area of the container aligned with the sequential pixel rows may be the longitudinal axis of the container. In other words, the sequential pixel rows may be aligned with the longitudinal axis of the container. In other words, the pixel rows may always extend along the longitudinal axis (in particular the longitudinal center axis) of the container. If multiple sequential pixel rows are captured, the pixel rows of each sequential pixel row may be aligned with the longitudinal axis of the corresponding container.
[0027] According to one development, at least one line image can be created from the captured sequential pixel rows. In other words, a plurality of pixel rows, in particular those that are temporally and preferably spatially sequential, can be combined to form a line image. Each line image can be considered to consist of a plurality of pixel rows arranged next to each other, in particular those that are temporally and preferably spatially sequential.
[0028] The line image can be analyzed to determine the inspection result. For example, the line image can show whether there are contaminants in the container or in the liquid contained in the container. The line image is especially designed as a two-dimensional image. For example, contaminants in the container can be particularly accurately identified from such a line image.
[0029] According to one development, the method may comprise the following steps:
[0030] The area scan camera, the coverage area and / or the transported container are aligned so that the container remains in the coverage area of the area scan camera for as long as possible while being transported through the coverage area. This can be achieved, for example, by making the direction of the coverage area as parallel as possible to the transport direction. The transport direction can be parallel to the direction of the coverage area. In particular, the transport direction can extend within the coverage area designed as a detection plane.
[0031] This allows to make maximum use of the coverage area. Thus, for example, depending on the exposure time of the area scan camera and the rotation speed of the container (or the liquid contained in the container), as many pixel rows and row images consisting of them as possible can be created for each container. This can improve the inspection results.
[0032] Additionally, mechanical back movement of the swivel arm or mirror optics is eliminated, which would otherwise have a time-consuming effect, meaning that inspection time increases in direct proportion to the reduction in back movement.
[0033] According to one development, the method may comprise the following steps:
[0034] An optical lens system (and / or at least one lens), in particular at least one telecentric lens, at least one bi-telecentric lens and / or at least one endocentric lens, is provided to avoid image distortion when capturing sequential pixel rows by the area scan camera. In this way, deformations can be avoided or at least reduced, thereby obtaining more accurate detection results.
[0035] According to one development, the method may comprise the following steps:
[0036] A trigger signal is generated based on the movement of the container, wherein the trigger signal is used to synchronize the sequential pixel rows with at least one moving container. In this way, the movement of the container can be synchronized with the generation of the pixel rows, so that the movement of the container can be compensated. The trigger signal can be related to the position of the container.
[0037] The time course of the inspection can be controlled by at least one parameter to compensate for the movement of the container. For example, such parameters can be a start / stop or pixel row capture signal, an offset of a certain number of pixel rows, a container number selection or input, a first pixel row for capture, and / or a synchronous / asynchronous mode.
[0038] According to one development, the capture of at least one pixel row can be performed by fading in pixels (pixel rows) of an area scan camera that contribute to the pixel row and fading out pixels (pixel rows) of an area scan camera that do not contribute to the pixel row. For example, fading in or fading out the corresponding pixels (pixel rows) can be achieved by activating or deactivating individual sensors on the image sensor or its pixel matrix. The image sensor can be designed in the form of a chip, such as a CCD chip, a CMOS chip, etc.
[0039] According to one development, the fading in and / or out of the pixels of the area scan camera for generating at least one pixel row can be synchronized with the movement of the container, in particular with its position, by a trigger signal. In this way, sequential pixel rows synchronized with the movement of the container can be easily created.
[0040] The above object is further achieved by a device for inspecting cylindrical containers having the features of claim 10. The container may be a rotationally symmetrical container, such as a bottle, a vial, an ampoule or a syringe. The container may be transparent, in particular to the human eye.
[0041] The device comprises a transport device for transporting containers along a transport direction. The transport device can be designed to transport (move) containers sequentially or step by step.
[0042] The device further comprises at least one rotating device for rotating the container and / or the liquid contained in the container about the longitudinal axis of the respective container in a rotation direction.
[0043] The apparatus also includes an area scan camera having a coverage area. The area scan camera and / or the transport device are designed and arranged to allow the container to pass through the coverage area of the area scan camera.
[0044] The device is intended to capture at least one sequence of pixel rows by means of an area scan camera. The pixel rows are aligned with a designated area of the container or aligned with a designated area of the container from different rotational positions of the container. The device is also aligned to combine the captured sequence of pixel rows into a line image.
[0045] Rows of pixels are captured sequentially in time and space.
[0046] Thus, the container can be tracked as it is transported through the coverage area. To do this, the area scan camera does not have to move with the container.
[0047] According to one development, the area scan camera can be arranged fixedly in the device. In other words, the area scan camera can be fixed and therefore cannot move. In particular, the area scan camera does not move with the container in the transport direction. In this way, a movement mechanism for the area scan camera can be omitted.
[0048] According to one development, the device may comprise a lens system. The area scan camera may have a lens. The device or the area scan camera may comprise at least one lens. The lens may be a telecentric lens, a bi-telecentric lens or an endocentric lens. In this way, image distortions may be avoided or at least reduced when capturing a sequence of pixel rows using the area scan camera.
[0049] According to one development, the device can be designed to carry out any of the methods according to the above statements. Regarding the advantages that can be achieved thereby, reference is made to the statements related to the method. For further design of the device, the measures related to the method and / or the measures explained below can be used. BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Further features, details and advantages of the invention emerge from the wording of the claims and from the following description of exemplary embodiments with reference to the accompanying drawings, in which:
[0051] Figure 1 An apparatus for inspecting a container is shown;
[0052] Figure 2 shows a row of pixels captured by an area scan camera;
[0053] Figure 3 is used Figure 1 A schematic diagram of a method for inspecting a container by a device in FIG. 1 ; and
[0054] Figure 4 is used Figure 1 Schematic diagram of other embodiments of the method for inspecting a container with a device in FIG.
[0055] In the following description and drawings, corresponding components and elements have the same reference numerals. To improve clarity, not all reference numerals are shown in all drawings. DETAILED DESCRIPTION
[0056] Figure 1 Schematically shown is a device 32 for inspecting a container 10. In the present example, the container 10 is a vial filled with a liquid 18.
[0057] The device 32 has a transport device 34, which in the present example is designed in the form of a conveying wheel or a transport turntable. The transport device 34 transports the container 10 in a transport direction 16. In the present example, the container 10 is moved on a circular path by means of the transport device 34.
[0058] The device 32 further comprises a rotating device 36. The rotating device is designed to be able to rotate each transported container 10 about the longitudinal axis 20 in the direction of rotation 22. In the present example, the rotating device 36 is designed in the form of a separate rotating receiver 37. In this example, each transported container 10 is arranged in a separate receiver 37 of the rotating device 36. In other words, each container 10 received in the receiver 37 is rotated about the corresponding longitudinal axis 20 by means of the receiver 37.
[0059] The device 32 further comprises an area scan camera 12 having a coverage area 14. In the present example, the area scan camera 12 is arranged immovably (fixed). In other words, the area scan camera 12 is immovable, in particular immovable relative to the transport device 34. In the present example, the area scan camera 12 has a bi-telecentric lens 30.
[0060] The area scan camera 12 , the coverage area 14 and the transport device 34 are designed and arranged relative to one another in such a way that the container 10 is transported through the coverage area 14 of the area scan camera 12 by means of the transport device 34 .
[0061] Figure 2 2 shows a pixel row 26 captured by means of the area scan camera 12. In the illustrated coverage 14 of the area scan camera 12, the container 10 with the liquid 18 contained therein is completely imaged. In this example, the pixel row 26 corresponds to a row of pixels ( Figure 2 ). A pixel row is a vertical line in Figure 2 The pixels (image points) of the vertically oriented rows of the coverage area 14 in the area scan camera 12 can be selected according to the position of the container 10 arranged in the coverage area 14. Figure 2 The desired pixel rows 26 or desired pixel columns oriented vertically in the coverage area 14 in .
[0062] Figure 3 Shows the use of Figure 1 A method for inspecting a container 10 with the device 32 in FIG.
[0063] exist Figure 3 , the coverage area 14 of the area scan camera 12 is represented by a dashed rectangle. In this example, the coverage area 14 is in the form of a rectangular plane.
[0064] In the coverage area 14 of the area scan camera 12, the container 10 is imaged at a first position P1 at a time point T1. The container 10 is transported in a transport direction 16 (towards Figure 31 (left side in FIG. 1 ) is transported through the coverage area 14 of the area scan camera 12. The same container 10 is shown at a later time point T2 in a second position P2. During the transport through the coverage area 14, the container 10 rotates about its longitudinal center axis 21 in a rotation direction 22.
[0065] A liquid 18 is contained within the container 10. In the liquid 18 (and therefore within the container 10), (unwanted) contaminants in the form of foreign matter 11 are present.
[0066] At time T1, the area scan camera 12 captures a pixel line 26 of the container 10 at the first position P1. The pixel line 26 at time T1 extends along the longitudinal center axis 21 of the container 10. The container 10 is transported or moved further in the transport direction 16 by means of a transport device 34 (shown only schematically).
[0067] At time point T2 , container 10 has reached position P2 and, in this example, has been fully rotated (360°) about longitudinal center axis 21 .
[0068] Between the time point T1 and the time point T2, a plurality of pixel rows 26 are captured by means of the area scan camera 12. Figure 3 As the area scan camera 12 in the coverage area 14 moves from right to left (in the transport direction 16), the corresponding pixel row 26 extending through the longitudinal center axis 21 of the container 10 also moves in the transport direction 16. Therefore, the pixel row 26 also moves within the coverage area 14, all in a similar manner to the container 10.
[0069] The pixel rows 26 captured in this way can be reassembled sequentially in time to form a row image 28. Such a row image 28 is schematically shown in FIG. Figure 3 The row image 28 corresponds to the unfolded side surface of the container 10 (see Figure 3 Container 10 is shown on the left side of row image 28 in FIG.
[0070] The foreign body 11 can be seen particularly clearly in the line image 28. Therefore, due to the foreign body 11, the container 10 shown can be identified as non-compliant.
[0071] Figure 4 Shown by Figure 1 Other embodiments of methods of inspecting a container 10 with the device 32 are described below.
[0072] The embodiment shown is Figure 3 The embodiment shown differs in that two containers 10 are shown simultaneously in the coverage area 14 of the area scan camera 12. A first container 13 is shown at position P1 and a second container 15 is shown at position P2.
[0073] In this example, two pixel rows 26 are now captured simultaneously. In this example, a first pixel row 27 extends along the longitudinal center axis 21 of the first container 13 and a second pixel row 29 extends along the longitudinal center axis 21 of the second container 15 .
[0074] and Figure 3 , two pixel rows 27, 29 migrate together with the two containers 13, 15 in the transport direction 16. Subsequently, a first row image can be created from the first pixel row 27 and a second row image can be created from the second pixel row 29. Thus, two row images 28 (not shown) can be created from the first pixel row 27 and the second pixel row 29. In this example, the first row image corresponds to the unfolded side surface of the first container 13 and the second row image corresponds to the unfolded side surface of the second container 15.
[0075] In this way, two (or more) containers 10 may be inspected simultaneously using the same area scan camera 12 .
Claims
1. A method for inspecting a cylindrical container (10), comprising the following steps: - providing an area scan camera (12) having a coverage area (14); - providing a container (10); - transporting the container (10) along a transport direction (16) through the coverage area (14) of the area scan camera (12); - rotating the container (10) and / or the liquid (18) contained in the container (10) in a rotation direction (22) about a longitudinal axis (20) of the associated container (10) when the container (10) is located in the coverage area (14) of the area scan camera (12); - capturing at least one sequence of pixel rows (26) by means of the area scan camera (12), wherein the pixel rows (26) are aligned with a specified area of the container (10) or are aligned with a specified area of the container (10) from different rotational positions of the container (10), wherein the pixel rows are captured sequentially in time and space.
2. The method according to claim 1, characterized in that At least two sequential pixel rows (26) are at least partially captured simultaneously by means of the area scan camera (12), wherein each sequential pixel row (26) is aligned with a specified area of a further container (10) or is aligned with a specified area of a further container (10) from a different rotational position of the respective container (10).
3. The method according to claim 1 or 2, characterized in that: The designated area of the container (10) aligned with the sequential pixel rows (26) is the longitudinal axis (20) of the container (10).
4. The method according to any one of the preceding claims, characterized in that At least one row of an image (28) is created from the captured sequential rows of pixels (26).
5. The method according to any one of the preceding claims, characterized in that The method comprises the following steps: - aligning the area scan camera (12), the coverage area (14) and / or the transported container (10) so that the container (10) remains within the coverage area (14) of the area scan camera (12) for a maximum time while being transported through the coverage area (14).
6. The method according to any one of the preceding claims, characterized in that The method comprises the following steps: - providing an optical lens system, in particular at least one telecentric lens, at least one bi-telecentric lens and / or at least one endocentric lens (30), in order to avoid image distortions when capturing sequential pixel rows (26) by means of the area scan camera (12).
7. The method according to any one of the preceding claims, characterized in that The method comprises the following steps: - generating a trigger signal as a function of the movement, in particular the position, of the container (10), wherein the trigger signal is used to synchronize the sequential pixel rows (26) with the moving container (10), in particular in time and space.
8. The method according to any one of the preceding claims, characterized in that Capturing of the at least one pixel row (26) is performed by fading in pixels of the area scan camera (12) that contribute to the pixel row (26) and fading out pixels of the area scan camera (12) that do not contribute to the pixel row (26).
9. The method according to claim 7 or 8, characterized in that: The fading in and / or out of the pixels of the area scan camera (12) for generating at least one pixel row (26) is synchronized with the movement, in particular the position, of the corresponding container (10) by means of the trigger signal.
10. An apparatus (32) for inspecting a cylindrical container (10), comprising: a transport device (34) for transporting the container (10) in a transport direction (16), at least one rotating device (36) for rotating the container (10) and / or the liquid (18) contained in the container (10) about the longitudinal axis (20) of the respective container (10) in a direction of rotation (22), - an area scan camera (12) having a coverage area (14), wherein the area scan camera (12) and / or the transport device (34) are designed and arranged such that the container passes through the coverage area (14) of the area scan camera (12), characterized in that The device (32) is designed to be able to capture at least one sequence of pixel rows (26) with the aid of the area scan camera (12), wherein the pixel rows (26) are aligned with a specified area of the container (10) or are aligned with a specified area of the container (10) from various rotational positions of the container (10), wherein the device (32) is also designed to be able to combine the captured sequence of pixel rows (26) to form a row image (28), wherein the pixel rows are captured sequentially in time and space.
11. The device (32) according to claim 10, characterized in that The area scan camera (12) is immovably arranged within the device (32).
12. The device (32) according to claim 10 or 11, characterized in that The device (32) comprises a lens system, in particular at least one telecentric lens, at least one bi-telecentric lens and / or at least one endocentric lens (30), to avoid image distortion when capturing sequential pixel rows (26) by means of the area scan camera (12).
13. The device (32) according to any one of claims 10 to 12, characterized in that The device (32) is designed to be able to carry out the method according to any one of claims 1 to 9.