Method and apparatus for inspecting cylindrical containers

Abstract

The present invention relates to a method for inspecting cylindrical containers (10), comprising the steps of: providing an area camera (12) having a detection area (14); providing the container (10); conveying the container (10) in a conveying direction (16) past the detection area (14) of the area camera (12); rotating the container (10) and / or a liquid (18) contained therein in a rotational direction (22) about a longitudinal axis (20) of the respective container (10) while the container (10) is located in the detection area (14) of the area camera (12); and photographing at least one sequence of pixel rows (26) with the area camera (12), the pixel rows (26) being aligned with a predetermined area of ​​the container (10) or with the predetermined area of ​​the container (10) from different rotational positions of the container (10). The present invention further relates to an apparatus (32) for inspecting a cylindrical container (10).

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.

[0002] When inspecting cylindrical containers, the Line Scan Method can be used. A line camera is used for this. The line camera can capture a pixel row that is aligned with the object. The pixel row can be represented by individual pixels arranged next to each other along a straight line. The pixel row can be represented as a (pixel) vector. The pixel row can be considered to be one-dimensional. One dimension of the object can be recorded or represented by the pixel row. The container to be inspected is moved in the conveying direction and rotated in the process. The container is guided to pass in front of the line camera, which allows one of the containers to be detected by the line camera.

[0003] The line camera is moved together in the conveying direction from a starting position with the container detected by the line camera. A number of pixel rows of the container are sequentially created by the line camera. The row images are then stitched together into a (two-dimensional) row image. For a cylindrical container, such a row image corresponds, for example, to the unfolded peripheral surface of the cylindrical container.

[0004] In such a row image, possible damage to the container and / or foreign objects therein can be better represented or recognized, especially because optical distortions (e.g. due to the rounded shape of the inspected container) are minor and minimal in a (one-dimensional) pixel row compared to a conventional (two-dimensional) surface image.

[0005] As soon as enough pictures have been taken (or pixel rows created) by the line camera, it moves back to its starting position, where it can detect the next container. In this case, the line camera must be moved again in the conveying direction with the next container and then moved back to the starting position again. This process is repeated for each container to be inspected.

[0006] Therefore, the line camera must be moved back and forth along the conveying direction. For this purpose, various moving mechanisms can be used.

[0007] Alternatively, a movable mirror optical system can be used to make it possible to track the movement of the transported container. Again, various movement mechanisms can be used.

[0008] The disadvantage here is that with a line camera only one container can be inspected at a time and, moreover, a movement mechanism is required, which can be a source of disturbances, errors, inaccuracies, etc.

[0009] SUMMARY OF THE DISCLOSURE It is therefore an object of the present invention to provide a method and an apparatus for inspecting cylindrical containers, by which the above mentioned drawbacks are obviated.

[0010] The above problem is solved by a method for inspecting cylindrical containers with the features of claim 1. The container may be a rotationally symmetric container, such as a bottle, vial, ampoule or syringe, etc. The container may in particular be designed to be transparent to the human eye.

[0011] The method includes the following steps.

[0012] Providing an area camera with a detection area. The area camera is in particular a camera with a two-dimensionally arranged recording medium. The area camera can have a sensor (e.g. a CCD sensor) with a matrix of pixels (image pixels), which allows two-dimensional (surface) image capture with only one exposure cycle. The detection area is in particular two-dimensional. The detection area can be configured as a (in particular rectangular) detection surface.

[0013] Preparing a container (to be inspected).

[0014] Conveying the container through the detection field of the area camera in a conveying direction, which may correspond to a straight line and / or at least partially to a circular or elliptical path. The container may be conveyed continuously or in steps.

[0015] Rotating the containers and / or the liquid contained therein in a rotational direction about the longitudinal axis of each container while the containers are located in the detection field of the area camera.

[0016] With the aid of an area camera, at least one sequence of pixel rows is photographed (read out), the pixel rows being aligned with a predefined area of ​​the container. In particular, the container is not rotated, whereas the liquid in the container is rotated. The container may be rotated in front of the detection area. Before the container is moved to the detection area, the rotational movement of the container can be stopped, whereby the container is no longer rotated. In this case, however, the liquid in the container continues to rotate. This allows the container to be transported past the detection area, where the container is not rotated in the detection area, but the liquid in the container is rotated.

[0017] Alternatively, the pixel rows are aligned with a predetermined region of the container from different rotational positions of the container, in particular while the container (together with the liquid) is rotated and while the container is moved past the detection region.

[0018] Each captured row of pixels corresponds specifically to a one-dimensional image.

[0019] A pixel row can be formed using individual pixels (a pixel sequence) arranged next to each other along a straight line, but it is equally conceivable that a pixel row can be formed from two or more adjacent pixels (a sequence of two or more adjacent pixels) arranged next to each other along a straight line.

[0020] As the containers are moved through the detection field of the area camera, each container can generate (image) a sequence of pixel rows, the pixel rows being imaged sequentially in time, such that, for example, a first pixel row can be imaged at a first time point and a second pixel row adjacent to the first pixel row can be imaged at a second time point that is subsequent to the first time point.

[0021] In other words, at a first time point, a first pixel row can be imaged. At a second time point, a second pixel row can be imaged. At a third time point, a third pixel row can be imaged, etc. Furthermore, the first pixel row, the second pixel row and the third pixel row can each represent consecutive (in time) pixel rows. In other words, pixel rows can be imaged sequentially in time. The first pixel row, the second pixel row and the third pixel row can each be (spatially) adjacent pixel rows or can be represented by (spatially) adjacent images.

[0022] The pixel rows are imaged sequentially in time and space.

[0023] In this manner, the container can be tracked as it is transported through the detection field of the area camera without the need for the area camera to move together with the container.

[0024] According to one further development, at least two sequences of pixel rows are captured at least partially simultaneously using an area camera, the pixel rows of each sequence may be aligned to a predefined area of ​​another container, and the pixel rows of each sequence may be aligned to a predefined area of ​​another container from different rotational positions of the respective container.

[0025] In this manner, multiple containers can be tracked as they are transported through the sensing area, and therefore multiple containers can be inspected at once (simultaneously) by the same area camera.

[0026] According to one development, the predetermined region of the container, to which the pixel rows of a sequence are aligned, may be the longitudinal axis of the container. In other words, the pixel rows of a sequence may be aligned to the longitudinal axis of the container. In other words, the pixel rows may always extend along the longitudinal axis of the container, in particular along the central longitudinal axis. In the recorded sequences of pixel rows, the pixel rows of each sequence of pixel rows may be aligned to the longitudinal axis of the respective container.

[0027] According to one development, at least one row image can be created from the imaged sequence of pixel rows. In other words, a number of pixel rows, in particular consecutive in time and preferably in space, can be stitched together to form a row image. Each row image can be considered as being assembled from a number of pixel rows, in particular consecutive in time and preferably in space, arranged side by side.

[0028] The line image can be analyzed to determine a test result. It can be ascertained in the line image, for example, whether impurities are present in the container or in the liquid contained in the container. The line image is in particular configured as a two-dimensional image. From such a line image, impurities in the container, for example, can be particularly well identified.

[0029] According to one development, the method comprises the following step: aligning the area camera, the detection area and / or the transported container in such a way that the container remains in the detection area of ​​the area camera as long as possible during the transport through the detection area. This can be achieved, for example, by the detection area being oriented as parallel as possible to the transport direction. The transport direction can be oriented parallel to the detection area. The transport direction can in particular run through the detection area configured as a detection surface.

[0030] This allows the detection area to be maximally utilized, for example by creating as many pixel rows as possible for each container and a combined row image from these, depending on the exposure time of the area camera and the rotation speed of the container (or the liquid contained in the container), which can lead to improved inspection results.

[0031] Additionally, the otherwise time-intensive mechanical retraction movements of the pivot arm or mirror optics are eliminated, i.e. the inspection time is correspondingly increased due to the unnecessary retraction movements.

[0032] According to one development, the method comprises the following step: providing an optical lens system (and / or at least one objective lens), in particular at least one telecentric, bi-telecentric and / or endocentric objective lens, in order to avoid image distortions when capturing the sequence of pixel rows with the area camera, so that distortions can be avoided or at least reduced, which leads to more accurate inspection results.

[0033] According to one development, the method comprises the following steps: generating a trigger signal dependent on the movement of the container, and using this trigger signal to synchronize the sequence of pixel rows with the at least one moving container, so that the movement of the container can be synchronized with the generation of the pixel rows and thus the movement of the container can be compensated. The trigger signal can be dependent on the position of the container.

[0034] The time course of the examination can be controlled by means of at least one parameter, which compensates for the movement of the containers, such parameters can be, for example, a start / stop or pixel row imaging signal, a shift around a certain number of pixel rows (or pixel columns), a selection or input of the number of containers, the first pixel row (or pixel column) for imaging and / or a synchronous / asynchronous mode.

[0035] According to one development, the image of at least one pixel row can be taken by turning on the pixels (a row of pixels or a number of rows of pixels) of the area camera which contribute to the pixel row and by deactivating the pixels (a row of pixels or a number of rows of pixels) of the area camera which do not contribute to the pixel row. Turning on or off the display of the respective pixels (a row of pixels or a number of rows of pixels) can be effected, for example, by activating or deactivating individual sensors of the image sensor or of the pixel matrix of the image sensor. The image sensor can be in the form of a chip, for example embodied as a CCD chip, a CMOS chip, etc.

[0036] According to one development, the trigger signal can be used to synchronize the start and / or stop of displaying the pixels of the area camera with the movement of the container, in particular the position of the container, for generating at least one pixel row, so that a sequence of pixel rows synchronized with the movement of the container can be created in a simple manner.

[0037] The above problem is further solved by a device for inspecting cylindrical containers with the features of claim 10. The container may be a rotationally symmetric container, such as a bottle, a vial, an ampoule or a syringe. The container may be designed to be transparent, in particular to the human eye.

[0038] The apparatus includes a conveying device for conveying the containers in a conveying direction. The conveying device may be configured to convey (move) the containers continuously or in steps.

[0039] The apparatus further includes at least one rotating device for rotating the containers and / or liquids contained therein in a rotational direction about a longitudinal axis of each container.

[0040] The apparatus further includes an area camera having a detection area, the area camera and / or the transport device constructed and arranged such that the container passes through the detection area of ​​the area camera.

[0041] The apparatus is configured to capture at least one sequence of pixel rows using an area camera, the pixel rows being aligned to a predefined region of the container or to a predefined region of the container from different rotational positions of the container, and the apparatus is further configured to combine the captured sequence of pixel rows into a row image.

[0042] The pixel rows are imaged one after the other in time and space.

[0043] This allows the container to be tracked as it is transported through the detection area without the need to move the area camera along with the container.

[0044] In one further development, the area camera can be arranged stationary in the device. In other words, the area camera can be arranged stationary and thus cannot be moved. The area camera, in particular, cannot be moved together with the container in the conveying direction. In this way, a movement mechanism for the area camera can be omitted.

[0045] According to one development, the device may include a lens system. The area camera may have an objective lens. The device or the area camera may include at least one objective lens. The objective lens may be a telecentric objective lens, a bi-telecentric objective lens or an endocentric objective lens. This makes it possible to avoid or at least reduce image distortion when capturing a sequence of pixel rows with the area camera.

[0046] According to one development, the device may be configured to carry out the method according to the above description. For the advantages obtained, reference is made to the relevant description of the method. In further embodiments of the device, the means described in connection with the method and / or the means further described below may be used.

[0047] Further features, details and advantages of the invention emerge from the claims and from the following description of embodiments based on the drawings. [Brief description of the drawings]

[0048] [Figure 1] FIG. 1 shows an apparatus for inspecting containers. [Diagram 2] FIG. 2 is a diagram showing pixel rows photographed by an area camera. [Diagram 3] 2A to 2C are diagrams illustrating a method for inspecting a container using the device of FIG. 1. [Figure 4] 10A-10C illustrate another embodiment of a method for inspecting a container using the apparatus of FIG.

[0049] In the following description and in the drawings, corresponding components and elements are designated with the same reference numerals, and for clarity, not all reference numerals are shown in all figures.

[0050] 1 shows diagrammatically an apparatus 32 for inspecting a container 10, which here is a bottle filled with a liquid 18.

[0051] The device 32 has a transport device 34, which here is designed in the form of a transport wheel or a transport carousel, by means of which the containers 10 are transported in the transport direction 16. Here, the containers 10 are moved by the transport device 34 on a circular track.

[0052] The device 32 further comprises a rotating device 36, which is configured to rotate each of the transported containers 10 in a rotation direction 22 around the respective longitudinal axis 20. The rotating device 36 is here configured in the form of individual rotating receiving parts 37. Each of the transported containers 10 is here arranged in a separate receiving part 37 of the rotating device 36. In other words, each of the containers 10 received in the receiving parts 37 is rotated by the receiving parts 37 around the respective longitudinal axis 20.

[0053] The device 32 further comprises an area camera 12 with a detection area 14. The area camera 12 is arranged here stationary (fixed), in other words, the area camera 12 does not move, in particular relative to the transport device 34. Here, the area camera 12 comprises a bi-telecentric objective lens 30.

[0054] The area camera 12 , the detection area 14 and the transport device 34 are constructed and arranged relative to one another such that the container 10 is transported past the detection area 14 of the area camera 12 by the transport device 34 .

[0055] In Fig. 2, a pixel row 26 is shown captured by the area camera 12. In the illustrated detection area 14 of the area camera 12, a container 10 with a liquid 18 therein is entirely captured. The pixel row 26 here corresponds to an array of pixels in the detection area 14 (vertical in Fig. 2). A pixel column refers to an array of pixels in the detection area 14, which is vertical in Fig. 2. Depending on where in the detection area 14 the container 10 is located, a desired pixel row 26 of the detection area 14 of the area camera 12 or a desired pixel column, which is vertical in Fig. 2, can be selected.

[0056] FIG. 3 illustrates a method of inspecting container 10 using apparatus 32 of FIG.

[0057] 3, the detection area 14 of the area camera 12 is shown by a dashed rectangle. The detection area 14 here is configured in the form of a rectangular plane.

[0058] A container 10 is imaged at a first position P1 in the detection field 14 of the area camera 12 at a time T1. The container 10 is transported past the detection field 14 of the area camera 12 in a conveying direction 16 (to the left in FIG. 3). The same container 10 is imaged at a later time T2 in a second position P2. During its transport through the detection field 14, the container 10 is rotated in a rotational direction 22 about its longitudinal central axis 21.

[0059] Contained within the container 10 is a liquid 18. Disposed within the liquid 18 (and thus within the container 10) are (undesirable) impurities in the form of foreign bodies 11.

[0060] A pixel row 26 of the container 10 is imaged by the area camera 12 at a first position P1 at a time T1. The pixel row 26 extends along a central longitudinal axis 21 of the container 10 at the time T1. The container 10 is further transported or moved in a transport direction 16 by a transport device 34, which is only indicated diagrammatically.

[0061] At time T2, the container 10 reaches position P2, where it has now been rotated completely (by 360°) about its central longitudinal axis 21.

[0062] Between time T1 and time T2, a number of pixel rows 26 are captured by the area camera 12. As the container 10 is moved from right to left (in the conveying direction 16) in the detection area 14 of the area camera 12 in Fig. 3, the corresponding pixel rows 26, which extend through the central longitudinal axis 21 of the container 10, also move in the conveying direction 16. The pixel rows 26 thus move together in the detection area 14 as well as the respective container 10.

[0063] The pixel rows 26 captured in this way can be recombined in time-sequential order into a row image 28. Such a row image 28 is shown diagrammatically at the bottom of Figure 3. Row image 28 corresponds to the unfolded peripheral surface of container 10 (see container 10 depicted to the left of row image 28 in Figure 3).

[0064] The foreign object 11 is particularly easily discernible in the row image 28. The container 10 shown can therefore be identified as being abnormal due to the foreign object 11.

[0065] FIG. 4 illustrates a method of inspecting container 10 using apparatus 32 of FIG. 1 according to another embodiment.

[0066] The illustrated embodiment differs from the embodiment shown in Fig. 3 in that two containers 10 are imaged at the same time in the detection field 14 of the area camera 12. A first container 13 is imaged at position P1 and a second container 15 is imaged at position P2.

[0067] Here, two pixel rows 26 are imaged at the same time, a first pixel row 27 extending along the central longitudinal axis 21 of the first container 13 and a second pixel row 29 extending along the central longitudinal axis 21 of the second container 15.

[0068] Analogously to the embodiment of Fig. 3, the two pixel rows 27, 29 move together with the two containers 13, 15 in the conveying 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, from the first pixel row 27 and the second pixel row 29, two row images 28 can be created (not shown). The first row image here corresponds to the unfolded peripheral surface of the first container 13. The second row image here corresponds to the unfolded peripheral surface of the second container 15.

[0069] In this manner, the same area camera 12 can be used to inspect two (or more) containers 10 simultaneously.

Claims

1. A method for inspecting a cylindrical container (10), comprising the steps of: Providing an area camera (12) having a detection area (14); Providing said container (10); conveying the container (10) in a conveying direction (16) through the detection area (14) of the area camera (12); rotating the containers (10) and / or the liquid (18) contained therein (10) in a rotational direction (22) about a longitudinal axis (20) of each of the containers (10) while the containers (10) are located in the detection area (14) of the area camera (12); and using the area camera (12) to capture at least one sequence of pixel rows (26), the pixel rows (26) being aligned to a predetermined region of the container (10) or to a predetermined region of the container (10) from different rotational positions of the container (10), the pixel rows being captured sequentially in time and space.

2. 2. The method according to claim 1, characterized in that, using the area camera (12), at least two sequences of pixel rows (26) are photographed at least partially simultaneously, the pixel rows (26) of each sequence being aligned with a predetermined area of ​​another container (10) or with a predetermined area of ​​another container (10) from different rotational positions of the respective container (10).

3. 3. The method according to claim 1 or 2, characterized in that the predetermined area of ​​the container (10) to which the pixel rows (26) of a sequence are aligned is the longitudinal axis (20) of the container (10).

4. 4. The method according to claim 1, further comprising the step of generating at least one row image (28) from the captured sequence of pixel rows (26).

5. The method includes the steps: The method according to any one of claims 1 to 4, characterized in that it includes a step of aligning the area camera (12), the detection area (14) and / or the container (10) being transported so that the container (10) remains in the detection area (14) of the area camera (12) for as long as possible during the transport through the detection area (14).

6. The method includes the steps: The method according to any one of claims 1 to 5, characterized in that it includes a step of preparing an optical lens system, in particular at least one telecentric objective lens (30), bi-telecentric objective lens (30) and / or endocentric objective lens (30), in order to avoid image distortion when photographing the sequence of pixel rows (26) using the area camera (12).

7. The method includes the steps: A method according to any one of claims 1 to 6, characterized in that a trigger signal is generated that is dependent, in particular on the position, of the movement of the container (10), and that the trigger signal is utilized to synchronize, in particular in time and space, the sequence of pixel rows (26) with the moving container (10).

8. 8. The method according to claim 1, further comprising the step of capturing the image of at least one pixel row (26) by starting to display the pixels of the area camera (12) that contribute to the pixel row (26) and stopping to display the pixels of the area camera (12) that do not contribute to the pixel row (26).

9. The method according to claim 7 or 8, characterized in that the trigger signal is used to synchronize the start and / or stop of displaying the pixels of the area camera (12) with the corresponding movement, in particular the position, of the container (10) to generate at least one pixel row (26).

10. An apparatus (32) for inspecting a cylindrical container (10), comprising: a conveying device (34) for conveying said containers (10) in a conveying direction (16); at least one rotating device (36) for rotating said containers (10) and / or the liquid (18) contained therein (10) in a rotational direction (22) about the longitudinal axis (20) of each said container (10); 1. An apparatus (32) for inspecting cylindrical containers (10), comprising: an area camera (12) having a detection area (14), said area camera (12) and / or said transport device (34) constructed and arranged such that said container passes through said detection area (14) of said area camera (12), The apparatus (32) is configured to capture at least one sequence of pixel rows (26) using the area camera (12), the pixel rows (26) being aligned to a predetermined area of ​​the container (10) or to a predetermined area of ​​the container (10) from different rotational positions of the container (10), the apparatus (32) being further configured to combine the captured sequence of pixel rows (26) into a row image (28), the pixel rows being captured sequentially in time and space.

11. 11. The device (32) of claim 10, characterized in that the area camera (12) is arranged stationary in the device (32).

12. The device (32) according to claim 10 or 11, characterized in that in order to avoid image distortion when photographing a sequence of pixel rows (16) using the area camera (12), the device (32) comprises an optical lens system, in particular at least one telecentric objective lens (30), bi-telecentric objective lens (30) and / or endocentric objective lens (30).

13. The device (32) according to any one of claims 10 to 12, characterized in that the device (32) is configured for carrying out the method according to any one of claims 1 to 9.

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