System for acquiring an image of a decorative element present on a transparent face of a container

Abstract

The invention relates to an acquisition system for acquiring an image of a decorative element present on a transparent face of a container. The acquisition system comprises a first image acquisition unit (3) comprising an image acquisition device (4), a device (6) for positioning a container in an inspection zone (18) so that a decorative element of the container present on a first face (26) is oriented towards the image acquisition device (4) and that the image acquisition device can take an image of a second face of the container through the first face (26). The acquisition system comprises a light source (8) configured so that its light beam (28) illuminates the first face (26) of the container. The invention is characterised in that the light source (8) is capable of emitting a light beam (28) that illuminates the decorative element on the first face (26) of the container without illuminating the second face of the container.

Description

Description Title of the invention: System for acquiring an image of a design present on a transparent face of a container Technical field to which the invention relates

[0001] The present invention relates to the technical field of automated control of decorations or inscriptions applied to a transparent or translucent object.

[0002] The invention relates more particularly to a control method and a control device enabling the automatic control of objects within a manufacturing chain in order to detect those objects which do not meet predefined quality criteria. Technological background

[0003] In the field of glass container decoration, there are many known decoration processes, among which we can mention: the application of decorative accessories such as labels, medallions, stickers or decals, the application by screen printing of a monochrome or colour decoration, lacquering and metallization, engraving by mechanical removal of material, etching or frosting with acid.

[0004] Screen printing is a common method of decorative application, involving the successive application of different layers of colored ink in an automated machine, according to various patterns, to achieve, for example, a final polychrome design. After these layers of ink or enamel are applied, the decorated items are fired to set and fix the inks or enamels applied to their surfaces.

[0005] Applying screen-printed designs to glass containers offers numerous advantages, particularly in terms of strength and durability. Indeed, screen-printed designs are engineered to withstand multiple cleaning and reuse cycles, making it a particularly attractive option for companies looking to reduce manufacturing costs and their environmental impact.

[0006] Before being reused, glass containers must undergo a rigorous cleaning process to remove all traces of products or contaminants. This process includes several steps, such as rinsing, washing with hot water and detergent, rinsing with cold water, and sterilization.

[0007] It should be noted that, after a certain number of cleaning and reuse cycles, the screen-printed design on glass containers may deteriorate or lose its luster. This deterioration can be caused by various factors, such as mechanical wear, exposure to chemicals, or the use of overly aggressive cleaning methods.

[0008] In some cases, this degradation can render the glass container unusable, because the decoration no longer meets quality standards or because the identification marks are no longer legible, making the container untraceable.

[0009] Existing automated inspection systems for transparent containers have significant limitations. Conventional approaches, such as those described in US patent 2005 / 069191 A1, use lighting systems that simultaneously illuminate the front and back surfaces of transparent containers, creating visual overlap artifacts that compromise inspection accuracy. These systems then require complex algorithmic post-processing by subtracting reference images to eliminate extraneous information from the opposite surface, significantly increasing processing time and system complexity.

[0010] Other approaches, such as described in US 2014 / 015960 A1, use sequential directional lighting but are limited to detecting physical defects on opaque labels, not addressing the specific problem of overlapping designs on opposite sides in transparent containers.

[0011] Thus, the need arose for an automated quality control solution for decorations on glass containers after cleaning, to ensure that the decorations meet the required quality standards before reuse. Object of the invention

[0012] To solve these problems specific to transparent containers and avoid the drawbacks of prior art algorithmic post-processing solutions, the invention proposes a system for acquiring at least one image of a design on a first transparent and / or translucent face of a container, the container comprising a second face opposite the first face, the acquisition system comprising a first image acquisition unit, the first image acquisition unit comprising an image acquisition device; and - a positioning device capable of placing the container in a designated inspection zone, in the inspection zone, the decoration of the first face of the container being oriented towards the image acquisition device to allow said image acquisition device to take an image of the second face of the container, through the first face of the container; and - a light source capable of emitting a light beam, said light source being configured so that its light beam illuminates the first face of the container, when the image acquisition device takes an image of said container in the inspection area.

[0013] The invention is remarkable in that, when the container is in the inspection area, the light source is able to emit a beam of light illuminating the decoration of the first face of the container, without illuminating the second face of said container.

[0014] Advantageously, the second face visible through the first face of the container is not directly illuminated by the light source when the acquisition device takes an image of the first face illuminated by said light source. Consequently, the image of the second face is barely visible or not visible at all in the image taken by the acquisition device. Therefore, the image of the second face does not overlap with that of the first face. The acquisition system thus allows for easier detection and control of a design present on one face of a transparent and / or translucent container.

[0015] The term "decoration" refers specifically to a graphic or visual representation that can be applied to the surface of a container for aesthetic, informational, or functional purposes. This representation can take various forms, such as patterns, logos, images, text, or codes.

[0016] The term "container" refers, for example, to a bottle comprising at least one lateral face, at least partially transparent and / or at least partially translucent. The bottle may be made of glass or a synthetic polymer. Preferably, the container comprises a longitudinal axis and at least one lateral face extending along or substantially along said longitudinal axis. The first lateral face of the container mentioned above may be parallel or substantially parallel to the longitudinal axis of the container. "Longitudinal axis" means an imaginary line passing through the center of the container and extending in the direction of its longest length.

[0017] Unlike conventional systems that correct superposition artifacts through software processing after acquisition, the invention physically eliminates the problem at its source through a selective lighting configuration. This preventative approach allows for the direct acquisition of usable images without requiring algorithmic correction, calibration with reference images, or differential comparison.

[0018] In another embodiment, the positioning device includes obscuring means that reduce ambient light in the inspection area. These obscuring means can be opaque panels or curtains placed around the inspection area to block external light and create a dark and controlled environment. By reducing ambient light, the obscuring means allow for more precise images of a design present on the front face of a container, thus facilitating inspection and the detection of any defects in said design.

[0019] According to another embodiment of the invention, when the container is present in the inspection area, the light source is capable of emitting a beam of light illuminating only the decoration on the first face of the container. This embodiment allows only a specific area of ​​interest in the decoration to be illuminated. This specific geometric configuration ensures that the beam of light remains confined to the first face, physically preventing the opposite face from being illuminated.

[0020] According to another embodiment of the invention, when the container is present in the inspection area, the decoration of the first face of the container is illuminated by the light source, at an angle of incidence equal to or greater than 35°, this value preferably being between 55° and 89°.

[0021] In another embodiment, when the container is present in the inspection area and the container includes a longitudinal axis, the image acquisition device and the light source are arranged to face the first face of the container, and the optical axis of the image acquisition device and the axis of the light beam emitted by the light source lie in a plane parallel or substantially parallel to the longitudinal axis of the container, preferably including the longitudinal axis of the container. In other words, the image acquisition device and the light source are arranged to be along the same face of the same container present in the inspection area and, preferably, aligned along the longitudinal axis of the container.

[0022] This embodiment advantageously limits the space occupied by the image acquisition device and the light source around the container. For example, the light source can be placed above or below the container to avoid obstructing its radial perimeter. The terms "above" and "below" refer to the spaces facing the ends that define the container along its longitudinal axis.

[0023] Thus, as mentioned below, several image acquisition devices and several light sources can be arranged around the container, so as to allow images to be obtained from several viewpoints of the same container.

[0024] In one embodiment, the positioning device is capable of introducing several identical or substantially identical containers into the inspection zone, simultaneously or successively, in the same or substantially the same way, and the light source is oriented so that its light beam illuminates only one container at a time within the inspection zone. Thus, the image acquired by the acquisition device is not susceptible to degradation by observing its second face, illuminated by the reflection of the light beam emitted by the light source on another container present in or near the inspection zone.

[0025] According to a preferred embodiment, the containers introduced into the inspection area by the positioning device are identical or substantially identical, and each container extends along a longitudinal axis, and the positioning device is configured to move each container in the inspection area in a direction normal or substantially normal to the longitudinal axis of the containers, and the light source is arranged to illuminate the first face of each container such that the light beam emitted by said light source forms with the longitudinal axis of each container an angle of 55° or less, this value preferably being between 45° and 1°.The value of this angle is chosen based on the distance between a first container illuminated by the light source and an adjacent container, so that if the first container is absent, the light source cannot illuminate an adjacent container when the image acquisition device takes a picture. In other words, the light source is positioned so that its beam cannot illuminate two adjacent containers, either directly or indirectly. "Indirect" means, for example, illuminating another container with a beam of light from the light source after passing through a first container.

[0026] According to another embodiment of the invention, when the container is present in the inspection area, the light source is capable of emitting a light beam composed of parallel or substantially parallel light rays. This embodiment provides more homogeneous illumination of an area of ​​interest on the first face of the container.

[0027] In other words, the light rays emitted by the light source are parallel or nearly parallel within the inspection area, such that the illumination of the first face of the container is identical or nearly identical as the container moves within the inspection area. This embodiment advantageously allows the acquisition device to produce images with the same or nearly the same contrast, even when each image corresponds to a different positioning of the container within the inspection area.

[0028] The positioning of the container in the inspection area, for example along the direction of the beam emitted by the light source, does not then influence little or no contrast is affected in the images acquired by the image acquisition device. Therefore, this embodiment allows for greater tolerance in the positioning of the container within the inspection area, along a direction parallel or substantially parallel to the light beam incident on the first face of the container.

[0029] This embodiment is particularly advantageous when the positioning device moves a container within the inspection area with relative inaccuracy. This is the case, for example, with belt conveyors, where the positioning of each container can vary from a few millimeters to several millimeters relative to the same edge of the conveyor.

[0030] According to another advantage, this embodiment also allows the acquisition of identical or substantially identical images, the contrast of which is little or not influenced by significant variations in shape and / or inclination between the inspected containers.

[0031] In other words, the invention allows for greater tolerance in the positioning of a container within the inspection zone when acquiring an image of the container's first face. Measurements performed from this image can thus be automated more accurately because the image's contrast level is less, or not at all, influenced by the container's positioning within the inspection zone.

[0032] According to the invention, the area of ​​interest preferably includes at least part of a setting.

[0033] According to another embodiment of the invention, when the container is present in the inspection area, the light source is capable of emitting a light beam whose cross-section is elliptical or rectangular.

[0034] According to another embodiment, the light source is of the telecentric type.

[0035] According to another embodiment of the invention, when the container is present in the inspection area, the first face of the container is oriented so as to form with an optical axis of the image acquisition device, an angle whose value is between 75° and 105°, preferably of the order of 90°.

[0036] According to another embodiment of the invention, the positioning device is capable of moving a container within the inspection area according to a direction of movement. For example, the positioning device may include a chain conveyor or a belt conveyor, suitable for supporting and moving glass containers within the inspection area. As another example, the positioning device may include a mechanical gripper, capable of grasping the neck of a container and moving it within the inspection area.

[0037] According to another embodiment of the invention, the acquisition system comprises at least one second image acquisition unit, identical or substantially identical to the first image acquisition unit, and at least one second image acquisition unit is arranged to allow the acquisition of an image of the container from a different viewpoint than the first image acquisition unit when the container is in the inspection area. Preferably, the positioning device is common to the image acquisition units. In other words, the acquisition system may comprise a single positioning device common to each acquisition unit.

[0038] According to another embodiment of the invention, the acquisition system comprises several image acquisition units, identical or substantially identical to the first image acquisition unit, and the image acquisition units are positioned all around the positioning device, so as to allow the image acquisition system to take images of several faces of a container present in the inspection area. Preferably, the acquisition system may comprise a single positioning device common to each acquisition unit.

[0039] In the inspection zone, the optical axes of several image acquisition devices may be coplanar or substantially coplanar. According to a preferred embodiment, the positioning device is configured to move a container within the inspection zone, along a direction of movement, and the direction of movement is parallel or substantially parallel to the plane defined by several optical axes of the image acquisition devices.

[0040] According to another embodiment, when the container is present in the inspection area and the container includes a longitudinal axis, the optical axes of several image acquisition devices are included or substantially contained in a plane perpendicular or substantially perpendicular to the longitudinal axis of said container.

[0041] According to another embodiment, at the inspection zone, at least one acquisition unit includes at least one reflecting mirror, deflecting the optical axis of the image acquisition device by an angle between 60° and 120°, preferably on the order of 90°. This embodiment advantageously allows the image acquisition device to be positioned above or below the positioning device, in order to significantly reduce the overall size of the acquisition system around said positioning device.

[0042] Another advantage is that using a reflecting mirror allows the optical axis of an image acquisition device to be brought as close as possible to the direction of movement of the positioning device within the inspection area. In other words, the reflecting mirror reduces the angle formed between the optical axis of an image acquisition device and the direction of movement of a container within the inspection area. The acquisition system is then able to take images all around a container moved by the positioning device, without hindering its movement.

[0043] According to another embodiment of the invention, the acquisition system includes a control unit configured to successively command each image acquisition unit to take at least one image of a container present in the inspection area. In other words, the control unit is configured so that a single light source illuminates a container present in the inspection area when an image acquisition unit takes an image of said container. This embodiment advantageously ensures that the other faces of the container are not illuminated when the system takes an image of a desired face of said container.

[0044] According to another embodiment, the time interval between the acquisition of two images taken successively by two acquisition units is equal to or less than 2 ms.

[0045] According to another embodiment of the invention, the control unit is coupled to the positioning device, so that the images of the same container present in the inspection area, taken by the acquisition system, are carried out within a time interval dependent on the speed at which the container passes through the inspection zone.

[0046] According to another embodiment of the invention, the control unit is configured so that the images of the same container taken by the acquisition system are taken during a movement of the container in the inspection area which is equal to or less than 2 mm, preferably equal to or less than 1 mm.

[0047] According to another embodiment of the invention, the acquisition system includes a storage unit, the storage unit comprising a method for checking the quality of a decoration present on a container, from the images acquired by the detection system.

[0048] The inspection process may include a step of assembling images of the same container taken by different acquisition units. Preferably, the assembly step is configured to allow a view of each side face of the container. This embodiment advantageously makes it possible to obtain a complete image of a design present on a side face of the container, regardless of its orientation within the inspection area.

[0049] According to another embodiment of the invention, the acquisition system comprises a computing unit connected to the storage unit as well as to several image acquisition units mentioned above, so as to allow the implementation of the control process saved by the storage unit.

[0050] According to another embodiment of the invention, the computing unit is capable of transmitting a rejection signal to a switching system, the switching system being present downstream of the positioning device, so as to allow the switching system to isolate a container whose decoration is identified as being of insufficient quality by the control process.

[0051] According to one embodiment of the invention, the control unit is configured to instruct each image acquisition unit to take at least three successive images of the same container at different positions within the inspection zone, the positions being spaced a distance apart determined according to the speed of movement of the container within said inspection zone. This configuration makes it possible to compensate for the Positioning tolerances inherent to industrial processes, including variations in container ovality and mechanical clearances in conveying devices. By way of non-limiting example, when the container has a convex outer surface, the positions mentioned above are spaced between 0.5 mm and 1.5 mm, preferably 1 mm.

[0052] According to one embodiment of the invention, the system includes analysis means configured to select, from among the three images acquired by each image acquisition unit, the image exhibiting the best centering and sharpness characteristics of the container's design. This automatic selection ensures optimal inspection quality regardless of variations in the container's positioning within the inspection area.

[0053] According to one embodiment of the invention, the system includes a container presence detector positioned upstream of the inspection area, said presence detector being connected to the control unit to trigger the image acquisition sequence upon detection of the container. This configuration allows for precise synchronization of the acquisitions with the actual position of the container on the positioning device.

[0054] According to one embodiment of the invention, the analysis means are configured to select the optimal image based on at least one criterion chosen from: contrast analysis of the design, edge detection of the design, and / or evaluation of the overall image sharpness. Contrast analysis identifies the image with the greatest differentiation between the design and the substrate, while edge detection assesses the precision of the design's borders. Evaluation of the overall sharpness eliminates blurry images caused by vibrations or movement of the container.

[0055] According to one embodiment of the invention, the system comprises between four and twelve image acquisition units distributed around the positioning device, preferably eight image acquisition units. This configuration allows for complete inspection of the container's periphery while maintaining an optimal balance between inspection coverage and system complexity.

[0056] Of course, the various characteristics, variants and forms of embodiment mentioned above can be associated with each other. others according to various combinations, insofar as they are not incompatible or mutually exclusive. Description of the figures

[0057] The invention will be better understood from the following description, which relates to preferred embodiments, given by way of non-limiting examples, and explained with reference to the accompanying schematic drawings, in which:

[0058] [Fig. 1] illustrates a perspective view of a first embodiment of an image acquisition system according to the invention, comprising an image acquisition unit composed of an image acquisition device, a positioning device and a light source;

[0059] [Fig. 2] illustrates a side view of a second embodiment of an acquisition system according to the invention, comprising several image acquisition units;

[0060] [Fig. 3] illustrates a front view of the second embodiment of the acquisition system, visible in figure 2;

[0061] [Fig. 4] illustrates a bottom view of the second embodiment of the acquisition system, visible in figure 2;

[0062] [Fig. 5] illustrates a top view of the second embodiment of the acquisition system visible in Figure 2. Detailed description of the invention

[0063] As a reminder, the invention proposes an automated quality control solution for decorations present on glass containers, after cleaning, to ensure that the decorations conform to the required quality standards prior to their reuse.

[0064] Figure 1 illustrates a non-limiting embodiment of a first embodiment of an acquisition system 2 according to the invention, comprising an image acquisition unit 3.

[0065] The image acquisition unit 3 includes an image acquisition device 4, a positioning device 6 and a light source 8.

[0066] The image acquisition device 4 includes a digital camera 10 with a sensitivity range between 350 and 1000 nm, preferably between 400 and 700 nm.

[0067] According to the present example, the acquisition system 2 includes a mechanical arm 12 holding a reflecting mirror 14 opposite the digital camera 10. The reflecting mirror 14 is oriented so as to deflect the optical axis 16 of the digital camera, at an angle of approximately 90°, towards an inspection area 18 in which there is a glass container 20.

[0068] More specifically, the container 20 is brought into the inspection area 18 by the positioning device 6. In this case, the positioning device 6 is a chain conveyor, capable of moving the container 20 in a direction of movement AA'.

[0069] In this example, the container 20 is a cylindrical glass bottle extending along a longitudinal axis. The side wall 22 of the container, extending along its longitudinal axis, is transparent or translucent. The side wall 22 includes a decoration 24 on one face 26. In this case, the decoration 24 is a barcode positioned on the body of the bottle.

[0070] As illustrated by Figure 1, the light source 8 is capable of emitting a light beam 28 illuminating the decoration 24 present on the first face of the container, when the image acquisition device takes an image of said container in the inspection area 18.

[0071] Remarkably, when the container 20 is present in the inspection zone 18, the light source 8 is able to emit a light beam 28 illuminating the decoration present on the first face 26 of the container, without illuminating a second face of the container opposite said first face.

[0072] Advantageously, the second face of the container, visible through its first face (26), is barely or not at all visible through said first face, because the second face is less illuminated, or not illuminated at all, compared to the first face when the acquisition device takes an image of said first face. Consequently, the image of the second face is barely or not at all visible in the image taken by the acquisition device. The acquisition system thus allows for easier detection and therefore easier control of a design present on the first face of a transparent and / or translucent container.

[0073] Preferably, the light source 8 emits a light beam 28 illuminating only the decoration 24 present on the first face of the container. The decoration 24 on the first face of the container is illuminated by the light source at an angle of incidence equal to or greater than 35°, this value preferably being between 55° and 89°.

[0074] A second variant of an acquisition system 30 according to the invention is illustrated by figures 2 to 5. This second variant differs from the previous one in that the acquisition system 30 comprises several image acquisition units, identical or substantially identical to the image acquisition unit 3, the positioning device 6 is common to the image acquisition units 3 and the image acquisition units are positioned all around the positioning device 6, so as to allow the image acquisition system 30 to take images of several faces of the container present in the inspection area 18.

[0075] As an illustration, figures 2 to 4 show the light sources 8 simultaneously emitting their light beam 28, thus demonstrating the advantageous arrangement of the acquisition units 3 to capture images all around the container 20. This arrangement ensures that at least one image of the decoration 24 present on the first face of the container is obtained, regardless of its orientation in the inspection area 18.

[0076] According to the invention, the acquisition system 30 comprises a control unit (not shown) configured to successively command each image acquisition unit 3 to take at least one image of a container present in the inspection area. In other words, the control unit is configured so that a single light source 8 illuminates the container when an image acquisition unit 3 takes an image of said container.

[0077] The control unit is coupled to the positioning device 6 so that images of the same container taken by the acquisition system 30 are acquired within a time interval dependent on the speed of the container's passage through the inspection zone. Preferably, the control unit is configured so that images of the same container taken by the acquisition system 30 are acquired during a container displacement within the inspection zone of 2 mm or less, preferably 1 mm or less.

[0078] According to a third embodiment of an acquisition system according to the invention, not illustrated in the figures, the acquisition system comprises, in addition to the embodiments described above, a multiple acquisition strategy to compensate for the positioning tolerances of the container within the inspection zone inherent in its movement by a conveyor. This embodiment takes into account the ovality tolerances of the containers of ±1 mm and the necessary clearances on the positioning device, generating a centering offset of the containers of ±1 mm.

[0079] To achieve this, the acquisition system includes a presence detector (not shown) positioned upstream of the inspection zone on the positioning device. This presence detector is connected to the control unit and configured to detect the approach of a container to the inspection zone. When a container is detected, the control unit triggers an acquisition sequence synchronized with the container's speed on the conveyor.

[0080] In practice, when a container approaches the center of the inspection zone, each image acquisition unit takes a first image at a position upstream of the theoretical center of the inspection zone. A second image is taken when the container is theoretically at the center of the inspection zone. A third image is taken downstream of the theoretical center. The spacing between these three positions is determined based on the container's speed of movement and typically corresponds to a displacement of 0.5 mm to 2 mm between each acquisition.

[0081] In this embodiment of the invention, the acquisition system comprises eight image acquisition units distributed around the positioning device. It should be noted that the invention is not limited to this number of acquisition units, which can range from 3 to 12, preferably from 6 to 10. The acquisition sequence can be performed according to two main variations.

[0082] According to a first variant, each image acquisition unit successively takes its three images before the next unit begins its sequence.

[0083] According to a second preferred variant, all acquisition units successively take their first image, then all successively take their second image, and finally all successively take their third image. This second variant has the advantage that the second images of all acquisition units are taken when the container is optimally centered in the inspection area.

[0084] For each image acquisition unit, the processing unit analyzes the three acquired images according to predefined selection criteria. The first criterion involves a contrast analysis of the background, selecting the image with the greatest difference in brightness between the background and the support. The second criterion uses edge detection of the background, favoring the image with the sharpest and best-defined edges. The third criterion evaluates the overall sharpness of the image by analyzing the modulation transfer function, eliminating images degraded by motion blur or vibrations.

[0085] The processing unit automatically selects, for each image acquisition unit 3, the image with the best characteristics according to one or a combination of these criteria, thus ensuring optimal inspection quality regardless of variations in container positioning within the inspection area. This intelligent selection maintains consistent inspection accuracy despite mechanical tolerances in the conveyor system.

Claims

DEMANDS

1. Acquisition system (2, 30) for at least one image of a decoration on a first transparent and / or translucent face (26) of a container, the container comprising a second face opposite the first face (26), the acquisition system (2, 30) comprising a first image acquisition unit (3), the first image acquisition unit comprising: - an image acquisition device (4); and - a positioning device (6) capable of placing the container in a so-called inspection zone, in the inspection zone (18), the decoration of the first face (26) of the container being oriented towards the image acquisition device (4) to allow said image acquisition device (4) to take an image of the second face of the container, through the first face (26) of the container; and - a light source (8) capable of emitting a light beam (28), said light source (8) being configured so that its light beam (28) illuminates the first face (26) of the container, when the image acquisition device (4) takes an image of said container in the inspection zone (18); characterized in that, when the container is present in the inspection zone (18), the light source (8) is capable of emitting a light beam (28) illuminating the decoration of the first face (26) of the container, without illuminating the second face of said container.

2. Acquisition system (2, 30) according to claim 1, characterized in that when the container is present in the inspection area (18), the light source (8) is capable of emitting a light beam (28) illuminating only the decoration of the first face (26) of the container.

3. Acquisition system (2, 30) according to claim 1 or 2, characterized in that when the container is present in the inspection zone (18), the decoration on the first face (26) of the container is illuminated by the light source (8), at an angle of incidence whose value is equal to or greater than 35°, this value preferably being between 55° and 89°.

4. Acquisition system (2, 30) according to any one of claims 1 to 3, characterized in that when the container is present in the inspection zone (18), the light source (8) is capable of emitting a light beam (28) composed of parallel or substantially parallel light rays.

5. Acquisition system (2, 30) according to any one of claims 1 to 4, characterized in that when the container is present in the inspection area and the container includes a longitudinal axis, the image acquisition device and the light source are arranged so as to face the first face of the container, and in that the optical axis of the image acquisition device and the axis of the light beam emitted by the light source are included in a plane parallel or substantially parallel to the longitudinal axis of said container.

6. Acquisition system (2, 30) according to any one of claims 1 to 5, characterized in that when the container is present in the inspection zone (18), the first face (26) of the container is oriented so as to form with an optical axis (16) of the image acquisition device (4), an angle whose value is between 75° and 105°, preferably of the order of 90°.

7. Acquisition system (30) according to any one of claims 1 to 6, characterized in that it comprises at least one second image acquisition unit, identical or substantially identical to the first image acquisition unit, and in that at least one second image acquisition unit is arranged so as to allow the acquisition of an image of the container from a different point of view than the first image acquisition unit, when the container is present in the inspection area (18).

8. Acquisition system (30) according to claim 7, characterized in that it comprises several image acquisition units, identical or substantially identical to the first image acquisition unit, and in that the image acquisition units are positioned all around the positioning device (6), so as to allow the image acquisition system (2, 30) to take images of several faces of the container present in the inspection area (18).

9. Acquisition system (30) according to claim 8, characterized in that when the container is present in the inspection area (18) and the container includes a longitudinal axis, the optical axes of several image acquisition devices are contained or substantially contained in a plane perpendicular or substantially perpendicular to the longitudinal axis of the container.

10. Acquisition system (30) according to any one of claims 7 to 9, characterized in that it comprises a control unit configured to command successively each image acquisition unit to take at least one image of the container in the inspection area (18).

11. Acquisition system (30) according to claim 10, characterized in that the control unit is configured to command each image acquisition unit to take at least three successive images of the same container at different positions in the inspection zone (18), the positions being spaced at a distance determined according to the speed of movement of the container in said inspection zone.

12. Acquisition system (30) according to claim 11, characterized in that it comprises analysis means configured to select, among the three images acquired by each image acquisition unit, the image exhibiting the best centering and sharpness characteristics of the container decoration.

13. Acquisition system (30) according to claim 11 or 12, characterized in that it comprises a container presence detector placed upstream of the inspection area (18), said presence detector being connected to the control unit to trigger the image acquisition sequence based on the detection of the container.

14. Acquisition system (30) according to any one of claims 11 to 13, characterized in that the analysis means are configured to select the optimal image according to at least one criterion chosen from: background contrast analysis, background edge detection, and overall image sharpness assessment.

15. Acquisition system (30) according to any one of claims 7 to 14, characterized in that the system comprises between four and twelve image acquisition units distributed around the positioning device (6), preferably eight image acquisition units.

Images