Method for non-contact in-line inspection of containers and station for carrying out said method

Abstract

The invention relates to a method for the in-line inspection of containers (2), each having a vertical axis and at least one outer contour to be inspected; according to the method:-the measuring head (4) is configured to acquire an image of at least one outer contour of each container by optical projection,-for each movement cycle, the measuring head is positioned such that the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container when the measuring head performing circular motion is rotated, and-the measuring head is positioned such that the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container. And the measuring head moves linearly parallel to the translation direction so as to acquire an image of the outer contour of the whole periphery of the container.

Description

Technical Field

[0001] The present invention relates to the technical field of inspecting transparent or translucent containers, such as bottles, jars, vials, ampoules or syringes made of glass or polyethylene terephthalate (PET).

[0002] The subject matter of the invention relates more particularly to the field of inspection of containers of this type, with the aim of monitoring or evaluating dimensional characteristics exhibited by these containers, such as measurements, and detecting defects of the burr or pit type.

[0003] The subject matter of the present invention is particularly advantageous in measuring container diameters (such as the outer diameter of a container ring or container body) or revealing defects present on such container rings (particularly at horizontal mold seams), but this is not its only application. Background Art

[0004] In the field of container manufacturing, it is known to inspect container rings for defects that could affect the container's appearance or, more seriously, for defects that could pose a real danger to the user, such as burrs or pits near the neck. It is also known to inspect the neck ring of each container to determine whether it meets dimensional standards, in particular to ensure correct stoppering and unstoppering of the container, the sealing of capsules, lids, or screw caps, and in particular the flatness of the neck ring surface, or the correct fixing of capsules or screw caps according to the geometry of the neck ring threads of glass or PET containers. The prior art provides various devices for optical container inspection.

[0005] For example, US Patent No. 5,753,905 discloses a device for inspecting the external features of containers. The device includes a light source that illuminates the container's outer contour from one side, and a camera located on the other side of the container retrieves an image of the container's contour, which appears as a dark image against a light background. As the container is rotated about its vertical axis, the camera captures an image at each rotational increment, inspecting the entire periphery of the container. The speed of this inspection device is limited by the container handling method, making it impossible to control the containers at the known production speeds of the container production line. Specifically, the inspection machine handling rotating containers interrupts the production line's flow, which involves moving the containers along a conveyor belt, then transporting them to a rotating station and inspection station, and then back to the conveyor belt. These automated mechanical operations limit the maximum speed of the inspection line. Furthermore, whenever the specifications of the inspected containers change, these rotating container handling machines must be adjusted, requiring significant manual effort, particularly the replacement of variable equipment to adapt the transport to the shape and size of the container series being manufactured. Finally, the purchase, operation, and maintenance costs of these machines are very high.

[0006] Document DE102019121835 discloses a method for measuring the wall thickness of containers queued along a production line. This method utilizes a continuously moving measuring head that circumnavigates a first container while linearly moving around it. During this motion around the container, the measuring head projects light onto the container along a constant perpendicular direction, or optical axis, to the glass container surface. The light reflected from the glass container's surface is received by the measuring head. Based on the light received by the measuring head, the wall thickness is measured using a non-contact optical measurement method. After circling the first container, the measuring head's movement is repeated to perform the measurement on the second container in the queue.

[0007] According to the exemplary embodiment described, a robot with a pivoting arm is used to move the measuring head. The advantage of the solution described in this document is that it can inspect containers without stopping the linear movement of the container queue. However, this document does not allow the diameter of the container to be measured, nor does it reveal whether there are defects in the container ring. In addition, the kinematic implementation of the measuring head is relatively complex and cannot keep up with the high speeds of containers, which can reach hundreds of containers per minute. Specifically, such a mobile robot composed of different pivot axes generates large-amplitude moment arms and significant inertial forces. Similarly, mounting the measuring head on the robot's pivoting arm also leads to problems such as payload, deformation, and wear, making it difficult to provide a reliable and economically viable measurement solution in industrial production. In addition, the cost of a high-powered, fast robot to keep up with the speeds required to inspect containers on the production line is also high.

[0008] US5296701A discloses a method for inspecting containers in which the container is stopped and a head positioned above the container rotates around the container to obtain an image of the container mouth. This device is unsatisfactory because it requires stopping the bottle and does not allow the outer contour to be generated.

[0009] EP3597549A1, which relates to the more advanced field of bottle handling during filling, describes a system comprising a turntable on which bottles are placed at predetermined intervals. Several shuttles or movable carts equipped with cameras capable of measuring the liquid fill level are arranged in a closed loop and track the bottles as they pass over a portion of the turntable. This system is not beneficial because it requires perfect synchronization between the conveyor belt and the bottles. A single slip of a bottle on a conventional conveyor belt can render the system unusable. Furthermore, this system requires the use of multiple shuttles and multiple sensors or cameras, making it cost-ineffective. Finally, this system prevents the production of contoured products. Summary of the Invention

[0010] The object of the present invention is to remedy the drawbacks of the prior art by providing a method designed to perform an on-line inspection of the outer contour of a container over its entire periphery using a safe and economically acceptable technique, even at high container movement speeds.

[0011] To achieve this object, the method according to the invention aims to inspect a row of containers, each of which has a vertical axis and at least one outer contour to be inspected; according to the method, the containers are moved in a vertical position in a translational direction on a conveying plane in a queue so as to continuously advance through an inspection station, the inspection station comprising a non-contact measuring head having a rotation axis, the measuring head being mounted to rotate about this axis, and the measuring head moving in continuous movement cycles, so as to continuously inspect the containers during their translation through the inspection station, each movement cycle of the inspected container comprising an outward stroke and a return stroke as well as a rotation, so as to inspect the entire periphery of the container. According to the method: - the measuring head is configured to acquire an image of at least one outer contour of each container by optical projection, - for each movement cycle, the measuring head is positioned so that during the rotation of the measuring head performing the circular movement, the axis of rotation is substantially coaxial with the vertical axis of the container and the measuring head moves linearly parallel to the translation direction in order to acquire an image of the outer contour of the entire periphery of the container.

[0012] According to an exemplary embodiment, the measuring head is configured to acquire an image of the outer contour of each container by optical projection, and wherein, for each movement cycle, the measuring head rotates through an angular range of at least 360° to acquire an image of the outer contour of the entire periphery of the container.

[0013] According to a further exemplary embodiment, the measuring head is configured to acquire images of two diametrically opposed portions of the outer contour of the container by optical projection, and wherein, for each movement cycle, the measuring head rotates through an angular range of at least 180° to acquire images of the outer contour of the entire periphery of the container.

[0014] Advantageously, for each movement cycle, the measuring head is rotated over a range of at least 180° during the outward stroke while being moved linearly, and during the return stroke the measuring head is moved linearly without being rotated.

[0015] Typically, for two consecutive movement cycles of the measuring head relative to two consecutive containers, the measuring head is rotated in opposite directions.

[0016] According to a feature of the invention, the measuring head is configured to have an engagement volume for the container so that the vertical axis of the container can be substantially coaxial with the rotation axis of the measuring head, and to have a disengagement volume so that the measuring head can be disengaged relative to the container, and the measuring head is moved to engage around the container via its engagement volume so that the rotation axis of the measuring head is substantially coaxial with the vertical axis of the container and to disengage from the container via its disengagement volume.

[0017] According to a variant embodiment, the measuring head is configured to include an image capture system capable of delivering an image of at least a first outer contour of the container within a first observation area, and at least one lighting system, the image capture system illuminating the first observation area in the background of the first outer contour, and the image capture system being controlled during the rotation of the measuring head to deliver an image containing a projection of the first outer contour of the container illuminated from behind.

[0018] According to another variant embodiment, the measuring head is configured to include an image capture system and at least one lighting system, the image capture system being capable of transmitting an image of at least a second outer contour of the container within a second observation area, the second outer contour being symmetrical to the first outer contour relative to a vertical axis of the container, the at least one lighting system illuminating the second observation area in the background of the second outer contour, and the image capture system being controlled during the rotation of the measuring head to provide an image containing a projection of the second outer contour of the container illuminated from behind.

[0019] Preferably, the method determines the position of the vertical axis of each container traveling in translation through the inspection station in the conveying plane and controls the movement of the measuring head such that during its rotation the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container.

[0020] Another subject of the present invention is an in-line inspection station for containers, each container having a vertical axis and at least one outer contour to be inspected, and each container being moved in a vertical position in a queue along a translation direction by a conveyor belt so as to continuously advance through the inspection station, the inspection station comprising: a non-contact measuring head having an axis of rotation about which the measuring head is mounted to rotate in a circular motion, the measuring head comprising an image capture system which delivers an image capable of delivering at least a first outer contour of the container within a first observation area, and at least one lighting system which illuminates the first observation area in the background of the first outer contour, - an arrangement for moving the measuring head, configured to position the measuring head such that during a rotation of the measuring head the axis of rotation is substantially coaxial with the vertical axis of the container and configured to move the measuring head linearly parallel to the translation direction, - a unit for commanding the measuring head and the mobile structure, receiving information from a system for determining the position of the vertical axis of each container traveling in translation through the inspection station on the plane of the conveyor, the command unit being configured to move the measuring head in continuous movement cycles to continuously inspect the containers during their translation through the inspection station, each movement cycle for inspecting a container comprising an outward stroke and a return stroke as well as a rotation to inspect the entire periphery of the container, for each movement cycle the mobile structure positioning the measuring head so that during the rotation of the measuring head the axis of rotation is substantially coaxial with the vertical axis of the container and the measuring head moves linearly parallel to the direction of translation, the command unit controlling the image capture system so as to acquire an image of the outer contour of the entire periphery of the container during the rotation of the measuring head.

[0021] According to an exemplary embodiment, the structure for moving the measuring head includes a motor-driven structure for linearly moving the measuring head in a direction parallel to the translation direction, the motor-driven structure being mounted on a component capable of moving in a direction perpendicular to the translation direction, the motor-driven structure being equipped with a frame for carrying the measuring head, the frame including a support member driven to rotate around a rotation axis by a motor.

[0022] Typically, the measuring head is configured with an engagement volume for the container such that a vertical axis of the container can be substantially coaxial with the rotation axis of the measuring head, and a disengagement volume to enable disengagement of the measuring head relative to the container.

[0023] For example, the measuring head is configured with an engagement volume corresponding to the disengagement volume or is designed to communicate with the disengagement volume in order to form a volume that traverses the support in the translation direction.

[0024] According to a variant embodiment, the image capture system is capable of delivering an image of at least a second outer contour of the container in a second observation area, this second outer contour being symmetrical to the first outer contour relative to a vertical axis of the container, the lighting system illuminating the second observation area in the background of the second outer contour, and then controlling the image capture system during the rotation of the measuring head to deliver an image containing a contour projection of the second outer contour of the container illuminated from behind.

[0025] For example, the image capture system includes at least one camera that views the container directly or using at least one folding mirror.

[0026] Preferably, the camera is mounted on the frame while being centered on the axis of rotation, while viewing the container using at least one folding mirror mounted on a support driven in rotation about the axis of rotation.

[0027] According to a further exemplary embodiment, the image capture system comprises at least one camera which is mounted on a support which is rotationally driven about a rotation axis.

[0028] For example, the lighting system comprises at least one light source, which illuminates the container directly or using at least one folding mirror.

[0029] According to another example, the lighting system comprises at least one light source mounted on a support, the support being rotationally driven around a rotation axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] [ Figure 1 ] Figure 1 is a perspective view of a first exemplary embodiment of an inspection station according to the present invention.

[0031] [ Figure 2 ] Figure 2 Yes Display Figure 1 Front view of the inspection station in the first characterization step.

[0032] [ Figure 2A ] Figure 2A It is basically along Figure 2 The top view of line IIA is obtained.

[0033] [ Figure 2B ] Figure 2B It is basically along Figure 2 A lateral view of the IIB line is obtained.

[0034] [ Figure 2C ] Figure 2C is based on Figure 1 Example of a captured image of a container profile obtained at an inspection station.

[0035] [ Figure 3 ] Figure 3 Yes Display Figure 1 Front view of the inspection station in the second characterizing step of inspecting the container.

[0036] [ Figure 4 ] Figure 4 Yes Display Figure 1 Front view of an inspection station in a third characterizing step in which a container following a previously inspected container in a queue is inspected.

[0037] [ Figure 5 ] Figure 5 is a perspective view of a second exemplary embodiment of an inspection station according to the present invention.

[0038] [ Figure 6 ] Figure 6 Yes Display Figure 5 Front view of the inspection station in the first characterizing step of inspecting the container.

[0039] [ Figure 6A ] Figure 6A It is basically along Figure 6The top view obtained by the VIA line.

[0040] [ Figure 6B ] Figure 6B It is basically along Figure 6 A side view of the VIB line acquisition.

[0041] [ Figure 6C ] Figure 6C is based on Figure 5 Example of a captured image of a container profile obtained at an inspection station.

[0042] [ Figure 7 ] Figure 7 Yes Display Figure 5 A top view of the inspection station in the second characterizing step of inspecting the container.

[0043] [ Figure 8 ] Figure 8 Yes Display Figure 5 FIG. 1 is a top view of an inspection station in a third characterizing step in which a container following a previously inspected container in the queue is inspected.

[0044] [ Figure 9 ] Figure 9 Yes Display Figure 5 A top view of the inspection station during the fourth characterizing step of the inspection.

[0045] [ Figure 10 ] Figure 10 Yes Display Figure 5 FIG. 1 is a top view of an inspection station in a fifth characterizing step in which a container following a previously inspected container in the queue is inspected.

[0046] [ Figure 11 ] Figure 11 is a top view schematic diagram showing an exemplary embodiment of a system for capturing images of two opposing contours of a container using a camera and a folding mirror.

[0047] [ Figure 12 ] Figure 12 is a top view schematic diagram showing an exemplary embodiment of a system for capturing images of two opposing silhouettes of a container using a camera without any folding mirrors.

[0048] [ Figure 13 ] Figure 13 is a top view schematic diagram showing an exemplary embodiment of a system for capturing images of two opposing silhouettes of a container using two cameras without any folding mirrors.

[0049] [ Figure 14A ] Figure 14A is a schematic top view showing an exemplary embodiment of a measuring head in a position awaiting engagement with a container.

[0050] [ Figure 14B ] Figure 14B is a schematic top view showing an exemplary embodiment of a measuring head in a position in which a container is engaged.

[0051] [ Figure 14C ] Figure 14C is a schematic top view showing an exemplary embodiment of a measurement head in an intermediate position rotating around a container to capture an image.

[0052] [ Figure 14D ] Figure 14D is a schematic top view showing an exemplary embodiment of a measuring head in a position in which a container is detached from the measuring head.

[0053] [ Figure 14E ] Figure 14E is a schematic top view showing an exemplary embodiment of the measuring head in a position in which the measuring head has returned to a position in which it awaits engagement with a new container.

[0054] [ Figure 15 ] Figure 15 is a front cross-sectional view of a variant embodiment of a measuring head in which a camera and a light source are mounted on a fixed part of the measuring head.

[0055] [ Figure 15A ] Figure 15A It is basically along Figure 15 A cross-sectional view obtained from the XVA line.

[0056] [ Figure 15B ] Figure 15B It is basically along Figure 15 Cross-sectional view obtained along the XVB line. DETAILED DESCRIPTION

[0057] As can be seen from the accompanying drawings, the subject matter of the present invention relates to a method and an inspection station 1 for automatically acquiring images of the outer contour of a container 2 moving at high speed. The invention relates to the so-called "inline" control of the container after a transformation or manufacturing step in order to control the quality of the container or of the transformation or manufacturing process.

[0058] The method is adapted to the speed at which the containers 2 are travelling. Ideally, the inspection station 1 is capable of handling production at production rates (eg 100 to 1000 containers per minute, typically around 500 containers per minute).

[0059] The present invention provides a considerable improvement by inspecting containers as they travel, thereby avoiding container rotation that is unsuitable for production speeds, as such arrangements involving relative rotation of the container with respect to the light source and / or sensor would cause the container to be "stopped in motion" or move very slowly.

[0060] In a known manner, containers 2, freshly formed by any type of equipment known per se, are managed by a conveyor belt 3. In the illustrated example, the containers 2 are successively deposited in vertical positions on the conveyor belt to form a container queue. The containers 2 are transported in a queue by the conveyor belt 3, which has a horizontal conveying plane defined by a longitudinal axis X parallel to the translation direction and a transverse axis Y perpendicular to the translation direction. As can be seen in the figure, the containers 2 are moved in a queue on the conveying plane X, Y, along a translation direction F parallel to the longitudinal axis X and in vertical positions relative to a vertical axis Z perpendicular to the conveying planes X, Y.

[0061] Advantageously, the container 2 is a container made of a transparent or translucent material, such as a bottle, jar, vial, ampoule, or syringe made of glass or PET. In the example shown in the figure, each container 2 has a bottom 2f placed on a conveyor belt 3 and a vertical wall 2v rising from the bottom 2f along a vertical axis 2z and terminating in a so-called neck ring 2b. The neck ring 2b has a neck ring surface 2s corresponding to the flat surface used to seal the container, and a side wall 2l, for example, with a groove suitable for gripping in the case of a syringe, or for attaching any system for closing the container, such as a crimping capsule, a screw-on nut, a fixed compression ring, or a wire cage. Different closure systems are not shown here but are well known. In the case of bottle-type containers 2, the vertical wall 2v, starting from the bottom 2f, partially forms the bottle body, which is connected to the neck 2c by a shoulder 2e. The vertical wall 2v can be cylindrical, conical, or have any cross-section (such as square, rectangular, or kidney-shaped, such as for vials). One advantage of the neck ring inspection solution is that the method and the inspection station 1 according to the invention are applicable to container bodies of any shape.

[0062] Containers 2 are transported by a conveyor belt 3 for successive transport to various processing and inspection stations. As can be seen in the figure, according to the present invention, containers 2 are arranged in a vertical queue along a translation direction F to progress successively through an inspection station 1. Inspection station 1 is mounted close to conveyor belt 3 to enable inspection of each container 2. Inspection station 1 is implemented within a fixed area of limited length relative to the length of the conveyor belt and can be implemented at any suitable location, depending on the nature of the inspection to be performed.

[0063] The inspection station 1 includes a measuring head 4 configured to acquire, by optical projection, a contactless image of the container's outer contour over the entire periphery of each container 2 passing through the inspection station. The measuring head 4 has an axis of rotation a, about which it is mounted for rotation in a circular motion, either in a clockwise direction (schematically indicated by arrow h) or in a counterclockwise direction (schematically indicated by arrow ah). The measuring head 4 includes an image capture system 5 capable of transmitting an image of at least a first outer contour Pe of the container 2 in a first observation area C, and at least one illumination system 6, which illuminates the first observation area C against the background of the first outer contour.

[0064] The outer contour Pe of the container 2 corresponds to the contour of at least a portion of the container, taken on a plane passing through the vertical axis Z and perpendicular to the conveying plane XY. Figure 2C In the example shown, the image capture system 5 captures the outer contour Pe of the container 2, which corresponds to one side of the container neck ring 2b and part of the neck ring surface 2s. Figure 6C In the example shown, the image capture system 5 captures a first outer profile Pe of the container 2 (which corresponds to one side of the neck ring 2 b and a portion of the container neck ring surface 2 s) and a second outer profile Pe of the container 2 (which corresponds to the symmetrical side of the neck ring 2 b and a portion of the container neck ring surface 2 s). Of course, the outer profile Pe of the container 2 may correspond to other portions of the container, such as the main body of the container.

[0065] As will be explained in detail later in this specification, the measuring head 4 is mounted so as to be rotatable for inspecting the entire periphery of the container 2. Thus, an image of the container's outer contour Pe is acquired during each incremental rotation. By acquiring images of the entire circumference of the container 2's outer contour Pe by the measuring head 4, dimensional characteristics exhibited by these containers, such as the diameter of the container ring or the diameter of the container body, can be assessed. Furthermore, defects, such as those in the container ring or horizontal mold seams, can be revealed.

[0066] The image capture system 5 and the lighting system 6 are mounted on the measuring head 4 in any suitable manner to ensure that at least the outer contours of a plurality of containers are acquired by optical projection. Figure 2B and Figure 6B In the exemplary embodiment shown, the measuring head 4 comprises a support 9 supported by a frame 11. The support 9 is driven by a motor 12 of a known type (e.g., an electric motor) to rotate relative to the frame 11 in two directions of rotation about an axis of rotation a. The motor 12 is mounted on the frame 11 and drives the support 9 in rotation directly or via a mechanical transmission. The support 9 can be rotated relative to the frame 11 in any suitable manner. In other words, the support 9 forms the rotatable, movable part of the measuring head 4 relative to the frame 11, which forms the fixed part of the measuring head.

[0067] according to Figure 1 、 Figure 2 、 Figure 2A 、 Figure 2B and Figure 2C In the exemplary embodiment shown, the image capture system 5 is configured to deliver an image of a single first outer contour of the container in a first single observation area, and the lighting system 6 illuminates the first observation area C in the background of the first outer contour. Figure 5 、 Figure 6 、 Figure 6A 、 Figure 6B 、 Figure 6C and Figures 7 to 13 In the exemplary embodiment shown, the image capture system 5 is configured to transmit an image of a first outer contour in a first observation area C and an image of a second outer contour of the container in a second observation area C, the second outer contour being symmetrical to the first outer contour relative to a vertical axis a of the container, the lighting system 6 illuminating the first observation area in the background of the first outer contour and illuminating the second observation area in the background of the second outer contour.

[0068] The image capture system 5 comprises at least one camera 5a with a lens, which observes the container 2 directly or using at least one folding mirror 5b. The lighting system 6 comprises at least one light source 6a, which illuminates the container 2 directly or using at least one folding mirror 6b.

[0069] like Figure 2A and Figure 2BAs shown, the image capture system 5 includes a camera 5a, which observes the container 2 using three folding mirrors 5b positioned between the camera 5a and the container. In this example, each of these folding mirrors 5b has a 45° deflection angle relative to the rotation axis a. In this example, the camera 5a is mounted on a frame 11, centered about the rotation axis a, and observes the container 2 using the folding mirrors 5b mounted on a support 9. Each folding mirror 5b extends along a vertical axis Z, with a height adapted to the height of the container portion to be observed. For example, the support 9 may be in the form of a circular disk extending from its lower surface. This structure, extending along the vertical axis Z, allows for the attachment of the folding mirrors 5b to direct light toward the camera. In this example, the illumination system 6 includes a light source 6a mounted on the support 9 to illuminate the viewing area of the camera 5a. The light source 6a is attached to the lower surface of the support 9, so that the light source 6a and the folding mirrors 5a are positioned on both sides of the container, tangentially illuminating the edge of the container 2 to image the container's outer contour. In this way, container 2 is placed in the field of view of camera 5a, which can be directly or folded by folding mirror 5b. Container 2 is then located in the optical path between light source 6a and camera 5a, which captures the image. The viewing optical axis of camera 5a (directly or folded by folding mirror 5b) is positioned so that the outline of the container is optically projected in the image, with the light source in the background. More precisely, this arrangement allows the outline projected in the image to be visualized using a light ray tangential to the container's edge.

[0070] according to Figure 6A and 6B In the exemplary embodiment shown, the image capture system 5 includes a camera 5a configured to observe the container 2 in two observation areas using a folding mirror 5b. According to this example, the camera 5a is mounted on a frame 11, centered about a rotation axis a, and observes the container 2 using a folding mirror 5b mounted on a support 9 to observe a first outer contour and a second outer contour of the container that are symmetrical about the vertical axis a. The lighting system 6 includes two light sources 6a mounted on the support 9 to illuminate the two observation areas of the camera 5a. The light sources 6a are attached to the lower surface of the support 9 such that, for each pair of light sources 6a and folding mirror 5b, the light sources 6a and folding mirror 5b are located on opposite sides of the container, tangentially illuminating both edges of the container 2 to enable imaging of two symmetrical or diametrically opposed outer contours of the container.

[0071] In the above example, camera 5a is mounted on frame 11 so that the camera is fixed relative to the rotationally driven support 9. According to another exemplary embodiment (not shown), it should be noted that camera 5a can be mounted on support 9 that is rotationally driven about its axis of rotation. In this solution, camera 5a is mounted directly on support 9 instead of, or together with, folding mirror 5b.

[0072] Likewise, it should be noted that in Figure 6A and Figure 6B In the exemplary embodiment shown, a single camera 5a uses two sets of folding mirrors 5b to observe the container 2 in two different observation areas C. The optical schematic of this arrangement is shown in FIG. Figure 11 As shown. Of course, Figure 12 As shown, the image capture system 5 may also include a camera 5a that directly observes the container 2 in an observation area C covering two opposite sides of the container, imaging two diametrically opposed outer contours of the container. Figure 13 As shown, the image capture system 5 can comprise two cameras 5a, each camera directly observing the container 2 in two different observation areas C.

[0073] exist Figure 2A 、 Figure 2B and Figure 6A 、 Figure 6B In the exemplary embodiment described in FIG, the lighting system 6 comprises one light source or two light sources 6a, respectively, mounted on a support 9, which is driven to rotate around a rotation axis. Figure 11 As shown, two viewing areas C can be illuminated by one light source, or as Figure 12 Similarly, in the above example, the container 2 is directly illuminated by one or more light sources 6a mounted on the support 9. Of course, the light source can also illuminate the container 2 using at least one reflector or folding mirror 6b attached to the support 9.

[0074] Figure 15 、 Figure 15A and Figure 15B A variant embodiment is shown in which the light source 6a is an annular light source attached to the frame 11 and illuminates a folding mirror 6b attached to a support 9 that is rotationally driven around an axis of rotation a. The lighting folding mirror 6b is positioned to reflect light from a portion or angular section of the light source 6a located above it, which portion of the annular light source changes during the rotation of the support 9. According to this exemplary embodiment, the light source 6a can be controlled in an independent section so as to provide illumination only for a sector-shaped area that coincides vertically with the lighting folding mirror 6b. Figure 15 In FIG, the arrows indicate the direction of travel of the light. The lighting folding mirror 6b is positioned to extend on one side of the container, while the folding mirror 5b of the image capture system 5 is attached to the support 9 to extend on the other side of the container 2 ( Figure 15 and Figure 15A ).

[0075] The image capture system 5 includes two additional folding mirrors 5b, positioned between the first folding mirror 5b and the lens of a camera 5a attached to the frame 11, the optical axis of the camera 5a being coaxial with the rotation axis a. These three folding mirrors 5b are angled, for example, at 45° to the horizontal to bring the image of the container contour into the camera's optical axis. It should be noted that the folding of the observation area C toward the camera 5a can be accomplished using not three, but two folding mirrors 5b with different angles relative to the horizontal. Of course, one or more of the folding mirrors 5b of the image capture system can be replaced by a prism, as can the illumination folding mirror 6b. It should be noted that, according to this variant embodiment, the light source 6a and camera 5a are mounted on the frame 11, i.e., on the fixed part of the measuring head 4. This solution avoids the use of power or signal transmission cables between the fixed part (frame 11) and the movable part (support 9) of the measuring head, or the use of cable-free signal and power transmission methods such as rotary contact, optical, and / or magnetic coupling between the fixed part (frame 11) and the movable part (support 9).

[0076] According to another feature, the inspection station 1 includes a structure 15 for moving the measuring head 4. The structure is configured to position the measuring head 4 during its rotation so that the rotation axis a is substantially coaxial with the vertical axis 2z of the container 2, and is configured to linearly move the measuring head 4 parallel to the translation direction F. Thus, the frame 11 of the measuring head 4 is moved by the movement structure 15 to position the rotation axis a of the support 9 substantially coaxial with the vertical axis 2z of the container 2. According to an exemplary embodiment, the movement structure 15 for the measuring head 4 includes a motor drive structure 16 for linearly moving the measuring head in a direction parallel to the translation direction F of the conveyor. The motor drive structure 16 is equipped with the frame 11 carrying the measuring head 4 so that the measuring head 4 can be linearly moved back and forth along the translation direction F. For example, the motor drive structure 16 comprises a linear guide system that supports the measuring head 4. The linear guide can be of any type, such as one or two guide rails, along which the movable frame 11, mounted, for example, on bearings, slides. The measuring head 4 or the movable frame 11 is pulled by a toothed belt driven by a linear motor or a pinion driven by a rotary motor.

[0077] It should be noted that the motor-driven structure 16 and the container 2 may need to be relatively aligned in the transverse direction Y to maintain the rotation axis a of the measuring head substantially coaxial with the vertical axis 2z of the container 2. This relative alignment can be performed based on the position of each container in a determined transverse direction Y to compensate for variations in the container's position in the transverse direction Y, or based on the position of each container portion (e.g., the neck ring) in the determined transverse direction Y to compensate not only for variations in the container's position in that direction but also for variations in the vertical direction of each container. To this end, a first solution is to move the motor-driven structure 16 in the transverse direction Y based on the determined position of each container or container portion being measured. For example, the motor-driven structure 16 is mounted on an assembly 17 that is movable in the transverse direction Y perpendicular to the translation direction F. The combined movement of the assembly 17 and the motor-driven structure 16 allows the measuring head 4 to be positioned at any position in the conveying plane X. An alternative approach that does not require movement of the measuring head 4 in the transverse direction Y is to move the container in the transverse direction Y by a motor-driven transverse centering system before it enters the inspection station 1 or as it passes through the inspection station. However, if the observation area of the image capture system 5 is wider and if the measuring head 4 has a larger transverse volume for accommodating the containers, the movement of the measuring head 4 in the transverse direction Y can also be omitted.

[0078] According to an advantageous feature of the embodiment, the mobile structure 15 is also configured to be able to adjust the position of the measuring head 4 along the vertical axis Z. This adjustment possibility makes it possible to adjust the position of the measuring head 4 relative to the height of the container 2 and the area of the container to be inspected. In a strict sense, this height adjustment is preferably carried out before inspecting a series of containers of substantially the same overall height.

[0079] As a result of the foregoing description, the mobile structure 15 of the measuring head 4 is configured to be mounted above the container 2 (i.e., the conveyor belt 3). The measuring head 4 is positioned above the container so that the axis of rotation a can extend substantially coaxially with the vertical axis 2z of the container. However, in order to be able to image the outer contour of the container, the image capture system 5 and the lighting system 6 must be positioned to the side of the container. Therefore, the support 9 is positioned above the container 2, extending in the direction of the conveyor belt 3, so that the image capture system 5 and the lighting system 6 can extend on both sides of the side of the container 2. It should be noted that the position of the image capture system 5 and the lighting system 6 along the vertical axis Z depends on the area of the contour of the container to be imaged. If the outer contour of the container to be imaged is related to the neck ring, the image capture system 5 and the lighting system 6 are positioned flush with the container neck ring. If the outer contour of the container to be imaged is related to the container body, the image capture system 5 and the lighting system 6 are positioned on both sides of the container body 2. In this case, the support 9 extends along the vertical axis Z with a height greater than that required for imaging the outer contour of the neck ring in order to correctly position the image capture system 5 and the lighting system 6 relative to the container body.

[0080] According to an advantageous feature, the measuring head 4 remains at the same altitude along the vertical axis Z during its movement between inspecting different containers 2. In other words, the measuring head 4 is positioned so that it is traversed by the containers 2, with the image capture system 5 and the illumination system 6 extending laterally therefrom. It should be understood that the measuring head 4 is positioned in the path of the containers and does not alter their linear path. Thus, each container 2 is laterally engaged by the measuring head 4, which moves through the inspection station 1 to follow the container's movement.

[0081] The measuring head 4, or more precisely the support 9, is configured to have an engagement volume Ve for the container 2, such that the vertical axis 2z of the container is substantially coaxial with the axis of rotation a of the measuring head 4, and a disengagement volume Vd, such that the measuring head 4 can be disengaged relative to the container. These engagement and disengagement volumes correspond to free volumes, defined between the image capture system 5 and the illumination system 6, so that the container can be positioned such that the axis of rotation a of the measuring head 4 is coaxial with the vertical axis of the container 2.

[0082] exist Figure 2B and Figure 6B In the example shown, the support 9 is configured with an engagement volume Ve, which is designed to communicate with a disengagement volume Vd, forming a volume that traverses the support 9 in the translational direction. Thus, the measuring head 4 can engage via this transverse volume surrounding the container 2. The container remains engaged in this volume during both rotational and linear movement of the measuring head 4. To disengage the container, the support 9 is positioned so that the disengagement volume is oriented in the translational direction.

[0083] 14A to 14E Another variant embodiment is shown in which the support 9 is configured to have an engagement volume Ve comparable to the disengagement volume Vd. It should be noted that by eliminating the portion of the support 9 located between the lines 9a ( Figure 14A ), the engagement volume and the disengagement volume can be made into a transverse type.

[0084] According to another characteristic of the invention, the inspection station 1 comprises a system 19 for determining the position of the vertical axis 2z of each container 2 as it passes through the inspection station 1 in translation, along at least the translation direction X. In practice, according to one exemplary embodiment, this determination system 19 is configured to determine the position of the vertical axis 2z of each container 2 in the translation direction X before the container 2 enters the inspection station, considering the translation speed of the container to be constant between the time of detection and the time of passage through the inspection station. It should be noted that this determination system 19 can take into account the position of each container along the longitudinal axis X during all or part of its passage through the inspection station.

[0085] The determination system 19 must be configured to know the position of the container 2 along the translation direction X, but can also be configured to determine the position along the transverse direction Y. The determination system 19 is capable of determining at least the position of each container (or its collar) along the translation direction X, and even along the conveying planes X and Y, multiple times or continuously during the container's passage through the inspection station 1. The position along the translation direction X or along the conveying planes X and Y can also be directly determined by analyzing the measuring head 4 and the captured container images. Specifically, while the position of the measuring head 4, rotated about the rotation axis a and translated along the translation direction X, is known, the position of each container (or its collar) within the observation area is also known based on a profile of the container's nominal diameter at that height. More precisely, when the measuring head simultaneously observes two opposing profiles, the container's axis can be located in the image as being centered between the two profiles. Multiple positioning systems, such as a light curtain system, can be incorporated to control the placement of containers within the observation area at the entrance to the inspection station and then maintain the rotation axis a coaxial with the container's axis during their passage through the inspection station.

[0086] This determination system 19 can be implemented in any suitable manner, for example using a system that takes into account the speed of the conveyor belt 3 and one or two units (optical barriers) or at least one camera for capturing images of the containers before they enter the inspection station 1. In this way, this determination system 19 knows the position of each container in the conveying plane of the vertical axis 2z during its movement through the inspection station 1.

[0087] According to another feature of the present invention, the inspection station 1 includes a command unit 21 for the measuring head 4 and the mobile structure 15. The command unit 21 receives information from the determination system 19 regarding the position of the vertical axis 2z of each container 2. The command unit 21 is configured to move the measuring head 4 in a continuous movement cycle to continuously perform contactless inspection of the container as it translates through the inspection station 1. Each movement cycle for inspecting a container 2 includes an outward stroke and a return stroke during which the entire periphery of the container is inspected by rotation. For each movement cycle, the command unit 21 controls the mobile structure 15 to position the measuring head 4 so that the rotation axis a is substantially coaxial with the vertical axis 2z of the container during the rotation of the measuring head 4. The command unit 21 controls the operation of the motor 12 to rotate the measuring head 4 and the mobile structure 15, while simultaneously moving the measuring head parallel to the translation direction F while maintaining the rotation axis substantially coaxial with the vertical axis 2z of the container. The command unit 21 controls the image capture system 5 to acquire an image of the outer contour of the entire periphery of the container during the rotation of the measuring head 4.

[0088] The command unit 21 is implemented in any suitable manner to move the measuring head 4 and acquire images of the entire periphery of each container 2. The command unit 21 may include an axis control board unit or a power converter unit to control the rotary and / or linear motors. The command unit 21 is also an electronic data processing unit and may be implemented as any type of computer system, including a computer, external peripherals (display unit, storage unit, keyboard, connection to various factory networks, etc.), programs, databases, etc. The images captured by the camera are analyzed to ensure quality control, in particular to monitor or evaluate the dimensional characteristics of the containers and / or to observe or analyze the containers for defects.

[0089] The inspection station 1 described above makes it possible to implement the on-line inspection method of the containers directly derived from the above.

[0090] According to this method, the containers 2 are moved in a vertical position in a translation direction F in order to continuously pass through the inspection station 1 according to the invention, which includes the measuring head 4. The purpose of the method according to the invention is to move the measuring head 4 in a continuous movement cycle in order to continuously inspect the containers 2 without contact during their translation through the inspection station. It must be understood that the inspection of the containers 2 is carried out without changing the translational movement of the containers imposed by the conveyor belt 3.

[0091] As defined, each movement cycle of the measuring head 4 is intended to inspect, without contact, a container 2 driven by the conveyor belt 3 in translation. Each movement cycle for inspecting a container 2 includes an outward stroke and a return stroke, during which the measuring head rotates to inspect the entire periphery of the container. To position the measuring head 4 relative to each container 2 passing through the inspection station 1, the method according to the present invention determines the position of the vertical axis 2z of each container 2 translated through the inspection station along the translation direction F. To this end, the command unit 21 receives information from the system 19, which determines at least the position of the vertical axis 2z of each container 2 along the translation direction F. The command unit 21 controls the movement of the measuring head 4 such that, during rotation, the axis of rotation a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container. Furthermore, it should be noted that the command unit 21 controls the movement of the measuring head 4, and in particular the motor 12, such that the engagement volume Ve of the measuring head is positioned to allow the measuring head to engage around the container 2, thereby enabling the vertical axis 2z of the container to be substantially coaxial with the axis of rotation a of the measuring head.

[0092] During the outward stroke, the measuring head 4 moves with the movement of the container 2. The measuring head 4 moves parallel to the translation direction F. The command unit 21 controls the movable structure 15, more specifically, the motor-driven linear movable structure 16, in a direction F1, aligned with the direction of container movement. During the outward stroke, the measuring head 4 is positioned so that, during its rotation, the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container. "Substantially coaxial" means that, at a minimum, the command unit 21 controls the movable structure 15 based on the container's position so that the analyzed profile remains within the field of view of the measuring head 4. When the determination system 19 determines at least the position of each container or its neck ring along the translation direction (longitudinal axis X) multiple times or continuously during the container's passage through the inspection station, the command unit 21 controls the movable structure 15, more specifically, the motor-driven linear movable structure 16, through servo control, such that the rotation axis a of the measuring head 4 remains substantially coaxial with the vertical axis 2z of the container during its passage through the inspection station 1.

[0093] It is possible to provide that the command unit 21 controls the mobile structure 15, in particular the movable assembly 17, as a function of the position of the container along the transverse axis Y. The combined movement of the measuring head 4 along the axes X and Y allows the axis of rotation a of the measuring head to be coaxial with the longitudinal axis 2z of the container. It is also possible to provide that the same command unit 21 controls the motor-driven means for transverse centering of the containers, as described above, before they enter the inspection station 1 or while they are being conveyed through the inspection station 1.

[0094] During the outward stroke, the measuring head 4 is rotationally controlled to inspect the entire periphery of the container 2, while its axis of rotation a remains substantially coaxial with the vertical axis 2z of the container. It will be recalled that the measuring head 4 can be moved in translation so that its axis of rotation a remains substantially coaxial with the vertical axis 2z of the container. While the measuring head 4 is moving in translation, the command unit 21 controls the motor 12 to rotate the measuring head 4. Simultaneously, the command unit 21 controls the camera(s) 5a and, optionally, the light source(s) 6a (if the latter are commanded to illuminate in flash or pulse mode only during the image acquisition phase).

[0095] According to the present invention, the measuring head 4 is configured to capture at least one image of the outer contour of each container 2 by optical projection. Furthermore, when capturing the contour images, the command unit 21 controls the camera 5a so that an image is captured at each rotational increment of the container, such that the number of images per rotation is greater than 36, for example. In other words, the method aims to capture at least one image for every 10° rotation of the container 2. For example, the number of images of the container 2 over a 360° rotation ranges from 36 to 96 or 360. The container rotational increment between each captured image represents the angular range traversed by the container, for example, from 10° to less than 3.75° or 1°. The limit on the number of images is related to the optoelectronic technology (maximum video frequency of the camera, sensitivity of the sensor), the maximum brightness of the light source (typically an LED), and the amount of data that can be transmitted, stored, and analyzed (memory capacity, transmission speed, and processor computing power).

[0096] The outward stroke of the inspection cycle of the container 2 is followed by a return stroke in which the measuring head 4 is brought back into position for inspecting the next container in the queue.

[0097] It should be noted that at the end of the outward stroke, the command unit 21 controls the movement of the measuring head 4, in particular the motor 12, so that the disengagement volume Vd of the measuring head is positioned in a position that allows the measuring head to be disengaged relative to the container 2, thereby allowing the container to continue its movement. During the return stroke, the command unit 21 controls the mobile structure 15, more precisely the motor-driven linear mobile structure 16, in a direction F2 opposite to the direction of movement of the container. It should be noted that during most of the return stroke, no container is present in the inspection station 1.

[0098] The command unit 21 optionally controls the movable assembly 17 to predict the position of the measuring head 4 relative to the next container to be inspected. For example, at the end of the return stroke, the measuring head 4 is essentially back to its initial position at the beginning of the movement cycle. The command unit 21 controls the movement of the measuring head 4 to perform a new inspection cycle on the next container in the queue.

[0099] Figure 1 、 Figure 2 、 Figure 2A 、 Figure 2B and Figure 2C A first exemplary embodiment of the inspection method according to the invention is shown, in which the image capture system 5 is configured to deliver an image of a single outer contour of a container in a viewing area that is illuminated against the background of the outer contour by the lighting system 6. According to this exemplary embodiment, for each movement cycle, the measuring head 4 rotates over an angular range of at least 360° in order to acquire an image of the outer contour of the entire periphery of the container 2.

[0100] For the movement cycle for inspecting the container 2, the command unit 21, which receives information from the system 19, controls the movement of the measuring head 4, in particular the motor 12, so that the engagement volume Ve of the measuring head is positioned so as to allow the measuring head to engage around the container 2 ( Figure 2 , Figure 2A After the measuring head is positioned so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container, the command unit 21 controls the motor-driven linear moving structure 16 in the direction F1 and also controls the motor 12 to rotate the measuring head 4 at least 360° and 380°, for example. At the same time, the command unit 21 controls the camera 5a and the light source to obtain an image of the contour of the entire periphery of the container ( Figure 3 ).

[0101] At the end of the outward stroke, the command unit 21 controls the movement of the measuring head 4, in particular the motor 12, so as to position the disengagement volume Vd of the measuring head so as to allow the measuring head to be disengaged relative to the container 2. The command unit 21 controls the movement structure 15 for the return stroke of the measuring head 4, thus bringing the measuring head 4 back to a position allowing it to perform a new inspection cycle on the next container in the queue ( Figure 4 ).

[0102] Figure 5 、 Figure 6 、 Figure 6A 、 Figure 6B 、 Figure 6C and Figures 7 to 10 A second exemplary embodiment of the inspection method according to the invention is shown, wherein the image capture system 5 is configured to deliver an image of a first outer contour in a first observation area and an image of a second outer contour of the container in a second observation area, the second outer contour being symmetrical to the first outer contour with respect to a vertical axis 2z of the container. Figure 6C As can be seen in FIG, this example can obtain two symmetrical outer contours of, for example, a neck ring. It should be noted that this example can also obtain the inner contour of the neck ring, allowing the size of the inner diameter of the container mouth to be measured.

[0103] According to this preferred embodiment, the measuring head 4 rotates over an angular range of at least 180° to capture an image of the outer contour of the entire periphery of the container. Advantageously, the command unit 21 controls the motor 12 to rotate the measuring head 4 over an angular range between 180° and 220°. Compared to a method in which the measuring head 4 rotates 380°, this method allows for faster inspection because, for the same transport and rotational speeds, the length of the inspection station 1 is divided by two; and / or, for the same speed and translation distance but the rotational speed is divided by two, a more stable inspection can be performed; and / or, for the same speed and translation distance but the rotational speed is divided by two, images can be captured at rotational increments divided by two, thereby enabling a higher-resolution inspection.

[0104] For the movement cycle for inspecting the container 2, the command unit 21, which receives information from the system 19, controls the movement of the measuring head 4, in particular the motor 12, so that the engagement volume Ve of the measuring head is positioned so as to allow the measuring head to engage around the container 2 ( Figure 6A After the measuring head is positioned so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container, the command unit 21 controls the motor-driven linear moving structure 16 in the direction F1 and controls the motor 12 to rotate the measuring head 4 in the clockwise direction h, for example, by 220°. At the same time, the command unit 21 controls the camera 5a and the light source 6a to obtain a contour image of the entire periphery of the container ( Figure 7 )

[0105] At the end of the outward stroke, the command unit 21 controls the movement of the measuring head 4, in particular the motor 12, so as to position the disengagement volume Vd of the measuring head so as to allow the measuring head to be disengaged relative to the container 2. The command unit 21 controls the movement structure 15 for the return stroke of the measuring head 4, in order to position the measuring head so as to perform a new inspection cycle on the next container in the queue ( Figure 8 It should be noted that in the case where the measuring head 4 has a transverse engagement volume and a disengagement volume, the measuring head 4 will be positioned in the correct position to receive a new container when leaving the container. In other words, the measuring head 4 maintains its orientation between the position where the container leaves the measuring head and the position where the new container engages the measuring head ( Figure 7 and Figure 8 ). Thus, during the return stroke, the measuring head 4 is only in translation, not in rotation, regardless of the magnitude of the rotation during the outward stroke. It should be noted that the measuring head 4 with transverse engagement and disengagement volumes offers another advantage in the event of a malfunction or stoppage, since the measuring head does not obstruct the translational travel of the container. The measuring head 4 with transverse volumes for the engagement and disengagement volumes, with its rotation angle limited to 180°, constitutes a preferred variant embodiment.

[0106] The measuring head 4 can then inspect the next container in the queue. For a new movement cycle for inspecting a container 2, the command unit 21, which receives information from the system 19, controls the measuring head 4 so that the rotation axis a is substantially coaxial with the vertical axis 2z of the container. The command unit 21 controls the mobile structure 15, in particular the linear mobile structure 16 driven by the motor in the direction F1, and also controls the motor 12 to rotate the measuring head 4 in the counterclockwise direction ah, for example, by more than 220°. At the same time, the command unit 21 controls the camera 5a and the light source 6a to obtain a contour image of the entire periphery of the container ( Figure 9 ).

[0107] At the end of the outward stroke, the command unit 21 controls the mobile structure 15 for the return stroke of the measuring head 4 in order to position the measuring head in order to perform a new inspection cycle on the next container in the queue ( Figure 10 ).

[0108] As can be seen from the exemplary embodiment for each movement cycle, in the outward stroke of the measuring head 4, the measuring head 4 is rotated over a range of at least 180° while the measuring head 4 is moved linearly, whereas the movement of the measuring head 4 in the return stroke is not rotated. Therefore, for two consecutive movement cycles of the measuring head 4 relative to two consecutive containers in the queue, the direction of rotation of the measuring head 4 is opposite. When the light source and / or the camera are rotationally fixed on the support 9, the rotation of the measuring head 4 in alternating directions offers the advantage of being able to control the winding of the power cable of the measuring head 4. Of course, if the light source and the camera are fixed relative to the frame 11 ( Figure 15 ), or if cable-free signal and power transmission means (rotating contact, optical and / or magnetic coupling type) are used between the light source or camera mounted on the rotating support 9 and the frame 11, there is no problem of cable winding and unwinding. An example of a rotating contact cable is a connector for a coaxial cable used in accordance with the so-called The camera is powered and controlled by the communication standard.

[0109] 14A to 14E A third exemplary embodiment of the inspection method according to the invention is shown, in which the measuring head 4 is configured with an engagement volume Ve that is comparable to a disengagement volume Vd. Figure 14A The engagement volume is shown positioned on the path of the container 2 to be inspected. In this position, the container 2 can enter the measuring head 4 so that the light source 6a and the folding mirror 5b are located on both sides of the container ( Figure 14B ).

[0110] For the movement cycle for inspecting this container 2, the command unit 21, which receives information from the system 19, controls the mobile structure 15 so that the axis of rotation a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container. The command unit 21 controls the motor-driven linear movement structure 16 in the direction F1 and simultaneously controls the motor 12 to rotate the measuring head 4 by 180° to obtain two symmetrical outer contours, or in the counterclockwise direction ah, for example, by 380° ( Figure 14C and Figure 14D At the same time, the command unit 21 controls the camera 5a and the light source to obtain a contour image of the entire periphery of the container during the rotation of the measuring head.

[0111] At the end of the outward stroke, the disengagement volume Vd of the measuring head is then positioned to allow the measuring head to be disengaged relative to the container 2. The command unit 21 controls the motor-driven linear movement structure 16 in the direction F2 in order to bring the measuring head to a position allowing a new inspection cycle to be performed on the next container in the queue. Furthermore, the command unit 21 controls the motor 12 in the clockwise direction h so that the engagement volume Vd of the measuring head is positioned to allow the measuring head to be engaged with a new container 2 ( Figure 14E ).

[0112] As can be seen from this variant embodiment, in which the engagement volume Ve is equal to the disengagement volume Vd, it is recommended to rotate the measuring head during the return stroke in order to return the engagement volume Ve to the side where the next container arrives. Furthermore, if cables are present between the frame 11 and the support 9 for mounting the light source and camera, the direction of rotation of the support 9 during the return stroke is opposite to that during the outward stroke. It should be noted that the rotation during the return stroke can be any amount if deflecting mirrors are used to secure the camera and light source to the frame 11, or if power and signal transmission is performed via rotary contact (primarily power), optical coupling (signal only), or magnetic coupling.

[0113] The preferred variant aims to not rotate the measuring head during the return stroke. Since no rotation control is required during the return stroke and the Coriolis effect is not present, this preferred variant without rotation during the return stroke is much faster. For example, the translation speed of the return stroke is 30% greater than the translation speed of the outward stroke. This translation-only return stroke is possible in the following cases: - whether the engagement volume Ve or the disengagement volume Vd is transverse or non-transverse, the rotation over the outward stroke is approximately 360°, Whether rotated by 180° or 360°, the engagement volume Ve and the disengagement volume Vd constitute the transverse volume.

[0114] In other words, the measurement head can only be used if it does not have any lateral engagement and disengagement volumes and its rotation is limited to 180° ( Figure 14A Figure 14E ) is required, a return stroke with rotation is required.

[0115] It should also be noted that the control law of the translational movement, and in particular of the acceleration, during the outward stroke is such that, at the beginning of the outward stroke, during the calibration or entry phase, the axis of rotation a is brought rapidly but gradually into alignment with the vertical axis 2z of the container, with axis a being either in front of or behind the vertical axis 2z during the calibration phase. The same reasoning applies during the phase of exiting the inspection station, and therefore at the end of the outward stroke and the beginning of the return stroke.

Claims

1. A method for the in-line inspection of containers (2), each container (2) having a vertical axis (2z) and at least one outer contour to be inspected; according to the method, the containers are moved in a queue in a vertical position along a translation direction on a conveying plane (X, Y) to continuously advance through an inspection station, the inspection station comprising a non-contact measuring head (4), the non-contact measuring head (4) having a rotation axis (a), the measuring head being mounted to rotate about the rotation axis (a), and the measuring head moving in a continuous movement cycle, thereby continuously inspecting the containers during their translation through the inspection station, each movement cycle of inspecting a container comprising an outward stroke and a return stroke as well as a rotation, thereby inspecting the entire periphery of the container, It is characterized by: The method comprises: - configuring the measuring head (4) to acquire an image of at least one outer contour of each container by optical projection, - For each movement cycle, the measuring head (4) is positioned so that, during the rotation of the measuring head performing a circular movement, the rotation axis (a) is substantially coaxial with the vertical axis (2z) of the container and the measuring head is moved linearly parallel to the translation direction, thereby acquiring an image of the outer contour of the entire periphery of the container.

2. The method according to claim 1, wherein The measuring head (4) is configured to acquire an image of the outer contour of each container by optical projection, and wherein, for each movement cycle, the measuring head rotates within an angular range of at least 360°, thereby acquiring an image of the outer contour of the entire periphery of the container.

3. The method according to claim 1, wherein The measuring head (4) is configured to acquire images of two diametrically opposed portions of the outer contour of the container by optical projection, and wherein, for each movement cycle, the measuring head rotates through an angular range of at least 180°, thereby acquiring images of the outer contour of the entire periphery of the container.

4. The method according to the preceding claim, wherein For each movement cycle, the measuring head is rotated through a range of at least 180° during the outward stroke while being simultaneously moved linearly, and is moved linearly without rotation during the return stroke.

5. A method according to any one of the preceding claims, wherein For two consecutive movement cycles of the measuring head relative to two consecutive containers, the measuring head is rotated in opposite directions.

6. A method according to any one of the preceding claims, wherein The measuring head (4) is configured to have an engagement volume (Ve) for the container so that the vertical axis (2z) of the container can be substantially coaxial with the rotation axis (a) of the measuring head, and a disengagement volume (Vd) so that the measuring head can be disengaged relative to the container, and wherein the measuring head (4) is moved to engage around the container via the engagement volume so that the rotation axis of the measuring head is substantially coaxial with the vertical axis of the container and disengages from the container via the disengagement volume.

7. A method according to any one of the preceding claims, wherein The measuring head (4) is configured to include an image capture system (5) and at least one lighting system (6), the image capture system (5) being capable of delivering an image of at least a first outer contour of the container within a first observation area, the lighting system (6) illuminating the first observation area in the background of the first outer contour, and wherein the image capture system (5) is controlled during rotation of the measuring head to deliver an image comprising a projection of the first outer contour of the container illuminated from behind.

8. The method according to the preceding claim, wherein The measuring head (4) is configured to include an image capture system (5) and at least one lighting system (6), the image capture system (5) being capable of transmitting an image of at least a second outer contour of the container within a second observation area, the second outer contour being symmetrical to the first outer contour relative to a vertical axis of the container, the at least one lighting system (6) illuminating the second observation area in the background of the second outer contour, and wherein the image capture system is controlled during the rotation of the measuring head to transmit an image containing a projection of the second outer contour of the container illuminated from behind.

9. A method according to any one of the preceding claims, wherein The position of the vertical axis (2z) in the conveying plane (X, Y) of each container traveling in translation through the inspection station is determined, and wherein the movement of the measuring head (4) is controlled such that during its rotation the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container.

10. An in-line inspection station for containers, each container having a vertical axis (2z) and at least one outer contour to be inspected, and each container being moved in a queue in a vertical position in a translational direction by a conveyor belt (3) to continuously advance through the inspection station, the inspection station comprising: a non-contact measuring head (4) having an axis of rotation (a), said measuring head being mounted to rotate in a circular motion about said axis of rotation (a), said measuring head comprising an image capture system (5) capable of delivering an image of at least a first outer contour of said container within a first observation area, and at least one lighting system (6) illuminating said first observation area against the background of said first outer contour, - a structure (15) for moving the measuring head (4), configured to position the measuring head so that during rotation of the measuring head the axis of rotation is substantially coaxial with the vertical axis of the container and to move the measuring head linearly parallel to the translation direction, - a unit (21) for commanding the measuring head (4) and the mobile structure (15), receiving information from the system (19) for determining the position of the vertical axis of each container that moves in translation through the inspection station in the plane of the conveyor belt, the command unit (21) being configured to move the measuring head in continuous movement cycles so as to continuously inspect the container during its translation through the inspection station, each movement cycle for inspecting a container comprising an outward stroke and a return stroke as well as a rotation so as to inspect the entire periphery of the container, for each movement cycle the mobile structure positioning the measuring head so that during the rotation of the measuring head the axis of rotation is substantially coaxial with the vertical axis of the container and the measuring head moves linearly parallel to the translation direction, the command unit controlling the image capture system so as to acquire an image of the outer contour of the entire periphery of the container during the rotation of the measuring head.

11. The inspection station according to claim 10, wherein: The structure (15) for moving the measuring head comprises a motor-driven structure (16) for linearly moving the measuring head in a direction parallel to the translation direction, the motor-driven structure (16) being mounted on a component (17) capable of moving in a direction perpendicular to the translation direction, the motor-driven structure (16) being equipped with a frame (11) for carrying the measuring head, the frame (11) comprising a support (9) driven in rotation by a motor (12) around the rotation axis.

12. The inspection station of claim 11, wherein: The measuring head (4) is configured with an engagement volume (Ve) for the container so that the vertical axis of the container can be substantially coaxial with the axis of rotation of the measuring head, and a disengagement volume (Vd) so that the measuring head can be disengaged relative to the container.

13. The inspection station of claim 12, wherein: The measuring head (4) is configured to have an engagement volume corresponding to the disengagement volume or designed to communicate with the disengagement volume, thereby forming a volume that traverses the support in the translation direction.

14. The inspection station according to any one of claims 10 to 13, wherein The image capture system (5) is capable of delivering an image of at least a second outer contour of the container within a second observation area, the second outer contour being symmetrical to the first outer contour relative to the vertical axis of the container, and the lighting system (6) illuminates the second observation area in the background of the second outer contour, and wherein the image capture system is then controlled during the rotation of the measuring head to deliver an image containing a contour projection of the second outer contour of the container illuminated from behind.

15. The inspection station according to any one of claims 10 to 14, wherein The image capture system (5) comprises at least one camera (5a) which views the container directly or using at least one folding mirror (5b).

16. The inspection station of claim 15, wherein: The camera (5a) is mounted on the frame (11) while being centered on the rotation axis and observing the container using at least one folding mirror (5b) mounted on the support (9), which is driven in rotation around the rotation axis.

17. The inspection station of claim 15, wherein: The image capture system (5) comprises at least one camera (5a) mounted on the support (9), which is driven in rotation about the rotation axis.

18. The inspection station according to any one of claims 10 to 17, wherein The lighting system (6) comprises at least one light source (6a) which illuminates the container directly or using at least one folding mirror (6b).

19. The inspection station of claim 18, wherein: The lighting system (6) comprises at least one light source (6a) mounted on the support, and the support (9) is driven to rotate around the rotation axis.

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